Q. What is Sick Sinus Syndrome?

Ans.

When a slow resting pulse fails to accelerate normally with exercise, it has been labeled chronotropic incompetence, however, there is little doubt that the understanding of this syndrome is incomplete. A slower than normal acceleration of the heart rate during exercise would be a protective mechanism in ischaemia, assuring a longer diastolic time to perfuse the myocardium. It is found that the reduced hear rate response to exercise identifies a cohort of patients with poor ventricular function many of whom have severe coronary narrowing and are subject to an increased prevalence of future coronary events.