Temporal Variability of ECG Risk Markers and Clinical Outcomes in Non-Dilated Left Ventricular Cardiomyopathy

Area of Science:

• Cardiology
• Electrophysiology
• Medical Diagnostics

Background:

• Non-dilated left ventricular cardiomyopathy (NDLVC) is a condition with increased risk of ventricular arrhythmias (VA) and sudden cardiac death (SCD).
• The temporal variability and clinical significance of electrocardiogram (ECG) risk markers in NDLVC are not well understood.

Purpose of the Study:

• To evaluate the temporal variability of ECG-derived risk markers in NDLVC patients.
• To investigate the association between these ECG markers and major adverse cardiac events, specifically heart failure (HF) and VA hospitalization.

Main Methods:

• Prospective study of 55 NDLVC patients with serial ECG monitoring (24h Holter, signal-averaged ECG, 12-lead ECG) over one year.
• Analysis of nine ECG risk markers including PVC burden, NSVT, QTc interval, SDNN, DC, TO/TS, and TWA.
• Follow-up for 39.5 months to assess HF and VA hospitalizations, with logistic regression for outcome associations.

Main Results:

• Significant temporal changes in at least one ECG marker were observed in 67.3% of patients, most notably in TWA, NSVT, and PVC burden.
• Only standard deviation of NN intervals (SDNN) showed a significant inverse association with VA hospitalization risk (OR=0.98, p=0.006).
• No ECG marker changes were associated with heart failure hospitalization.

Conclusions:

• NDLVC patients exhibit considerable temporal variability in noninvasive ECG risk markers.
• Most ECG marker fluctuations do not correlate with clinical outcomes.
• SDNN demonstrates an inverse association with VA risk, highlighting its potential role in risk stratification for NDLVC patients.