Validation of Continuous Radionuclide Left Ventricular Functioning Monitoring in Detecting Silent Myocardial Ischemia During Balloon Angioplasty of the Left Anterior Descending Coronary Artery David S. Kayden, MD, Michael S. Remetz, MD, Henry S. Cabin, MD, Lawrence I. Deckelbaum, MD, Michael W. Cleman, MD, Frans J. Th. Wackers, MD, and Barry L. Zaret, MD Silent myocardiai ischemia has been inferred from transient ST-segment depression during continuous electrocardiographic monitoring. Re- cently, continuous ambulatory monitoring of left ventricular (LV) function using a radionuciide technique (VEST) has demonstrated episodes of significant silent LV dysfunction in the absence of electrocardiographic changes. To validate the demonstration of silent LV dysfunction with this technique, 12 men were studied during percuta- neous transluminai coronary angiopiasty. A total of 18 left anterior descending coronary artery balloon inflations were performed. Balloon infia- tions at 8 f 2 atm (4 to 10 atm) lasted 70 f 16 seconds. Seventeen of 18 inflations were associ- ated with a decrease in LV ejection fraction >O.lO. Mean LV ejection fraction decreased from 0.53 f 0.08 to 0.28 f 0.11 (p <O.OOOl). In contrast, there was pain in only 10 inflations and ST-segment changes in 7. LV dysfunction was associated with a minimal increase in end- diastolic volume (4 f 3%, p <0.003), and a ma- jor increase in relative end-systolic volume (69 f 43%, p <O.OOl). These data suggest that con- tinuous monitoring of LV function with the VEST can sensitively detect silent ischemic decreases in LV function occurring during angiopiasty, and provide further validation of the use of this tech- nique for detecting silent myocardiai ischemia. (Am J Cardioi 1991;67:1339-1343) From the Section of Cardiology, Department of Internal Medicine, and the Section of Nuclear Medicine, Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut. Manu- script received December 10, 1990; revised manuscript received and accepted February 19, 199 1. Address for reprints: David S. Kayden, MD, Cardiology Division, Health Sciences Center (T-17-020), State University of New York, Stony Brook, New York 11794-8171. A mbulatory left ventricular (LV) function moni- toring is a new technique of continuously mon- itoring LV ejection fraction using standard principles of electrocardiographic-gated radionuclide ventriculography.’ With this device (the VEST), de- creases in LV ejection fraction have been demonstrated both with and without chest pain in ambulatory pa- tients and have identified an increased risk of future cardiac events.2,3 Basedon both animal and human in- vestigation, it is likely that measures of LV perfor- mance may be a more sensitive means of detecting si- lent ischemia.4-1 l Balloon inflation in the course of transluminal coro- nary angioplasty is a human model of transient myo- cardial ischemia due to acute reduction of coronary blood flow. During angioplasty, echocardiographic and contrast angiocardiographic studies have demonstrated significant LV dysfunction during coronary balloon oc- clusion.12-18 Although several studies have demonstrated a good correlation of ejection fraction measuredby VEST and standard gamma camera during exercise,2T19,20 the abil- ity of the VEST to detect abrupt decreases in LV ejec- tion fraction during known myocardial ischemia has not been investigated. The present study was undertak- en to assess the ability of the VEST to detect episodes of transient LV dysfunction in a well-defined human model of myocardial ischemia: balloon coronary angio- plasty. METHODS Patients: Twelve men (aged 45 to 77 years, mean 65 f 9) with clinical angina undergoing percutaneous transluminal coronary angioplasty of the proximal or midleft anterior descendingcoronary artery were stud- ied. To maximize the occurrence of LV dysfunction during balloon inflation, only patients with normal or near-normal global ejection fraction, and minimal or no regional wall motion abnormality of the anterior wall were eligible for participation in the study. Patients EJECTION FRACTION DURING ANGIOPIASTY 1339