Serial electrocardiographic changes in patients with idiopathic dilated cardiomyopathy

Area of Science:

• Cardiology
• Electrophysiology
• Medical Diagnostics

Background:

• Broad QRS duration and bundle-branch blocks in dilated cardiomyopathy (DCM) are linked to adverse patient outcomes.
• Long-term data on the evolution of QRS duration and morphology in DCM patients are scarce.
• Understanding these changes is crucial for predicting prognosis and guiding treatment.

Purpose of the Study:

• To investigate long-term changes in ventricular activation and atrioventricular (AV) conduction in DCM patients using serial electrocardiograms (ECGs).
• To assess the progression of QRS duration and morphology over a minimum 5-year follow-up period.
• To correlate changes in QRS parameters with the development of ventricular conduction defects.

Main Methods:

• Retrospective analysis of serial ECGs from 165 DCM patients.
• Data collected between 2003 and 2022, with a minimum follow-up of 5 years.
• Evaluation of QRS duration, morphology, and presence of bundle-branch blocks.

Main Results:

• Mean QRS duration significantly increased from 106.2 ± 25.3 ms at baseline to 114.2 ± 29 ms at the last follow-up (p < 0.0001).
• A ≥10 ms increase in QRS duration was observed in patients with a higher prevalence of ventricular conduction defects (68%).
• 13.8% of patients experienced QRS broadening, with over 50% developing a left bundle branch block (LBBB) pattern.

Conclusions:

• QRS duration tends to prolong over the long term in DCM patients, signifying worsening ventricular conduction.
• Progressive QRS widening and the development of LBBB are significant findings in this cohort.
• These ECG changes highlight the dynamic nature of electrical abnormalities in DCM and their association with conduction system disease.