Usefulness and limitation of dobutamine stress echocardiography to predict acute response to cardiac resynchronization therapy.
BACKGROUND
It has been hypothesized that a long-term response to cardiac resynchronization therapy (CRT) could correlate with myocardial viability in patients with left ventricular (LV) dysfunction. Contractile reserve and viability in the region of the pacing lead have not been investigated in regard to acute response after CRT.


METHODS
Fifty-one consecutive patients with advanced heart failure, LV ejection fraction <or= 35%, QRS duration > 120 ms, and intraventricular asynchronism >or= 50 ms were prospectively included. The week before CRT implantation, the presence of viability was evaluated using dobutamine stress echocardiography. Acute responders were defined as a >or=15% increase in LV stroke volume.


RESULTS
The average of viable segments was 5.8 +/- 1.9 in responders and 3.9 +/- 3 in nonresponders (P = 0.03). Viability in the region of the pacing lead had an excellent sensitivity (96%), but a low specificity (56%) to predict acute response to CRT. Mitral regurgitation (MR) was reduced in 21 patients (84%) with acute response. The presence of MR was a poor predictor of response (sensibility 93% and specificity 17%). However, combining the presence of MR and viability in the region of the pacing lead yields a sensibility (89%) and a specificity (70%) to predict acute response to CRT.


CONCLUSIONS
Myocardial viability is an important factor influencing acute hemodynamic response to CRT. In acute responders, significant MR reduction is frequent. The combined presence of MR and viability in the region of the pacing lead predicts acute response to CRT with the best accuracy.
Sénéchal
Mario
M
Department of Cardiology, Institut de Cardiologie de Québec, Hôpital Laval, Québec, Canada. mario.senechal@crhl.ulaval.ca
Lancellotti
Patrizio
P
Garceau
Patrick
P
Champagne
Jean
J
Dubois
Michelle
M
Magne
Julien
J
Blier
Louis
L
Molin
Frank
F
Philippon
François
F
Dumesnil
Jean G
JG
Pierard
Luc
L
O'Hara
Gilles
G
D002304:Cardiac Pacing, Artificial / Q000379:methods*; D004280:Dobutamine; D004452:Echocardiography / Q000379:methods*; D005080:Exercise Test / Q000379:methods; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000000981:diagnostic imaging* / Q000517:prevention & control*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D014665:Vasodilator Agents; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000209:etiology / Q000517:prevention & control*
D014665:Vasodilator Agents; D004280:Dobutamine