Acute contractile recovery extent during biventricular pacing is not associated with follow-up in patients undergoing resynchronization.

Background: It has been reported that contractility, as assessed using dobutamine infusion, is independently associated with reverse remodeling after CRT. Controversy, however, exists about the capacity of this approach to predict a long-term clinical response. This study's purpose was to assess whether long-term CRT clinical effects can be predicted according to acute inotropic response induced by biventricular stimulation (CRT on), as compared with AAI-VVI right stimulation pacing mode (CRT off), quantified at the time of implantation.
Methods: In 98 patients (ejection fraction 29 ± 10%), acute changes in left ventricular (LV) elastance ( Ees ), arterial elastance ( Ea ), and Ees / Ea , as assessed from slope changes of the force-frequency relation obtained when the heart rate increased, and also assessed while measuring triplane LV volumes and continuous noninvasive blood pressure, were related to death or rehospitalization during a 3-year follow-up. Other covariances tested were age, gender, disease etiology, QRS duration, amount of mitral regurgitation, LV diastolic volume, ejection fraction, and the degree of asynchrony and longitudinal strain at baseline.
Results: There was a marked increment in the Ees slope with CRT (interaction P  = 0.004), no Ea change, and modest Ees / Ea increase (interaction P  < 0.05). In Cox analysis, however, neither slope changes nor baseline values of Ees , Ea , and Ees / Ea were associated with long-term follow-up. Only ventricular diastolic volume (direct relation P  = 0.002) and QRS duration (inverse relation P  = 0.009) predicted death/rehospitalization.
Conclusions: Acute contractile recovery in CRT patients is not associated with 3 years prognosis. Instead, death or rehospitalization can be predicted from QRS duration and LV diastolic volume at baseline.