Electrophysiological study and radiofrequency ablation of hemodynamically-instable ventricular arrhythmias in a patient with pulmonary hypertension: A case report.

INTRODUCTION: Hemodynamically-instable ventricular arrhythmias (VAs) are rare in patients with pulmonary hypertension (PH). To the best of our knowledge, only 1 case has been reported so far. Moreover, the pathogenesis of this kind of arrhythmia remains obscured and its treatment is challenging. Here we report another case and presented the substrate for VAs initiation and therapeutic effect of radiofrequency ablation. PATIENT CONCERNS: This is a 57-year-old man who presented paroxysmal palpitation associated with presyncope at rest. Surface electrocardiogram (ECG) revealed frequent ventricular premature contractions and non-sustained ventricular tachycardia when symptoms occurred. He also had a history of severe PH which was secondary to atrial septal defect and partial anomalous pulmonary venous drainage and suffered from obvious dyspnea when climbing stairs World Health Organization Class III (WHO Class III). DIAGNOSIS: Hemodynamically-instable VAs associated with severe PH. INTERVENTION: Echocardiography revealed enlargement of right ventricle (right ventricle [RV]: 43 mm). Electrophysiological examination showed the origin of VAs is next to a small low-voltage zone of RV. Radiofrequency delivery at the origin successfully terminated VAs without occurrence of complication. OUTCOME: The patient was free from arrhythmias and got an improvement of exercise tolerance, just with mild dyspnea when climbing stairs World Health Organization Class II (WHO class II), during six-month follow up. LESSONS: This case suggests the low-voltage zone of remodeled RV, which may be secondary to increased pulmonary artery pressure, serves as the substrate for VAs initiation in patient with PH. Radiofrequency ablation can successfully terminate VAs and the termination of VAs can significantly improve the patient's impaired exercise tolerance.