Clinical significance of PQ segment depression in acute Q wave anterior wall myocardial infarction.

OBJECTIVES

This study was designed to evaluate the clinical significance of PQ segment depression and to examine the frequency of PQ segment depression in infarction-associated pericarditis.

BACKGROUND

PQ segment deviation is almost as characteristic as the classic ST segment deviation and is detected in most patients with pericarditis. However, the incidence and clinical characteristics of PQ segment depression in acute myocardial infarction are not defined.

METHODS

Three hundred four consecutive patients with acute Q wave anterior wall myocardial infarction were examined carefully by auscultation, electrocardiogram, echocardiogram and chest roentgenogram. The diagnosis of pericarditis was made on the basis of pericardial rub detected by more than two observers during the 1st 3 days after hospital admission. At least 0.5 mm of PQ segment depression from the TP segment observed for > 24 h in both limb and precordial leads was considered diagnostic of PQ segment depression.

RESULTS

A pericardial rub was present in 65 patients (21%) and absent in 239 patients. PQ segment depression was detected in both limb and precordial leads in 30 patients (10%): 18 patients with pericardial rub and 12 patients without pericardial rub. On the basis of five clinical variables, multivariate analysis was performed to determine the important variables related to the occurrence of PQ segment depression. Pericardial rub was selected with left ventricular segments with advanced asynergy as a significant factor related to PQ segment depression. There were 31 in-hospital deaths, and a significantly higher hospital mortality rate was observed in patients with PQ segment depression (23% vs. 9%).

CONCLUSIONS

Although PQ segment depression was observed in a minority of patients with infarction-associated pericarditis, it was one of the clinical signs of larger infarct size and increased hospital deaths.