COMPARISON OF CONTINUOUS VECTORCADIOGRAPHY AND 12 LEAD ST SEGMENT MONITORING IN ACUTE CORONARY SYNDROMES.
B.Aliprandi-Costa*, -V.Solanki, J.Lumbv, K.England, M.Dowling, B.Freedman.
Dept of Cardiology, University of Sydney, Concord RG Hospital, Sydney.
The detection of myocardial ischaemia on continuous 2 or 3 lead electrocardiographic recordings in patients with unstable angina is associated with adverse prognosis. Multiple lead ST segment monitoring is more sensitive in detecting ischaemia, but accurate and reliable techniques for monitoring ischaemia are required if these are to be used in clinical decision making and early risk stratification.
METHOD: We studied 35 patients (8 women and 27 men, mean age 65yrs) admitted to the CCU with unstable angina (n= 27) or non Q-wave myocardial infarction (n=8). All patients underwent simultaneous ST segment monitoring for 24hrs using a Hewlett Packard Vectorcardiographic (MIDA) monitor (VCG) and either a Mortara 12 lead ST segment monitor (STM) or Mortara 12 lead full disclosure Holter recorder. Data for both STM and VCG were stored for subsequent analysis for the occurrence and duration of ischaemia. Ischaemia was defined as a change of 50mV of the absolute spatial vector magnitude (ST-VM) lasting for 1 minute for VCG and a deviation of > I mm in two contiguous leads for 12 lead STM.
RESULTS. Ischaemic episodes were detected in 14 of the 35 patients (40%) by both STM and VCG (100% concordance). A total of 41 ischaemic episodes were detected by both techniques with no significant difference in the number of episodes in 24hrs per patient between the STM and the VCG. The mean duration of ischaemia in 24hrs detected by VCG was 285±252 mins/patient and 267±246 by the STM (p=ns). 9 of 14 patients had >60mins ischaemia in 24hrs on STM and 9 on VCG (100% concordance). The mean duration of individual episodes did not differ between the VCG (127± 194 mins) and STM (1 14 ±184, p=ns).
CONCLUSIONS.. Both 12 lead STM and VCG appear equally accurate in detecting ischaemia in patients with acute coronary syndromes, although the vectorcardiographic monitor presents this information as a single ST-VM real-time trend.
