Abstract
Ventricular pre-excitation is one of the rarest causes of cardiomyopathy induced or mediated by arrhythmia. Right accessory pathways, specifically with left bundle branch block pattern, can cause ventricular dysfunction, since abnormal ventricular activation resulting from anterograde atrioventricular conduction can cause atrioventricular, interventricular, and intraventricular dyssynchrony, with asynchronous contraction of the ventricular wall and mitral regurgitation. An asymptomatic patient, with ventricular pre-excitation with left bundle branch block and moderate ventricular dysfunction at echocardiography, was described. The electrophysiological study demonstrated an accessory route of anterior location and with an anterograde refractory period of 600 ms, successfully performing radiofrequency ablation and substantial improvement of ventricular function.
Highlights
Anomalous accessory pathways are remnants tissues resulting from incomplete embryological development of the atrioventricular (AV ) ring and failure of fibrous separation between the atria and ventricles
Occasional episodes of paroxysmal supraventricular tachycardia (PSVT) are generally not associated with the development of ventricular dysfunction, there is a possibility in cases of incessant tachycardia
It can be plausibly concluded that the ablation of the accessory pathway was able to practically reverse secondary cardiomyopathy induced by ventricular desynchronism to the accessory pathway of the left bundle branch block (LBBB) pattern
Summary
Anomalous accessory pathways are remnants tissues resulting from incomplete embryological development of the atrioventricular (AV ) ring and failure of fibrous separation between the atria and ventricles. In ventricular pre-excitation syndrome, known as Wolff-ParkinsonWhite syndrome, AV conduction occurs, partially or totally, through the accessory pathway, which results in earlier activation (pre-excitation) of the ventricles[1] It is a relatively common anomaly, with an estimated 1-3/1000 live births[1]. Abnormal ventricular activation resulting from early anterograde conduction may cause atrioventricular, interventricular, and intraventricular desynchrony and result in cardiomyopathy[3] In this case report, a patient with pre-excitation of the right ventricle and depressed left ventricular function is presented, in which successful ablation of the accessory pathway resulted in substantial improvement of the left ventricular ejection fraction (LVEF). She is currently asymptomatic in outpatient follow-up, with stable systolic ventricular function at the lower limit of normality, in extremely irregular use of beta-blocker (carvedilol), an inhibitor of the angiotensin-converting enzyme – medications she started after ablation
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