Multicenter Post-Infarction Program - MPIP

Description:

The Multicenter Post-Infarction Program was a prospective, risk-stratification study of the role of physiologic measurements of heart function in patients who survived the coronary care unit phase of an acute myocardial infarction.

Hypothesis:

Three primary risk variables (an ejction fraction <40%, 10 or more ventricular ectopic depolarizations per hour, and angina pectoris) will have significant, independent effects on survival.

Study Design

Study Design:

Patients Screened: 4090
Patients Enrolled: 866
NYHA Class: 38% had NYHA Class II-IV at baseline
Mean Follow Up: 1-3 years
Mean Patient Age: <70 years
Female: 22
Mean Ejection Fraction: mean EF=46%

Patient Populations:

Age <70 years Survived the coronary care unit phase of an acute MI

Exclusions:

Life-threatening coexisting disorder Lived at distance from the clinic that travel for follow-up would be unusually difficult

Primary Endpoints:

All-cause mortality at 1 year Cardiac mortality due to atherosclerotic coronary heart disease Sudden cardiac death

Drug/Procedures Used:

Two-channel 24-hour Holter recordings were analyzed by computer. Ventricular ectopic depolarizations were categorized by mean frequency per hour. Ejection fractions were determined on the nuclear-medicine equipment available at the respective enrolling institiutions. The development of angina pectoris was defined as precordial pressure-type discomfort in the interim between transfer from the CCU and hospital discharge. Other variables included in the risk stratification analysis for mortality were prior MI, NYHA class, presence of rales while in the CCU, heart rate in the CCU, presence of anterior MI.

Principal Findings:

The mortality rate was 9% in the first year of follow-up. A progressive increase in cardiac mortality to 1 year was seen as the EF fell below 40% and as the number of ventricular ectopic depolarizations exceeded one per hour. Mortality was increased in patients with EF<40% (RR 2.4, p<0.001), ventricular ectopy of 10 or more depolarizations per hour (RR 1.6, p<0.05), NYHA class II-IV (RR 1.9, p<0.001), and rales (RR 3.3, p<0.001). EF had a stronger effect on mortality than ventricular ectopy of >=10 depolarizations per hour. The lowest risk group was found to be patients with none of the factors (mortality <3% by 2 years; 33% of the population) and the highest risk group was those with all 4 factors (60% mortality; 2% of the population).

Interpretation:

Physiologic measurements of heart function along with certain clinical characterisitics permit risk stratifiction in patients surviving the early post-infarction course.

References:

N Engl J Med 1983;309:331-336 Circulation 1984;69:250-258

Clinical Topics: Arrhythmias and Clinical EP, EP Basic Science, SCD/Ventricular Arrhythmias

Keywords: Risk, Myocardial Infarction, Follow-Up Studies, Respiratory Sounds, Heart Rate, Ventricular Premature Complexes


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