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[Exercise echocardiography to differentiate dilated cardiomyopathy from ischemic left ventricular dysfunction]
Jesús Peteiro Vázquez1, Lorenzo Monserrat Iglesias, Eugenia Vázquez Rey
1Servicio de Cardiología Hospital Juan Canalejo, A Coruña, Spain. jpeteiro@mundo-r.com
Insights
Exercise echocardiography accurately differentiates ischemic left ventricular dysfunction (ILVD) from dilated cardiomyopathy (DC). Patients with ILVD showed impaired LV function during exercise, unlike those with DC, potentially reducing invasive procedures.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Echocardiography
Background:
- Dobutamine echocardiography is established for differentiating dilated cardiomyopathy (DC) from ischemic left ventricular dysfunction (ILVD).
- Exercise echocardiography (EE) has not been extensively studied for this differentiation.
- Contractile reserve during exercise may differ between DC and ILVD patients.
Purpose of the Study:
- To evaluate the utility of exercise echocardiography (EE) in distinguishing between dilated cardiomyopathy (DC) and ischemic left ventricular dysfunction (ILVD).
- To test the hypothesis that DC patients exhibit greater left ventricular ejection fraction (LVEF) increase during exercise compared to ILVD patients.
Main Methods:
- A study group of 82 patients with moderate to severe left ventricular (LV) dysfunction underwent maximal treadmill exercise echocardiography (EE).
- Patients were categorized into ILVD (significant coronary artery stenosis) and DC groups based on EE criteria.
- EE criteria included changes in regional wall motion and LVEF from baseline to peak exercise.
Main Results:
- The ILVD group demonstrated significantly less exercise capacity (Mets) and lower heart rate x systolic blood pressure product compared to the DC group.
- Regional and/or global LV dysfunction occurred more frequently in ILVD patients during exercise (79% vs. 28%).
- EE achieved 79% sensitivity and 72% specificity for detecting ILVD.
Conclusions:
- Exercise echocardiography is effective in identifying patients with ischemic left ventricular dysfunction (ILVD).
- Impaired global and/or regional LV function during exercise accurately identifies ILVD.
- This non-invasive method may decrease the necessity for invasive diagnostic procedures.
Objectives:
Previous studies have shown the usefulness of dobutamine echocardiography to differentiate dilated cardiomyopathy (DC) from ischemic left ventricular dysfunction (ILVD), but no studies have been made using exercise echocardiography (EE). We hypothesized that most patients with DC have some contractile reserve and experience an increase in left ventricular ejection fraction (LVEF) during exercise, as opposed to patients with ILVD. Differences in response to EE may be useful to clinically differentiate between these two entities.
Patients And Method:
Between 1 March 1995 and 1 March 2001, we performed 4,133 EE studies on 3,830 patients. Of 289 patients (8%) with moderate or severe LV dysfunction (biplane LVEF < 41% and left ventricular end-diastolic diameter > 5.2 cm), 207 were excluded: 111 for a history of myocardial infarction; 28 for scarring on echocardiography (regional akinesia/dyskinesia with thinning and/or increased brightness); 13 for previous revascularization procedures; 9 for aortic valve disease; 11 for a known cause of cardiomyopathy; and 35 for not undergoing angiography. The study group was therefore composed of 82 patients who were encouraged to perform maximal treadmill EE. EE criteria for ILVD were either impaired regional wall motion (RWM) or a decrease/no change in LVEF from baseline to peak exercise, while criteria for DC were RWM improvement/no change and LVEF increase. The ILVD group was formed by 39 patients with stenosis >/= 70% diameter stenosis of a major epicardial coronary artery or major branch vessel. The remaining 43 patients constituted the DC group.
Results:
The number of coronary risk factors (ILVD 2.0 1.1; DC 1.9 1.1), baseline LVEF (ILVD 30 7; DC 30 8), and exercise-induced angina (ILVD 23%; DC 14%) did not differ between groups (p = NS). ILVD patients achieved less Mets (6.6 3.1 vs 8.3 2.8; p < 0.05), had a lower heart rate x systolic blood pressure product (22 5 vs 27 7; p < 0.001), and developed regional and/or global LV dysfunction more frequently (79 vs 28%; p < 0.001). Sensitivity, specificity, positive and negative predictive values and global accuracy for ILVD detection were 79% (95% CI: 70-88), 72% (95% CI: 63-81), 72% (95% CI: 63-81), 79% (95% CI: 67-85), and 76% (95% CI: 69-83), respectively.
Conclusion:
Global and/or regional LV function impairment with exercise is accurate in identifying patients with ILVD. This method could reduce the need for invasive procedures.