Prognostic value of vasodilator myocardial perfusion imaging in patients with left bundle-branch block

Clinical characteristics and value in early reperfusion therapy for new onset right bundle branch block in patients with acute myocardial infarction

The value of the right bundle branch block (RBBB) in the treatment of acute myocardial infarction remains unclear. Studies on the RBBB may significantly influence the treatment of acute myocardial infarction. A total of 845 patients with acute myocardial infarction who underwent primary coronary angiography at Henan Provincial People's Hospital were analyzed. Higher peak enzyme levels, a higher ratio of Killip ≥II and closer proximal occlusion of infarct-related artery (IRA) were observed in patients with RBBB compared with those without. The ratio of TIMI flow 0/1 of IRA and ratio of received primary percutaneous coronary intervention (PCI) to IRA in the RBBB group were significantly higher compared with those in the left (L) BBB or no BBB groups. The in-hospital major adverse cardiac events (MACE) incidence in the RBBB group was higher compared with that in the no BBB group, but there was no significant difference between the RBBB and LBBB groups. Logistic regression revealed that proximal occlusion and TIMI flow 0/1 of IRA were predictive factors of RBBB. Cox regression analysis identified RBBB [risk ratio (RR), 4.682; P<0.001] and LBBB (RR, 3.687; P<0.001) as independent predictors of in-hospital MACE. The cumulative one-year survival rate in the RBBB group was significantly lower than those in the no BBB group (P<0.05) and the LBBB group (P<0.05). Similar to the guidelines regarding new onset of LBBB, new onset RBBB should be considered as a standard indicator for reperfusion therapy; as RBBB is associated with more severe symptoms, and higher incidents of complete occlusion of IRA and primary PCI treatment compared with LBBB.

Assessment of an incidental finding of left bundle-branch block

Incidental left bundle-branch block occurs in up to 1.5% of healthy adults without symptoms or signs of cardiovascular disease. It may be found during investigation for non-cardiac disease, during preoperative assessment, private health screening or inpatient monitoring. This article outlines how to assess these patients.

Patients with left bundle branch block pattern and high cardiac risk myocardial SPECT: does the current management suffice?

INTRODUCTION

Myocardial perfusion SPECT (MPS) is frequently used for cardiovascular risk stratification. The significance of MPS in patients with abnormal electrical ventricular activation is often questionable. This review assesses the value of MPS for risk stratification of patients with intrinsic left bundle branch block or that due to right ventricular apical pacing.

METHODS

We reviewed the literature by a search of the MEDLINE database (January 1980 to September 2010). The terms prognosis or prognostic value were combined with SPECT and LBBB or pacing or pacemakers. MPS was categorised as low and high risk according to the original definitions.

RESULTS

We identified 11 studies suitable for review. A low-risk MPS is associated with a low risk of cardiac events whereas high-risk MPS carries a 4.8-fold increased risk, 95% CI [3.2 - 7.2] (p < 0.0001). Despite secondary prevention and an improved medical and interventional care, these figures have hardly changed over time.

CONCLUSION AND CLINICAL IMPLICATIONS

A low-risk MPS permits a policy of watchful waiting whereas a high-risk MPS requires further analysis and treatment. The persistent high cardiac death and acute myocardial infarction rate after a high-risk MPS suggest that the current management of these patients does not suffice and needs reconsideration.

Prognostic value of automated vs visual analysis for adenosine stress myocardial perfusion SPECT in patients without prior coronary artery disease: a case-control study

PURPOSE

We aimed to evaluate the prognostic value of automated quantitative hypoperfusion parameters derived from adenosine stress myocardial perfusion SPECT (MPS) for predicting sudden or cardiac death (CD) in case-controlled patients with suspected coronary artery disease (CAD).

METHODS

We considered patients with available adenosine stress Tc-99m sestamibi MPS scans and follow-up information. 81 CD patients from a registry of 428 patients documented by the National Death Index were directly matched in a retrospective case-control design to patients without CD by key clinical parameters (age by deciles, gender, no early revascularization, pre-test likelihood categories, diabetes, and chest pain symptoms). Multivariable analysis of stress MPS total perfusion deficit (STPD) and major clinical confounders were used as predictors of CD. Visual 17-segment summed stress segmental scores (VSSS) obtained by an expert reader, were compared to STPD.

RESULTS

CD patients had higher stress hypoperfusion measures compared to controls [STPD: 7.0% vs 3.6% (P < .05), VSSS: 5.3 vs 2.1 (P < .05)]. By univariate analysis, STPD and VSSS have similar predictive power (the areas under receiver operator characteristics curves: STPD = 0.64, VSSS = 0.63; Kaplan-Meier models: χ(2) = 7.59, P = .0059 for STPD and χ(2) = 11.10, P = .0009 for VSSS). The multiple Cox proportional hazards regression models with continuous perfusion measures showed that STPD had similar power to normalized VSSS as a predictor for CD (χ(2) = 4.92; P = .027) vs (χ(2) = 8.90; P = .003).

CONCLUSIONS

Quantitative analysis is comparable to expert visual scoring in predicting CD in a case-controlled study.

Prognostic value of exercise echocardiography in patients with left ventricular systolic dysfunction and known or suspected coronary artery disease

BACKGROUND

The prognostic value of exercise echocardiography (ExE) in patients with left ventricular systolic dysfunction (LVSD) has not been characterized. We sought to assess the value of ExE for predicting outcome in patients with LVSD and known/suspected coronary artery disease.

METHODS

This study is a retrospective analysis of a prospectively collected database of 1,107 patients who underwent treadmill ExE and had resting LVSD (left ventricular ejection fraction <50%). Ischemia was defined as an increase in wall motion score index from rest to exercise. The end points were all-cause mortality and major cardiac events (MACE).

RESULTS

Overall, 494 patients (44.6%) developed new or worsening wall motion abnormalities. During a mean follow-up of 4.1 +/- 3.4 years, 301 patients died and 166 had a MACE. In patients with mild LVSD, the 5-year mortality rate was 8.8% in those without ischemia and 21% in those with ischemia (P < .001). For patients with moderate LVSD without ischemia, the 5-year mortality rate was 18.3%, whereas it was 29.2% when ischemia was present (P = .009). In those with severe LVSD, the 5-year mortality rate was 23.9% without ischemia and 35.7% with ischemia (P = .03). In the multivariate analysis, increase in wall motion score index was an independent predictor of mortality (hazard ratio 2.25, 95% CI 1.26-2.06, P = .001) and MACE (hazard ratio 2.60, 98% CI 1.34-5.04, P = .005). The addition of the ExE results to clinical, resting echocardiography and exercise variables provided significant incremental prognostic information for predicting mortality (P = .001) and MACE (P = .005).

CONCLUSIONS

The ExE provides significant information for predicting outcome in patients with LVSD and known/suspected coronary artery disease.

Myocardial perfusion SPECT identifies patients with left bundle branch block patterns at high risk for future coronary events

BACKGROUND

The value of myocardial perfusion SPECT (MPS) for patients with left bundle branch block (LBBB) or right ventricular apical (RVA) pacing seems reduced. The prognosis of patients with only abnormal activation related perfusion defects (AARD) due to LBBB or RVA-pacing is similar to those with a normal MPS. We assessed the prognostic value of MPS in patients with LBBB or RVA pacing.

METHODS

Patients with LBBB or RVA pacing referred for vasodilator stress MPS between April 2002 and January 2006 were analyzed. Group 1 are patients with normal MPS and MPS with AARD. Group 2 are patients with an MPS with a perfusion defect extending outside the AARD area. Events were cardiac death, acute myocardial infarction and coronary revascularization.

RESULTS

In Group 1 (101 patients) 12 events and in Group 2 (96 patients) 45 events occurred during a mean follow-up of 2.6 +/- 1.5 years. The prognosis of Group 2 was significantly worse (49%) compared with Group 1 (91%). The annual cardiac death rate was 0.7%/year in Group 1 and 6.4%/year in Group 2 (P < .001). The prognosis of patients with LBBB was not different from those with RVA pacing.

CONCLUSION

Group 2 had a significantly worse cardiac prognosis compared to Group 1. The annual cardiac death rate of <1% in Group 1 warrants a watchful waiting strategy, whereas the cardiac death rate in Group 2 warrants aggressive invasive coronary strategies.

Prognostic value of peak and post-exercise treadmill exercise echocardiography in patients with known or suspected coronary artery disease

AIMS

Although peak may have higher sensitivity than post-treadmill exercise echocardiography (EE) for the detection of coronary artery disease (CAD), its prognostic value remains unknown. We sought to assess the relative values of peak and post-EE for predicting outcome in patients with known/suspected CAD.

METHODS AND RESULTS

We studied 2947 patients who underwent EE. Wall motion score index (WMSI) was evaluated at rest, peak, and post-exercise. Ischaemia was defined as the development of new or worsening wall motion abnormalities with exercise. Separate analyses for all-cause mortality and major cardiac events (MACE) were performed. Ischaemia developed in 544 patients (18.5%). Among them, ischaemia was detected only at peak exercise in 124 patients (23%), whereas 414 (76%) had ischaemia at peak plus post-exercise imaging and six patients (1%) had ischaemia only at post-exercise. During follow-up, 164 patients died. The 5-year mortality rate was 3.5% in patients without ischaemia, 15.3% in patients with peak ischaemia alone, and 14% in patients with post-exercise ischaemia (P < 0.001 normal vs. ischaemic groups). In the multivariate analysis, post-exercise WMSI was an independent predictor of MACE [hazard ratio (HR) 1.87, 95% confidence interval (CI) 1.09-2.19, P = 0.02]. Peak exercise WMSI was an independent predictor of MACE (HR 2.19, 95% CI 1.30-3.69, P = 0.003) and mortality (HR 1.58, 95% CI 1.07-2.35, P = 0.02). The addition of peak EE results to clinical, resting echocardiography, exercise variables, and post-EE provided incremental prognostic information for MACE (P = 0.04) and mortality (P = 0.04).

CONCLUSION

Peak treadmill EE provides significant incremental information over post-EE for predicting outcome in patients with known or suspected CAD.

Prediction of mortality and major cardiac events by exercise echocardiography in patients with normal exercise electrocardiographic testing

OBJECTIVES

We sought to assess the value of exercise echocardiography (EE) for predicting outcome in patients with known or suspected coronary artery disease and normal exercise electrocardiogram (ECG) testing.

BACKGROUND

The prognostic value of EE in patients with normal exercise ECG testing has not been characterized.

METHODS

We studied 4,004 consecutive patients (2,358 men, mean age [+/- SD] 59.6 +/- 12.5 years) with interpretable ECG who underwent treadmill EE and did not develop chest pain or ischemic ECG abnormalities during the tests. Wall motion score index (WMSI) was evaluated at rest and with exercise, and the difference (DeltaWMSI) was calculated. Ischemia was defined as the development of new or worsening wall motion abnormalities with exercise. End points were all-cause mortality and major cardiac events (MACE).

RESULTS

Overall, 669 patients (16.7%) developed ischemia with exercise. During a mean follow-up of 4.5 +/- 3.4 years, 313 patients died, and 183 patients had a MACE before any revascularization procedure. The 5-year mortality and MACE rates were 6.4% and 4.2% in patients without ischemia versus 12.1% and 10.1% in those with ischemia, respectively (p < 0.001). In the multivariate analysis, DeltaWMSI remained an independent predictor of mortality (hazard ratio [HR]: 2.73, 95% confidence interval [CI]: 1.40 to 5.32, p = 0.003) and MACE (HR: 3.59, 95% CI: 1.42 to 9.07, p = 0.007). The addition of the EE results to the clinical, resting echocardiographic and exercise hemodynamic data significantly increased the global chi-square of the models for the prediction of mortality (p = 0.005) and MACE (p = 0.009).

CONCLUSIONS

The use of EE provides significant prognostic information for predicting mortality and MACE in patients with interpretable ECG and normal exercise ECG testing.

The prognostic significance of typical perfusion defects on vasodilator stress myocardial perfusion SPECT in patients with left bundle branch block or right ventricular apical pacing

PURPOSE

Left bundle branch block (LBBB) and ventricular pacing may induce typical artefacts that appear as perfusion defects in myocardial perfusion single photon emission computed tomography (MPS). We assessed the prognosis of patients with LBBB or right ventricular apical (RVA) pacing who had chest pain and an MPS with only abnormal activation-related defects (AARD).

METHODS

All patients with LBBB or ventricular pacing referred for vasodilator stress MPS between April 2002 and January 2006 were analyzed. AARD were defined as small, nontransmural, fixed defects and small reversible defects in well-defined regions always accompanied with concomitant wall motion abnormalities.

RESULTS

Ninety-seven patients were included, with a mean follow-up period of 3+/-1.3 years. MPS showed AARD in 57 and it was completely normal in 40 patients. No significant difference in cumulative cardiac event-free follow-up was observed between patients with AARD (93%) and normal MPS (85%). The average annual cardiac event rate was not significantly different between the groups (1.7 and 4.3% per year, respectively). No difference was found between patients with LBBB and RVA pacing.

CONCLUSION

Patients with chest pain and LBBB or RVA pacing who show AARD on MPS have a comparable prognosis as patients with abnormal activation and a normal MPS. This justifies MPS for risk stratification of patients with chest pain and LBBB or RVA pacing.

Accuracy of non-invasive techniques for diagnosis of coronary artery disease and prediction of cardiac events in patients with left bundle branch block: a meta-analysis

PURPOSE

Non-invasive evaluation of coronary artery disease (CAD) in patients with left bundle branch block (LBBB) has limitations inherent to different tests, and the relative merits of these tests are unclear. This meta-analysis assessed the accuracy of the frequently used non-invasive techniques, including exercise electrocardiography (ECG), myocardial perfusion imaging (MPI) and stress echocardiography (SE), for detection of CAD and prediction of cardiac events in patients with LBBB.

METHODS

A review was conducted of all reports on detection of CAD and prediction of cardiac events in patients with LBBB (published between January 1970 and December 2004), and revealed 55 diagnostic and nine prognostic reports with sufficient details to calculate test accuracy. Weighted (by sample size) sensitivity and specificity were calculated. Summary relative risk ratios (95% confidence intervals) were calculated.

RESULTS

Overall sensitivity was higher for exercise ECG and (quantitatively analysed) MPI than for SE (83.4% and 88.5% versus 74.6% respectively, p<0.0001). SE had a higher specificity (88.7%) than MPI (41.2%) and exercise ECG (60.1%) (p<0.0001). Based on analysis of eight reports, the relative risk of cardiac death or myocardial infarction in patients with an abnormal SE and MPI was elevated more than sevenfold, but it did not differ by imaging modality (p=0.9).

CONCLUSION

Meta-analysis of non-invasive CAD assessment in LBBB patients revealed that exercise ECG and MPI had the highest sensitivity, while SE had the highest specificity. The prognostic accuracy of MPI and SE appeared similar.

Functional capacity and cardiovascular assessment: submaximal exercise testing and hidden candidates for pharmacologic stress

Submaximal exercise testing is often used to estimate functional capacity in non-athletes, to assess cardiovascular disease in elderly or frail patients, to demonstrate exercise equipment, or to risk-stratify patients after myocardial infarction. However, submaximal exercise testing is not sufficiently sensitive, specific, or predictive to have widespread clinical utility, except in post-myocardial infarction protocols. Many patients for whom submaximal exercise testing is not useful are unable to exercise sufficiently for maximal testing and are referred for imaging with pharmacologic stress. Although some patients who are unable to exercise adequately are easily recognized, many are not. The identification of such patients before they fail a maximal exercise test attempt is beneficial to both the patient and the imaging laboratory.

The prognostic value of pharmacologic stress myocardial perfusion imaging in patients with permanent pacemakers

BACKGROUND

The aim of this study is to assess the prognostic value of pharmacologic stress (adenosine or dipyridamole) myocardial perfusion imaging in patients with permanent electronic ventricular pacemakers.

METHODS AND RESULTS

Between October 1986 and December 1995, 93 patients with pacemakers underwent pharmacologic stress testing with myocardial perfusion single photon emission computed tomography imaging. Follow-up information on 91 patients (98%) was obtained. Mean follow-up was 5.6 +/- 2.4 years. Previously published clinical and image variables were analyzed for their prognostic significance with regard to cardiac death, cardiac death/nonfatal myocardial infarction, and cardiac death/nonfatal myocardial infarction/late revascularization. The presence of a high-risk scan was a significant predictor of subsequent cardiac death by both univariate (chi 2 = 9.4, P < .001) and multivariate analysis (chi 2 = 6.5, P = .01) after adjustment for clinical score. Clinical score was not a significant predictor of cardiac death.

CONCLUSION

This study demonstrates that pharmacologic stress myocardial perfusion imaging provides significant prognostic information in patients with permanent pacemakers. In this population, pharmacologic stress myocardial perfusion imaging can differentiate patients at high risk of a subsequent cardiac event from those at low risk. These results support the American College of Cardiology/American Heart Association guideline recommendations for pharmacologic stress perfusion imaging in patients with permanent pacemakers.

Prognostic value of exercise stress myocardial perfusion imaging in patients with permanent pacemakers

One hundred eight patients with single- or dual-chamber pacemakers underwent exercise myocardial perfusion imaging with thallium-201 or technetium-99m sestamibi. A high-risk scan (a large fixed defect, a large reversible defect, or evidence of cardiomyopathy) identified patients at high risk for cardiac death on both a univariate and multivariate basis.

Relationship of myocardial perfusion imaging findings to outcome of patients with heart failure and suspected ischemic heart disease

BACKGROUND

We retrospectively identified heart failure patients with suspected ischemic heart disease who underwent myocardial perfusion imaging (MPI) to examine the relationship of MPI findings to subsequent patient outcomes.

METHODS

The study group consisted of 336 patients with heart failure, left ventricular ejection fraction <45%, and suspected ischemic heart disease who underwent MPI during the period of January 1991 to December 31, 1997. Patients were divided in 3 subgroups: group A (n = 137), large fixed perfusion defects; group B (n = 77), large reversible perfusion defects; and group C (n=122), absence of a large reversible or fixed perfusion defect.

RESULTS

Overall, the 5-year mortality rate was high at 49.2% +/- 3.1%. Mortality was significantly different (P =.009) among the 3 subgroups. Groups A and B had a similar 5-year mortality rates >50%. Group C had a relatively better, but still substantial 5-year mortality rate of 40%. The overall revascularization rate was low (9.7% in 5 years).

CONCLUSION

These results indicate a high 5-year mortality rate in patients with large myocardial perfusion defects (fixed or reversible) and presumably an ischemic etiology for their heart failure. Patients with no large or absent perfusion defects had more favorable survival outcomes.

Myocardial perfusion scintigraphy: the evidence

This review summarises the evidence for the role of myocardial perfusion scintigraphy (MPS) in patients with known or suspected coronary artery disease. It is the product of a consensus conference organised by the British Cardiac Society, the British Nuclear Cardiology Society and the British Nuclear Medicine Society and is endorsed by the Royal College of Physicians of London and the Royal College of Radiologists. It was used to inform the UK National Institute of Clinical Excellence in their appraisal of MPS in patients with chest pain and myocardial infarction. MPS is a well-established, non-invasive imaging technique with a large body of evidence to support its effectiveness in the diagnosis and management of angina and myocardial infarction. It is more accurate than the exercise ECG in detecting myocardial ischaemia and it is the single most powerful technique for predicting future coronary events. The high diagnostic accuracy of MPS allows reliable risk stratification and guides the selection of patients for further interventions, such as revascularisation. This in turn allows more appropriate utilisation of resources, with the potential for both improved clinical outcomes and greater cost-effectiveness. Evidence from modelling and observational studies supports the enhanced cost-effectiveness associated with MPS use. In patients presenting with stable or acute chest pain, strategies of investigation involving MPS are more cost-effective than those not using the technique. MPS also has particular advantages over alternative techniques in the management of a number of patient subgroups, including women, the elderly and those with diabetes, and its use will have a favourable impact on cost-effectiveness in these groups. MPS is already an integral part of many clinical guidelines for the investigation and management of angina and myocardial infarction. However, the technique is underutilised in the UK, as judged by the inappropriately long waiting times and by comparison with the numbers of revascularisations and coronary angiograms performed. Furthermore, MPS activity levels in this country fall far short of those in comparable European countries, with about half as many scans being undertaken per year. Currently, the number of MPS studies performed annually in the UK is 1,200/million population/year. We estimate the real need to be 4,000/million/year. The current average waiting time is 20 weeks and we recommend that clinically appropriate upper limits of waiting time are 6 weeks for routine studies and 1 week for urgent studies.

Thallium-201 myocardial SPECT in a patient with mirror-image dextrocardia and left bundle branch block

A 53-year-old male patient with a previous diagnosis of situs inversus with mirror-image dextrocardia underwent thallium-201 (Tl-201) stress-redistribution myocardial perfusion single photon emission computed tomography (SPECT). Electrocardiogram (ECG) obtained on right hemithorax revealed constant complete left bundle branch block. Tl-201 stress-redistribution SPECT images revealed abnormal perfusion with reversible ischemia in the anteroseptal, septal and inferoseptal walls. Coronary angiography performed 1 month after SPECT study was normal. This case illustrates that false positive reversible perfusion defects can be seen in patients with mirror-image dextrocardia associated with constant complete left bundle branch block. To our knowledge, this is the first reported case of mirror-image dextrocardia and constant complete left bundle branch block with false positive Tl-201 SPECT findings.

Long-term outcome and the use of revascularization in patients with heart failure, suspected ischemic heart disease, and large reversible myocardial perfusion defects

BACKGROUND

The potential role of coronary revascularization in the management of patients with congestive heart failure and suspected ischemic heart disease remains to be defined. Myocardial perfusion imaging can identify patients with ischemic heart disease as the etiology for left ventricular dysfunction who might benefit from revascularization.

METHODS

We retrospectively identified heart failure patients with suspected ischemic heart disease who had large reversible perfusion defects to determine their long-term outcome and rate of revascularization. The study group consisted of 77 patients with congestive heart failure, left ventricular ejection fraction <45%, and suspected ischemic heart disease who underwent myocardial perfusion imaging during the period of January 1, 1991, to December 31, 1997, and had large reversible perfusion defects.

RESULTS

The 5-year mortality rate was 57.6%. The revascularization rate was only 13% for 5 years of follow-up. The number of patients undergoing revascularization was too small to assess its impact on outcome.

CONCLUSION

These results indicate a high 5-year mortality rate and a low utilization of coronary revascularization in patients with heart failure and large reversible perfusion defects. The low rate of revascularization reflects at least in part the absence of the generalizability of the existing literature to the optimal means of treating patients with heart failure and myocardial ischemia and points to the need for a randomized clinical trial.

Prognostic value of pharmacologic stress echocardiography in patients with left bundle branch block

PURPOSE

Although coronary artery disease is a frequent cause of left bundle branch block, the prognostic value of myocardial ischemia in patients with this conduction abnormality has not been defined. We investigated the value of pharmacologic stress echocardiography in risk stratification of patients with left bundle branch block.

PATIENTS AND METHODS

Three hundred eighty-seven patients [230 men and 157 women, mean (+/- SD) age, 64 +/- 9 years] with complete left bundle branch block on the resting electrocardiogram underwent dobutamine (n = 217) or dipyridamole (n = 170) stress echocardiography to evaluate suspected or known coronary artery disease. A summary wall motion score (on a one to four scale) was calculated. The primary end points were cardiac death and nonfatal myocardial infarction.

RESULTS

A positive echocardiographic result (evidence of ischemia) was detected in 109 (28%) patients. During a mean follow-up of 29 +/- 26 months, there were 21 cardiac deaths and 20 myocardial infarctions, 63 patients underwent coronary revascularization, and 1 patient received a heart transplant. In a multivariate analysis, four clinical and echocardiographic variables were associated with increased risk of cardiac death: resting wall motion score index [hazard ratio (HR) = 7.5 per unit; 95% confidence interval (CI), 2.8 to 20; P = 0.001], previous myocardial infarction (HR = 2.9; 95% CI, 1.1 to 7.3; P = 0.02), diabetes (HR = 2.7; 95% CI, 1.1 to 6.6; P = 0.03), and the change in wall motion score index from rest to peak stress (HR = 3.0 per unit; 95% CI, 1.0 to 8.6; P = 0.04). The 5-year survival was 77% in the ischemic group and 92% in the nonischemic group (P = 0.02). Four variables were associated with increased risk of cardiac death or infarction: previous myocardial infarction (HR = 3.4; 95% CI, 1.7 to 6.8; P = 0.0005), diabetes (HR = 2.4; 95% CI, 1.2 to 4.6; P = 0.01), resting wall motion score index (HR = 2.2 per unit; 95% CI, 1.1 to 4.1; P = 0.02), and positive echocardiographic result (HR = 2.2; 95% CI, 1.1 to 4.5; P = 0.03). The 5-year infarction-free survival was 60% in the ischemic group and 87% in the nonischemic group (P < 0.0001). Stress echocardiography significantly improved risk stratification in patients without previous myocardial infarction (P = 0.0001), but not in those with previous myocardial infarction (P = 0.08). In particular, it provided additional value over clinical and resting echocardiographic findings in predicting cardiac events among patients without previous infarction.

CONCLUSIONS

Myocardial ischemia during pharmacologic stress echocardiography is a strong prognostic predictor in patients with left bundle branch block, particularly in those without previous myocardial infarction.