Medical approach to post-COVID-19 high-grade ventricular arrhythmias: a case report

COVID-19 is a significant risk factor for cardiovascular complications, including arrhythmias, especially in patients with underlying cardiac disease. These risks are particularly pronounced in individuals with pre-existing structural heart abnormalities such as hypertrophic cardiomyopathy (HCM). We present the case of a 50-year-old man with a history of obstructive HCM treated with myectomy and mitral valve replacement, who developed frequent palpitations following a COVID-19 infection. The patient was on bisoprolol and acenocoumarol for blood pressure control and anticoagulation. Physical examination was unremarkable except for a metallic mitral valve tone. ECG showed sinus rhythm with one ventricular extrasystole; echocardiography revealed no new abnormalities. Holter monitoring documented a 10.48% burden of monomorphic ventricular extrasystoles and a non-sustained monomorphic ventricular tachycardia with a warm-up/cool-down phenomenon. Increasing bisoprolol, adding mexiletine, and later combining bisoprolol with amiodarone failed to resolve symptoms. Cardiac MRI showed subepicardial myocardial scarring, suggesting prior myocarditis, but no active inflammation. Ultimately, switching to propranolol 40 mg t.i.d. led to symptom resolution, with no arrhythmias on follow-up. The patient remained stable on propranolol for six months before returning to bisoprolol. This case highlights the potential for COVID-19 to exacerbate arrhythmic complications in HCM and demonstrates the effectiveness of non-selective beta-blockers in resistant arrhythmias.