Tachycardial disorders of cardiac rhythm as a cause of left ventricular dysfunction.

The study was designed to assess the effect of chronic and paroxysmal supraventricular tachycardia (SVT) on left ventricular (LV) function as well as to study changes in LV function following surgical correction of tachycardia. A total of 59 patients with SVT were examined (mean age 22.3 +/- 4.1 years), of these 29 had chronic SVT (Group I) and 30 had paroxysmal SVT (Group II). LV function was assessed using M-mode and Doppler echocardiography. Group I patients were found to have LV dysfunction the signs of which diminished considerably following surgical correction of tachycardia. In the period between paroxysms, i.e., when in sinus rhythm, Group II patients showed a decrease in LV contractility. Reduction in LV function during SVT paroxysm was more pronounced in patients with more frequent SVT paroxysms. The results confirm an adverse effect of chronic and frequent SVT on LV myocardial contractility.