Tachycardia Related Cardiomyopathy: Response to Control of the Arrhythmia

To evaluate the clinical response of five children with automatic atrial tachycardia (AA T) and associated cardiomyopathy to arrhythmia control, we compared pretreatment and posttreatment 24hour ECG heart rates, cardiothoracic ratio by chest radiograph, and echocardiographic measures of ventricular ,function. Two children were treated with amiodarone, two with surgical excision and cryoablation of the ectopic focus, and one with digoxin alone. Signijicantly slower mean heart rates were achieved, along with a dominant sinus rhythm and improvement in symptoms. Control of the AAT resulted in improved mean cardiothoracic ratio (0.53 pre vs 0.49 post; P = 0.021, as well as improvement in a number of echocardiographic measurements: mean shorteningfraction (20% pre vs 34% post; P = 0.006), mean ejection fraction (36% pre vs 50% post; P < 0.01), mean velocity of’ circumferential fiber shortening (0.62 pre vs 1.20 post; P = 0.003). Mean E-point septa1 separation corrected for enddiastolic dimension also showed a trend toward improvement (0.25 pre vs 0.16 post; P = 0.11). Right ventricular endocardial biopsies in four were nonspecific; an atrial biopsy from surgery showed a Purkinje fiber-like tissue in one patient, but was nonspecijic in another. We conclude that cardiomyopathy can be causally linked to automatic atrial tachycardia and that aggressive medical and/or surgical management is warranted in those patients with signs and symptoms of impaired ventricular function. (J Interven Cardiol 1989:2:4)