Electrophysiological Effects of Late PCI After MI

Not Applicable

Completed

Conditions: Cardiovascular Diseases
Heart Diseases
Myocardial Infarction
Coronary Disease
Arrhythmia
Ventricular Fibrillation

Interventions: Procedure: PCI
Drug: Optimal Medical Therapy

Registration Number: NCT00119847

Lead Sponsor: University of Maryland, Baltimore

Brief Summary: The purpose of this study is to determine if opening blocked arteries with heart balloons and stents prevents heart rhythm problems in individuals 3 to 28 days after a heart attack.

Detailed Description: BACKGROUND:

There is now unequivocal evidence that early coronary reperfusion using either thrombolytics or primary angioplasty results in a long-term mortality reduction among individuals who have had a heart attack. The benefit of early reperfusion (less than 6 hours after the heart attack) was initially attributed to myocardial salvage and the resultant preservation of left ventricular function. However, it is now known that the survival benefit associated with thrombolytic therapy is not consistently associated with a major improvement in left ventricular ejection fraction (LVEF). These observations led to the formulation of the "late open artery hypothesis," which suggests that clinical outcomes can potentially be improved by late reperfusion after a heart attack. Observational clinical studies have suggested that late patency of the infarct-related artery (IRA) after thrombolysis is associated with a survival benefit that is independent of LVEF and therefore cannot be solely explained by salvage of myocardium. Definitive proof of the late open artery hypothesis is currently lacking, however, because previous studies that have evaluated late percutaneous transluminal coronary angioplasty (PTCA) of occluded IRAs after a heart attack have produced conflicting results.

These findings led to the organization of the Occluded Artery Trial (OAT), an international, NHLBI-funded, randomized trial of 2,200 participants. OAT is testing the hypothesis that mechanical reperfusion of an occluded IRA with PTCA and percutaneous coronary intervention (PCI) 3 to 28 days after a heart attack in high-risk individuals will reduce mortality, recurrent heart attacks, and hospitalization for class IV congestive heart failure. Enhancement of electrical stability is one of the major mechanisms that has been proposed to explain the association of an open IRA with an improved prognosis independent of myocardial salvage.

DESIGN NARRATIVE:

This study is an ancillary study of OAT. It will characterize the effects of late PCI of occluded IRAs on the most important and clinically relevant noninvasive markers of vulnerability to malignant ventricular arrhythmias: heart rate variability, T wave variability, and signal-averaged electrocardiography. These analyses will be performed in 300 participants at baseline, 30 days, and 1 year following a heart attack in order to determine the effects of late PCI on the autonomic nervous system, ventricular repolarization, and ventricular conduction abnormalities.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 300

Inclusion Criteria

Has experienced a heart attack 3 to 28 days prior to study entry
Persistently occluded IRA defined as either: 1) Thrombolysis in Myocardial Infarction (TIMI) 0, with no flow beyond the site of occlusion; or 2) TIMI 1, with penetration of dye beyond the site of occlusion without dye reaching the distal vessel
LVEF less than 50% or proximal occlusion in a large vessel
Normal sinus rhythm
QRS duration less than 120 ms
Able to return for follow-up assessment of arrhythmia markers one month and one year after study entry

Exclusion Criteria

Has a clinical indication for revascularization (post-heart attack angina at rest; significant inducible ischemia; or significant left main or triple vessel disease requiring PTCA or CABG)
Current serious illness or condition that limits 3-year survival
Severe valvular disease
Chronic total occlusion
New York Heart Association Class III-IV congestive heart failure
Prior left ventricular aneurysm in the recent heart attack location
Is a poor candidate for PTCA/stent on the basis of angiographic or clinical criteria
Cannot medically survive anticoagulation during PTCA/stent or antiplatelet therapy after stent
Pregnant

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
PCI+MED	PCI	Percutaneous Coronary Intervention (PCI) with angioplasty and stenting of the infarct-related artery and optimal medical therapy
PCI+MED	Optimal Medical Therapy	Percutaneous Coronary Intervention (PCI) with angioplasty and stenting of the infarct-related artery and optimal medical therapy
MED	Optimal Medical Therapy	Optimal medical therapy alone

Primary Outcome Measures

Name	Time	Method
Short-termed Fractal Scaling Exponent (Alpha 1)	Baseline, one year	Nonlinear measurement of heart rate variability, change between baseline and 1 year is the primary outcome.

Secondary Outcome Measures

Name	Time	Method
T-wave Variability	Baseline and one year	Variability in T wave morphology, change between baseline and one year
Filtered QRS Duration	Baseline and one year	Signal-averaged ECG