B P7 C61 Approach to the Patient with Cardiac Arrhythmias Flashcards
The presence of regular cannon A waves in the jugular venous pulse would be consistent with 1:1 retrograde ventriculoatrial activation are seen in this type of tachycardias
JT
AVRT
AVNRT
VT
Physical examination features of AV dissociation, such as
1.
2.
3.
- Intermittent “cannon” A waves, indicative of right atrial contraction against a closed tricuspid valve
- Variable intensity of the S1
- Variable peak SBP
The _________________ and ________________ during the physical examination can be useful to interrupt arrhythmias sensitive to autonomic tone or identify the patient with a hypersensitive carotid sinus reflex.
Valsalva maneuver
Carotid sinus massage (CSM)
The most definitive responses to CSM are ___________________, as may be observed in AVRT, AVNRT, sinus node reentry, adenosine-sensitive AT, and idiopathic RVOT tachycardia.
Tachycardia termination
CSM generally does not affect reentrant ______________ or junctional tachycardias
Ventricular
During wide-QRS tachycardias with a 1:1 relationship between the P waves and QRS complexes, vagal influence can terminate or slow a supraventricular tachycardia (SVT) that depends on the AV node for perpetuation; on the other hand, vagal effects on the AV node can transiently block retrograde conduction and thus establish the diagnosis of VT by demonstrating AV dissociation
__________________ the awareness of the heartbeat that may be caused by a rapid heart rate, irregularities in heart rhythm, or an increase in the force of cardiac contraction, as occurs with a post–extrasystolic beat;
Palpitations
The ventricular systole that ends the compensatory pause is often responsible for the actual palpitation, the result of a more forceful contraction from prolonged _________________ or increased motion of the heart in the chest.
Ventricular filling
_____________________ constitute the most common causes of palpitations
PAC or PVC
Low-risk features of palpitations include:
- Isolated palpitations not induced by exercise
- The absence of structural heart disease or symptoms such as syncope or chest pain
- No family history of SCD
- Normal 12-lead ECG
Commonly referred to as “fainting” or “passing out,” is a tranient, self-limited loss of consciousness and posture resulting from a drop in blood pressure with cerebral hypoperfusion
Syncope
When caused by a cardiac arrhythmia, the onset of syncope is _________ and the duration is usually _________, with or without a preceding aura, and it is ________ typically followed by a postictal confusional state.
Rapid
Brief
Not followed by postictal state
____________ does not begin with or anticipate the syncope
Seizure
Syncope with early seizure activity is frequently caused by epilepsy, whereas later seizure activity is more likely caused by a cardiac arrhythmia with cerebral hypoperfusion.
Criteria for immediate evaluation of syncope
Structural heart disease
HF
Significant LV dysfunction or hypertrophy
Prior MI
Clinical features
Exertional syncope
Syncope while supine
Palpitations associated with syncope
Family history of SCD
ECG features
VT
Bifascicular block
IVCD
Sinus bradycardia, SA block
Preexcited QRS complex
Prolonged or short QT
Brugada pattern on ECG
T wave inversion or late potentials in the right precordial leads
Significant comorbidities
Anemia
Electrolyte imbalance
The most common type of reflex syncope
Neurocardiogenic
SCD caused by cardiac arrhythmias is most often the result of _________ or _____
VT
VF
In well-adjudicated cases, _____ is the most common finding in SCD and can be the first and last manifestation
Coronary heart disease (CHD)
Up to ___% of cases of SCD occur in patients with some form of structural heart disease, such as CHD, cardiomyopathy, or congenital heart disease.
80%
Other cardiac causes of SCD, referred to as “autopsy negative,” include primary electrical diseases such as _____.
LQTS
Brugada syndrome
Catecholaminergic polymorphic ventricular tachycardia (CPVT)
Idiopathic ventricular fibrillation (IVF)
Wolff-Parkinson-White (WPW) syndrome
___________, ____________, ___________ may precipitate cardiac arrest in the setting of a variety of structural heart diseases, arrhythmogenic cardiomyopathy (arrhythmogenic right ventricular cardiomyopathy/dysplasia, ARVC/D), and primary electrical diseases such as LQTS (types 1 and 2) and CPVT.
Exercise
Emotional upset
Stress
Exercise, emotional upset, or stress may precipitate cardiac arrest in the setting of a variety of _____.
Structural heart diseases
Arrhythmogenic cardiomyopathy (ARVC/D)
Primary electrical diseases: LQTS (types 1 and 2) and CPVT
SCD in LQTS3 or Brugada syndrome is more likely to occur at ________ or ________.
Rest
Sleep
Fever is a common precipitant of the characteristic ECG abnormality and arrhythmias in _______________.
Brugada syndrome
Give ECG abnormalities
WPW syndrome
LQTS/SQTS
Brugada syndrome
ARVC/D
Delta wave
Prolonged/short QT interval
Right precordial ST segment abnormalities
Epsilon waves
In a stable patient, if P waves are not clearly visible, the administration of _____ while running a rhythm strip may cause transient AV block and either terminate the tachycardia or allow discernment of P waves and diagnosis of the arrhythmia
Adenosine by rapid intravenous bolus (6 mg followed by 12 mg if no response to the first dose)
___________________ may be particularly useful in the evaluation of patients who experience symptoms with exertion
Exercise electrocardiographic stress testing
A _____ after the end of exercise (delay in return to baseline) is associated with a worse CV prognosis, as is a rapid resting heart rate.
Persistent elevation in heart rate
_____ beats of nonsustained VT can occur in normal subjects, especially elderly persons, and its occurrence nei- ther implicates ischemia or other forms of heart disease nor predicts
increased CV morbidity or mortality
3-6 beats
Ventricular ectopy occurs in about half of patients with CAD, generally appearing more reproducibly and at lower heart rates (<___ beats/min) than in healthy individuals and often in the early recovery period.
Frequent PVCs (>____per minute), polymorphic PVCs, and VT are more likely to occur in patients with CAD.
< 130 bpm
> 10/min
In patients with Brugada syndrome, significant ST-segment elevation with coving of the ST segment during the _____ phase predicts arrhythmic events during follow-up.
Recovery phase
The fundamental diagnostic principle in managing patients with an undocumented cardiac rhythm disturbance is to _____
Record the ECG during a symptomatic episode and establish a causal relation between the arrhythmia and symptoms
From _____% of patients experience a symptom during a 24-hour recording; in _____% the complaint is caused by an arrhythmia
25-50%: symptoms
2-15%: arrhythmia
Give possible diagnoses for wide complex tachycardia
VT
SVT wiht aberrancy
Preexcited tachycardia
ECG findings that favor VT
1.
2.
3.
- AV dissociation
- Fusion beats, capture beats
- Tachycardia beats identical to PVCs during sinus rhythm
________________ is most useful in patients with frequent (daily or more often) symptoms.
Holter monitoring is most useful in patients with frequent (daily or more often) symptoms.
Significant rhythm disturbances are uncommon in healthy young persons. _____ can be observed and are not necessarily abnormal.
Sinus bradycardia with HR of 35-40 beats/min
Sinus arrhythmia with pauses > 3 seconds
Sinoatrial exit block
Type I (Wenckebach) second-degree AV block (often during sleep)
Wandering atrial pacemaker
Junctional escape complexes
PACs
PVCs
Apple watch: Sensitivity of __% and specificity __% in identifying patients with silent atrial fibrillation
Sensitivity: 87%
Specificity: 97%
_____________ are indicated when symptoms occur less frequently (e.g., several episodes per month), and because the monitors are typically patient activated, and well-suited for correlating symptoms with rhythm disturbances.
Event recorders
However, frequent PVCs (>__% of the total) have been shown to produce a cardiomyopathy and heart failure in some people, which can be reversed following elimination of the PVCs. Most patients with ischemic heart disease, particularly after MI, exhibit PVCs when they are monitored for 24 hours.
> 15%
The frequency of PVCs progressively increases during the first several weeks and then decreases at about __ months after infarction.
6 months
_____ PVCs are associated with a two- to five- fold increased risk for cardiac or sudden death in patients after MI, but treating these PVCs may not improve the prognosis. Recent data indicate that _____ of PVCs after MI may improve previously depressed ventricular function
Frequent and complex PVCs
Ablation
_____________________ are typically used for the evaluation of suspected serious arrhythmias that occur infrequently and cannot be provoked at diagnostic EPS.
Implantable monitors or insertable loop recorders (ILRs)
An ILR, a single-lead ECG monitoring device placed subcutaneously at approximately the level of the anterior second rib, monitors the cardiac rhythm for as long as 24 to 36 months.
________ variability is used to evaluate vagal and sympathetic influences on the sinus node (inferring that the same activity is also occurring in the ventricles) and to identify patients at risk for a CV event or death.
Heart rate variability
R-R variability predicts all-cause mortality after MI, as does left ventricular ejection fraction or nonsustained VT
Measure of reflex vagal control of the heart
Heart rate turbulence
Abnormal heart rate turbulence is a strong independent predictor of mortality in patients with CAD and dilated cardiomyopathy.
Reflection of heterogeneity in refractoriness and conduction velocity, which is a hallmark of reentrant arrhythmias.
- QRS and QT dispersion
- T wave abnormalities
Beat-to-beat alternation in the amplitude or morphology of the ECG recording of ventricular repolarization, the ST segment, and the T wave.
T wave alternans
It has been found in conditions favoring the development of ventricular tachyarrhythmias, such as ischemia and LQTS, and in patients with ventricular arrhythmias. A positive T wave alternans test result has been associated with a worse arrhythmic prognosis in various disorders, including ischemic heart disease and nonischemic cardiomyopathy
Method for recording cardiac electrical activity at the skin surface and spatially integrating it with imaging data (currently, cardiac CT scanning).
Electrocardiographic imaging
Useful in the evaluation of patients without structural heart disease and recurrent syncope in whom there is suspicion that exaggerated vagal tone producing cardioinhibitory and/or vasodepressor responses
Tilt-table testing (TTT)
TTT has been suggested as a useful tool in the diagnosis of and therapy for _____
- Recurrent idiopathic vertigo
- Chronic fatigue syndrome
- Recurrent TIA
- Repeated falls of unknown etiology in elderly patients without much evidence
Relative contraindications of TTT
- Severe CAD with proximal coronary stenoses
- Known severe CVD
- Severe mitral stenosis
- LVOTO (e.g., aortic stenosis)
Patients are placed on a tilt table in the supine position and tilted upright to a maximum of ______ degrees for 20 to 45 minutes or longer if necessary.
60 to 80 degrees
_______ is administered as a bolus or infusion, may provoke syncope in patients whose initial upright TTT result shows no abnormalities or, after a few minutes of tilt, may shorten the time needed to produce a positive response on the test.
Isoproterenol
An initial intravenous isoproterenol dose of 1 μg/min can be increased in 0.5-μg/min steps until symptoms occur or a maximum of 4 μg/min is given
Isoprotproterenol induces a vasodepressor response in upright susceptible patients (decrease in heart rate and blood pressure along with nearsyncope or syncope).
Tilt-table test (TTT) results are positive in _____ of patients susceptible to neurally mediated syncope.They are reproducible in approximately 80% of patients but have a _____% false-positive response rate.A positive test result is more meaningful when it reproduces symptoms that have occurred spontaneously.
2/3 to 3/4
10-15% false positive response rate
Exaggerated activation of a central reflex in response to TTT produces a stereotypic response of an initial increase in ______________, followed by __________ in blood pressure and then a reduction in heart rate characteristic of neurally mediated hypotension
Increase Heart rate, Drop in BP
Reduction in HR
POTS is another aberrant variant of a neurocardiogenic reflex characterized by the inability to tolerate the upright posture and a dramatic increase (>_____ beats/min) in heart rate (>120 beats/min) within 10 minutes of assuming an upright posture
HR increase of > 30 bpm to > 120bpm within 10 mins of assuming an upright posture
Identify
Normal response
A normal response is an early, slight drop in BP with a compensatory increase in HR mediated by the autonomic nervous system.
Identify
Vasodepessor
Pure vasodepressor response is a relatively sudden drop in BP without a marked change in HR,
Identify
Cardioinhibitory
Pure cardioinhibitory response shows a sudden decrease in HR without a change in BP
Identify
Mixed
Mixed response shows decreases in both HR and BP.
Identify
Autonomic failure
Progressive fall in BP is not counteracted by an increase in HR
Identify
Postural tcahycardia
In POTS, an exaggerated increase in HR is seen.
