ONLINE COMPUTERIZED VECTORCARDIOGRAPHY MONITORING OF MYOCARDIAL-ISCHEMIA DURING CORONARY ANGIOPLASTY - COMPARISON WITH 12-LEAD ELECTROCARDIOGRAPHY

Background: With new interventions minimizing ischemic myocardial inju ry, accurate and reliable techniques for the detection and continuous monitoring of myocardial ischemia are essential. We compared two techn iques used for the detection of myocardial ischemia during coronary an gioplasty: on-line computerized vectorcardiographic (cVCG) monitoring and the standard electrocardiography (ECG) leads or the complete 12-le ad ECG. Methods: Thirty patients scheduled for routine angioplasty wer e included in the study. cVCG was recorded continuously. The electrode s were placed according to the lead system described by Frank and conn ected to a computerized system for on-line vectorcardiography. A 12-le ad ECG was recorded simultaneously. The absolute variable spatial ST v ector magnitude (ST-VM) and the relative variable spatial ST change ve ctor magnitude (STC-VM) were calculated and compared with the standard 12-lead ECG for the detection of ischemia. Results: The sum of deviat ion in ST segment in all 12 standard ECG leads correlated closely with STC-VM, irrespective of which artery was occluded. STC-VM indicated i schemia during the first balloon inflation in 87% of the patients and demonstrated ischemia in more patients than the standard 12-lead ECG. Myocardial ischemia was not demonstrated by ST-VM in five out of 26 pa tients with ischemia according to STC-VM. In these cases, mainly direc tional vector changes and fewer changes in magnitude were observed. Co nclusion: Compared with 12-lead ECG, on-line cVCG is a more sensitive method of detecting myocardial ischemia during coronary angioplasty an d the reading is easier and faster. Our results support STC-VM greater than or equal to 0.050 mV as the criterion for ischemia during angiop lasty; ST-VM should be applied together with STC-VM.