Echographic assessment of atrial transport, mitral movement, and ventricular performance following electroversion of supraventricular arrhythmias

Controversy attends the extent and temporal sequence of improvements in hemodynamic function resulting from the return of atrial contraction following cardioversion of supraventricular arrhythmias. Thus, mitral, left atrial (LA) and left ventricular (LV) echograms were obtained before, and one hr after conversion of supraventricular arrhythmias to normal sinus rhythm, by direct current countershock, in patients with chronic coronary disease or cardiomyopathies without valvular dysfunction. The duration of the rhythm disturbance varied from one day to 5 yr in 22 patients, and was indeterminate in 13. Atrial systole immediately produced prominent mitral 'A' waves with anterior valve excursion of 7.5 mm (range 3 to 12) in 33 of the 35 patients (94%). The two patients with atrial electromechanical dissociation reverted to atrial fibrillation within one week. Cardioversion caused a decline in LA diameter (3.5 to 3.2 cm, P< .001), and a rise in LV end diastolic dimension (5.2 to 5.5 cm, P< .001), while LV end systolic dimension was unchanged (4.2 cm). Thereby stroke volume rose. Heart rate fell an average of 16 beats/min. Depressed cardiac output was improved + 0.84 L/min/m ². Thus, in the majority of patients with acute or chronic supraventricular arrhythmias without mitral valve disease, cardioversion promptly restores effective atrial contraction, decreases LA size, and results in substantial hemodynamic beefit.