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Limited utility of interatrial block in predicting ischemia on coronary angiography in patients with suboptimal
Vignendra Ariyarajah1, David H Spodick, Jaxon Fernandes
1Preventive Cardiology, Massachusetts Veterans Epidemiology Research and Information Center, Veterans Affairs Boston Healthcare System, 150 South Huntington Avenue, Boston, Massachusetts 02130, USA. vignendra@hotmail.com
Insights
Interatrial block (P waves > or = 110 ms) shows limited utility in predicting myocardial ischemia in patients with suboptimal exercise tests. Early P-wave duration changes during exercise may offer better insights for these patients.
Area of Science:
- Cardiology
- Electrophysiology
- Diagnostic Testing
Background:
- Interatrial block (P wave duration ≥ 110 ms) is linked to exercise-induced myocardial ischemia.
- Its role in patients with suboptimal (< 3 min) exercise tolerance tests (ETT) is understudied.
Purpose of the Study:
- To assess the relationship between resting and exercise-induced P-wave duration changes and coronary artery disease (CAD) in patients with suboptimal ETT.
Main Methods:
- Prospective study of 51 patients with interatrial block and CAD undergoing coronary angiography after suboptimal ETT.
- A control group of 64 patients without interatrial block was used for comparison.
- Obstructive lesions (>70%) on angiography indicated myocardial ischemia.
Main Results:
- Interatrial block patients had more obstructive coronary lesions, but not statistically significant (p=0.25).
- A P-wave duration increase > 20 ms during exercise was more frequent in interatrial block patients with positive ETT.
- New interatrial block development during exercise correlated with significant CAD in patients without baseline interatrial block.
Conclusions:
- Interatrial block has limited predictive value for myocardial ischemia in suboptimal ETT.
- Further research on early P-wave duration changes and new interatrial block during exercise could improve ETT interpretation in borderline cases.
Introduction:
Interatrial block (P waves > or = 110 ms) is thought to be associated with underlying myocardial ischemia during exercise but has not been extensively investigated in patients with suboptimal or borderline exercise tolerance tests (< 3 min exercise). We utilized coronary angiography to assess the relationship of both, the resting baseline and exercise induced increase in P-wave duration with coronary artery disease among patients who had undergone such tests.
Methods:
We prospectively identified 51 consecutive patients with interatrial block who had coronary artery disease and hypertension but not atrioventricular valvular heart disease, and had undergone coronary angiography to evaluate myocardial ischemia after a suboptimal exercise tolerance test. A control group of 64 consecutive exercise tolerance test patients with similar preliminary characteristics but without interatrial block at rest was used for comparison. Patients from both groups were then appraised for significant obstructive lesions (> 70%) on coronary angiography that were suggestive of myocardial ischemia.
Results:
Obstructive coronary artery lesions suggestive of myocardial ischemia were more frequent among interatrial block patients but this was not statistically significant (p=0.25). However, change in P-wave duration of > 20 ms occurred more frequently in interatrial block patients in the presence of a positive exercise tolerance test. Among patients without interatrial block at baseline, more patients who developed new interatrial block had significant disease on coronary angiography.
Conclusion:
The utility of using interatrial block toward predicting myocardial ischemia among patients with suboptimal exercise tolerance tests is limited. However, further investigation on the early change in P-wave duration in patients with interatrial block and the development of new interatrial block during exercise could be helpful in optimizing exercise tolerance tests, particularly when borderline or suboptimal.
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