PISA - A New Noninvasive Method for Early Detection and Quantification of Ischemia in Hypertensive Patients

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Abstract
Hypertension if untreated, is known to produce cardiac damage. Cardiac complications result from the effects of hypertension on the myocardium and/or to accelerated atherosclerotic changes in the coronary arteries. Presently availa ble diagnostic tools are able to detect cardiac complications only when they are relatively at an advanced stage. Early detection of cardiac complications would have the advantage of early treatment, with potential for reversal. PISA (Phase- Invariant Signature Algorithm) - a new noninvasive method has been shown by us to have high sensitivity and specificity for diagnosis of ischemic heart disease. This method was therefore used in 25 healthy individuals, 20 patients with doc umented ischemic heart disease and 50 hypertensive patients (duration 1-6 years) with no end-organ disease in order to determine if these patients have myocardial ischemia and/or infarction. These patients were on antihypertensive medication. Healthy individuals as expected, had phase-invariant PISA signa ture and low PISA index. All 20 patients with documented ischemic heart dis ease had phase variant signature and had high PISA index in two or more leads. The sensitivity of this method for detection of ischemic heart disease was found to be 100%. Twenty-nine of the 50 hypertensive patients were found to have phase-variant (abnormal) PISA signatures and their PISA index was beyond the upper limit of normal PISA range (mean + 3S.D. of healthy individual). This study suggests that these 29 hypertensive patients possibly have ischemic heart disease. This PISA study indicates that 8 patients have anterior wall, 10 inferior wall, and 11 both anterior and inferior wall ischemia and/or infarction. These twenty-nine patients have varying degree of ischemia and/or infarction.