European Journal of Echocardiography Advance Access published online on May 1, 2008
European Journal of Echocardiography, doi:10.1093/ejechocard/jen146
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Prolonged total isovolumic time predicts cardiac events following coronary artery bypass surgery
1 Second Division of Cardiology, University Clinical Centre of Kosova, Prishtina, Kosovo
2 Royal Brompton Hospital, London, UK
3 Umea Heart Centre, Umea University, Sweden
Received 19 December 2007; accepted after revision 21 March 2008.
* Corresponding author. Tel: +46 90 7851428; fax: +46 90 137633. E-mail address: henein{at}googlemail.com
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Abstract |
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Aims: Left ventricular (LV) systolic dysfunction may be associated with compromised stroke volume, which may be caused by asynchrony, reflected on the prolongation of isovolumic time (t-IVT). To assess the prognostic role of Doppler echocardiographic measurements in predicting cardiac events after coronary artery bypass grafting (CABG).
Methods and results: The study included 74 patients undergoing routine CABG. A pre-CABG Doppler echocardiographic assessment of LV dimensions, filling and ejection was performed and t-IVT was determined as [60 – (total ejection time + total filling time)]. Follow-up period was 18 ± 12 months. Of the 74 patients (age 65 ± 16 years, 59 males), 29 underwent hospital admission for a cardiac event or died. There were no differences in age, gender, incidence of previous infarct or mitral regurgitation, LV-EDD (left ventricular end-diastolic dimension), left atrial or right ventricular size in patients with cardiac events compared with those without events. Left ventricular end-systolic dimension (LV-ESD) was greater (4.5 ± 0.9 vs. 3.9 ± 0.9 cm, P = 0.003), fractional shortening (FS) was lower (21 ± 4 vs. 32 ± 8%), E:A ratio and Tei index were higher (2.1 ± 0.8 vs. 1.0 ± 0.6 and 0.9 ± 0.3 vs. 0.6 ± 0.3, all P < 0.001), and t-IVT was longer (16 ± 5 vs.10 ± 4 s/min, P < 0.001) in patients with events. Multivariate predictors of post-CABG events (odds ratio 95% confidence interval) were low FS [0.66 (0.50–0.87), P < 0.001], high E:A ratio [l4.13 (1.17–14.60), P = 0.028], large LV-ESD [0.19 (0.05–0.84), P = 0.029], and long t-IVT [1.37 (1.02–1.84), P = 0.035].
Conclusion: Despite satisfactory surgical revascularization, long t-IVT and systolic dysfunction suggest persistent ventricular dyssynchrony that contributes to post-CABG cardiac events. Early assessment of such patients for potential benefit from electrical resynchronization may optimize their cardiac performance and hence clinical outcome.
Keywords: Coronary artery disease; Coronary artery bypass grafting; Doppler echocardiography; Total isovolumic time