Graded exercise testing early after myocardial revascularization surgery.

Abstract

The response to early graded exercise testing (GXT) was studied in 227 patients at a mean of 15.3 days after myocardial revascularization surgery (MRS). GXT followed a modified Bruce protocol without multiples of resting energy expenditure (MET) restrictions and a target heart rate (HR) of 90% of age-predicted maximal HR. The decision as to precisely when to administer the GXT after surgery was made on an individual case basis by the cardiovascular surgeon and the attending cardiologist. For the data analysis, patients were grouped according to the number of days the GXT was administered after surgery: group 1, 7 to 14 days (n = 164); group 2, 15 to 28 days (n = 46); and group 3, greater than 28 days (n = 17). The use of beta blockers was also determined on an individual case basis by the attending cardiologist rather than on a random basis. Ninety-seven of the 227 patients were on beta blockers. Ventricular ectopic activity (VEA), ST-segment changes (STTC), peak HR, peak systolic blood pressure (SBP), peak rate-pressure product (RPP), and peak METs were assessed during exercise. No major complications occurred during testing. Approximately two thirds (67.4%) of the tests were terminated voluntarily by the patient, and 22.5% were stopped by the attending physician. Only 10.1% of the subjects reached the target HR. Chi-square analysis failed to reveal any association between time of testing after surgery and either STTC or VEA. Analysis of variance failed to reveal any effects of group or beta blocker on peak METs attained during GXT; however, patients not using beta blocker medication attained higher peak HR, SBP, and RPP.(ABSTRACT TRUNCATED AT 250 WORDS)