What is the clinical evidence from this study?

Study design: Cohort. Population: Acute Myocardial Infarction (n=463). Intervention: QTc interval measurement at discharge. Primary outcome: Long-term prognosis.

January 12, 1980

QTC Intervals at Discharge after Acute Myocardial Infarction and Long‐Term Prognosis

Key Result

Measurements of QTc interval at discharge had no long-term predictive value for prognosis in survivors of acute myocardial infarction.

Study Design

Type

Cohort (n=463)

Structured PICO

Does QTc interval at discharge predict long-term prognosis in survivors of acute myocardial infarction?

Population

Survivors of acute myocardial infarction (AMI), mean age 65 years (n=463, noted as '46.3' in text likely due to OCR error).

Intervention

QTc interval measurement at hospital discharge

Outcome

Long-term prognosishard clinical

Routine measurement of QTc interval at discharge after an acute myocardial infarction does not offer long-term prognostic value, largely due to confounding effects of medications like digitalis.

Abstract

QTc intervals were measured retrospectively in 46.3 survivors of AMI with a mean age of 65 years. The measurement was made one at discharge from hospital. Patients with anterior infarcts had significantly longer QTc intervals than those with inferior or uncertain infact localization. A weak but significant correlation was found between S-GOT maximum and QTc interval. Patients with ventricular arrhythmias in the CCU had longer QTc intervals. Patients with a poor long-term prognosis had significantly shorter QTc intervals. This finding was explained by digitalis therapy. Among patients without bundle branch block, digitalis and quinidine, those below 66 years of age who died within the first six months tended to have longer QTc intervals than the survivors. It is concluded that measurements of QTc interval at discharge have no long-term predictive value. This factor may, however, have some bearing on the short-term prognosis in younger patients without therapy which affects the QTc interval.

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