To characterize structural, electrical, and autonomic cardiovascular manifestations in patients with myasthenia gravis (MG) evaluated at a tertiary university hospital in Colombia.

A descriptive case-series study included adults (≥18 years) with confirmed MG evaluated between January 2019 and January 2025 at Hospital Universitario San Ignacio, Bogotá. Demographic, clinical, and immunologic data (anti-acetylcholine receptor [AChR] and anti-muscle-specific kinase [MuSK] antibodies), thymoma status, and treatment were recorded. Cardiovascular assessment included symptoms, 12-lead electrocardiogram (ECG), and transthoracic echocardiography (TTE). Autonomic modulation was evaluated using the ΔHR/ΔSBP index (change in heart rate per change in systolic blood pressure), calculated by linear regression for daytime and nighttime intervals. Quantitative variables were analyzed using Mann–Whitney U tests.

Fourteen patients were included (median age 55.5 years; 71% female). Thymoma was present in 43%, and 50% were receiving immunosuppressive therapy. Cardiovascular symptoms included palpitations (71%), hypotension (29%), and chest pain (21%). ECG abnormalities were frequent: sinus tachycardia (5), atrial flutter (2), sinus bradycardia (2), atrial fibrillation (1), prolonged QTc (1), and low voltage (2). Only 4 patients had normal ECGs. Mean left ventricular ejection fraction was 60.7% vs 62.8% in patients without ECG alterations (p = 0.517). Scatterplot analysis of the ΔHR/ΔSBP index revealed baroreflex asynergy and nocturnal sympathetic overactivity in several cases.