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Significance of R wave changes in exercise-induced supraventricular extrasystoles. Angiographic correlates
A P Michaelides1, G P Vyssoulis, P G Paraskevas
1University Cardiac Unit, Hippokrateion General Hospital, Athens, Greece.
Insights
Changes in R wave amplitude during exercise-induced supraventricular extrasystoles can indicate coronary artery disease (CAD). An increase or no change in R wave amplitude suggests CAD, while a decrease suggests no significant CAD.
Area of Science:
- Cardiology
- Clinical Electrophysiology
- Diagnostic Imaging
Background:
- Exercise stress testing is crucial for diagnosing coronary artery disease (CAD).
- Supraventricular extrasystoles (SVEs) during stress tests can provide additional diagnostic information.
- R wave amplitude changes in SVEs relative to sinus beats are not well-characterized in CAD.
Purpose of the Study:
- To assess the clinical significance of R wave amplitude changes in exercise-induced SVEs compared to preceding sinus beats.
- To determine if these R wave amplitude changes can predict the presence and severity of CAD.
- To evaluate the correlation between R wave amplitude changes and left ventricular function.
Main Methods:
- 94 patients undergoing cardiac catheterization for suspected CAD were studied.
- Treadmill stress testing using the Bruce protocol was performed within a month post-catheterization.
- R wave amplitude changes in SVEs (R(x-s)) were compared to preceding sinus beats and correlated with CAD severity and ejection fraction.
Main Results:
- R wave amplitude increased or remained unchanged (R(x-s) >= 0) in patients with CAD, while it decreased in those without significant CAD (P < .0001).
- R(x-s) values positively correlated with the number of obstructed coronary arteries (P < .01) and negatively with left ventricular ejection fraction (r = -.82 to -.90).
- R(x-s) >= 0 showed 79% sensitivity and 90% specificity for CAD detection, and 89% sensitivity/57% specificity for left ventricular dysfunction.
Conclusions:
- An R wave amplitude increase or no change (R(x-s) >= 0) during SVEs is indicative of CAD.
- This finding also suggests multivessel disease and impaired left ventricular performance.
- A negative R(x-s) value is associated with minimal CAD and normal ejection fraction.
Abstract:
To evaluate the clinical significance of observed R wave amplitude changes in exercise-induced supraventricular extrasystoles in comparison to the preceding sinus beat, 94 patients catheterized for possible coronary artery disease (CAD) were studied. Significant CAD was documented in 63 patients--34 with myocardial infarction (group A1) and 29 without (group A2)--whereas 31 patients had normal coronary arteries or coronary lesions less than 30% (group B). All patients underwent treadmill stress testing using the Bruce protocol within a month after cardiac catheterization. R wave amplitude increased or remain unchanged in extrasystole (R(x-s) > or = 0) in patients with CAD, while it decreased (negative R(x-s) in patients without significant CAD (P < .0001). In patients with CAD R(x-s) values were positively related to the number of obstructed coronary arteries (P < .01), while no significant difference was found between groups A1 and A2. The correlations of R wave amplitude changes in extrasystoles were significant with coronary obstruction score values (r = .82 and .85 in groups A1 and A2, respectively) and with left ventricular ejection fraction values (r = -.88, -.86 and -.90 in groups A1, A2, and B, respectively). R(x-s) > or = 0 value had a sensitivity of 79% and a specificity of 90% for CAD detection, while sensitivity was higher (89%) and specificity was lower (57%) for the prediction of left ventricular dysfunction. It is concluded that R(x-s) > or = 0 value is indicative of CAD, multivessel disease, and poor left ventricular performance, while its negative value is combined with minimal or no CAD and normal ejection fraction values.