Case report: high-grade atrioventricular block in suspected COVID-19 myocarditis

Ashok, Vishnu; Loke, Wei Ian

BACKGROUND: In the ongoing pandemic of COVID-19, respiratory failure has been reported as the main cause of death in those who develop critical illness. A few cases of concurrent myocarditis have been reported, but the extent of cardiac complications with the SARS-CoV-2 strain of coronavirus is still largely unknown. CASE SUMMARY: A 53-year-old man, suspected to have COVID-19 due to a new-onset cough, shortness of breath, and hypoxia, was referred to Cardiology with sudden symptomatic bradycardia. Initial rhythm analysis revealed Type 2 atrioventricular block (Mobitz II). On arrival at the coronary care unit, he was found to be in complete heart block (Type 3). Routine blood tests showed normal electrolytes and renal function, and no elevation in troponin-I levels. Echocardiography showed mild impairment in left ventricular systolic function, with no regional wall motion abnormalities or valvular lesions. He then developed high-degree AV block lasting 6.2 s, prompting the need for an urgent permanent pacemaker implantation. DISCUSSION: Just over a third of patients with myocarditis reportedly develop a rise in cardiac troponin. Clinically suspected myocarditis can occur in the absence of a troponin rise and rarely can cause high-grade bradyarrhythmias. Myocarditis and non-specific cardiac arrhythmias have been reported in a few cases of COVID-19, but this is the first reported case of a high-grade atrioventricular conduction block with SARS-CoV-2 infection.