Long-term mortality with multiple treadmill exercise test abnormalities: comparison between patients with and without...

Area of Science:

• Cardiology
• Preventive Medicine
• Exercise Physiology

Background:

• Poor exercise capacity, abnormal heart rate response, and ECG abnormalities on treadmill tests are independent mortality predictors.
• The combined prognostic value of these three variables was assessed in patients with and without known cardiovascular disease (CVD).

Purpose of the Study:

• To compare the combined relationship of exercise capacity, heart rate response, and ECG abnormalities with all-cause mortality.
• To determine if multiple exercise test abnormalities signify a "CVD risk equivalent" in individuals without diagnosed CVD.

Main Methods:

• Analysis of 10,897 patients referred for treadmill exercise testing (1986-1991), with a 16-year average follow-up.
• Abnormalities defined as exercise capacity <74%, heart rate reserve <68 bpm, or ST depression ≥1 mm.
• Cox proportional hazards regression used to assess mortality risk based on 0, 1, 2, or 3 abnormal exercise test findings.

Main Results:

• Poor exercise capacity and limited heart rate reserve increased mortality risk in both CVD and no-CVD groups (P < .0001).
• Abnormal exercise ECGs predicted mortality only in the no-CVD group (P < .0001).
• Patients without CVD and ≥2 abnormalities showed a similar age-adjusted mortality risk (HR 1.01) as those with CVD but normal tests.

Conclusions:

• A combined assessment of multiple exercise test variables confirms their prognostic significance.
• The presence of two or more exercise test abnormalities may represent a "CVD risk equivalent" in patients without known cardiovascular disease.