Repolarization abnormalities detected by magnetocardiography in patients with dilated cardiomyopathy and ventricular arrhythmias

J Cardiovasc Electrophysiol. 2001 Jul;12(7):772-7. doi: 10.1046/j.1540-8167.2001.00772.x.


Introduction: Abnormal repolarization is one of the acknowledged mechanisms leading to malignant ventricular arrhythmias. We used a novel magnetocardiographic technique to investigate the role of inhomogeneous repolarization in patients with nonischemic dilated cardiomyopathy prone to sustained ventricular arrhythmias.

Methods and results: Forty-nine dilated cardiomyopathy patients were studied, 18 with a history of sustained ventricular tachycardia (n = 6) or ventricular fibrillation (n = 12) and 31 with no ventricular arrhythmias. The magnetocardiogram was registered and QT apex and QT end intervals were determined by a computer algorithm. Inhomogeneity of repolarization was characterized with indices describing QT apex and QT end dispersion, and T wave end duration. In addition, time-domain late fields of the QRS complex in magnetocardiography and QT dispersion in 12-lead ECG were determined. T wave end was longer in the arrhythmia group in patients with sinus rhythm (87 +/- 15 msec vs 73 +/- 12 msec; P = 0.005) and in those not having bundle branch block. Magnetocardiographic late fields of the QRS complex were not different between groups. QT apex and end dispersion on magnetocardiography or 12-lead ECG showed no difference.

Conclusion: Prolongation of the end part of the T wave revealed by magnetocardiography is related to malignant ventricular arrhythmias in dilated cardiomyopathy. The results suggest that abnormal repolarization rather than delayed conduction underlies the arrhythmias in this disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Cardiology / methods*
  • Cardiomyopathy, Dilated / complications
  • Cardiomyopathy, Dilated / physiopathology*
  • Electrocardiography
  • Electrophysiology
  • Female
  • Humans
  • Magnetics*
  • Male
  • Middle Aged
  • Tachycardia, Ventricular / etiology
  • Tachycardia, Ventricular / physiopathology*
  • Time Factors
  • Ventricular Fibrillation / etiology
  • Ventricular Fibrillation / physiopathology*