Distinct left bundle branch block pattern in ischemic and non-ischemic dilated cardiomyopathy

Area of Science:

• Cardiology
• Medical Diagnostics

Background:

• Dilated cardiomyopathy (DCM) frequently presents with advanced left bundle branch block (LBBB) on electrocardiograms (ECG).
• Differentiating the etiology of DCM, specifically ischemic (IC) versus non-ischemic (NIC), is crucial for appropriate patient management.

Purpose of the Study:

• To investigate if specific patterns of LBBB on surface ECG can distinguish between ischemic and non-ischemic dilated cardiomyopathy.
• To identify novel ECG criteria for differentiating DCM etiologies in the presence of LBBB.

Main Methods:

• Analysis of ECGs from 41 patients with DCM and LBBB, categorized into NIC (n=26) and IC (n=15) groups.
• Digital measurement of ECG duration and voltage, focusing on precordial leads (V1-V3).
• Receiver operating characteristic (ROC) analysis to determine the discriminative power of ECG parameters.

Main Results:

• No significant difference in S wave notching in leads V1-V3 between NIC and IC groups.
• Significantly higher voltages in precordial leads V2, V3, and their sum (Sigma V1-V3) were observed in the NIC group.
• ECG lead V3 voltage exceeding 2100 microV demonstrated high discriminative power (AUC=0.805), with 85% sensitivity and 73% specificity for identifying NIC.

Conclusions:

• A single ECG criterion, the voltage of lead V3, is a valuable parameter.
• This parameter can effectively identify patients with dilated cardiomyopathy of non-ischemic origin when advanced LBBB is present.