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Postmyocardial Infarction Patients Susceptible to Ventricular Tachycardia Show Increased T Wave Dispersion Independent of Delayed Ventricular Conduction
Author(s) -
OIKARINEN LASSE,
VIITASALO MATTI,
KORHONEN PETRI,
VÄÄNÄNEN HEIKKI,
HÄNNINEN HELENA,
MONTONEN JUHA,
MÄKIJÄRVI MARKKU,
KATILA TOIVO,
TOIVONEN LAURI
Publication year - 2001
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1046/j.1540-8167.2001.01115.x
Subject(s) - medicine , cardiology , qrs complex , ventricular tachycardia , repolarization , infarction , myocardial infarction , signal averaging , magnetocardiography , electrophysiology , signal transfer function , digital signal processing , analog signal , electrical engineering , engineering
Arrhythmia Markers After Myocardial Infarction.Introduction: Experimentally, both delayed ventricular conduction and nonhomogeneous ventricular repolarization contribute to reentrant arrhythmias. We tested the hypothesis that increased T wave dispersion is independent of delayed ventricular conduction associated with arrhythmia vulnerability in postmyocardial infarction (post‐MI) patients. Methods and Results: We studied 32 post‐MI patients with clinical or inducible monomorphic ventricular tachycardia (VT group), 28 post‐MI patients without arrhythmias (MI group), and 13 healthy controls, using magnetocardiographic (MCG) mapping with signal averaging. Twelve‐lead ECG was the reference. Filtered QRS duration (fQRS) and T wave peak to T wave end interval (TPE) were used as measures of ventricular conduction and nonhomogeneity in ventricular repolarization, respectively. In MCG, the VT group showed the longest fQRS ( 135 ± 34 msec vs 114 ± 22 msec in the MI group; P = 0.012 ). Mean TPE and maximum TPE in VT versus MI groups were 78 ± 9 msec versus 70 ± 6 msec ( P < 0.001 ) and 117 ± 23 msec versus 104 ± 19 msec ( P = 0.020 ), respectively. Maximum TPE did not correlate with fQRS in the VT group ( r = 0.063; P = NS ) but did correlate in the MI group ( r = 0.396; P = 0.037 ). For identification of post‐MI patients prone to VT, selection of cutoff values for fQRS > 140 msec and mean TPE > 81 msec gave sensitivity and specificity of 41% and 89%, and 31% and 96%, respectively. Their combination increased sensitivity to 63% while maintaining 89% specificity. Conclusion: Post‐MI patients susceptible to VT show increased T wave dispersion independent of delayed ventricular conduction.