SHM Converge Scientific Abstract ePoster Gallery-Rare Case of Myotonic Dystrophy With Supraventricular Tachycardia Complication

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This case report describes a 47-year-old man diagnosed with myotonic dystrophy type 1 (DM1), a multisystem genetic disorder that can cause serious cardiac complications. The patient presented with progressive adult-onset distal and facial weakness, muscle atrophy, difficulty rising from a chair, gait problems, and trouble with fine motor tasks such as writing and turning a car ignition. Physical examination and EMG findings of diffuse myotonic discharges supported the diagnosis of DM1. Brain MRI showed nonspecific abnormalities, moderate cerebral atrophy, small vessel ischemic changes, and ventriculomegaly.<br /><br />Because cardiac disease is a major cause of morbidity and the second leading cause of death in DM, a cardiac evaluation was performed. ECG demonstrated sinus rhythm with marked sinus arrhythmia and left axis deviation. A 48-hour ambulatory ECG monitor revealed premature ventricular complexes, atrial ectopy, and multiple short runs of supraventricular tachycardia (6–16 beats, 117–170 bpm), consistent with an AV nodal re-entry mechanism. Echocardiography showed normal left ventricular size and systolic function with an ejection fraction of 60–64%.<br /><br />The discussion emphasizes that cardiac involvement in DM is common and may precede obvious neuromuscular symptoms. Conduction disease, likely related to myocardial fibrosis, occurs in a substantial proportion of patients, and arrhythmias such as PVCs and AV block are frequent. Since diagnosis of DM is often delayed, clinicians should consider DM in younger patients with unexplained arrhythmias or neuromuscular symptoms.<br /><br />Regular surveillance is essential. Annual ECG and echocardiography are recommended, with additional studies such as electrophysiology testing or tissue Doppler imaging when needed. Early recognition and management of cardiac complications can help prevent adverse outcomes in patients with DM.

Asset Subtitle

Andi Liang

Meta Tag

Author List Andi Liang, Jory Shive, Muhammad Bajwa, Tarif Khair

Category Clinical Vignettes

Concept Myotonic Dystrophy

Concept Cardiac Complication

Concept Conduction abnormality

Concept Cardiac Arrhythmia

Concept Cardiac Surveillance

Distinguished Non-Finalist

Presenter Organization McGovern Medical School

Presenting Author Andi Liang

Track Adult

Keywords

myotonic dystrophy type 1

DM1

cardiac complications

arrhythmia

conduction disease

electrocardiogram

supraventricular tachycardia

premature ventricular complexes

muscle weakness

echocardiography

Myotonic Dystrophy

Cardiac Complication

Conduction abnormality

Cardiac Arrhythmia

Cardiac Surveillance