Cardiovascular Manifestations in Myasthenia Gravis: Beyond the Neuromuscular Junction
Diana Riaño1, Andres Felipe Cardenas Cruz1, Martin Rebolledo Del Toro2, Andres Ricaurte-Fajardo1, Alba Lucia Marentes1
1Department of Neuroscience, 2Department of Internal Medicine, Pontificia Universidad Javeriana
Objective:

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


Background:
Although MG is classically a disorder of the neuromuscular junction, cardiovascular involvement—ranging from arrhythmias and myocarditis to autonomic dysfunction—has been increasingly recognized, affecting 10–16% of patients. Pathophysiologic mechanisms include thymoma-associated myocarditis and cross-reactive autoantibodies such as anti-Kv1.4. Evidence of baroreflex asynergy and nocturnal sympathetic hyperactivity suggests an underdiagnosed form of cardiac dysautonomia in MG.
Design/Methods:

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.


Results:

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.


Conclusions:
Cardiovascular manifestations in MG may be subclinical yet diverse, encompassing arrhythmias and autonomic dysregulation. Routine ECG, TTE, and circadian autonomic assessment could facilitate early detection and multidisciplinary management of this underrecognized complication.
10.1212/WNL.0000000000216362
Disclaimer: Abstracts were not reviewed by Neurology® and do not reflect the views of Neurology® editors or staff.