Exercise versus recovery electrocardiography for predicting outcome in hypertensive patients with chest pain.
BACKGROUND
Exercise electrocardiography has limited prognostic accuracy in hypertensives because of unsatisfactory specificity. We prospectively used comparative stress-recovery heart rate-adjusted ST (ST/HR) analysis to predict mortality in a consecutive population of hypertensives with chest pain.


METHODS
The stress-recovery index (SRI), defined as the difference between ST/HR areas during exercise and recovery, was derived in 460 hypertensive with known (n=360, 78%) or suspected (n=100, 22%) coronary artery disease. To assess whether it added prognostic information to routinely obtained information, clinical data, the resting ejection fraction, and exercise testing data were entered into a sequential Cox's model; the SRI was entered last. Model validation was performed by bootstrap adjusted by the degree of optimism in estimates. Survival analysis was performed using the product-limit Kaplan-Meier method.


RESULTS
During a median follow-up of 28 months (interquartile range, 13-44 months), 32 (7%) patients died, 23 (5%) suffered from acute myocardial infarction and 60 (13%) underwent late (> 3 months) revascularization. Male gender (hazard ratio, 1.53; 95% confidence interval, 1.01-2.34), peak double product (hazard ratio, 0.70; 95% confidence interval, 0.54-0.90) and the SRI (hazard ratio, 0.69; 95% confidence interval, 0.59-0.81 for interquartile difference) were independent predictors of outcome. The SRI increased the prognostic power of the model on top of clinical and exercise testing variables (concordance index, + 10%; discrimination index, + 32%) and showed the widest area under the ROC curve to predict outcome as compared with exercise-only ST analysis and the ST/HR index. Moreover, it provided a significant discrimination of survival.


CONCLUSIONS
The SRI predicts all-cause mortality in hypertensive patients with chest pain and provides additional prognostic information over clinical and standard exercise testing data.
Bigi
Riccardo
R
CNR, Institute of Clinical Physiology, Niguarda Hospital, Milan, Cardiovascular Unit, 'Campo di Marte' Hospital, Lucca, Italy. rbigi@tiscali.it
Cortigiani
Lauro
L
Gregori
Dario
D
De Chiara
Benedetta
B
Parodi
Oberdan
O
Fiorentini
Cesare
C
D000368:Aged; D002637:Chest Pain / Q000175:diagnosis* / Q000401:mortality*; D004562:Electrocardiography / Q000379:methods*; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate; D006801:Humans; D006973:Hypertension / Q000401:mortality*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D016019:Survival Analysis