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Abstract. We describe a patient with frequent, symptomatic, and drug-refractory premature ventricular contractions (PVCs) with a right bundle branch block, inferior axis morphology suggestive of a left ventricular outflow tract (LVOT) origin. Successful ablation of the PVCs was performed from the left coronary cusp of the aortic valve.We discuss our patient and review the literature regarding patients with ventricular arrhythmias arising from the coronary cusps, with special emphasis on the use of the electrocardiogram to aid localization of the focus.
Key Words. electrocardiogram, premature ventricular contractions, catheter ablation, left ventricular outflow tract, sinus of Valsalva
Case Report
A 68-year-old man presented for evaluation of frequent PVCs that had been present for almost 20 years. Because he had symptoms of palpitations and fatigue associated with these, he was treated with multiple antiarrhythmic drugs, including quinidine, disopyramide, mexiletine, and flecainide, but these caused intolerable side effects or were ineffective. A recent 24-hour Holter monitor demonstrated 41,872 PVCs, 1,042 couplets, frequent bigeminy, but no ventricular tachycardia. Up to 1,970 PVCs per hour and 45 PVCs per minute were noted. Approximately one-third of all ventricular beats were ectopic in origin. Left ventricular function was previously normal, but recent echocardiography showed a mild reduction in ventricular systolic function. Several electrocardiograms (ECGs) revealed normal sinus rhythm with frequent PVCs and couplets with a right bundle branch, inferior axis morphology (Fig. 1). Following his initial evaluation at our clinic, he was treated with ethmozine 250 mg three times daily. The patient noted a marked improvement in his symptoms. Subsequent ECGs and rhythm strips demonstrated abolition of all PVCs. Unfortunately, he developed intolerable side effects to ethmozine and requested a catheter ablation procedure.
An electrophysiologic study was performed. Ethmozine was withheld for three days prior to the procedure. At baseline, frequent PVCs and couplets with a right bundle branch block, inferior axis morphology were again noted. Quadripolar catheters were placed in the right ventricular apex and His bundle region via the right femoral vein. Even though the ECG morphology suggested an LVOT origin, the right ventricular outflow tract was mapped, but a pace map match with the spontaneous PVCs was not obtained. For this reason, the LVOT was then mapped. To define the anatomy and create "roadmaps" of the LVOT and aortic...