Silver and colleagues [1] describe an algorithm that uses factors derived from patient history and electrocardiographic data and that attempts to reliably identify patients with a resting LVEF of 40% or greater soon after myocardial infarction. This patient group is known to have a better prognosis, to require less initial drug therapy, and to need less specialized testing. Silver and colleagues' "prediction rule" consists of four sequential questions, all of which—if answered negatively—assure a global LVEF of 40% or greater with a predictive accuracy of 99%. Unfortunately, however, 47 of 116 patients (41%) in their "validation set" with an objectively proven LVEF of 40% or greater were not identified because of at least one positive answer to the four questions.

From a derivation set of 200 patients [2], the predictive value of the simple sphygmomanometrically monitored bedside Valsalva maneuver for the detection of left ventricular systolic dysfunction as assessed by resting radionuclide ventriculography has been determined and applied prospectively to several patient validation sets [3], including patients evaluated 3 weeks after myocardial infarction [4]. The positive and negative predictive values of the presence and absence of a normal "sinusoidal" systolic arterial pressure response for an LVEF of 40% or greater were 91% and 55%, respectively—values consistent with those of the algorithm proposed by Silver and colleagues. More importantly, however, the Valsalva maneuver is applicable to approximately 90% of patients, excluding only those with atrial fibrillation, critical valvular stenosis, atrial septal defect, abdominal aortic aneurysm, and inability to be temporarily weaned from oral ß-blocker therapy. This appreciably smaller "unpredictable group" would allow detection of 40% more low-risk patients than would use of historical and electrocardiographic findings alone. Moreover, the Valsalva maneuver, when done 3 weeks after myocardial infarction, is safe if purposely limited to 10 seconds of straining [4].

A simple inexpensive risk-stratification scheme might incorporate both techniques: use of a history-based algorithm during hospitalization for acute myocardial infarction plus use of the patient-performed Valsalva maneuver 2 weeks later in the physician's office. This combination should permit detection of more than 80% of low-risk patients, without the need for expensive technology.