Two severe complications post-percutaneous intramyocardial septal radiofrequency ablation in a patient with failed alcohol septal ablation: pulseless electrical activity cardiac arrest and pericardial tamponade-a case report.

Background: Alcohol septal ablation (ASA) can be recommended for patients with drug-refractory hypertrophic obstructive cardiomyopathy (HOCM). Recently, percutaneous intramyocardial septal radiofrequency ablation (PIMSRA) was reported as a safe and effective treatment for HOCM. Case summary: We present a case report of pulseless electrical activity (PEA), cardiac arrest, and pericardial tamponade occurring post-PIMSRA. We performed PIMSRA for the patient with HOCM after failed ASA. Two hours post-PIMSRA, transthoracic echocardiography (TTE) revealed that the hypokinetic basal intraventricular septal (IVS) thickness increased with aggravation of systolic anterior motion of the mitral valve. After the occurrence of subsequent PEA cardiac arrest, veno-arterial extracorporeal membrane oxygenation (VA-ECMO) support was provided. With sinus rhythm restoration and blood pressure stabilization after ECMO removal, the patient had pericardial tamponade on Day 3 post-PIMSRA. After excluding apparent myocardial perforation and draining haemorrhagic effusion under TTE guidance, her symptoms and haemodynamic status improved. She was asymptomatic at her one-year follow-up. The left ventricular outflow tract gradient (LVOTG) at rest and the thickness of the basal IVS reduced to 5 mmHg and 12 mm, respectively. Discussion: We assumed that the main causes of PEA cardiac arrest and pericardial tamponade in our case were ablation-related tissue oedema at the basal IVS and blood leakage possibly related to puncture haemorrhage, respectively. While waiting for myocardial oedema to resolve, ECMO was applied as a bridge-to-recovery therapeutic approach. Pericardiocentesis is a strategy for the emergency drainage of pericardial effusion. It is essential to distinguish life-threatening complications with TTE for management planning post-PIMSRA.