Home Automatic External Defibrillator Trial - HAT

Description:

The goal of this trial was to evaluate a strategy of an automated external defibrillator (AED) and cardiopulmonary resuscitation (CPR) compared with CPR alone in patients at intermediate risk for sudden cardiac arrest.

Hypothesis:

AED and CPR will be more effective in improving survival than CPR alone.

Study Design

  • Randomized
  • Stratified

Patients Enrolled: 7,001
NYHA Class: Class I: 65%, class II: 29%, class III: 5%
Mean Follow Up: 37 months
Mean Patient Age: 62 years
Female: 17
Mean Ejection Fraction: 45%

Patient Populations:

• Patients who had an anterior wall Q-wave or non–Q-wave MI who did not have an indication for an internal cardiac defibrillator
• Spouse or companion at home willing to perform CPR and/or AED

Exclusions:

• Patients with an internal cardiac defibrillator
• Patients who already had an AED
• Patients with a "do-not-resuscitate" order

Primary Endpoints:

Change in all-cause mortality

Secondary Endpoints:

• Death from sudden cardiac arrest
• Survival from sudden cardiac arrest at home
• Outcome after the use of an AED

Drug/Procedures Used:

Patients who were stable after an anterior myocardial infarction (MI), and in whom an internal cardiac defibrillator was not indicated, were randomized to AED and CPR (n = 3,495) or CPR alone (n = 3,506).

Concomitant Medications:

Among both groups, the use of aspirin was 87%, beta-blockers was 79%, angiotensin-converting enzyme inhibitors was 82%, and statins was 89%.

Principal Findings:

All patients had an anterior MI (64% were Q-wave and 36% were non–Q-wave). The median time from MI until enrollment was 1.7 years. Patients were home alone a median of 1.5 hours per day. In the AED group, 4.8% of the patients had a spouse or companion unable or unwilling to use the AED in follow-up compared with 4.0% in the control group.

The primary outcome, all-cause mortality, occurred in 6.4% of the AED group and in 6.5% of the CPR alone group (p = 0.77). The primary outcome did not vary among various subgroups tested: age, gender, Q-wave versus non–Q-wave MI, or nationality.

The cause of death was tachyarrhythmia in 38%, heart failure in 21%, noncardiovascular in 38%, and unidentified causes in the remainder; 13% of all deaths were witnessed sudden cardiac deaths at home. There were 19 resuscitations in each group, with eight of each occurring at home.

Interpretation:

Among patients at intermediate risk after a Q-wave or non–Q-wave MI without a primary indication for an internal cardiac defibrillator, use of an AED and CPR was not associated with a difference in all-cause mortality compared with CPR alone.

Although sudden cardiac death among intermediate-risk populations remains a significant public health problem, the primary cause of death in this trial was actually noncardiac. There were very few resuscitations that occurred at home (eight in each group). Part of the explanation for the low event rate and limited study power was the excellent use of life-saving cardiac medications (for example, beta-blockers and statins). This reenforces the importance of optimal medical management and continued cardiovascular and noncardiovascular risk stratification among intermediate-risk MI patients.

References:

Bardy GH, Lee KL, Mark DB, et al. Home use of automated external defibrillators for sudden cardiac death. N Engl J Med 2008;358:1793-804.

Results of the Home Automatic External Defibrillator Trial (HAT). Presented by Dr. Gust Bardy at the SCAI-ACC i2 Summit/American College of Cardiology Annual Scientific Session, Chicago, IL, March/April 2008.

Clinical Topics: Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Implantable Devices, SCD/Ventricular Arrhythmias, Acute Heart Failure

Keywords: Cause of Death, Ethnic Groups, Myocardial Infarction, Defibrillators, Public Health, Tachycardia, Ventricular, Cardiopulmonary Resuscitation, Ventricular Fibrillation, Heart Failure, Death, Sudden, Cardiac


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