Cardiac resynchronization therapy is indicated for which condition?

Cardiac resynchronization therapy is indicated for which condition?

• A. Prevention of sudden cardiac death
• B. Dyssynchronous ventricular activation and/or QRS prolongation
• C. Replacement of heart function
• D. Providing only right ventricular pacing

Answer: (B)

Cardiac resynchronization therapy is used to correct the problem of ventricle dyssynchrony caused by conduction delays, most commonly a left bundle branch block pattern that makes the two ventricles contract at different times. When the ventricles don’t pump together, cardiac output drops and symptoms of heart failure worsen. CRT works by delivering pacing to both the right ventricle and the left ventricle (via a coronary sinus lead) so that the ventricles contract in a coordinated, synchronized fashion. This resynchronization often improves stroke volume, reduces mitral regurgitation, and can lead to reverse remodeling and symptom relief. A prolonged QRS on ECG signals this dyssynchrony and helps identify patients who are likely to benefit from CRT, making dyssynchronous ventricular activation and/or QRS prolongation the correct indication. By contrast, preventing sudden cardiac death is typically the role of an implantable cardioverter-defibrillator, not CRT alone; replacing heart function points to transplant or mechanical support; and providing only right ventricular pacing does not achieve the needed biventricular synchronization CRT provides.

Cardiac resynchronization therapy is used to correct the problem of ventricle dyssynchrony caused by conduction delays, most commonly a left bundle branch block pattern that makes the two ventricles contract at different times. When the ventricles don’t pump together, cardiac output drops and symptoms of heart failure worsen. CRT works by delivering pacing to both the right ventricle and the left ventricle (via a coronary sinus lead) so that the ventricles contract in a coordinated, synchronized fashion. This resynchronization often improves stroke volume, reduces mitral regurgitation, and can lead to reverse remodeling and symptom relief. A prolonged QRS on ECG signals this dyssynchrony and helps identify patients who are likely to benefit from CRT, making dyssynchronous ventricular activation and/or QRS prolongation the correct indication.

By contrast, preventing sudden cardiac death is typically the role of an implantable cardioverter-defibrillator, not CRT alone; replacing heart function points to transplant or mechanical support; and providing only right ventricular pacing does not achieve the needed biventricular synchronization CRT provides.