ECG Findings in Dilated Cardiomyopathy (DCM)

Common ECG Abnormalities in DCM

The European Society of Cardiology recommends that left bundle branch block (LBBB) be recognized as a common ECG finding in DCM patients, present in approximately 30-40% of cases, and is often associated with more advanced disease 1
T-wave inversions are commonly seen in the lateral and inferior leads, representing repolarization abnormalities, according to the European Heart Journal 1
Intraventricular conduction defects, including widened QRS complexes (>110 ms), are frequently observed in DCM patients, even without complete bundle branch block, as reported by the European Heart Journal 1, 2
Abnormal Q waves are present in approximately 15-19% of DCM patients, particularly in the inferior and/or lateral leads, which may be confused with prior myocardial infarction, according to Circulation 3
Low voltage QRS complexes are particularly common in advanced DCM, as reported by the European Heart Journal 2

Lamin A/C mutations often present with first-degree AV block and pathological Q waves in the inferior and/or lateral leads, according to the European Heart Journal 1
Dystrophin mutations may show similar ECG patterns to Lamin A/C mutations with conduction abnormalities, as reported by the European Heart Journal 1

Ventricular arrhythmias are present in approximately 30% of DCM patients, even with only mildly dilated LV cavity, according to the European Heart Journal 1
Atrial arrhythmias, including supraventricular tachycardias, are common in DCM patients, especially in advanced disease, as reported by the European Heart Journal and Circulation 1, 4
Sinus tachycardia is a common finding in DCM patients, particularly in later stages of the disease, according to Circulation 3

QT dispersion can identify DCM patients at greatest risk for cardiac death, as reported by Circulation 3

The European Heart Journal recommends that ECG findings be interpreted in conjunction with imaging studies (echocardiography, cardiac MRI) for comprehensive evaluation of DCM patients 1, 5

The American Heart Association recommends that all DCM patients have an initial cardiac evaluation with ECG at diagnosis, and asymptomatic DCM patients <10 years of age should have ECG evaluation every 2 years, increasing to annual evaluation after age 10, as reported by Circulation 6
Patients with LV dysfunction, dilation, or arrhythmias should be reevaluated at least annually, according to Circulation 6
Ambulatory ECG monitoring is recommended for risk stratification, particularly in patients with LVEF <30-35% or age ≥17 years, as reported by Circulation 3, 6