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Dobutamine echocardiography in idiopathic dilated cardiomyopathy: clinical and prognostic implications
Bruno Pinamonti1, Andrea Perkan, Andrea Di Lenarda
1Department of Cardiology, Ospedale Maggiore, Piazza Ospedale 1, 34129, Trieste, Italy. bpinamonti@hotmail.com
Insights
The dobutamine echocardiographic test (DET) in idiopathic dilated cardiomyopathy (IDCM) patients shows a positive response is linked to better outcomes. However, its added prognostic value beyond clinical assessment is limited.
Area of Science:
- Cardiology
- Diagnostic Imaging
Background:
- Dobutamine echocardiographic test (DET) is used for coronary artery disease, but its role in idiopathic dilated cardiomyopathy (IDCM) is less understood.
- Optimal medical therapy, including beta-blockade (BB), is standard for IDCM patients.
Purpose of the Study:
- To evaluate the clinical role of DET in IDCM patients.
- To determine the prognostic implications of 'contractile reserve' identified by DET in IDCM patients on optimal medical therapy.
Main Methods:
- 51 IDCM patients underwent DET at diagnosis.
- A positive DET (DET+) was defined by significant increase in left ventricular ejection fraction (LVEF) and/or reversed restrictive filling pattern.
- Improvement at follow-up was assessed using combined clinical and echo-Doppler criteria.
Main Results:
- 43% of patients were DET+.
- DET+ patients had less severe symptoms, smaller ventricles, higher LVEF, and lower pulmonary pressure.
- DET+ was associated with more favorable outcomes, but its incremental prognostic power over clinical evaluation was limited.
Conclusions:
- DET response in IDCM patients is linked to a more favorable prognosis, suggesting an earlier disease stage.
- While statistically significant, the added prognostic value of DET response in IDCM patients is of limited clinical utility.
- Further research is needed to fully clarify the prognostic value of DET in IDCM.
Abstract:
The dobutamine echocardiographic test (DET) is frequently used in coronary artery disease to detect viable myocardium, but few data are available about its role in idiopathic dilated cardiomyopathy (IDCM). The aims of this study were to evaluate the clinical role of DET and the prognostic implications of the 'contractile reserve' in patients with IDCM treated with optimal medical therapy, including beta-blockade (BB). A total of 51 patients with IDCM underwent DET at diagnosis. A positive response to DET (DET+) was judged to be a significant increase (> or =10 points) in left ventricular ejection fraction (LVEF) with a peak value > or =40%, and a reversed restrictive left ventricular filling pattern (RFP) if present at baseline study. Improvement at follow-up was defined according to combined clinical and echo-Doppler criteria. In all, 22 patients (43%) were classified as DET+. DET+ patients were less symptomatic (P<0.001), with lower heart rate (P<0.01), less enlarged left and right ventricles (P<0.0001 and P<0.05), higher LVEF (P=0.0001), less frequent RFP (P=0.01), and lower pulmonary pressure (P<0.01). At follow-up (34+/-16 months), 21 patients had improved, while four had died and seven had received a transplant. Among clinical data, NYHA classes I-II (OR=0.25, P=0.07) and BB dosage (OR=0.97, P<0.005) were significantly associated with higher transplant-free survival at multivariate analysis. The addition of DET+ (OR=0.34, P<0.05) showed a moderate but significant improvement of sensitivity, but the predictive power of the model remained low (sensitivity, 0.67; specificity, 0.55). Absence of left bundle branch block (OR=0.27, P<0.01) and BB dosage (OR=1.03, P<0.005), but not DET+, were predictive of improvement. In patients with IDCM, DET response is associated with a more favourable outcome, since it suggests an earlier stage of the disease. However, in the light of our data, the incremental prognostic power of DET response compared to clinical evaluation at enrollment, despite being significant, seems to be of limited clinical value. Further studies should be carried out in order to clarify the prognostic value of DET in IDCM patients.