Reproducibility of on‐line vectorcardiography measurements in patients with and without acute ischaemic heart disease

Abstract

Abstract. Lundin P, Jensen J, Eriksson SV (Department of Medicine, Danderyd Hospital, Danderyd, Sweden, and Department of Medicine, Huddinge Hospital, Stockholm, Sweden). Reproducibility of on-line vectorcardiography measurements in patients with and without acute ischaemic heart disease. J Intern Med 1997; 242: 117-24.Objectives. The aim of the present study was to determine inter and intraobserver variations of measurements with on-line vectorcardiography (VCG). Design. The VCG registrations were evaluated by two independent observers. One observer also evaluated the VCG registrations on two separate occasions. Monitored VCG variables were: ST vector magnitude (ST-VM), ST vector lead X (ST-X), ST change vector magnitude (STC-VM) and QRS vector difference (QRS-VD). Subjects: On-line VCG was performed for 24 hours in 60 patients (10 with low probability of ischaemic heart disease, 25 with unstable angina pectoris and 25 with acute myocardial infarction). Results. A close correlation between the two observers and small coefficients of variation were found regarding the ST-VM initial value (r ϭ 0.99, 4.7), the ST-X maximum depression (r ϭ 0.99, 3.2) and the QRS-VD end value (r ϭ 0.98, 5.6). A less close correlation and higher coefficients of variation were found regarding the number of QRS-VD episodes (r ϭ 0.94, 41.5), ST-VM episodes (r ϭ 0.89, 37.8) and STC-VM episodes (r ϭ 0.87, 35.1). Correlation coefficients and coefficients of variations for VCG measurements performed on two separate occasions by one observer ranged from 0.97 to 0.99 and from 18.1 to 1.8 respectively. Three (12%) of 25 patients with acute myocardial infarction did not meet the VCG infarction criterion (QRS-VD Ն 15 Vs) by both observers. In addition, five (20%) of the 25 patients with unstable angina pectoris met the VCG infarction criterion by both observers. Conclusion. The inter and intraobserver variation for VCG interpretations was low, but the number of QRS-VD, ST-VM and STC-VM episodes varied between the two observers. This finding suggests that additional training may improve the results. Caution is also recommended in using VCG to rule out or establish the diagnosis of acute myocardial infarction.

Diabetes mellitus is a strong negative prognostic factor in patients with myocardial infarction treated with thrombolytic therapy

“…Evaluation of the VCG registrations was performed by an independent observer who evaluated the registrations without knowledge of the patient history. Inter‐ and intra‐observer variability has been described previously [16].…”

“…The continuous ECG monitoring system (MIDA CoroNet; Ortivus Medical AB, Täby, Sweden) has been presented in detail previously [16]. ST‐VM, which reflects the ST vector change, was analysed.…”

Ischaemia monitoring with on‐line vectorcardiography during dobutamine stress echocardiography in patients after an episode of unstable coronary artery disease

“…The coefficient of vari-ation was 5.1%. We have previously reported the interobserver variability of absolute VCG measurements [18]. In that study, the corresponding coefficients of variation for ST-VM, STC-VM and QRS-VD were 4.7%, 4.9% and 5.6% respectively.…”

Vectorcardiography: A Tool for Non-invasive Detection of Reperfusion and Reocclusion?

“…In a recent study, VCG registrations from sixty patients were randomly evaluated by two independent observers. A close correlation between the two observers was found regarding the ST-VM initial value (r = 0.99), ST-VM episodes (r = 0.89) and STC-VM episodes (r = 0.87) (42). The kappa coefficient for agreement in classification of the patients with versus without VCG signs, indicating reperfusion, was 0.98 (p <0.001), indicating high interobserver agreement.…”