B P7 C66 Atrial Fibrillation: Clinical Features, Mechanisms, and Management Flashcards
1
Q
Atrial fibrillation (AF) is a supraventricular arrhythmia characterized electrocardiographically by _____. The f waves, _____ beats/min, are variable in amplitude, shape, and timing.
Atrial flutter waves have a rate of 250 to 350 beats/min and are constant in timing and morphology
A
Low-amplitude baseline oscillations (fibrillatory or f waves from the fibrillating atria) and an irregularly irregular ventricular rhythm
300 to 600 bpm
2
Q
The ventricular rate during untreated AF typically is _____ beats/min.
Patients with the Wolff-Parkinson-White (WPW) syndrome can experience ventricular rates during AF exceeding _____ beats/min because of conduction over the accessory pathway
A
100 to 160 bpm
250 bpm
3
Q
The ventricular rate during AF can appear more regular when _____.
A
(1) Rate is extremely rapid (>170 beats/min)
(2) Junctional tachycardia independently controls the ventricles
(3) High-degree atrioventricular (AV) block with a regular escape rhythm
(4) QRS complexes all are paced
4
Q
Atrial fibrillation that terminates spontaneously within 7 days is termed _____, and AF present continuously for more than 7 days is called _____. AF that persists for longer than 1 year is termed _____. The term _____ AF is used when the patient and clinician jointly decide to abandon further attempts at restoring and/or maintaining sinus rhythm
A
Paroxysmal: < 7 days
Persistent: > 7 days
Longstanding persistent: > 1 year
Permanent AF: abandon attempts at restoring/maintaining SR
5
Q
_____ atrial fibrillation refers to AF that occurs in patients younger than 60 years who do not have hypertension or any evidence of structural heart disease.This designation is a historical descriptor that has been variably applied to different low-risk subsets of AF patients.
A
Lone AF
6
Q
Paroxysmal AF also can be classified clinically on the basis of the autonomic setting in which it most often occurs. Approximately 25% of patients with paroxysmal AF have _____ AF, in which AF is initiated in the setting of high vagal tone, typically in the evening when the patient is relaxing or during sleep. Drugs exerting a vagotonic effect (e.g., digitalis) can aggravate vagotonic AF, and drugs with a vagolytic effect (e.g., disopyramide) may be particularly appropriate for prophylactic therapy.
_____ AF occurs in approximately 10% to 15% of patients with paroxysmal AF in the setting of high sympathetic tone, as during strenuous exertion. In patients with adrenergic AF, beta blockers not only provide rate control but may prevent episodes of AF. Most patients have a mixed or random form of paroxysmal AF, with no consistent pattern of onset. In some, alcohol can be a precipitant.
A
Vagotonic AF (25% of Paroxysmal AF)
Adrenergic AF (10-15% of paroxysmal AF)
7
Q
_____ is the most common arrhythmia treated in clinical practice and the most common arrhythmia for which patients are hospitalized; approximately 33% of arrhythmia-related hospitalizations are for AF.
A
Atrial fibrillation
8
Q
Independent risk factors for the development of AF
A
Advanced age
CHF
Male sex
Tall stature
Family hx of AF < 50 y/o
LAE
Hypertension
Obesity
OSA
8
Q
***The three main mechanistic concepts of AF that have emerged over time consist of _____.
A
Multiple reentrant wavelets
Rapidly discharging autonomic foci
Single reentrant circuit with fibrillatory conduction
9
Q
A key breakthrough that had an immediate therapeutic impact was the recognition that in many patients, AF is triggered and/or maintained by rapidly firing foci in the _____.
A
Pulmonary veins
10
Q
In persistent AF, changes in the atrial substrate, including _____ that contributes to slow, discontinuous, and anisotropic conduction, may give rise to wandering or stationary reentry. It is for this reason that the outcomes of AF ablation targeted at the pulmonary veins (PVs) alone results in lower efficacy than in patients with paroxysmal AF.
A
Interstitial fibrosis
11
Q
It is now well established that susceptibility to AF is heritable. Individuals who have a first-degree relative with AF have a ___% increased risk of developing AF.
A
40%
12
Q
The majority of patients with AF have _____.
A
Hypertension (usually with left ventricular hypertrophy) or some other form of structural heart disease
13
Q
The most common cardiac abnormalities associated with AF are:
A
Hypertensive heart disease
Ischemic heart disease
Mitral valve disease
Hypertrophic cardiomyopathy
Dilated cardiomyopathy
14
Q
The possible mechanisms of AF in patients with sleep apnea include _____.
A
Hypoxia
Autonomic tone surges
Hypertension
15
Q
Available data suggest that _____ are responsible for the relationship between obesity and AF.
A
Atrial dilation
Increase in local and systemic inflammatory factors
16
Q
A growing body of data has demonstrated that ____ fat is strongly associated with the presence, severity, and recurrence of AF in many clinical settings.
A
Epicardial fat
17
Q
The most likely arrhythmogenic mechanisms by which epicardial fat predisposes to AF include _____.
A
Adipocyte infiltration
Profibrotic effects
Proinflammatory effect
18
Q
The _____ study demonstrated that sustained weight loss and exercise can reduce the AF burden.
A
LEGACY
19
Q
The most common symptoms are _____._____ can occur because of release of atrial natriuretic peptide.
A
Palpitations
Fatigue
Dyspnea
Effort intolerance
Lightheadedness
Polyuria
20
Q
A _____ may be helpful by maintaining sinus rhythm for at least a few days to determine whether a patient feels better in sinus rhythm.This strategy is especially valuable in a patient under the age of 80 years who presents for a routine physical examination and is found to be in AF.
A
“Diagnostic cardioversion”
21
Q
Rather than quickly declaring the patient “asymptomatic,” many experienced clinicians will _____ to evaluate symptomatic improvement. This strategy also is useful in patients with newly diagnosed persistent AF as the longer a patient is in continuous AF, the more difficult it is to restore and maintain sinus rhythm. This approach can provide a basis to pursue a rhythm-control versus rate-control strategy.
A
Restore sinus rhythm with a cardioversion
22
Q
Causes of syncope in AF
A
(1) long sinus pause on termination of AF in a patient with the sick sinus syndrome
(2) AF with a RVR because of neurocardiogenic (vasodepressor) syncope triggered by the tachycardia or because of a severe drop in blood pressure caused by a reduction in cardiac output
23
Q
The hallmark of AF on physical examination is an _____.
A
Irregularly irregular pulse
24
Short R-R intervals during AF do not allow adequate time for left ventricular diastolic filling, resulting in a low stroke volume and the absence of palpable peripheral pulse.This results in a _____ during which the peripheral pulse is not as rapid as the api- cal rate
Pulse deficit
25
When it is unclear from the history, _____ weeks of continuous or autotrigger ambulatory monitoring, or by mobile cardiac outpatient telemetry, is useful to determine whether AF is paroxysmal or persistent and to quantitate the AF burden in patients with paroxysmal AF.
2-4 weeks
26
If the symptoms occur on a daily basis, a _____ is appropriate. However, extended monitoring for 2 to 4 weeks with an event monitor or continuous rhythm monitor or by mobile cardiac outpatient telemetry is appropriate for patients whose symptoms are sporadic. Another option is an insertable monitor, which is placed subcutaneously and has a battery life of approximately 3 years.
Daily: 24-hour Holter recording
Sporadic: 2-4 weeks event monitor/continuous rhythm monitor
26
One of the most important benefits of a continuous monitor over weeks to years is that the _____.
Burden of AF can be precisely defined
27
The most important therapeutic goal in AF patients is to _____.
Prevent thromboembolic complications, especially stroke
28
The strongest predictors of ischemic stroke and systemic thromboembolism are _____.
(1) History of stroke or TIA
(2) Mitral stenosis
28
Aside from prior stroke, the best-established risk factors for stroke in patients with nonvalvular AF are _____.
Diabetes (RR 1.7)
Hypertension (RR, 1.6)
Heart failure (RR,1.4)
Age 70 or older (RR,1.4 per decade).
29
Renal failure also is an independent risk factor for stroke in patients with AF. The RR of a thromboembolic event in the absence of anticoagulation was ___ in patients with non–end-stage chronic kidney disease and ___ in patients requiring hemodialysis or a renal transplant.
Non endstage CKD (RR 1.4)
ESRD (HD/KT) (RR 1.8)
30
At present the CHA2DS2 -VASc score is recommended for estimation of stroke risk (_____).
Each risk factor counts as 1 point, with the exception of prior stroke or transient ischemic events and age 75 years, which count for 2 points.
Cardiac failure
Hypertension
Age >75 years (2 pts)
Diabetes
Stroke, or transient ischemic attack (TIA) (2 pts)
Vascular disease
Age 65 to 74 years
female Sex category
31
Correction for the inclusion of female sex is accomplished in the updated 2019 AF Guidelines by specifying a higher CHA2DS2-VASc score in women than in men (i.e.,____ in women and ___ in men to achieve a class I recommendation for anticoagulation) for each anticoagulation cutoff
Women: at least 3
Men at least 2
32
When considering the CHA2DS2-VASc score, it is important to recognize that there are risk factors for stroke that are not included in the CHA2DS2-VASc score. These include _____.
Left atrial size
AF burden
Mitral annular calcification
33
The annual risk of stroke is zero or close to zero when the CHA2DS2 -VASc score is ___, compared with approximately 3% when the CHA2DS2-VASc score is ____.
Risk 0% = Score 0
Risk 3% = score 3
34
The AF burden in persistent AF is ___% and always higher than in patients with paroxysmal AF
100%
35
The 2019 AHA/ACC/HRS AF Guidelines provides a class I level of evidence (LOE) B recommendation that the presence of _____ on an implanted device should prompt further evaluation to document clinically relevant AF to guide treatment decisions
Recorded atrial high rate episodes
36
In the absence of data from clinical trials, most clinicians today would advise anticoagulation for patients with device-detected AF who have episodes of _____.
At least 5 hours in duration and have an elevated stroke risk profile
37
An important consideration in patients treated with an oral anticoagulant is the risk of bleeding. Several risk-scoring systems have been developed to assess a patient’s susceptibility to hemorrhagic complications. The scoring system with the best balance of simplicity and accuracy is the HAS-BLED score. The components of this score are _____.
Each of these components is 1 point. As the score increases from 0 to the maximum of 9, there is a stepwise increase in the risk of bleeding in patients treated with warfarin.
Hypertension
Abnormal renal or liver function
Stroke
Bleeding history or predisposition
Labile international normalized ratio (INR)
Elderly (>75 years)
Drug (antiplatelet agent or NSAID) or alcohol use
38
The 2019 AHA/ACC/HRS AF Guidelines give a class I LOE A recommendation for anticoagulation of men with a CHA2DS2-VASc score of __ or higher and women with a CHA2DS2-VASc score of __ or higher.
Men: 2 or higher
Women: 3 or higher
39
Aspirin is _____ for preventing thromboembolic complications in patients with AF
Not effective
40
A meta-analysis of the major randomized clinical trials that compared warfarin with placebo for prevention of thromboembolism in patients with AF demonstrated that warfarin reduced the risk of all strokes (ischemic and hemorrhagic) by approximately _____%
60%
41
The target INR should be _____. This range of INRs provides the best balance between stroke prevention and hemorrhagic complications.
2.0 to 3.0
42
Maintaining the INR at a level of 2.0 or higher is important because even a relatively small decrease in INR from 2.0 to ____ more than doubles the risk of stroke.
1.7
43
The annual risk of a major hemorrhagic complication during anticoagulation with warfarin is in the range of _____%, and a strong predictor of major bleeding events is an INR greater than _____
1-2%
>3.0
44
Direct thrombin inhibitors and factor Xa inhibitors have several advantages over vitamin K antagonists such as warfarin: _____
(1) Fixed dosing regimen that eliminates the need for monitoring the INR
(2) Rapid onset and offset
(3) Equal or greater efficacy for stroke prevention
(4) Lower risk of intracranial hemorrhage
(5) No interactions with dietary factors such as alcohol or vitamin-K containing foods
(6) Fewer drug interactions
45
_____, an oral direct thrombin inhibitor, and _____, which are factor Xa inhibitors, are approved by the U.S. Food and Drug Administration (FDA) for prevention of stroke/ embolism in patients with nonvalvular AF. Randomized clinical trials demonstrated that each of these four DOACs is noninferior or superior to warfarin in efficacy and safety in patients with nonvalvular AF who had risk factors for stroke
Dabigatran - direct thrombin inhibitor
Rivaroxaban, Apixaban, and Edoxaban - FXa inhibitors
46
One of the most serious risks of anticoagulation is intracranial hemorrhage.
The trials, which were performed for FDA approval of each of these NOACs, revealed that the risk of intracranial hemorrhage is about ___% lower with DOACs compared with warfarin.
50% lower
47
DOACs also have some disadvantages compared with warfarin:
(1) Higher cost
(2) More gastrointestinal side effects in the case of dabigatran
(3) Twice-daily dosing for dabigatran and apixaban
(4) Absence of a readily available laboratory test to verify compliance
(5) Restricted use in patients with prosthetic valves
(6) Requires great care in patients with severe renal disease
48
Until recently another limitation of DOACs was that there were no specific reversal agents. However, reversal agents now are available for all DOACs. The first reversal agent to receive FDA approval, both for uncontrolled bleeding and the need for urgent surgery, was _____, an antibody fragment that reverses the anticoagulant effects of dabigatran within minutes. Since that time andexanet alfa has been approved for acute major bleeding in patients taking a factor Xa inhibitor. A limitation of andexanet alfa is high cost compared with a prothrombin concentrate.
Idarucizumab - Dabigatran
Andexanet Alfa - Factor Xa inhibitors
49
When a reversal agent is not available or not desired, administration of _____ can reverse the anticoagulant effect of the DOACs
Prothrombin complex concentrate
50
Valvular AF is defined as AF in patients with a _____.
Prosthetic valve
or
Moderate to severe mitral stenosis
50
The onset of action of the DOACs is approximately _____ hours after a dose.Their half-life is approximately _____ hours.The rapid onset of action and washout eliminates the need for bridging therapy with heparin when treatment with one of the DOACs is interrupted for a surgical or invasive medical procedure.
Onset: 1.5 to 2 hrs
t1/2: 12 hours
51
Because LMWH can be self-injected outside the hospital, it is a practical alternative to unfractionated heparin for initiation of anticoagulation with warfarin in patients with AF. Bridging therapy with LMWH should be continued until the INR is _____.
2.0 or higher
52
Approximately 90% of left atrial thrombi form in the _____, and therefore successful excision or closure of the LAA should greatly reduce the risk of thromboembolic complications in patients with AF.
Left atrial appendage
53
In recent years, several percutaneous LAA occlusion and ligation devices have been developed as alternatives to surgical closure techniques. These devices have their greatest utility in _____.
High-risk AF patients who cannot tolerate or who refuse to take an oral anticoagulant.
54
The only percutaneous occlusion device approved by the FDA specifically for stroke prevention as an alternative to warfarin is the _____. This nitinol plug covered with fenestrated fabric became widely available for clinical use after FDA approval in 2015.
After implantation of the device using femoral vein access and transeptal catheterization, anticoagulation with warfarin is recommended for at least _____ days, at which time anticoagulation can be discontinued if there is no TEE evidence of _____.
WATCHMAN (Boston Scientific, Marlborough, Massachusetts)
At least 45 days of warfarin
Peridevice flow
55
Another device used in the United States for LAA occlusion is the _____. This device has FDA approval for soft tissue approximation (not stroke prevention) and has been used off-label in clinical practice in the United States and elsewhere for LAA occlusion. A guidewire with a magnetic tip is inserted into the left atrium after transseptal catheterization and is positioned at the tip of the LAA. It functions as a rail for an epicardial snare.Entry into the pericardial space is attained using a percutaneous approach. A snare with a pretied suture is inserted into the pericardial space and guided toward the LAA.The pretied suture then is tightened to occlude the LAA
LARIAT (Sentreheart, Redwood City, California)
56
At present, the LARIAT device is being used in the ____ clinical trial, which is seeking to determine whether PV isolation plus appendage ligation with the LARIAT device is superior to PV isolation alone in patients with persistent AF.
AMAZE
57
_____ are considered class IIa and IIb recommendations, respectively, in situations where anticoagulation is contraindicated or the patient is undergoing cardiac surgery
Percutaneous (IIa) or surgical LAA occlusion(IIb)
58
Patients who present to the emergency department because of AF often have a rapid ventricular rate, and control of the ventricular rate is most rapidly achieved with intravenous _____
IV Diltiazem or esmolol
59
Cardioversion should ideally be preceded by TEE to rule out a left atrial thrombus if the AF has been _____.
Present for longer than 48 hours
or
If the duration is unclear and the patient is not already anticoagulated
60
However, if the patient has _____, immediate cardioversion without a TEE is advised.
Marked hemodynamic compromise
61
If the patient is hemodynamically stable, the decision to restore sinus rhythm by cardioversion is based on several factors, including _____
Symptoms
Prior AF episodes
Age
Left atrial size
Current AAD therapy
62
The advantages of early cardioversion are:
(1) Rapid relief of symptoms
(2) Avoidance of the need for TEE or therapeutic anticoagulation for 3 to 4 weeks before cardioversion if cardioversion is performed within 48 hours of AF onset
(3) Possibly a lower risk of early AF recurrence because of less atrial remodeling
63
A reason to defer cardioversion is the _____.
(1) Unavailability of TEE in a patient who has not been anticoagulated with AF of unclear duration or duration more than 48 hours.
(2) Left atrial thrombus by TEE
(3) Suspicion (based on prior AF episodes) that AF will convert spontaneously within a few days
(4) Correctable cause of AF such as hyperthyroidism
64
Pharmacologic cardioversion has the advantage of _____. In addition, the probability of an immediate recurrence of AF is _____ with pharmacologic cardioversion than with electrical cardioversion.
Not requiring general anesthesia or deep sedation
Lower (Pharmacologic cardioversion)
65
Pharmacologic cardioversion is unlikely to be effective if the duration of AF is longer than ___ days.
>7 days
66
Drugs that can be administered intravenously for cardioversion of AF consist of _____.
Ibutilide
Procainamide
Amiodarone
For AF episodes fewer than 2 to 3 days in duration, efficacy is approximately:
60% to 70% for ibutilide
40% to 50% for amiodarone
30% to 40% for procainamide
67
To minimize the risk of QT prolongation and polymorphic ventricular tachycardia, the use of ibutilide should be limited to patients with an ejection fraction _____.
>35%
68
Acute pharmacologic cardioversion of AF also can be attempted with oral drugs in patients without structural heart disease.The most common oral agents for acute conversion of AF are _____.
Propafenone (300 to 600 mg)
Flecainide (100 to 200 mg)
69
When flecainide is used, patients generally take a _____on AF onset and then take the flecainide one or more hours later.
It is recommended that these drugs be administered under surveillance upon first use, as patients may have a pronounced _____. If no adverse drug effects are observed, the patient may then be an appropriate candidate for episodic, self-administered AAD therapy on an outpatient basis (the “pill-in-the-pocket” approach).
Beta blocker
Postconversion pause
70
The efficacy of transthoracic cardioversion exceeds ____%. Biphasic waveform shocks convert AF more effectively than monophasic wave- form shocks and allow the use of lower energy shocks, resulting in less skin irritation. An appropriate first-shock strength using a biphasic wave-form is _____J, followed by higher output shocks if needed.
If a 360-J biphasic shock is unsuccessful, _____ should be infused before another shock is delivered because it lowers the defibrillation energy requirement and improves the success rate of transthoracic cardioversion.
>95%
Biphasic: 150-200J, ff by higher output shocks
Ibutilide (Lowers defibrillation energy)
71
Transthoracic cardioversion can fail to restore sinus rhythm. An _____, often results in successful repeat cardioversion
Increase in shock strength
Infusion of ibutilide
Repeat CV with greater pressure applied to the defibrillation patches
72
The second type of failure is an _____.This occurs in approximately 25% of AF episodes less than 24 hours in duration and 10% of episodes more than 24 hours in duration. For this type of cardioversion failure, an increase in shock strength is of no value. If the patient has not been receiving an oral rhythm-control agent, infusion of ibutilide may be helpful to prevent an immediate recurrence of AF.
Immediate recurrence of AF within a few seconds of successful conversion to sinus rhythm
73
Regardless of whether cardioversion is performed pharmacologically or electrically, therapeutic anticoagulation is necessary for _____ before cardioversion to prevent thromboembolic complications if the AF has been ongoing for more than 48 hours
Before cardioversion: 3 weeks or more of anticoagulation
74
If the time of onset of AF is unclear, for the sake of safety, the AF duration should be assumed to be more than 48 hours. These patients should be therapeutically anticoagulated for ______ after cardioversion to prevent thromboembolic complications that may occur because of _____.
Post cardioversion: 4 weeks
Atrial stunning
75
If the duration of AF is known to be _____ hours, cardioversion can be performed without anticoagulation
< 48 hrs
75
When AF duration exceeds 48 hours or is unclear, an alternative to 3 weeks of therapeutic anticoagulation before cardioversion is _____. If no thrombi are seen, the patient can be cardioverted safely but still requires 4 weeks of therapeutic anticoagulation after cardioversion to prevent thromboembolism related to atrial stunning
Anticogulation with heparin and a TEE to check for a left atrial thrombus
76
The major clinical benefit of the TEE-guided approach over the conventional approach is that _____.
Sinus rhythm is restored several weeks sooner
77
Several randomized studies have compared a rate-control strategy with a rhythm-control strategy in patients with AF. Overall, these studies have demonstrated a _____.
Significantly lower rate of rehospitalization with a rate-control strategy
But no significant differences in other major outcomes, such as all-cause mortality, strokes, bleeding events, worsening heart failure, or quality of life
78
The decision to pursue a rhythm-control strategy versus a rate- control strategy should be individualized based on several factors. These include the _____.
(1) Nature, frequency, and severity of symptoms
(2) Length of time that AF has been present continuously in patients with persistent AF
(3) Left atrial size
(4) Comorbidities
(5) Response to prior cardioversions
(6) Age
(7) Side effects and efficacy of the AADs already used to treat the patient
(8) Patient age and activity level
(9) Patient’s preference.
78
The duration of continuous AF is a predictor of the ability to restore and maintain sinus rhythm.The chance of successful AF rhythm control is higher in patients with paroxysmal or early persistent AF (<_____ months) than for patients who have been in continuous AF for one or more years.This is an important consideration when faced with asymptomatic or minimally symptomatic patients with newly diagnosed persistent AF.
< 6 mo
79
This prospective randomized clinical trial randomized 2204 patients with AF to catheter ablation or medical therapy.The primary endpoint was a composite of death, disabling stroke, serious bleeding, or cardiac arrest.
No difference in the primary endpoint was present after a median follow-up of 48.5 months.
But the secondary endpoint of death or cardiovascular hospitalizations was significantly lower in the ablation arm than in the medical therapy arm (51.7% vs. 58.1%, p = 0.001).
For this reason, the 2017 HRS/EHRA/ECAS Consensus Document on AF ablation provides a class IIb recommendation for catheter ablation of AF in patients who are asymptomatic
CABANA Trial
80
The 2014 and 2019 ACC/ AHA/HRS AF Guidelines advise that the optimal metric for rate control is a resting heart rate <_____ beats/min. Based on a single European clinical trial, a more lenient rate control metric of <110 beats/ min is provided with a class IIb recommendation. Assessment of the degree of heart rate control can be obtained with a 24-hour Holter monitor.A 12-lead ECG provides an indication of the resting ventricular rate but fails to provide information on the ventricular rate during a patient’s daily activities
AHA/HRS: <80 bpm
European: <110 bpm
81
Oral agents available for long-term heart rate control in patients with AF are digitalis, beta blockers, calcium channel antagonists, and amiodarone. The first-line agents for rate control are _____. A combination is often used to improve efficacy or to limit side effects by allowing the use of smaller dosages of the individual drugs.
Beta blockers and the calcium channel antagonists verapamil and diltiazem
82
In patients with sinus node dysfunction and tachycardia-bradycardia syndrome, the use of a beta blocker with _____ may provide rate control without aggravating sinus bradycardia
Intrinsic sympathomimetic activity
Pindolol
Acebutolol
82
Digitalis may adequately control the rate at rest but often does not provide adequate rate control during exertion as it works mainly by _____.Digitalis is no longer recommended for rate control except in patients with _____ because digitalis has been shown to increase the risk of all-cause mortality, particularly among patients with AF.
Increasing vagal tone
Heart Failure
The 2014 and 2019 AHA/ACC/HRS Guidelines recommend digoxin for rate control only in patients with heart failure
83
Amiodarone is much less frequently used for rate control than the other negative dromotropic agents because of the risk of organ toxicity associated with long-term therapy. Amiodarone can be an appropriate choice for rate control if the other agents are not tolerated or are ineffective. For example, amiodarone would be an appropriate choice for a patient with _____ who cannot tolerate either a calcium channel antagonist or a beta blocker and who has a rapid ventricular rate despite treatment with digitalis.
Persistent AF, heart failure, and reactive airway disease
Amiodarone as a rate-control medication is provided with a class IIb recommendation in the 2014 ACC/AHA/HRS AF Guidelines.
84
The results of studies on the efficacy of AADs for suppression of AF suggest that all the available drugs except amiodarone have similar efficacy and are associated with a _____% reduction in the odds of recurrent AF during 1 year of treatment
40% to 60%
85
The one drug that stands out as having higher efficacy than the others is amiodarone. In studies that directly compared amiodarone with sotalol or class I drugs, amiodarone was _____% more effective in suppressing AF. However, because of the risk of organ toxicity, amiodarone is not appropriate first-line drug therapy for most patients with AF. The 2014 and 2019 AHA/ACC/HRS AF Guidelines recommend that amiodarone be used as first-line antiarrhythmic medication only in patients with heart failure.
60% to 70%
86
Ventricular proarrhythmia from class Ia agents (quinidine, pro- cainamide, disopyramide) and class III agents (sotalol, dofetilide, dronedarone,amiodarone) is manifested as _____.
Risk factors for this type of proarrhythmia include _____.
QT prolongation and polymorphic ventricular tachycardia (torsades de pointes)
Female sex
LV dysfunction
Hypokalemia
Concomitant use of another QT-prolonging drug
87
The ventricular proarrhythmia from class Ic agents (flecainide and propafenone) manifests as _____, but not QT prolongation. They also increase the propensity for ventricular fibrillation in the setting of myocardial ischemia or infarction. For this reason, class Ic agents are not recommended in patients with established _____
Monomorphic ventricular tachycardia
Sometimes with widening of the QRS complex during sinus rhythm
Coronary artery disease (CAD) - contraindication for Class Ic drugs
88
In patients with AF in the setting of a structurally normal heart, _____ are all reasonable first-line drugs. _____ can be considered if the first-line agents are ineffective or not tolerated, especially if AF ablation is not preferred by the patient
Flecainide
Propafenone
Sotalol
Dofetilide
Dronedarone
Amiodarone
89
In patients with CAD, class Ic drugs have been found to increase the risk of death, and the safest first-line options are _____ ,with _____ reserved for use as a second-line agent.
1st line:
Dofetilide
Sotalol
Dronedarone
2nd line:
Amiodarone
90
In patients with heart failure, several AADs have been associated with increased mortality, and the only two drugs known to have a neutral effect on survival are _____.
Amiodarone
Dofetilide
91
After a higher mortality risk was demonstrated in a subsequent randomized clinical trial, _____ was labeled as being contraindicated when used as a rate-control agent and also in patients with decompensated heart failure.
Dronedarone
92
Experimental studies have indicated that _____ have favorable effects on electrical and structural remodeling
ACEi and ARBs
93
4 Pillars of AF management
Stroke prevention
Rate control
Rhythm control
Risk factor management
"S3R"
94
The modifiable AF risk factors consist of _____.
CAD
Obesity
Lack of cardiovascular fitness
Diabetes
Sleep apnea
Heart failure
Hypertension
Alcohol use
Tobacco
COLD SHHAT
95
Obesity is closely linked to the development of AF.The risk of developing AF increases _____% with every 5-point increase in BMI.
29% per 5 point increase in BMI
96
Hypertension is a modifiable risk factor for AF. Hypertension causes _____.
Ventricular hypertrophy
Atrial enlargement
Renin-angiotensin system
96
There also is a strong association between diabetes and AF, probably because of _____.
Fibrotic changes in the atria
Downregulation of connexin-43
Abnormalities of conduction in the atrium
97
Cigarette smoking augments the risk of AF by causing an increase in _____.
Sympathetic tone
Inflammation
Endothelial dysfunction
Atrial fibrosis
Oxidative stress
SIEAO MAI and Cigarette
98
Alcohol use has also been linked to development of AF. This link results from _____. A recent study demonstrated that abstinence from alcohol results in a reduction in AF burden
Acute oxidative stress
Direct cellular effects of alcohol on atrial myocytes
Activation of the sympathetic nervous system
ADA ALCOHOL
99
Based on the growing body of literature linking AF development to the presence of modifiable risk factors, especially obesity, the AHA/ ACC/HRS 2019 AF Guideline provides a class I LOE B recommendation that overweight and obese patients with AF should lose weight as part of a risk factor modification program. The goal of weight loss ideally should be a BMI of
27 kg/m2
100
The arrhythmia substrate of AF is ______. Furthermore, several factors that promote AF cannot be addressed simply by catheter ablation, including comorbidities (e.g., hypertension, obesity, obstructive sleep apnea), structural remodeling of the atria, systemic inflammatory factors, and genetic factors.
Not completely understood
Usually widespread
Variable between patients
Progressive
101
AF can recur after an initially successful ablation procedure. For this reason, AF ablation should not be considered a “cure” for AF but rather a _____ to keep the patient in sinus rhythm for as long as possible
Palliative measure
102
Circumferential antral isolation of the PVs results in 1 year of freedom from AF of between _____.
60% and 80% in patients with paroxysmal AF
40% to 60% in patients with persistent AF
20% to 40% in patients with longstanding persistent AF
103
The efficacy of AF ablation is closely linked with how success is defined and the intensity of ECG monitoring postablation. In general, the more monitoring performed, the _____.
Lower the success rate
104
The _____ trial recently examined this relationship closely. In this trial, 346 patients with paroxysmal AF were randomized to catheter ablation with the cryoballoon or with RF energy. An implantable rhythm monitor was implanted at least 1 month before ablation in all patients.
The success of AF ablation was approximately 55% at 1 year if the definition of success was defined as freedom from a 30 second or longer episode of an atrial arrhythmia after the 3-month blanking period.
The success rate increased to approximately 80% if the defi- nition of success was freedom from a symptomatic atrial arrhythmia.
Importantly, AF burden was reduced by approximately 98%.
The outcomes of AF ablation were similar in the cryoballoon and RF arms of the study.These results have been reproduced in a more recent trial.
CIRCA-DoSE Trial
105
In contrast to point-by- point RF ablation around the PVs, the _____ was designed to fit into the antrum of a PV and to create a circumferential ablation lesion using cryoenergy. Cryoenergy is delivered through the entire distal half of the second-generation cryoballoon catheter currently in clinical use. Complete occlusion of the PV by the inflated balloon is essential for reliable PV isolation.
Cryoballoon
106
Avoidance of entry of the cryoballoon into the luminal portion of a PV is important to avoid _____.The most commonly used cryoballoon catheter has a 28-mm diameter when the balloon is fully inflated.The relatively large size of the balloon typically allows occlusion of a PV from the antrum.A multielectrode catheter inserted through a central lumen of the cryoballoon catheter often allows recording of PV potentials during an application of cryoenergy. The endpoint of the cryoballoon ablation procedure is electrical isolation of all PVs
PV stenosis
107
_____ within the first minute of a cryoenergy application is a strong independent predictor of durable PV isolation.
Other independent predictors are a _____
In addition to the cryoballoon, a visually-guided laser balloon (VGLB) system now also is available for clinical use.
Disappearance or dissociation of PV potential
Other:
(1) Temperature recorded by a thermocouple proximal to the balloon of at least −40°C within 60 seconds of an application of cryoenergy
(2) Interval thaw time to 0°C of >10 seconds upon completion of a cryoenergy application
108
The cryoballoon procedures are _____.
Generally shorter
Require more fluoroscopy
Higher risk of phrenic nerve injury
Lower risk of pericardial tamponade
109
When performed by experienced operators, catheter ablation of AF has a major complication rate of _____%. The potential complications include _____.
1-3%
Femoral vein-related complications (1%)
Stroke (0.5%)
Cardiac tamponade (0.5% to 1.5%)
Pulmonary vein stenosis (0.5%)
Phrenic nerve injury (0.2%)
Death (0.1%)
110
The most feared complication of AF ablation is an ______.
The risk of esophageal perforation is reported to be in the range of 0.01% to 0.02%.60 Despite its rarity, this complication is of great concern because it often is lethal.
Patients typically present 3 to 14 days after ablation with one of more of the following: dysphagia, odynophagia, fever, leukocytosis, bacteremia, and stroke.
Computed tomography of the chest with intravenous contrast is the diagnostic test of choice.The presence of contrast in the esophagus or air in the mediastinum or cardiac chambers is indicative of an esophageal perforation or fistula formation. Instrumentation of the esophagus should be avoided.
Atrial esophageal fistula
111
There is evidence that _____ reduce the risk of esophageal injury.
(1) Limiting the power of RF energy applications to 20 to 25 watts for less than 30 seconds when ablating along the posterior left atrial wall
(2) Use of periprocedural proton pump inhibitors
112
This trial randomized 363 patients with AF heart failure, each of whom had an ICD, to catheter ablation or medical therapy. After a median follow-up of 37.8 months, the primary composite endpoint of death from any cause or hospitalization for worsening heart failure was lower in the ablation arm.
CASTLE AF study
AF in HF + ICD -> Catheter ablation vs Medical therapy
113
Because of the absence of strong data demonstrating a survival benefit of AF ablation in the absence of heart failure, this procedure is most commonly performed to improve quality of life in patients with symptomatic AF. Other factors to consider when recommending catheter ablation include the _____.
(1) Type of AF (paroxysmal, persistent, or longstanding persistent)
(2) Duration of continuous AF
(3) Severity of symptoms and quality of life
(4) Age
(5) Left atrial size
(6) Response to rate- and rhythm-control medications
(7) Response to cardioversion
(8) Patient preference
114
The current iteration of the procedure is the _____. This procedure has a similar lesion set, but various tools are used to create the lines of block instead of surgical incisions.These tools include a bipolar clamp RF ablation tool to electrically isolate the PVs. Cryoablation energy delivered with a handheld probe is used to create linear lesions. A bipolar RF clamp is used to electrically isolate the LAA.AF ablation using this open-chest approach is performed in conjunction with open-chest heart surgical procedures such as mitral valve repair or replacement or coronary artery bypass grafting.
Cox maze 4
114
A single randomized clinical trial and a review of cohort studies have indicated that surgical ablation has greater efficacy than catheter ablation but that it is associated with a higher rate of complications including the need for a _____.
Permanent pacemaker
115
In many centers, surgical ablation is reserved for AF patients who are poor candidates for catheter ablation, often due to the _____.
Presence of longstanding persistent AF
Severe left atrial dilation
Inefficacy of catheter ablation procedures
116
It is a useful strategy in patients who are symptomatic from AF because of a rapid ventricular rate that cannot be adequately controlled pharmacologically by medications and who either are not good candidates for AF ablation or have already undergone unsuccessful attempts at ablation.
AV node ablation
AV node ablation also can be helpful in patients with heart failure and AF to maximize the benefits of cardiac resynchronization therapy (CRT) if there already is not 100% ventricular pacing.
117
In patients with AF and an uncontrolled ventricular rate, AV node ablation improves the left ventricular ejection fraction (EF) if there is a _____.AV node ablation also has been shown to improve symptoms, quality of life, and functional capacity and to reduce the use of health care resources
Tachycardia-induced cardiomyopathy
118
The disadvantages of AV node ablation are that _____. Although symptoms and functional capacity typically improve after AV node ablation in patients with AF and an uncontrolled ventricular rate, some patients may not feel as well as during sinus rhythm.
iI creates a lifelong need for ventricular pacing and does not restore AV synchrony
119
Atrioventricular node ablation is a technically simple procedure with an acute and long-term success rate of 98% or higher and a very low risk of complications. In patients with persistent AF, a _____ is implanted.A _____ is appropriate if the AF is paroxysmal. Most patients have a good clinical outcome with right ventricular pacing, but in patients with left ventricular dysfunction, _____ is appropriate
Persistent AF: ventricular pacemaker
Paroxysmal AF: Dual-chamber pacemaker
LV dysfunction: biventricular pacing for CRT
120
In patients with an ischemic or nonischemic cardiomyopathy and EF of 30% to 35% or lower, an _____ may be appropriate for primary prevention of sudden death. However, a pacemaker without the ICD often is adequate for patients with a borderline EF (30% to 35%) and a rapid ventricular rate because the EF typically improves after the ventricular rate has been controlled by AV node ablation
CMP + EF <30-35%: PPI + ICD (primary prevention of SCD)
Borderline EF 30-35%: Pacemaker without ICD (EF improves with VR control after AVN ablation)
121
In patients without a bundle branch block, _____ pacing is optimal because it avoids the dyssynchrony associated with right ventricular pacing and eliminates the need for a lead in the coronary sinus that is required for biventricular pacing.
His bundle pacing
122
Atrial fibrillation is common after open heart surgery, occurring in _____% of patients who undergo coronary artery bypass graft (CABG) surgery or valve replacement. AF in this setting is associated with a twofold increase in the risk of postoperative stroke and is the most common reason for prolonged hospitalization
25-40%
123
The incidence of AF peaks on the _____ postoperative day.
2nd
124
The pathogenesis of postoperative AF is multifactorial and probably involves various combinations of _____.
Adrenergic activation
Atrial ischemia
Inflammation
Genetic factors
Electrolyte disturbances
125
Several risk factors for AF after open heart surgery have been identified, including _____.
Age over 70 years
History of prior AF
Male sex
LV dysfunction
Left atrial enlargement
Chronic lung disease
Diabetes
Obesity
126
The incidence of AF after open heart surgery can be significantly reduced by prophylactic treatment with _____.
Beta blockers
Amiodarone
Sotalol
127
______ is common after open heart surgery and can heighten the risk of AF.Magnesium administration has been reported to decrease the risk of postoperative AF
Hypomagnesemia
128
_____ pacing using temporary electrodes has been reported to reduce the risk of postoperative AF
Right atrial or biatrial
129
A number of other interventions have been assessed for their efficacy in reducing the incidence of AF after cardiac surgery, typically not in large randomized clinical trials.The use of _____ to address postoperative inflammation have produced variable results in reducing AF burden
Colchicine
Statins
Steroids
130
Another approach to the prevention of AF after cardiac surgery is injection of _____ toxin into the four major epicardial fat pads at operation.This causes temporary autonomic blockade and has been shown to reduce the incidence of AF after CABG to less than 10% and reduced the AF burden for up three years after surgery.
Botulinum
131
AF that occurs after cardiac surgery often resolves within ___ months.
3 months
132
Treatment with an oral anticoagulant should be ____ after discharge. Because new-onset AF after cardiac surgery often does not recur after 60 to 90 days, rhythm- control medications can be discontinued at that time, and if there is no subsequent evidence of symptomatic or asymptomatic AF, as confirmed by monitoring (e.g., 3- to 4-week autotrigger event monitor), anticoagulation can be safely discontinued unless needed for another indication.
Continued
133
New-onset AF occurs postoperatively in less than _____% of patients undergoing major noncardiac surgery. Some of the possible mechanisms of postoperative AF after cardiac surgery (e.g., sympathetic activation, electrolyte abnormalities, hypoxia) most likely also play a role in AF after noncardiac surgery. _____ have been shown to significantly reduce the risk of AF after major noncardiac surgery, but one must be vigilant for the development of _____.
<5%
Beta blockers
Bradycardia and hypotension
134
Patients with WPW syndrome who present in AF with a rapid ventricular rate should undergo _____ if there is hemodynamic instability.If the patient is hemodynamically stable, intravenous _____ can be used for pharmacologic cardioversion. Procainamide may be preferable to ibutilide because it blocks _____ before AF has converted to sinus rhythm
Unstable: transthoracic cardioversion
Stable: procainamide or ibutilide IV
Procainamide: blocks accessory pathway conduction and slows the ventricular rate
134
Patients with the WPW syndrome and an accessory pathway with a short refractory period can experience a very rapid ventricular rate during AF. Ventricular rates greater than _____ beats/min can result in loss of consciousness or precipitate ventricular fibrillation and a cardiac arrest.
250 to 300 bpm
135
Digitalis and calcium channel antagonists are contraindicated in patients with WPW syndrome and AF.These agents selectively block conduction in the AV node and can result in acceleration of conduc- tion through the accessory pathway
Digitalis and CCB
136
The preferred therapy for patients with WPW syndrome and AF with a rapid ventricular rate is _____.
Catheter ablation of the accessory pathway
137
Atrial fibrillation is a common arrhythmia in patients with heart failure, with a prevalence ranging from ___% in patients with NYHA functional Class I up to ___% in Class IV patients
NYHA I: 10%
NYHA IV: 50%
138
The deleterious hemodynamic effects of AF in HF are mediated by a _____.
Rapid and/or irregular ventricular rate and loss of AV synchrony.
139
The most appropriate rate-control drugs in patients with AF and systolic heart failure are _____. If necessary, _____ also can be used for rate control. In patients with diastolic heart failure, _____ can be used safely for rate control.
_____ are the only two rhythm-control drugs that are not associated with an increased risk of death in patients with heart failure.
Systolic HF: BB, Digitalis, Amiodarone
Diastolic HF: NDHP CCB
Amiodarone and dofetilide
140
Because left ventricular dysfunction and heart failure can be aggravated by right ventricular pacing, _____ pacing should be instituted after AV node ablation.
Biventricular
141
The decision to implant a biventricular pacemaker versus a biventricular ICD is based on clinical judgment. If it seems likely that the EF will remain less than 30% to 35% after optimal heart rate control, a _____ is appropriate for primary prevention of sudden cardiac death.It may take 2 to 3 months to evaluate the response of the LVEF to restoration of sinus rhythm.
Biventricular ICD
142
The _____ trial randomized 363 heart failure patients, each of whom had an ICD in place, to AF catheter ablation or medical therapy. After a median follow-up of 37.8 months, the pri- mary composite endpoint of death from any cause or hospitalization for worsening heart failure was lower in the ablation arm.64 While these studies strongly suggest that AF ablation should be considered in patients with heart failure, it is important to recognize that these trials were limited by small numbers of highly selected patients.
It is for this reason that the 2019 AHA/ACC/HRS AF Guidelines provides only a class ____ recommendation for AF ablation in patients with heart failure.
CASTLE AF
Class IIb AF ablation in HF
143
Atrial fibrillation occurs in approximately ___% of patients with hyper- trophic cardiomyopathy (HCM) and can cause severe hemodynamic impairment because of an inadequate diastolic filling time and loss of atrial-ventricular synchrony
25%
144
The prevalence of AF during pregnancy is very low, approximately 60/100,000 pregnancies. When it occurs, there often is underlying _____.
Congenital or valvular heart disease
Thyrotoxicosis
Electrolyte abnormalities
145
Transthoracic cardioversion is considered safe at ____ stages of pregnancy.
All
146
The decision to anticoagulate a pregnant woman with AF should be made using the same criteria as in nonpregnant women. If anticoagulation is deemed necessary, _____ is recommended from the _____ the due date, and _____ is recommended during the _____month of pregnancy.
Warfarin (not a DOAC)
Second trimester until 1 month before
Subcutaneous LMWH
First trimester and during the final month
147
The recommended pharmacologic agents for acute management of AF in pregnancy consist of intravenous _____ for rate control and _____ for conversion to sinus rhythm.
If ongoing therapy is deemed necessary, the recommended rate-control drug is _____. If ineffective, a _____ can be used, but only after the first trimester.
If there is no structural heart disease, _____ are recommended for long-term rhythm control.
In the patient with structural heart disease, _____ is recommended for rhythm control.
Rate control: IV metoprolol
Rhythm control: Flecainide or sotalol
Digoxin -> Beta blocker
Long term rhythm control (no structural disease): Flecainide, Sotalol
Structural disease: Amiodarone
148
The guidelines now recommend that _____ be considered for stroke prevention in patients who cannot tolerate or refuse to take an oral anticoagulant.
ASA + clopidogrel
149
The guidelines include specific recommendations of drugs for rate control during AF and that the effects of drug therapy on ventricular rate be measured at rest and during exercise to ensure adequate heart rate control.The criteria used for rate control are rates of _____ beats/min at rest and 90 to 115 beats/min during moderate exercise.
Rest: 60-80 bpm
Moderate exercise: 90-115 bpm
150
AF is present in up to ___% of patients with ACS and increases with patient age and severity of myocardial infarction (MI).AF is associated with increased in-hospital, 30-day ,and 1-year mortality rates in patients with ACS. Stroke rates are higher in patients with ACS and AF than in those without AF.AF is an independent predictor of poor long-term out- come in patients with ACS.
25%
151
Intravenous administration of _____ to patients with AF and a preexcitation syndrome may paradoxically accelerate the ventricular response and is not recommended.
Digitalis glycosides or nondihydropyridine calcium channel antagonists
152
The guidelines recommend intravenous _____ to slow the ventricular rate in patients and to improve LV function in patients with an acute MI.
If there is no LV dysfunction, bronchospasm, or AV block, an _____ is recommended for rate control.
(IV) amiodarone or digitalis
IV beta blocker or nondihydropyridine calcium antagonist
153
In _____, patients with HFrEF and ICDs or CRT-D and AF (paroxysmal or persistent) were randomized to receive catheter ablation versus medical therapy (rate or rhythm control) in addition to guideline directed management and therapy for HFrEF. Patients in the catheter ablation group had significantly reduced overall mortal- ity, hospitalization rate for worsening HF, and freedom from AF. Both studies were limited by relatively small and highly selected patient populations
CASTLE-AF (Catheter Ablation vs. Standard Conventional Treatment in Patients With LV Dysfunction and AF)
and
AATAC (Ablation versus Amiodarone for Treatment of Atrial Fibrillation in Patients with Congestive Heart Failure)
154
The _____ trial in 2204 patients randomized to either catheter ablation or drug therapy did not demonstrate that AF ablation was superior to drug therapy for the primary cardiovascular outcomes of death, disabling stroke, serious bleeding, or cardiac arrest over a median of 48 months of follow-up.
CABANA (Catheter Ablation verses Anti-arrhythmic Drug Ther- apy for Atrial Fibrillation)
155
_____ of the accessory pathway is recommended in patients with symptomatic AF and the WPW syndrome.
Immediate _____ is recommended if there is AF with a rapid ventricular rate and hemodynamic instability.
If the patient is hemodynamically stable, IV _____ is recommended for pharmacologic conversion of AF.
IV _____ should be avoided in patients with ventricular preexcitation during AF.
Catheter ablation
Electrical cardioversion
Procainamide or ibutilide
Digitalis and nondihydropyridine calcium channel antagonists
156
The guidelines recommend a _____ as first-line therapy for rate control in patients with AF and thyrotoxicosis. If a beta blocker cannot be used, _____ should be used for rate control. Prevention of thromboembolic complications is similar to patients without hyperthyroidism.
Beta blocker
Verapamil or diltiazem
157
The guidelines point out that there are not adequate data on the best rhythm-control medication to use for AF in the setting of HCM.The preferred therapy is either _____ for rate control or _____ by itself.
Disopyramide + beta blocker, verapamil, or diltiazem
Amiodarone
158
The guidelines recommend _____ for rate control of AF during pregnancy.
_____ is recommended if there is hemodynamic instability.
Except in patients with a low-risk profile,either aspirin or an anticoagulant is recommended for prevention of thromboembolic complications, depending on the stage of pregnancy.
_____ can be considered during the first trimester and last month of pregnancy in patients with risk factors for thromboembolism, and an oral anticoagulant can be considered during the second trimester in patients at high risk of thromboembolism.
When AF occurs during pregnancy, _____ can be considered for pharmacologic cardioversion in hemodynamically stable patients.
Digoxin,
Beta blocker
Nondihydropyridine calcium channel antagonist
DC cardioversion
Unfractionated or low-molecular- weight heparin
quinidine or procainamide
159
The primary therapy for AF in the setting of an acute pulmonary illness or exacerbation of chronic pulmonary disease should be correction of _____
_____ is recommended for rate control in patients with obstructive pulmonary disease.
_____ are not recommended in patients with bronchospastic disease, and _____are not recommended in patients with obstructive lung disease.
Hypoxemia and acidosis
Verapamil or diltiazem
Theophylline and beta-adrenergic agonists X Bronchospastic disease
Beta blockers, sotalol, propafenone, and adenosine X COPD
160
Obesity is associated with atrial remodeling and AF. Randomized and nonrandomized trials as well as observational studies support _____ to reduce AF burden.
Risk factor modification includes assessment and treatment of unde lying sleep apnea, hypertension, hyperlipidemia, glucose intolerance, and alcohol and tobacco use.
Weight reduction in addition to risk factor modification
