Systolic function during exercise in patients with coronary artery disease

Area of Science:

• Cardiology
• Physiology

Background:

• Coronary artery disease (CAD) impacts cardiac systolic function, particularly during physiological stress.
• Understanding the interplay between regional dysfunction and global performance is crucial for managing CAD.

Purpose of the Study:

• To investigate global and regional systolic function during exercise in patients with coronary artery disease.
• To differentiate the effects of exercise-induced ischemia versus prior infarction on cardiac performance.

Main Methods:

• Cardiac catheterization with biplane cineangiography and micromanometer pressures.
• Evaluation of systolic function in three groups: ischemia, control, and scar (prior infarction).
• Analysis of ventricular emptying, ejection fraction, stroke volume, and left ventricular pressure changes during exercise.

Main Results:

• Patients with ischemia showed decreased ejection fraction and stroke volume during exercise.
• The 'scar' group exhibited preserved stroke volume but impaired end-systolic volume dynamics.
• Extent of regional dysfunction correlated with the decrease in global ejection fraction.
• Nonischemic myocardium demonstrated augmented function (hyperfunction) during exercise, potentially compensating for ischemic areas.

Conclusions:

• Global systolic function in CAD during exercise is a complex interplay of regional ischemic dysfunction and compensatory hyperfunction of nonischemic myocardium.
• Both acute ischemic events and chronic effects of infarction significantly alter cardiac performance.
• Regional myocardial function critically determines overall cardiac output during stress in CAD patients.