Related Experiment Videos
Prognostic value of pharmacologic stress echocardiography in patients with left bundle branch block
L Cortigiani1, E Picano, C Vigna
1Cardiovascular Unit, Lucca Hospital, Italy.
Insights
Pharmacologic stress echocardiography identifies myocardial ischemia in patients with left bundle branch block, aiding risk stratification. This method is particularly valuable for predicting cardiac events in patients without prior myocardial infarction.
Area of Science:
- Cardiology
- Diagnostic Imaging
Background:
- Coronary artery disease frequently causes left bundle branch block.
- The prognostic significance of myocardial ischemia in this patient group is not well-defined.
Purpose of the Study:
- To assess the utility of pharmacologic stress echocardiography for risk stratification in patients with left bundle branch block.
- To determine if myocardial ischemia detected during stress echocardiography predicts cardiac events.
Main Methods:
- 387 patients with left bundle branch block underwent dobutamine or dipyridamole stress echocardiography.
- Wall motion scores were assessed at rest and peak stress.
- Primary endpoints included cardiac death and nonfatal myocardial infarction.
Main Results:
- Myocardial ischemia was detected in 28% of patients.
- Multivariate analysis identified resting wall motion score, prior myocardial infarction, diabetes, and stress-induced wall motion changes as predictors of cardiac death.
- Ischemia was associated with significantly lower 5-year survival and infarction-free survival rates.
- Stress echocardiography improved risk stratification in patients without prior myocardial infarction.
Conclusions:
- Myocardial ischemia identified by pharmacologic stress echocardiography is a potent prognostic marker in patients with left bundle branch block.
- Stress echocardiography offers significant prognostic value, especially for patients without a history of myocardial infarction.
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.