Duration of treadmill exercise testing combined with QRS score predicts adverse cardiac outcome at long-term follow-up.
OBJECTIVE
Total exercise duration and abnormal QRS score values are treadmill exercise testing (TET) prognostic parameters that have been shown to be significantly and independently associated with cardiac mortality. We evaluated the prognostic value of a new index (M score, Michaelides score) incorporating TET duration and QRS score values in a simple index.


METHODS
In this study, we included 626 patients, who underwent TET and coronary arteriography. Cardiac catheterization showed the presence of coronary artery disease in 64.3% of these patients. The M score was calculated by adding the value of the Athens QRS score to the duration of TET (in minutes). The outcome measure was a composite of myocardial infarction or death. Patients were prospectively followed for 38+/-21 months (median 36 months).


RESULTS
The composite endpoint was more frequent among the patients of the 1st quartile (M-score values <-5.8). In univariate analysis, mortality of the first-quartile patients was significantly higher (14 vs. 1.1%, P<0.001). In multivariate Cox's regression analysis for age, sex, diabetes, smoking status, hypertension, hypercholesterolemia, maximum ST depression at TET, angina during TET, coronary artery disease on angiography, and echocardiographic left ventricular ejection fraction, the first quartile of M-score values was found to be independently associated with the composite endpoint (relative risk = 3.26, 95% confidence interval = 2.01-5.29, P<0.001).


CONCLUSIONS
This study shows that a new index termed the M score, which incorporates QRS score and exercise duration, predicts mortality and occurrence of myocardial infarction at long-term follow-up of high-risk individuals, independently of TET-induced ST-segment changes.
Michaelides
Andreas P
AP
First Department of Cardiology, University of Athens Medical School, Hippokration Hospital, Athens, Greece. michaelides@freemail.gr
Andrikopoulos
George K
GK
Antoniades
Charalambos
C
Soulis
Dimitrios
D
Tzeis
Stylianos
S
Hatzistamatiou
Evangelos
E
Tzannos
Konstantinos
K
Fourlas
Christos
C
Seferlis
Christos
C
Stefanadis
Christodoulos I
CI
D000368:Aged; D006328:Cardiac Catheterization; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000150:complications / Q000175:diagnosis* / Q000401:mortality / Q000503:physiopathology; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000209:etiology* / Q000401:mortality / Q000503:physiopathology; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors