R wave amplitude during exercise. Relation to left ventricular function and coronary artery disease

Area of Science:

• Cardiology
• Exercise Physiology
• Diagnostic Imaging

Background:

• The R wave amplitude's response during exercise is a potential, yet underutilized, cardiovascular diagnostic marker.
• Distinguishing coronary artery disease (CAD) from normal physiology during stress testing requires reliable indicators.

Purpose of the Study:

• To investigate the diagnostic utility of R wave amplitude changes during maximal treadmill exercise.
• To correlate R wave amplitude variations with the severity of coronary artery disease and left ventricular function.

Main Methods:

• Maximal treadmill exercise tests were conducted on 14 healthy subjects and 62 CAD patients.
• Sequential measurements of R wave amplitude (mean delta R) were recorded during and after exercise.
• Correlation with left ventriculogram findings was analyzed.

Main Results:

• Normal subjects showed a decrease in mean delta R post-exercise, returning to baseline within 3 minutes.
• CAD patients exhibited an increase in mean delta R, most pronounced in those with severe disease (triple vessel, left main) or akinetic regions.
• R wave amplitude normalized within 5 minutes in CAD patients.
• No direct relationship was observed between R wave amplitude changes and ST segment variations.

Conclusions:

• Exercise-induced R wave amplitude changes can significantly improve the differentiation between patients with and without coronary artery disease.
• This measurement may serve as a valuable tool for identifying patients with impaired left ventricular function.
• Further research into R wave amplitude as a non-invasive diagnostic marker for CAD is warranted.