Can supraventricular tachycardia weaken the heart muscle?
Supraventricular tachycardia (fast rhythm originating from the upper chambers of the heart) can weaken the heart muscle if it persists for a long time. This weakening of the heart muscle is known as tachycardiomyopathy (heart muscle disease due to a persistently fast heart rate). Simply it is due to the fatigue of the contractile elements of the heart muscle. In long standing cases there could be significant damage to the heart muscle. But usually it is a reversible condition if the heart rate is brought down to a normal range.
Heart rate can be brought back to the normal range by treating the abnormal rhythm by medications or by electrical means. In electrical therapy known as radiofrequency catheter ablation, small electrodes are introduced into the heart through arteries or veins (blood vessels) and the origin of the abnormal rhythm localized by an electrophysiological study (basically a recording of electrical activity from various regions of the heart and giving artificial electrical signals to stimulate the heart from various points and recording the conduction of the signals). Once the origin is localized, tiny superficial burns are created using radiofrequency current, thereby removing the abnormal focus.
The usual type of supraventricular tachycardia which can be persistent is known as permanent junctional re-entrant tachycardia (PJRT). It is due to an accessory pathway between the atrium (upper chamber of the heart) and the ventricle (lower chamber of the heart) which bypasses the normal conduction system of the heart.