Cardiology MCQ & Review

Q. Which of the following drugs is found to be useful in idiopathic ventricular fibrillation ?

A. Quinidine

B. Bisoprolol

C. Verapamil

D. Sotalol

Explanation:

Idiopathic ventricular fibrillation has a high recurrence rate.

The recommended therapy is implantation of implantable cardioverter defibrillator. Currently, recommendations for a specific drug therapy are not available.

Antiarrhythmic agents had no effect on the recurrence rate in the patients from the Unexplained Cardiac Arrest Registry of Europe

In a study by Belhassen et al.,patients with IVF have received oral quinidine guided by serial electrophysiological studies. In patients receiving continuous quinidine treatment, no recurrences of VF were reported during a mean follow-up period of 9.1 ± 5.6 years. In a subset of patients, these promising results were confirmed during longterm follow-up.

Currently pharmacologic therapy serves as an adjunct to ICD therapy in patients with multiple ICD discharges.

References:

1.Belhassen B, Viskin S, Fish R, et al: Effects of electrophysiologic-guided therapy with Class IA antiarrhythmic drugs on the long-term outcome of patients with idiopathic ventricular fibrillation with or without the Brugada syndrome. J Cardiovasc Electrophysiol 10:1301–1312, 1999.
2. Belhassen B, Glick A, Viskin S: Excellent longterm reproducibility of the electrophysiologic efficacy of quinidine in patients with idiopathic ventricular fibrillation and Brugada syndrome. Pacing Clin Electrophysiol 32:294–301, 2009.

Answer: A (Quinidine)

Keywords: Cardiology review, Cardiology, Multiple choice questions, medical students, Electrophysiology, Ventricular fibrillation

All of the following statements about ventricular fibrillation are true except

1.Ninety to ninety-five percent of individuals with ventricular fibrillation reveal underlying structural heart disease.

2. No structural heart disease can be identified in 55% to 60% of patients.

3.According to the results of the Cardiac Arrest Survivors With Preserved Ejection Fraction Registry (CASPER) among patients with normal left ventricular function, idiopathic ventricular fibrillation (IVF) was diagnosed in 44% of patients with ventricular fibrillation without structural heart disease.

4.The diagnosis of idiopathic ventricular fibrillation (IVF) is based on the exclusion of currently known structural and primary electrical heart diseases following a complete noninvasive, invasive, and genetic workup.

Explanation:

-Ventricular fibrillation in patients without structural heart disease is rare. 90-95% of individuals with ventricular fibrillation reveal underlying structural heart disease

-No structural heart disease can be identified in only 5% to 10% of patients

-According to the results of the Cardiac Arrest Survivors With Preserved Ejection Fraction Registry (CASPER) among patients with normal left ventricular function, a causal diagnosis
for ventricular fibrillation can be found in 56%. Most diagnoses were primary electrical diseases (catecholaminergic polymorphic ventricular tachycardia [CPVT], long QT syndrome, early repolarization syndrome, and Brugada syndrome [69%]). In 31% of patients, a subtle structural heart disease (i.e., coronary spasm, subclinical arrhythmogenic right ventricular cardiomyopathy and myocarditis) was identified. In addition, idiopathic ventricular fibrillation (IVF) was diagnosed in 44% of patients with ventricular fibrillation without structural heart disease.

-The diagnosis of IVF is based on the exclusion of currently known structural and primary electrical heart diseases following a complete noninvasive, invasive, and genetic workup.

Ref:
1.Krahn AD, Healey JS, Chauhan V, et al: Systematic assessment of patients with unexplained cardiac arrest: Cardiac Arrest Survivors With Preserved Ejection Fraction Registry (CASPER). Circulation 120:278–285, 2009.

2. Rosso R, Kogan E, Belhassen B, et al: J-point elevation in survivors of primary ventricular fibrillation and matched control subjects: incidence and clinical significance. J Am Coll Cardiol 52:1231–1238, 2008.

3. Napolitano C, Bloise R, Monteforte N, et al. Sudden cardiac death and genetic ion channelopathies: long QT, Brugada, short QT, catecholaminergic polymorphic ventricular tachycardia, and idiopathic  ventricular fibrillation. Circulation 125:2027–2034, 2012.

Answer : B

Keywords: Cardiology review, Cardiology, Multiple choice questions, medical students, Electrophysiology, Ventricular fibrillation