Prolonged total isovolumic time predicts cardiac events following coronary artery bypass surgery

Left Ventricular Myocardial and Cavity Velocity Disturbances Are Powerful Predictors of Significant Coronary Artery Stenosis

Background and Aim: Dobutamine stress echocardiography (DSE) is a well-established noninvasive investigation for significant coronary artery disease (CAD). The aim of this study was to evaluate the accuracy of cardiac Doppler parameters in predicting CAD. Methods: We prospectively studied 103 consecutive patients with suspected CAD based on typical symptoms; 59 proved to have CAD, and 44 patients proved to have no-CAD (n = 44). All patients underwent a complete stress Doppler echocardiographic examination. Total isovolumic time (T-IVT) as a marker of cavity dyssynchrony and wall motion score index (WMSI) were also calculated. Results: At peak dobutamine stress, the compromised LV longitudinal excursion (MAPSE), systolic septal and lateral velocities (s’), and diastolic indices were more pronounced in the CAD patients compared with those without CAD, but LV dimension did not differ between groups (p > 0.05). The WMSI was higher and t-IVT more prolonged in patients with CAD (p < 0.01 for both). Similarly, the changes were more pronounced in patients with significant CAD compared with insignificant CAD. On multivariate model, Δ mean s’, OR 2.016 (1.610 to 3.190; p < 0.001), Δ E velocity OR 2.502 (1.179 to 1.108; p < 0.001), Δ t-IVT 2.206 (1.180 to 2.780; p < 0.001) and Δ WMSI OR 1.911 (1.401 to 3.001; p = 0.001) were the most powerful independent predictors of the presence of CAD, particularly when significant (>75%). Δ mean s’ < 5.0 was 85% sensitive, 89% specific with AUC 0.92. Respective values for Δ E velocity <6.0 cm/s were 82%, 90% and 0.91; for Δ t-IVT > 4.5, 78%, 77% and 0.81 and for Δ FT ≥ 150 ms, 76%, 78% and 0.84 in predicating significant CAD. WMSI ≥ 0.7 was 75% sensitive, 77% specific with AUC of 0.81 in predicting significant CAD. The accuracy of DSE was higher in significant CAD compared to insignificant CAD (80% vs. 74%; p = 0.03). Conclusions: Compromised LV longitudinal systolic function, lower delta E wave, prolonged t-IVT, and increased WMSI were the most powerful independent predictors of the presence and significance of CAD. These finding strengthen the role of comprehensive DSE analysis in diagnosing ischemic disturbances secondary to significant CAD.

Role of Electromechanical Dyssynchrony Assessment During Acute Circulatory Failure and Its Relation to Ventriculo-Arterial Coupling

Introduction

Two parallel paradigms of cardiovascular efficiency and haemodynamic optimisation coexist in haemodynamic research. Targeting ventriculo-arterial (VA) coupling [i.e., the ratio between arterial and ventricular elastance (E_V)] and electromechanical coupling are two promising approaches in acute circulatory failure. However, validation of the parameters of electromechanical coupling in critically ill patients is ongoing. Furthermore, a unifying link between VA and electromechanical coupling may exist, as E_V is correlated with different times of the cardiac cycle.

Materials and Methods

This study was a retrospective analysis of a prospectively collected observational database from one tertiary center ICU. We analyzed the relationship between electromechanical dyssynchrony and acute circulatory failure hemodynamics before and after treatment (i.e., fluid expansion, dobutamine, or norepinephrine infusion). The relationship between electromechanical coupling and VA coupling was also investigated. Adult patients with haemodynamic instability were included. Haemodynamic parameters, including arterial pressure, cardiac index, VA coupling, stroke work index/pressure–volume area (SWI/PVA), t-IVT, and Tei's index, were collected before and after treatment. A t-IVT of >12 s/min was classified as intraventricular dyssynchrony.

Results

We included 54 patients; 39 (72.2%) were classified as having intraventricular dyssynchrony at baseline. These patients with baseline dyssynchrony showed a statistically significant amelioration of t-IVT (from 18 ± 4 s to 14 ± 6 s, p = 0.001), left ventricular E_V [from 1.1 (0.72–1.52) to 1.33 (0.84–1.67) mmHg mL⁻¹, p = 0.001], VA coupling [from 2 (1.67–2.59) to 1.80 (1.40–2.21), p = 0.001], and SWI/PVA [from 0.58 (0.49–0.65) to 0.64 (0.51–0.68), p = 0.007]. Patients without baseline dyssynchrony showed no statistically significant results. The improvement in VA coupling was mediated by an amelioration of E_V. All patients improved their arterial pressure and cardiac index with treatment. The haemodynamic treatment group exhibited no effect on changing t-IVT.

Conclusion

Acute circulatory failure is associated with electromechanical dyssynchrony. Cardiac electromechanical coupling was improved by haemodynamic treatment only if altered at baseline. The improvement of cardiac electromechanical coupling was associated with the improvement of markers of cardiocirculatory efficacy and efficiency (i.e., SWI/PVA and VA coupling). This study was the first to demonstrate a possible link between cardiac electromechanical coupling and VA coupling in patients with acute circulatory failure.

Right ventricular time intervals - Comparison between pulsed wave Doppler and tissue Doppler imaging

BACKGROUND

Cardiac time intervals are used as indices of systolic and diastolic function. Echocardiographic assessment of these intervals is based on either pulsed wave Doppler (PWD) or tissue Doppler imaging (TDI). We investigated the agreement between the two techniques in the evaluation of right ventricular (RV) time intervals in healthy adults.

METHODS

In 123 healthy volunteers we used both PWD and TDI to assess RV time intervals (filling time - RVFT, ejection time - RVET), heart rate-corrected intervals (total filling time - t-FT, total ejection time - t-ET) and RV performance indices (total isovolumic time - t-IVT, myocardial performance index - MPI). Intraclass correlation coefficient (ICC) and Pearson analysis (r coefficient) were used to evaluate the agreement and correlation between the two techniques.

RESULTS

PWD and TDI had excellent agreement and correlation in measuring RVFT (ICC 0.94 [95% CI 0.85 - 0.97], r 0.91) whereas a good agreement was found for RVET (ICC 0.63[95% CI - 0.14 - 0.84]; r 0.68). Good agreement and strong correlation were found for both t-FT (ICC 0.67 [95% CI 0.36 - 0.82]; r 0.59) and t-ET (ICC 0.71 [95% CI - 0.06-0.88]; r 0.74). The two methods had lower agreement in assessing RV t-IVT (ICC 0.52 [95% CI 0.3187-0.6622]; r 0.57) and MPI (ICC 0.36 [95% CI - 0.05-0.43]; r 0.50).

CONCLUSION

In healthy adults, PWD and TDI are interchangeable in measuring RVFT, RVET, RV t-FT and RV t-ET. Lower agreement between the two techniques was found for RV t-IVT and MPI.

Correlation Between Echocardiographic and Hemodynamic Variables in Cardiothoracic Intensive Care Unit

OBJECTIVES

The echocardiographic indices have not been validated in critically ill population. The authors investigated the correlation between some echocardiographic and hemodynamic parameters.

DESIGN

Prospective, spontaneous, noninterventional observational study.

SETTING

Adult cardiothoracic intensive care unit, single center (Royal Brompton Hospital, London, United Kingdom).

PARTICIPANTS

Consecutive adult patients admitted to the cardiothoracic intensive care unit for severe respiratory failure, primary cardiocirculatory failure, and post-aortic surgery.

INTERVENTIONS

Clinical hemodynamic parameters (stroke volume [SV], cardiac output [CO], mean arterial pressure [MAP], and cardiac power index [CPI]) and echocardiographic indices of ventricular function (left ventricular total isovolumic time [t-IVT], mitral annular plane systolic excursion [MAPSE], and left ventricular fraction [LVEF]) were evaluated offline.

MEASUREMENTS AND MAIN RESULTS

The study comprised 117 patients (age 57.2 ± 19; 60.6% male). The t-IVT showed an inverse correlation with SV, CO, MAP, and CPI (r -67%; -38%; -45%; -51%, respectively). MAPSE exhibited a positive correlation with SV, CO, MAP, and CPI (r 43%; 44%; 34%; 31%, respectively). LVEF did not show any correlation. In the multivariate analysis the association between t-IVT and hemodynamics was confirmed for SV, CO, MAP, and CPI, with the highest partial correlation between t-IVT and MAP (R = -58%).

CONCLUSIONS

MAPSE and t-IVT are 2 reproducible and reliable echocardiographic indices of systolic function and ventricular efficacy associated with hemodynamic variables in cardiothoracic critically ill patients, whereas LVEF did not show any correlation.

Regional Left Ventricular Myocardial Dysfunction After Cardiac Surgery Characterized by 3-Dimensional Strain

BACKGROUND

Three-dimensional (3D) strain is an echocardiographic modality that can characterize left ventricular (LV) function with greater accuracy than ejection fraction. While decreases in global strain have been used to predict outcomes after cardiac surgery, changes in regional 3D longitudinal, circumferential, radial, and area strain have not been well described. The primary aim of this study was to define differential patterns in regional LV dysfunction after cardiac surgery using 3D speckle tracking strain imaging. Our secondary aim was to investigate whether changes in regional strain can predict postoperative outcomes, including length of intensive care unit stay and 1-year event-free survival.

METHODS

In this prospective clinical study, demographic, operative, echocardiographic, and clinical outcome data were collected on 182 patients undergoing aortic valve replacement, mitral valve repair or replacement, coronary artery bypass graft, and combined cardiac surgery. Three-dimensional transthoracic echocardiograms were performed preoperatively and on the second to fourth postoperative day. Blinded analysis was performed for LV regional longitudinal, circumferential, radial, and area strain in the 17-segment model.

RESULTS

Regional 3D longitudinal, circumferential, radial, and area strains were associated with differential patterns of myocardial dysfunction, depending on the surgical procedure performed and strain measure. Patients undergoing mitral valve repair or replacement had reduced function in the majority of myocardial segments, followed by coronary artery bypass graft, while patients undergoing aortic valve replacement had reduced function localized only to apical segments. After all types of cardiac surgery, segmental function in apical segments was reduced to a greater extent as compared to basal segments. Greater decrements in regional function were seen in circumferential and area strain, while smaller decrements were observed in longitudinal strain in all surgical patients. Both preoperative regional strain and change in regional strain preoperatively to postoperatively were correlated with reduced 1-year event-free survival, while postoperative strain was not predictive of outcomes. Only preoperative strain values were predictive of intensive care unit length of stay.

CONCLUSIONS

Changes in regional myocardial function, measured by 3D strain, varied by surgical procedure and strain type. Differences in regional LV function, from presurgery to postsurgery, were associated with worsened 1-year event-free survival. These findings suggest that postoperative changes in myocardial function are heterogeneous in nature, depending on the surgical procedure, and that these changes may have long-term impacts on outcome. Therefore, 3D regional strain may be used to identify patients at risk for worsened postoperative outcomes, allowing early interventions to mitigate risk.

Echocardiographic Predictors of Immediate Postoperative Outcomes in Patients With Severe Left Ventricular Systolic Dysfunction Undergoing On-Pump Coronary Artery Bypass Grafting

OBJECTIVES

The postoperative course following on-pump coronary artery bypass grafting (CABG) in patients with severe left ventricular (LV) systolic dysfunction is often unpredictable. Therefore, the aim of this study was to identify predictors of poor postoperative outcome in this subset of patients.

DESIGN

Prospective observational study SETTING: Single university hospital PARTICIPANTS: Forty patients with severe LV systolic dysfunction undergoing isolated on-pump CABG INTERVENTIONS: None MEASUREMENTS AND MAIN RESULTS: Comprehensive transesophageal echocardiographic examination was performed to obtain the indices of systolic and diastolic LV function after induction of anesthesia. A poor postoperative outcome was defined as patient death or vasoactive inotropic score≥20 for at least 6 hours and/or requiring intra-aortic balloon counterpulsation and/or mechanical ventilation for≥24 hours. Poor postoperative outcome was observed in 40% (16/40) of patients. Patients with poor postoperative outcomes had a significantly higher systolic dyssynchrony index, septal-lateral delay with a significantly lower global longitudinal strain and isovolumic acceleration, end-diastolic volume, end-systolic volume, and lateral and medial mitral annulus systolic velocity. In a binary logistic regression model, global longitudinal strain (odds ratio, 1.5, confidence interval [CI] 95%, 1.19-1.88, p = 0.001), septal-lateral delay (odds ratio, 1.02, 95% CI, 1.01-1.03; p = 0.001) and systolic dyssychrony index (odds ratio, 1.3, 95% CI, 1.13-1.48; p = 0.000) were found to be predictors of poor postoperative outcome.

CONCLUSION

Global longitudinal strain, systolic dyssynchrony index, and septal-lateral delay were reliable and accurate predictors of adverse outcomes in patients with severe LV systolic dysfunction undergoing on-pump CABG.

A Randomized Blinded Study of the Left Ventricular Myocardial Performance Index Comparing Epinephrine to Levosimendan following Cardiopulmonary Bypass

BACKGROUND

The objective was to evaluate the effect of epinephrine and levosimendan on the left ventricle myocardial performance index in patients undergoing on-pump coronary artery by-pass grafting (CABG).

METHODS

In a double-blind, randomized clinical trial, 81 patients (age: 45-65 years) of both genders were randomly divided to receive either epinephrine at a dosage of 0.06 mcg.kg(1).min(-1) (epinephrine group, 39 patients) or levosimendan at 0.2 mcg.kg(1).min(-1) (levosimendan group, 42 patients) during the rewarming of cardiopulmonary by-pass (CPB). Hemodynamic data were collected 30 minutes after tracheal intubation, before chest open (pre-CPB) and 10 minutes after termination of protamine (post-CPB). As the primary outcome, we evaluated the left ventricle myocardial performance index by the Doppler echocardiography. The myocardial performance index is the sum of the isovolumetric contraction time and the isovolumetric relaxation time, divided by the ejection time. Secondary outcomes were systolic and diastolic evaluations of the left ventricle and postoperative troponin I and MB-CK levels.

RESULTS

Of the 81 patients allocated to the research, we excluded 2 patients in the epinephrine group and 6 patients in the levosimendan group because they didn't wean from CPB in the first attempt. There was no statistical difference between the groups in terms of patient characteristics, risk factors, or CPB time. The epinephrine group had a lower left ventricle myocardial performance index (p = 0.0013), higher cardiac index (p = 0.03), lower systemic vascular resistance index (p = 0.01), and higher heart rate (p = 0.04) than the levosimendan group at the post-CPB period. There were no differences between the groups in diastolic dysfunction. The epinephrine group showed higher incidence of weaning from CPB in the first attempt (95% vs 85%, p = 0.0001) when compared to the levosimendan group and the norepinephrine requirement was higher in the levosimenandan group than epinephrine group (16% vs. 47%; p = 0.005) in post-CPB period. Twenty-four hours after surgery, the plasma levels of troponin I (epinephrine group: 4.5 ± 5.7 vs. levosimendan group: 2.5 ± 3.2 g/dl; p = 0.09) and MB-CK (epinephrine group: 50.7 ± 31 vs. levosimendan group: 37 ± 17.6 g/dl; p = 0.08) were not significantly different between the two groups.

CONCLUSION

When compared to levosimendan, patients treated with epinephrine had a lower left ventricle myocardial performance index in the immediate post-CPB period, encouraging an efficient weaning from CPB in patients undergoing on-pump CABG.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01616069.

Combined electrical and global markers of dyssynchrony predict clinical response to cardiac resynchronization therapy

AIM

To assess potential additional value of global left ventricular (LV) dyssynchrony markers in predicting cardiac resynchronization therapy (CRT) response in heart failure (HF) patients.

METHODS

We included 103 HF patients (mean age 67 ± 12 years, 83% male) who fulfilled the guidelines criteria for CRT treatment. All patients had undergone full clinical assessment, NT-proBNP and echocardiographic examination. Global LV dyssynchrony was assessed using total isovolumic time (t-IVT) and Tei index. On the basis of reduction in the NYHA class after CRT, patients were divided into responders and non-responders.

RESULTS

Prolonged t-IVT [0.878 (range, 0.802-0.962), p = 0.005], long QRS duration [0.978 (range, 0.960-0.996), p = 0.02] and high tricuspid regurgitation pressure drop [1.047 (range, 1.001-1.096), p = 0.046] independently predicted response to CRT. A t-IVT ≥ 11.6 s/min was 67% sensitive and 62% specific (AUC 0.69, p = 0.001) in predicting CRT response. Respective values for a QRS ≥ 151 ms were 66% and 62% (AUC 0.65, p = 0.01). Combining the two variables had higher specificity (88%) in predicting CRT response. In atrial fibrillation (AF) patients, only prolonged t-IVT [0.690 (range, 0.509-0.937), p = 0.03] independently predicted CRT response.

CONCLUSION

Combining prolonged t-IVT and the conventionally used broad QRS duration has a significantly higher specificity in identifying patients likely to respond to CRT. Moreover, in AF patients, only prolonged t-IVT independently predicted CRT response.

Incremental value of the preoperative echocardiogram to predict mortality and major morbidity in coronary artery bypass surgery

BACKGROUND

Although echocardiography is commonly performed before coronary artery bypass surgery, there has yet to be a study examining the incremental prognostic value of a complete echocardiogram.

METHODS AND RESULTS

Patients undergoing isolated coronary artery bypass surgery at 2 hospitals were divided into derivation and validation cohorts. A panel of quantitative echocardiographic parameters was measured. Clinical variables were extracted from the Society of Thoracic Surgeons database. The primary outcome was in-hospital mortality or major morbidity, and the secondary outcome was long-term all-cause mortality. The derivation cohort consisted of 667 patients with a mean age of 67.2±11.1 years and 22.8% females. The following echocardiographic parameters were found to be optimal predictors of mortality or major morbidity: severe diastolic dysfunction, as evidenced by restrictive filling (odds ratio, 2.96; 95% confidence interval, 1.59-5.49), right ventricular dysfunction, as evidenced by fractional area change <35% (odds ratio, 3.03; 95% confidence interval, 1.28-7.20), or myocardial performance index >0.40 (odds ratio, 1.89; 95% confidence interval, 1.13-3.15). These results were confirmed in the validation cohort of 187 patients. When added to the Society of Thoracic Surgeons risk score, the echocardiographic parameters resulted in a net improvement in model discrimination and reclassification with a change in c-statistic from 0.68 to 0.73 and an integrated discrimination improvement of 5.9% (95% confidence interval, 2.8%-8.9%). In the Cox proportional hazards model, right ventricular dysfunction and pulmonary hypertension were independently predictive of mortality over 3.2 years of follow-up.

CONCLUSIONS

Preoperative echocardiography, in particular right ventricular dysfunction and restrictive left ventricular filling, provides incremental prognostic value in identifying patients at higher risk of mortality or major morbidity after coronary artery bypass surgery.

Prolonged total isovolumic time is related to reduced long-axis functional recovery following valve replacement surgery for severe aortic stenosis

BACKGROUND

The left ventricular (LV) long axis (Lax) function is very sensitive in documenting myocardial abnormalities in aortic stenosis (AS). We hypothesized that Lax recovery after aortic valve replacement (AVR) is related to the extent of cavity dyssynchrony measured by total isovolumic time (t-IVT).

METHODS

A consecutive 107 patients (aged 70 ± 7 years, 70 male) with severe AS and Lax impairment were studied. T-IVT was measured before and after AVR. Reduced Lax function and its post-operative recovery were defined as mitral annular plane systolic excursion (MAPSE) ≦10 mm and an increase of MAPSE >10%, respectively.

RESULTS

LV function improved (EF: 43 ± 8 to 48 ± 10%; MAPSE: 7.9 ± 1.0 to 11.0 ± 2.4 mm) and t-IVT shortened (9.7 ± 3.7 to 7.0 ± 2.8s/min, p<0.01 for all) after AVR. Sixty-five (61%) patients had Lax recovery after a median of 32-month follow-up. Univariate predictors were LV size, LA dimensions, the presence of restrictive LV filling and prolonged t-IVT. Only LV end-systolic dimension, restrictive filling and t-IVT (OR 0.61, 95% CI 0.47-0.79, p<0.01) were independent predictors. A pre-operative t-IVT ≦ 9.3s/min was 81% sensitive and 63% specific in predicting Lax recovery (AUC 0.81, p<0.001). The prevalence of CAD or concomitant CABG were similar in 2 patient groups with different t-IVT.

CONCLUSIONS

Lax recovery was evident in the majority of AS patients after AVR. The lower prevalence of Lax recovery seen in patients with prolonged t-IVT suggests that dyssynchrony may play an important role in the process of adverse LV remodeling.

Independent and incremental prognostic value of Doppler-derived left ventricular total isovolumic time in patients with systolic heart failure

BACKGROUND

A prolonged total isovolumic time (T-IVT) has been shown to be associated with worsening survival in patients submitted to coronary artery surgery. However, it is not known whether it has prognostic significance in patients with chronic systolic heart failure (HF).

AIM

To determine the prognostic value of T-IVT in comparison with other clinical, biochemical and echocardiographic variables in patients with chronic systolic HF.

METHODS

Patients (n=107; age 68±12 years, 25% women) with chronic systolic HF, left ventricular ejection fraction (EF)<45%, and sinus rhythm, underwent a complete Doppler echocardiographic study, that included tissue Doppler long axis velocities and total isovolumic time (T-IVT), determined as [60-(total ejection time+total filling time)]. Plasma N-terminal pro-B natriuretic peptide (NT-pro-BNP) was also measured. The associations of dichotomous variables selected according to the Receiver Operator Characteristic analysis were assessed using the Cox proportional hazard model.

RESULTS

Follow-up period was 37±18 months. Multivariate predictors of events were T-IVT≥12.3% s/min, mean E/Em ratio≥10, log NT-pro-BNP levels≥2.47 pg/ml and LV EF≤32.5%. On Kaplan-Meier analysis, patients with prolonged T-IVT, high mean E/Em ratio, increased NT-pro-BNP levels and decreased LV EF had a worse outcome compared with those without. The addition of T-IVT and NT-pro-BNP to conventional clinical and echocardiographic variables significantly improved the chi-square for the prediction of the outcome from 33.1 to 38.0, (P<0.001).

CONCLUSIONS

Prolonged T-IVT added to the prognostic stratification of patients with systolic HF.

Left ventricular asynchrony and raised filling pressure predict limited exercise performance assessed by 6 minute walk test

BACKGROUND

Six minute walking test (6-MWT) may serve as a reproducible test for assessing exercise capacity in heart failure (HF) patients and can be clinically predicted. We aimed in this study to ascertain if global markers of ventricular asynchrony can predict 6MWT distance in a group of patients with HF and left ventricular (LV) ejection fraction (EF) <45%.

METHODS AND RESULTS

This study included 77 consecutive patients (60 ± 12 years) with stable HF. LV end-diastolic and end-systolic dimensions, shortening fraction (SF), EF, myocardial velocities, t-IVT, and Tei index were measured, as well as 6-MWT distance. Patients with limited exercise performance (≤ 300 m) had lower SF (p = 0.02) and EF (p = 0.017), longer t-IVT (p = 0.001), higher Tei index (p = 0.002) and higher E/E' ratio (p < 0.001) compared with good performance patients. In multivariate analysis, only E/E' ratio [0.800 (0.665-0.961), p = 0.017], and t-IVT [0.769 (0.619-0.955), p = 0.018] independently predicted poor exercise performance.

CONCLUSIONS

In heart failure patients, the higher the filling pressures and the more asynchronous the left ventricle, the poorer is the patient's exercise capacity. These findings highlight specific LV functional disturbances that should be targeted for better optimization of medical and/or electrical therapy.

Persistent ventricular asynchrony after coronary artery bypass surgery predicts cardiac events

AIM

The aim of this study was to identify echocardiographic LV systolic and diastolic measurements that predict clinical events post-coronary artery bypass graft (CABG) surgery.

METHODS

We collected data from 27 patients (age 70 +/- 7 years) who underwent elective CABG, before and within 6 weeks after surgery. LV systolic function was assessed by conventional echocardiographic parameters. A number of LV filling measurements were also made, which included total isovolumic time (t-IVT), Tei index, and restrictive filling pattern. Postoperative cardiac events were death or hospitalization for chest pain, breathlessness, or arrhythmia.

RESULTS

Patient's follow-up period was 17 +/- 10 months. Of the 27 patients (age 70 +/- 7 years, 22 male), 10 had postoperative cardiac events. LV ejection fraction (EF) and fractional shortening (FS) were lower (P = 0.01, and P = 0.007, respectively), t-IVT longer (P < 0.001), and Tei index was higher (P < 0.001) preoperatively in patients with events compared to those without. The same differences between groups remained after surgery; EF (P = 0.002), FS (P = 0.002), t-IVT (P < 0.001), and Tei index (P < 0.001). T-IVT was the only preoperative predictor of events (P = 0.038) but its postoperative value as well as that of FS predicted events (P = 0.034, and P = 0.042, respectively). T-IVT of 12.2 s/min and FS of 26% were 80% sensitive and 88% specific for predicting postoperative events.

CONCLUSION

Despite successful surgical revascularization residual impairment of LV systolic function and persistent asynchrony in the form of prolonged t-IVT are associated with postoperative events. Since these abnormalities remained despite full medical therapy, they may thus suggest a need for electrical resynchronization therapy.