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Electrophysiologic and imaging evidence for an occult myopathic substrate in patients with idiopathic ventricular

Adam C Lee1, Wendy Strugnell2, Eric Vittinghoff3

  • 1Department of Cardiology, The Prince Charles Hospital, Brisbane, Australia; Faculty of Medicine, University of Queensland, Brisbane, Australia; University of California San Francisco, San Francisco, CA, USA.

International Journal of Cardiology
|May 28, 2021
PubMed

Insights

Idiopathic ventricular arrhythmias (VA) may indicate early cardiomyopathy even without left ventricular dysfunction. Subtle cardiac magnetic resonance (CMR) and electrophysiology changes suggest an occult process in these patients.

Area of Science:

  • Cardiology
  • Electrophysiology
  • Cardiovascular Imaging

Background:

  • Idiopathic ventricular arrhythmias (VA) are typically benign but can lead to ectopy-mediated cardiomyopathy (EMC).
  • The presence of subclinical cardiomyopathy in patients with idiopathic VA and normal left ventricular (LV) function is not well understood.
  • This study investigates early fibrosis markers in idiopathic VA patients.

Purpose of the Study:

  • To assess for a cardiomyopathic substrate in patients with idiopathic VA using imaging and electrophysiologic markers.
  • To identify early signs of fibrosis in the absence of overt left ventricular dysfunction.
  • To compare findings between idiopathic VA groups and a control group.

Main Methods:

  • Cardiac magnetic resonance (CMR) imaging and ventricular electroanatomic mapping were performed.
  • Three groups were studied: idiopathic VA without LV dysfunction (Group 1), idiopathic VA with LV dysfunction (Group 2), and supraventricular tachycardia (SVT) controls (Group 3).
  • Global LV strain, T1 mapping, and electrogram (EGM) characteristics were analyzed.

Main Results:

  • Global LV strain was impaired in the presumed EMC group (Group 2).
  • Patients with idiopathic VA (Groups 1 and 2) showed shorter post-contrast T1 times and prolonged bipolar EGM duration compared to controls (Group 3).
  • No significant differences were found in unipolar/bipolar voltage or EGM deflection counts.

Conclusions:

  • Idiopathic VAs with seemingly normal hearts may exhibit subtle CMR and electrophysiologic changes.
  • These changes are similar to those seen in overt presumed EMC.
  • Findings suggest a potential occult cardiomyopathic process in patients with idiopathic VA.
Abstract

Keywords:
Cardiac magnetic resonance imagingCardiomyopathyPremature ventricular contraction arrhythmiaT1 mappingVentricular arrhythmia

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