Neil L. Coplan

Limitations of the exercise test as a screen for acute cardiac events in asymptomatic patients

Summary The exercise stress test has been shown to have limited effectiveness when used to screen asymptomatic patients at risk for acute cardiac events, failing to detect many patients who have sudden death or myocardial infarction over long-term followup. The explanation may be found in studies that show that acute cardiac events frequently occur secondary to rapid transformation of an atherosclerotic lesion (secondary to plaque rupture and thrombosis), which may change a previously non-critical lesion into a total occlusion. Furthermore, the risk of plaque disruption may not be related to the preexisting severity of coronary artery stenosis, making it difficult to screen patients with techniques such as exercise stress testing, which rely on demonstrating myocardial ischemia or flow heterogeneity resulting from a flow-limiting lesion. Effective reduction in the incidence of sudden death will depend upon the development of diagnostic techniques that are sensitive to the presence of nonocclusive (as well as occlusive) coronary lesions and upon treatment that will prevent the cascade associated with rapid arterial occlusion.

Evaluation of 85% predicted maximal heart rate as an end point for diagnostic exercise testing

similar to those obtained with other agents. The nonblinded design of our study is a limitation, since some patients might have spontaneous conversion. Thus our results encourage us to perform a double-blind randomized study. Finally, the incidence of side effects was low and we did not observe proarrhythmic effects in our study. In conclusion, propafenone is an effective therapy to convert AF to sinus rhythm in about 50% of cases and has a low incidence of side effects. Maintenance of sinus rhythm could also be achieved in almost all patients.

Carotid Sinus Massage and the Diagnosis of Syncope

Excerpt To the editor: The recent editorial on evaluation of syncope (1 ) did not mention the importance of looking for carotid sinus hypersensitivity. Symptomatic carotid sinus hypersensitivity is...