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QRS prolongation is associated with associated with adverse cardiac remodeling in hypertrophic cardiomyopathy

Hernan L Vera-Sarmiento1, Talha Tanriverdi2, David Hurtado-de-Mendoza3

  • 1Hypertrophic Cardiomyopathy Center of Excellence, Division of Cardiology, University of California San Francisco, San Francisco, CA, United States of America.

Journal of Electrocardiology
|November 11, 2024
PubMed

Insights

Abnormal signal-averaged electrocardiogram (SAECG) in hypertrophic cardiomyopathy (HCM) patients indicates significant structural and electrical remodeling. This finding highlights a more severe global myopathy in affected individuals.

Area of Science:

  • Cardiology
  • Electrophysiology
  • Cardiovascular Imaging

Background:

  • Signal-averaged electrocardiogram (SAECG) detects myocardial depolarization and identifies slow conduction in fibrotic tissue, a precursor to ventricular arrhythmias (VAs).
  • Hypertrophic cardiomyopathy (HCM) presents a high incidence of cardiac fibrosis and VAs, yet SAECG shows limited predictive value for VAs.
  • HCM-specific structural and electrical remodeling is hypothesized to explain the low predictive power of SAECG.

Purpose of the Study:

  • To investigate the relationship between abnormal SAECG findings and underlying structural/electrical remodeling in hypertrophic cardiomyopathy (HCM) patients.
  • To determine if HCM-specific remodeling contributes to the low predictive power of SAECG for ventricular arrhythmias (VAs).

Main Methods:

  • Retrospective study of 73 HCM patients with SAECG, transthoracic echocardiography (TTE), and cardiac magnetic resonance (CMR) imaging.
  • Patients classified into normal and abnormal SAECG groups based on filtered-QRS duration (fQRSd), root-mean-square-voltage (RMS40), and late potentials (LAS40).
  • Abnormal SAECG defined by fQRSd > 114 ms, RMS40 < 20 μV, or LAS40 > 38 ms.

Main Results:

  • Approximately 50% of HCM patients (37/73) exhibited abnormal SAECG.
  • The abnormal SAECG group showed significantly higher fQRSd and LAS40, larger left atrial size, reduced global LV longitudinal strain/strain rate, and impaired early diastolic strain rate.
  • CMR revealed higher LV-mass index (LVMI) and LV scar burden in the abnormal SAECG group; fQRSd correlated positively with LVMI and scar mass.

Conclusions:

  • Abnormal SAECG in HCM patients is associated with more extensive structural and electrical left ventricular (LV) remodeling.
  • These findings suggest that abnormal SAECG reflects a more severe global myopathy in HCM.
  • The study underscores the link between SAECG abnormalities and advanced cardiac remodeling in HCM.
Abstract

Keywords:
Global myopathyHypertrophic cardiomyopathyLeft ventricular remodelingMyocardial fibrosisSignal-averaged electrocardiogramVentricular arrhythmias

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