Arrhythmias therapeutic tutorial

Question 1

what is the atrial fibrilation

Answer 1

A common supraventricular tachyarrhythmia, caused by uncoordinated atrial activation resulting in an irregular ventricular response. Patients are often asymptomatic but have an irregular pulse on physical examination. When present, symptoms usually include palpitations and lightheadedness. Patients with atrial fibrillation are at an increased risk of stroke and other thromboembolic complications.

Question 2

what are the ECG findings of Afib?

Answer 2

• -Irregularly irregular RR intervals (The time interval between two successive ORS complexes varies unpredictably.)
• -P-waves are indiscernible
• -Tachycardia
• -Narrow QRS complex (< 0.12 seconds)

Question 3

what are the cardiovascular risk factors of Afib?

Answer 3

• -increasing age
• -Hypertension
• -Diabetes mellitus
• -Smoking
• -Obesity
• -Sleep apnea

Question 4

what are the Intrinsic cardiac disorders that increase the risk of Afib?

Answer 4

–Coronary artery disease
–Valvular heart disease (especially mitral valve disease)
–Congestive heart failure (CHF)
–Pre-excitation tachycardia (e.g., Wolff-Parkinson-White syndrome)
–Sick sinus syndrome (tachycardia-bradycardia syndrome)
–Cardiomyopathies
Pericarditis

Question 5

what are the Intrinsic cardiac disorders that increase the risk of Afib?

Answer 5

1) Pulmonary disease: COPD, pulmonary embolism, pneumonia
2) Hyperthyroidism
3) Catecholamine release and/or increased sympathetic activity
- -Stress: sepsis, hypovolemia, post-surgical state (especially following cardiac surgery), hypothermia
- -Pheochromocytoma
- -Cocaine, amphetamines
4) Electrolyte imbalances (hypomagnesemia, hypokalemia)
5) Drugs: e.g., adenosine, digoxin
6) Holiday heart syndrome: irregular heartbeat classically triggered by excessive alcohol consumption, but also sometimes by moderate consumption, stress, or lack of sleep
7) Chronic kidney disease

Question 6

what is the holiday heart syndrome?

Answer 6

This syndrome acquired its name because it typically occurs after binge drinking, which often coincides with vacations or holidays. The association with alcohol consumption is why this syndrome is not confined to the elderly, but may also be found in young adults. Patients with holiday heart syndrome usually have paroxysmal AF.

Question 7

what is the AF with Rapid ventricular response?

Answer 7

AF with a ventricular rate > 100 bpm (tachycardic AF)

Question 8

what are the antiarrhythmic drugs?

Answer 8

Group of drugs that are used to restore sinus rhythm in patients presenting with cardiac arrhythmias, as well as to prevent recurrent arrhythmias. Antiarrhythmic agents are classified into 5 classes according to their electrophysiological effect on the myocardium (i.e., sodium channel blocker, beta blocker, potassium channel blocker, calcium channel blocker, and others). Because all antiarrhythmic drugs are potentially proarrhythmic, they should be administered under ECG monitoring.

Question 9

what are the class I antiarrhythmic drugs?

Answer 9

• -Na+ channel blockers
  1) A Prolong action potential —Quinidine, Disopyramide
  2) B Shorten action potential—Lidocaine,
  3) C No effect on action potential –Flecainide, Propafenone

Question 10

what are the class II antiarrhythmic drugs?

Answer 10

–Beta-blockers—Metoprolol, Bisoprolol

Question 11

what are the class III antiarrhythmic drugs?

Answer 11

–K+ channel blockers—Amiodarone, Dronedarone, Sotalol, Dofetilide

Question 12

what are the class IV antiarrhythmic drugs?

Answer 12

–Ca++ channel blockers–Verapamil, Diltiazem

Question 13

what are the treatment strategies of AF?

Answer 13

• -Rhythm control (conversion of atrial fibrillation/flutter to sinus rhythm)
• -Heart rate control (slowing of heart rate) are possible treatment strategies

Question 14

what is the rate control?

Answer 14

A mainstay of treatment of atrial fibrillation to normalize the ventricular heart rate. Drugs used for rate control include beta-blockers (e.g., esmolol, propranolol, metoprolol) and nondihydropyridine calcium channel blockers (e.g., diltiazem, verapamil).

Question 15

what is the rhythm control?

Answer 15

A treatment strategy for atrial fibrillation to restore sinus rhythm and prevent atrial remodeling. Includes elective synchronized cardioversion and the use of antiarrhythmics, such as flecainide, propafenone, ibutilide, dofetilide, or amiodarone.

Question 16

in unstable AF, the rate or rhythm control is the priority?

Answer 16

• -rhythm
• -Unstable AF: emergent electrical cardioversion
• -If AF does not terminate, cardioversion should be repeated with increased shock energy after adjusting the electrodes’ position.

Question 17

what are the indications for rate vs rhythm control?

Answer 17

• -Elderly patients (Because elderly individuals have decreased clearance of antiarrhythmic drugs and are at increased risk of proarrhythmias (arrhythmias caused by antiarrhythmic therapy).)
• -Failure of rate-control strategy to control symptoms, Younger patients (Rhythm control strategies may be preferable among younger individuals in order to prevent ventricular remodeling.)

Question 18

what are the contraindications of rate vs rhythm control?

Answer 18

• -AF due to pre-excitation syndromes (The use of rate control drugs such as digoxin, amiodarone, calcium channel blockers and/or beta blockers depresses AV node conduction. In patients with WPW syndrome, AV blockade can lead to increased conduction through the aberrant pathway and thus precipitate ventricular tachycardia or ventricular fibrillation.)
• -Long-standing persistent AF (Atrial modeling occurs within 6 months of the onset of AF and any advantage that would have been gained by the use of the rhythm control strategy is lost.)

Question 19

what are the first-line drugs used for rate control?

Answer 19

• -1st choice: beta blockers (esmolol, propanolol, metoprolol) OR nondihydropyridine calcium channel blockers (diltiazem, verapamil)
• -2nd choice: digoxin
• -3rd choice: dronedarone, amiodarone (Possesses both rate- and rhythm-control mechanisms)

Question 20

what are the indications of Beta-blockers and CCBs in AF?

Answer 20

Beta-blockers are the ones most commonly used for rate control followed by nondihydropyridine calcium channel blockers. Beta-blockers are preferred when AF is due to hyperthyroidism. Beta-blockers should be avoided in a patient with COPD. nondihydropyridine calcium channel blockers (ndhp CCB) cannot be used among patients with decompensated heart failure (LV systolic dysfunction/low ejection fraction) because they are negatively inotropic and lead to worsening of heart failure. ndhp CCBs may, however, be used in heart failure with preserved normal LV systolic function

Question 21

what are the indications of digoxin in AF?

Answer 21

Digoxin is preferred as first-line therapy in patients with decompensated HF when beta blockers are contraindicated.

Question 22

what is the second line measure of rate control in AF?

Answer 22

• -AV nodal ablation and implantation of a permanent ventricular pacemaker
• -The pacemaker should ideally be implanted 4–6 weeks before AV nodal ablation. AV nodal ablation is an irreversible procedure and eliminates the need for rate control drugs. However, it leads to life long dependence on a pacemaker and should therefore not be performed without first attempting rate control with drug therapy. Maximum benefit is seen among elderly patients, patients with tachycardia-induced cardiomyopathy, and those refractory to rate control medications. A biventricular pacing system is recommended for AF patients with decompensated heart failure.

Question 23

What additional therapy patients with AF require during admission to the hospital?

Answer 23

–Anticoagulant Therapy to be considered in all patients in atrial fibrillation because of the stroke risk. Options include;
1)IV heparin followed by oral warfarin (Vitamin K Antagonist)
or
2)Novel/New Oral Anti-Coagulants (NOAC drugs with lower bleeding risks)
–Direct thrombin inhibitors
*Dabigatran,
–Factor Xa Inhibitors
*Apixaban
*Rivaroxaban
*Edoxaban

Question 24

In the presence of Atrial Fibrillation, the decision to anti-coagulate is based on…

Answer 24

• -Stroke Risk – CHA2DS2VASc Score
• -Bleeding Risk – HAS-BLED Score

–Anticoagulation is commenced where
stroke risk is moderately high, and
–bleeding risk is low.

Question 25

what is the CHA2DS2-VASc score?

Answer 25

A score used to assess thromboembolic risk and the risk for stroke in patients with atrial fibrillation. Also an acronym for the risk factors; major risk factors count for two points (indicated in the subscript of the acronym) while the other risk factors count for one point each: Congestive heart failure, Hypertension, Age ≥ 75 years (2 points), Diabetes mellitus, Stroke or TIA or thromboembolism (2 points), Vascular disease (prior MI, peripheral artery disease, or aortic plaque), Age 65–74 years, Sex category (female sex).

Question 26

in the CHA2DS2-VASc score, what risk factors are counted for 2 points?

Answer 26

• -Age ≥ 75 years

- -Stroke or TIA or thromboembolism

Question 27

based on CHA2DS2-Vasc, patients which how many points require anticoagulation?

Answer 27

1) Nonvalvular atrial fibrillation: The need for anticoagulation therapy is based on the CHA2DS2-VASc score
- -Score = 0: no anticoagulation
- -Score = 1: no anticoagulation OR treatment with oral anticoagulants
- -Score ≥ 2: oral anticoagulation with either warfarin or newer oral anticoagulants (dabigatran, rivaroxaban, apixaban)
2) Valvular atrial fibrillation: anticoagulation with warfarin is required regardless of the CHA2DS2-VASc score

Question 28

what is the HAS-BLED score?

Answer 28

A score used to estimate the bleeding risk in patients with atrial fibrillation who are starting or continuing anticoagulation therapy. Risk factors include uncontrolled hypertension, renal disease, liver disease, stroke history, labile INR, age > 65 years, alcohol use, prior major bleeding, and use of other medications that can predispose to bleeding (e.g., NSAIDs, aspirin).

Question 29

what score of HAS-BLED indicates high risk of bleeding?

Answer 29

A HAS-BLED Score > 3 indicates “high risk” of bleeding and hence caution and regular review of usage of anticoagulant or antiplatelet therapy required.

Question 30

what are the Options for Patients with Atrial Fibrillation and a High Risk of Bleeding?

Answer 30

• -Surgical or percutaneous left atrial appendage occlusion/exclusion
• -Watchman LA appendage closure device

Question 31

It would be very reasonable after 6 weeks of treatment to consider electrical or pharmacological cardioversion, as…

Answer 31

• -The patient has received 6 weeks of anticoagulation

- -Left atrial thrombus has been out ruled

Question 32

The possible benefits of restoration of sinus rhythm include…

Answer 32

–Symptom relief = most important reason for cardioversion
–Improved cardiac function due to coordinated atrial and ventricular contraction
Possible reduced risk of thromboembolism (not seen in AFFIRM and RACE),
–Possible avoidance of the need for longterm anticoagulation.

Question 33

electrical vs pharmacological cardioversion?

Answer 33

• -Electrical cardioversion involves having the patient fasted, under adequate anaethesia, and an electric shock (100 – 200 J) synchronized with the intrinsic activity of the heart.
• -Alternatively amiodarone is of proven efficacy in pharmacological cardioversion of atrial fibrillation present for more than 7 days.

Question 34

what is the pharmacologic management after cardioversion?

Answer 34

–Anticoagulation is continued for at least 4 weeks, and possibly indefinitely – thromboembolism appears to be most likely at times where rhythm is switching between the sinus and atrial fibrillation.
–Anti-arrhythmic therapy is generally not recommended except with frequent symptomatic recurrences.
In this situation, the following drugs may be used to maintain sinus rhythm in the longterm;
1)Amiodarone
2)Dronedarone
3)Flecainide

Question 35

Recurrent or persistent atrial fibrillation may also be corrected by…

Answer 35

• -Surgical ablation of fibrillation foci/pathways (Maze operation),
• -Left atrial catheter ablation of fibrillation foci/pathways using radiofrequency energy.