Can prolonged exercise-induced myocardial ischaemia be innocuous?

Area of Science:

• Cardiology
• Exercise Physiology
• Sports Medicine

Background:

• Current exercise guidelines for patients with ischaemic heart disease (IHD) focus on avoiding myocardial ischaemia.
• The safety and effects of exercise training that intentionally induces myocardial ischaemia are not well understood.

Purpose of the Study:

• To evaluate the safety and tolerability of intense and prolonged exercise training that exceeds the threshold for myocardial ischaemia in patients with IHD.

Main Methods:

• Twenty-two IHD patients were randomized into an ischaemic group (training to induce ischaemia) or a control group (standard guidelines).
• Training duration progressed to 60 minutes with continuous ECG monitoring.
• Cardiac troponin T (cTnT) levels and ambulatory ECG were monitored, and left ventricular function was assessed.

Main Results:

• The ischaemic group experienced myocardial ischaemia during exercise sessions, with ST-segment depression ranging from 1.0 to 2.1 mm.
• No significant arrhythmias or elevated cTnT levels were observed in either group.
• The ischaemic group maintained preserved left ventricular function.

Conclusions:

• Prolonged exercise sessions (up to 60 minutes) inducing repeated myocardial ischaemia are well-tolerated in IHD patients.
• This type of training does not lead to myocardial injury, significant arrhythmias, or left ventricular dysfunction.
• Intense exercise training may be a safe option for select IHD patients.