Prognostic implications of PR-segment depression in inferior leads in acute inferior myocardial infarction.
BACKGROUND
Concurrent atrial ischemia is usually overlooked in acute myocardial infarction (MI) due to its subtle electrocardiographic (ECG) changes, lack of clear-cut clinical picture, and prognostic significance. PR-segment depression in the inferior leads is a simplified ECG sign for detecting possible underlying atrial ischemia.


OBJECTIVE
The purpose of this study was to document the incidence, clinical characteristics, and prognostic implications of this ECG sign in the setting of acute inferior MI.


METHODS
Demographics, clinical characteristics, and outcomes of 463 consecutive patients presenting with acute inferior MI were reviewed. The in-hospital ECG was examined by two independent reviewers. The results were then compared between those with and without ECG sign.


RESULTS
Profound PR-segment depression > or = 1.2 mm in inferior leads was found in 9 of 463 (1.9%) patients. Patients with atrial ischemia tended to present earlier (2.4 +/- 2.6 vs. 7.0 +/- 8.2 h, p = 0.000) and had a higher frequency of first-degree atrioventricular block (77.8 vs. 30.6%, p = 0.028) and supraventricular arrhythmias (55.5 vs. 20.2%, p = 0.022). Of greater importance, it was significantly associated with an increased rate of cardiac free-wall rupture (33.3 vs. 2.0%, p = 0.001) and in-hospital mortality (44.4 vs. 11.7%, p = 0.015).


CONCLUSIONS
Profound PR-segment depression > or = 1.2 mm in inferior leads was associated with a complicated hospital course and poor short-term outcome in acute inferior MI. These patients were at high risk for the development of atrioventricular block, supraventricular arrhythmias, and cardiac free-wall rupture.
Jim
Man-Hong
MH
Department of Medicine, Queen Mary Hospital, Hong Kong, PRC. jimmanh2002@yahoo.com
Siu
Chung-Wah
CW
Chan
Annie On-on
AO
Chan
Raymond Hon-Wah
RH
Lee
Stephen Wai-Luen
SW
Lau
Chu-Pak
CP
D000368:Aged; D016022:Case-Control Studies; D004562:Electrocardiography; D005260:Female; D006325:Heart Atria / Q000503:physiopathology; D006329:Heart Conduction System / Q000503:physiopathology; D006341:Heart Rupture / Q000401:mortality / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000401:mortality / Q000503:physiopathology*; D011379:Prognosis