Abstract
BACKGROUND: Permanent junctional reciprocating tachycardia (PJRT) is a rare form of orthodromic atrioventricular reciprocating tachycardia involving a slowly conducting, decremental concealed accessory pathway. Its incessant nature may result in tachycardia-induced cardiomyopathy, which is reversible with timely rhythm control. CASE SUMMARY: A 41-year-old patient presented with progressive exertional dyspnoea and reduced exercise capacity. Continuous electrocardiogram monitoring revealed an incessant long RP narrow QRS tachycardia (heart rate 135 b.p.m.). Echocardiography demonstrated severe LV systolic dysfunction (LVEF 14%) and LV dilatation (LVEDD 63 mm). Coronary angiography and cardiac MRI excluded relevant structural or infiltrative cardiomyopathy. Electrophysiological study confirmed PJRT using a posteroseptal concealed accessory pathway. Catheter ablation at the site of earliest atrial activation resulted in immediate termination of tachycardia and loss of accessory pathway conduction. Post-ablation echocardiography showed early improvement in LVEF to 26%. The patient was discharged on guideline-directed medical therapy for heart failure. At 6-month follow-up, he remained asymptomatic, with no arrhythmia recurrence and recovery of LVEF to 50% with normalization of LV dimensions. DISCUSSION: This case highlights the reversibility of severe cardiomyopathy secondary to incessant PJRT. Even in cases with severe LV dysfunction, timely identification and ablation of the accessory pathway can achieve recovery of LV function. Careful electrophysiologic evaluation is essential to differentiate PJRT from other long RP tachycardias and guide curative therapy.