Significance of abnormal blood pressure response during exercise-induced myocardial dysfunction after recent acute myocardial infarction

Predicting severe ischemic events after uncomplicated myocardial infarction by exercise testing and rest and exercise radionuclide ventriculography

BACKGROUND

In 183 patients with uncomplicated myocardial infarction, exercise-induced angina, ST segment depression, decrease in ejection fraction, or inadequate increase in systolic blood pressure and low exercise tolerance were significantly associated with 4-year incidence of hard ischemic events.

METHODS AND RESULTS

Only the onset of both ST segment depression and a decrease in left ventricular ejection fraction with exercise was an independent predictor. ST segment depression and decrease in left ventricular ejection fraction had low sensitivity (61% and 70%) and specificity (56% and 51%) for hard ischemic events, but specificity increased to 78% when both were present. During medical therapy, 22 of 53 patients with both ST segment depression and a decrease in left ventricular ejection fraction with exercise had an ischemic event (i.e., 48.1% 4-year probability on Kaplan-Meier analysis vs 19.2% in the remaining 130 patients [p < 0.0005]).

CONCLUSIONS

Even if no single variable, derived from exercise testing, is a highly sensitive and specific predictor, specificity increases to a clinically relevant level by combining ST segment depression and a decrease in left ventricular ejection fraction with exercise, and in this way patients with recent infarction may be selected for coronary arteriography.

Abnormal systolic blood pressure response during exercise recovery in patients with angina pectoris

OBJECTIVES

This study was conducted to clarify the mechanisms of the abnormal systolic blood pressure response after exercise in patients with angina pectoris.

BACKGROUND

An abnormal systolic blood pressure response in patients with angina pectoris has been observed not only during exercise but also during the recovery period after exercise. However, the mechanisms of this abnormal response during recovery have not been elucidated.

METHODS

Thirty-five patients with angina pectoris and 17 control subjects underwent bicycle ergometric studies after insertion of a Swan-Ganz catheter.

RESULTS

In control subjects, all hemodynamic variables decreased rapidly after exercise. In 7 of the 35 patients, systolic blood pressure increased after exercise. The patients with angina were classified into two groups. In group I (17 patients), changes in systolic blood pressure during recovery were smaller than those in control subjects. In group II (18 patients) recovery of systolic blood pressure was normal. Changes in stroke index from rest to peak exercise were smaller in group I than in group II. Stroke index in both patient groups increased paradoxically during recovery. The increase in systemic vascular resistance index during recovery and the ratio of plasma norepinephrine concentration to cumulative work load were greater in group I than in group II.

CONCLUSIONS

An abnormal systolic blood pressure response after physical exercise in patients with angina pectoris is indicative of severe myocardial ischemia during exercise and may be caused by an increase in stroke volume due to recovery from myocardial ischemia and increased systemic vascular resistance secondary to exaggerated sympathetic nervous activity.

Exercise-induced hypotension in a male population. Criteria, causes, and prognosis

The objective of this study was to demonstrate the causes, optimal definition, and predictive value of exercise-induced hypotension occurring during treadmill testing. This study included all patients referred for clinical reasons to the Long Beach Veterans Administration Medical Center treadmill laboratory and then followed for a 2-year period for cardiac events. The population consisted of 2,036 patients who underwent testing from April 4, 1984, to May 7, 1987, 131 of whom exhibited exercise-induced hypotension (6.4%). We found that exercise-induced hypotension is usually related to myocardial ischemia or myocardial infarction, is best defined as a drop in systolic blood pressure during exercise below the standing preexercise value, and indicates a significantly increased risk for cardiac events (3.2-fold, p less than 0.005). This increased risk was not found in those having no previous myocardial infarction or no signs or symptoms of ischemia during the exercise test, and the increased risk was also not found in those undergoing a treadmill test within 3 weeks after a myocardial infarction. Exercise-induced hypotension appeared to be reversed by revascularization procedures, but confirmation of a beneficial effect on survival requires a randomized trial. The clinical importance of this study is that we have demonstrated that a drop in systolic blood pressure below standing preexercise values during treadmill testing indicates an increased risk for cardiac events except in certain subsets of patients.

Comparison of left ventricular function and contractile reserve after successful recanalization by thrombolysis versus rescue percutaneous transluminal coronary angioplasty for acute myocardial infarction

To determine how coronary reperfusion affects rest and exercise ventricular function after acute myocardial infarction (AMI), 63 patients with a patent infarct artery after intravenous thrombolytic therapy (lysis) were compared with 27 patients who failed thrombolysis but had successful acute recanalization by percutaneous transluminal coronary angioplasty (PTCA) as a "rescue" procedure. Contrast ventriculography was performed acutely and on day 7. Resting radionuclide ventriculography was performed at 24 hours and repeated with exercise on day 30. There were no differences in global ejection fraction (EF) between the 2 groups during acute contrast ventriculography. However, by 24 hours, the EF had deteriorated in the rescue group (40 +/- 17 vs 49 +/- 11% in the lysis group, p less than or equal to 0.05). No improvement occurred in either group on day 7. By day 30, an improvement in resting radionuclide EF 5.9 +/- 1.9% occurred in rescue patients and the difference between rescue and lysis groups was no longer significant (46 +/- 14 vs 50 +/- 11%, p = 0.12). A normal (greater than or equal to 5%) increase in EF with exercise occurred in 64%, with either normal or exercise-enhanced regional wall motion present in 67% of patients. A significant increase in EF occurred within the rescue group, from 46 +/- 14% at rest to 50 +/- 15% at peak exercise (p less than or equal to 0.0005). The EF increased with exercise from 50 +/- 11 to 58 +/- 15% in the lysis group (p less than or equal to 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)