Critical Care Medicine-Neurologic Disorders>>>>>Arrhythmias and Pacemaker
Question 10#

An 83-year-old male with a history of ischemic cardiomyopathy, systolic heart failure (LVEF 24%), and combined pacemaker and ICD for cardiac synchronization therapy (CRT-D) underwent coronary artery bypass graft (CABG) surgery three days ago. He still has atrial and ventricular epicardial pacing wires in place. He is now urgently admitted to the ICU with acute decompensation of his heart failure and volume overload. On transthoracic echocardiogram, his LVEF is reduced to 15% and the patient’s heart rhythm shows frequent alternating runs of AF/atrial flutter (HR 110s) and monomorphic VT (HR 100s). During these episodes, the patient becomes lightheaded because of mild hypotension.

Which of the following statements about the next steps in management is MOST accurate?

A. Overdrive pacing is not efficacious for breaking postoperative atrial flutter in patients that underwent heart surgery
B. Biatrial but not right atrial pacing reduces the incidence of AF after CABG
C. Epicardial overdrive pacing is contraindicated in patients with monomorphic VT
D. Procainamide is recommended as initial treatment of patients with stable sustained monomorphic VT
E. Verapamil and diltiazem are safe choices for patients with VTs and myocardial dysfunction

Correct Answer is D

Comment:

Correct Answer: D

Overdrive pacing has been shown to terminate postoperative atrial flutter in the vast majority of patients that underwent heart surgery. According to the AHA/ACC guidelines, rapid atrial pacing is useful for acute conversion of atrial flutter in patients who have pacing wires in place as part of a PPM or implantable cardioverter-defibrillator or for temporary atrial pacing after cardiac surgery. Both, temporary right atrial or biatrial pacing after CABG and other cardiac surgeries decreased the incidence of postoperative AF in the majority of the studies.

Procainamide is considered reasonable as an initial treatment modality for patients with stable sustained monomorphic VT. Direct-current cardioversion is recommended in patients with hemodynamically unstable, sustained monomorphic VT. AHA/ACC/ESC guidelines support the use of overdrive pacing in patients with refractory, slower VTs. However, electrical cardioversion/defibrillation should be immediately available, because acceleration of VT and degeneration to ventricular fibrillation are welldescribed complications. Intravenous amiodarone can be beneficial in patients with hemodynamically unstable, sustained monomorphic VT that was refractory to cardioversion or procainamide/other antiarrhythmic drugs. 

The AHA/ACC/ESC guidelines warn against the use of calcium channel blockers such as verapamil and diltiazem in patients with myocardial dysfunction for the purpose of terminating wide-QRS-complex tachycardias.

References:

  1. Page RL, Joglar JA, Caldwell MA, et al. 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia: executive summary: a report of the American College of Cardiology/American Heart Association Task force on clinical practice guidelines and the heart. Circulation. 2016;133:e471-e505.
  2. Daoud EG, Snow R, Hummel JD, et al. Temporary atrial epicardial pacing as prophylaxis against atrial fibrillation after heart surgery: a metaanalysis. J Cardiovasc Electrophysiol. 2003;14:127-132.
  3. Priori SG, Blomstrom-Lundqvist C. 2015 European Society of cardiology guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death summarized by co-chairs. Eur Heart J. 2015;36:2757-2759.
  4. Zipes DP, Camm AJ, Borggrefe M, et al. ACC/AHA/ESC 2006 guidelines for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death–executive summary: a report of the American College of Cardiology/American Heart Association Task Force and the European Society of Cardiology committee for practice guidelines (writing committee to develop guidelines for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death) developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society. Eur Heart J. 2006;27:2099-2140.