Prognostic significance of signal-averaged electrocardiogram after thrombolytic therapy and/or angioplasty during acute myocardial infarction (CAST substudy)

Pablo Denes*, Nabil El-Sherif, Richard Katz, Robert Capone, Mark Carlson, L. Brent Mitchell, Robert Ledingham, Cardiac Arrhythmia Suppression Trial (CAST) SAECG Substudy Investigators The Cardiac Arrhythmia Suppression Trial (CAST) SAECG Substudy Investigators

*Corresponding author for this work

Research output: Contribution to journalArticle

42 Scopus citations

Abstract

Thrombolytic therapy and angioplasty during the early phase of an acute myocardial infarction (AMI) have been shown to improve prognosis. Time-domain analysis of the signal-averaged electrocardiogram (SAECG) provides strong, independent prediction of arrhythmic events (arrhythmic death/resuscitated cardiac arrest) after AMI. To determine whether the prognostic significance of an abnormal SAECG (QRS duration ≥120 ms) measured after AMI is influenced by thrombolytic therapy/angioplasty given in the AMI period, the predictive value of SAECG was compared in patients with and without prior thrombolysis/angioplasty in a substudy of the Cardiac Arrhythmia Suppression Trial. Information was available in 787 patients. The average follow-up was 10 ± 3 months and arrhythmic events occurred in 33 patients (4.2%). The prevalence of abnormal SAECG in patients with and without thrombolytic therapy/angioplasty was 9.4% (34 of 363 patients) and 14.9% (63 of 424 patients), respectively (p < 0.02). The arrhythmic event rate for patients with abnormal SAECG with and without thrombolytic therapy/angioplasty was 20.6% (7 of 34 patients) and 20.6% (13 of 63 patients), respectively. The arrhythmic event rate for patients with normal SAECG with and without thrombolytic therapy/angioplasty was 0.9% (3 of 329 patients) and 2.8% (10 of 361 patients), respectively. It is concluded that in patients with an AMI (1) the use of thrombolytic therapy/angioplasty is associated with a significantly decreased prevalence of abnormal SAECG, (2) thrombolytic therapy/ angioplasty associated with a normal SAECG portends an excellent prognosis, and (3) an abnormal SAECG is predictive of an increased incidence of arrhythmic events in all patients regardless of prior thrombolytic therapy/angioplasty. Thus, thrombolytic therapy/angioplasty does not affect the prognostic significance of a subsequent abnormal SAECG.

Original languageEnglish (US)
Pages (from-to)216-220
Number of pages5
JournalThe American journal of cardiology
Volume74
Issue number3
DOIs
StatePublished - Aug 1 1994

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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