Characterization of super-response to cardiac resynchronization therapy

Association Between Left Ventricular Ejection Fraction Post-Cardiac Resynchronization Treatment and Subsequent Implantable Cardioverter Defibrillator Therapy for Sustained Ventricular Tachyarrhythmias

“…These patients in our study were identified in a multivariable analysis as those with nonischemic cardiomyopathy and also patients who had a higher pre-CRT-D LVEF. A recent study from Rickard et al 24 demonstrated that only baseline left bundlebranch block was strongly associated with a near normalization of LVEF to CRT. However, van Bommel et al 25 also noted an association of female sex and nonischemic cardiomyopathy with this response to CRT.…”

Superresponse to Cardiac Resynchronization Therapy

“…2 Indeed, several different echocardiographic parameters characterize superresponders in different settings, including an improvement in ESVI, EDVI, and EF (Table). 2,[4][5][6][7] The cutoff values are not consistent among different studies, even if the parameter used to define superresponse is the same. Finally, some studies rely at least in part on clinical variables to define superresponse.…”

“…Patients with extensive intraventricular conduction disease (ie, wide QRS complexes) and left bundle-branch block are more likely to become superresponders to CRT. 4,5 Similarly in the MADIT-CRT trial, QRS duration of ≥150 ms and left bundle-branch block, in addition to female sex, lack of prior myocardial infarction (and hence, most likely, lack of significant scar area), body mass index <30 kg/m 2 , and smaller baseline left atrial volume index are predictive of LVEF superresponse. 7 This is consistent with the repeated observations that patients with left bundle-branch block and prolonged QRS complex (>150 ms) generally respond better to CRT (Figure 2).…”

Cardiac Resynchronization Therapy in Patients With Class I–II Heart Failure and a Wide QRS

“…This finding is supported by the fact that LV pacing itself appears to ameliorate cardiac dysfunction in a subset of patients, 18 and LBBB remains the strongest predictor of normalization of LV function in a large clinical experience. 19 Nevertheless, the assumption that all subjects have the same trajectory of clinical deterioration is unlikely, and therefore the primary end point reduced by CRT may not represent true clinical deterioration of HF. We argue that there may be too much heterogeneity in the patient population included in MADIT-CRT and REVERSE enrollment criteria.…”

“…On the basis of published reports from MADIT-CRT and REVERSE, those with nonischemic dilated cardiomyopathy and an underlying wide QRS (Ն150 ms) are more likely to have LV remodeling solely as a consequence of the conduction abnormality and are therefore more likely to respond to CRT in terms of reverse remodeling. 19 Clearly, those with QRS Ն150 ms are also more likely to have underlying LBBB than those with QRS Ͻ150 ms. The fact that hemodynamic augmentation can be achieved with biventricular pacing does not mean that they can clinically benefit from CRT.…”