Left ventricular pacing site (LV-PS) was prospectively collected to test the influence of the anatomical LV-PS on the outcome of cardiac resynchronization therapy (CRT) and mortality. Four hundred... Show moreLeft ventricular pacing site (LV-PS) was prospectively collected to test the influence of the anatomical LV-PS on the outcome of cardiac resynchronization therapy (CRT) and mortality. Four hundred and twenty-six patients with standard indications for CRT underwent echocardiographic and clinical evaluation before and after CRT implantation. The LV-PS was determined from fluoroscopy using the clockwise principle (CP). The LV-PS was categorized into three prospectively defined groups: between 3 and 5 o'clock and longitudinal basal/mid-position (Group A, 'optimal'); between 12 and 2 o'clock and longitudinal mid-apical anterior position (Group B, 'non-optimal'); and all other (Group C, 'other'). Of 333 patients, followed for 0.9 years (mean), adequate images were available to define the LV-PS. Left ventricular pacing site was Group A for 118 patients, Group B for 56, and Group C for 159. The three groups were comparable regarding gender, aetiology, and NYHA class; however, patients in Group A were younger. No relation was found between the LV-PS groups and CRT outcome or all-cause mortality. However, further exploratory subanalyses suggest that LV-PS may impact outcomes in non-ischaemic patients, those with left bundle branch block, and when LV-PS is apical in location. Using the CP to define anatomical LV-PS, no relation was found between the LV-PS groups and CRT outcome and mortality. Exploratory analyses warrant further studies. Show less
Introduction Current guidelines recommend cardiac resynchronisation therapy (CRT) in patients with severe symptomatic heart failure, depressed left ventricular (LV) systolic function and a wide QRS... Show moreIntroduction Current guidelines recommend cardiac resynchronisation therapy (CRT) in patients with severe symptomatic heart failure, depressed left ventricular (LV) systolic function and a wide QRS complex (>= 120 ms). However, patients with heart failure having a narrow QRS complex might also benefit from CRT. Design setting patients interventions During the Predictors of Response to Cardiac Resynchronisation Therapy (PROSPECT) trial, 41 patients were enrolled in a 'narrow' QRS sub-study. These patients had a QRS complex <130 ms, but documented evidence of mechanical dyssynchrony by any of seven pre-defined echocardiographic measures. Results After 6 months of CRT, 26 (63.4%) patients showed improvement according to the Clinical Composite Score, 4 (9.8%) remained unchanged and 11 (26.8%) worsened. In patients with paired data, the 6-min walking distance increased from 334 +/- 118 m to 382 +/- 128 m, (p=0.003) and quality-of-life score improved from 44.2 +/- 19.7 to 26.8 +/- 20.2 (p<0.0001). Furthermore, there was a significant decrease in LV end-systolic diameter (from 59 +/- 9 to 55 +/- 12 mm, p=0.002) and in LV end-diastolic diameter (from 67 +/- 9 to 63 +/- 11 mm, p=0.007). Conclusion The results suggest that CRT may have a beneficial effect in heart failure patients with a narrow QRS complex and mechanical dyssynchrony as assessed by echocardiography. The majority of patients improved on clinical symptoms, and there was an evident reduction in LV diameters. Larger studies are needed to clearly define selection criteria for CRT in patients with a narrow QRS complex. Show less
Cardiac resynchronization therapy (CRT) is currently limited to those with left ventricular ejection fraction (LVEF) < 35%. To evaluate whether patients with LVEF > 35% might benefit from CRT... Show moreCardiac resynchronization therapy (CRT) is currently limited to those with left ventricular ejection fraction (LVEF) < 35%. To evaluate whether patients with LVEF > 35% might benefit from CRT, we performed a retrospective analysis of the predictors of response to CRT (PROSPECT) database. PROSPECT was a prospective, multicentre study that enrolled CRT patients based on enrolling centre-evaluated LVEF < 35%, but all echocardiograms were subsequently analysed by a core laboratory. Patients with core laboratory-measured LVEF > 35% (OVER35) were compared with those whose LVEF was < 35% (UNDER35). Clinical composite score (CCS) and change in LV end systolic volume (LVESV) were analysed from baseline to 6-month follow-up. Of 361 patients, 86 (24%) had LVEF > 35%. At entry, OVER35 had smaller LV volumes, shorter QRS duration, shorter 6-min walk distance, and were more likely to have ischaemic aetiology than UNDER35. Outcomes were comparable between the groups, with 62.8% of OVER35 improved in CCS (70.2% in UNDER35) and 50.8% of OVER35 improved in LVESV (57.8% in UNDER35). Patients with LVEF > 35%, New York heart association functional Class III-IV status, and QRS > 130 ms appear to derive clinical and structural benefit from CRT. As CRT may offer a valuable option for these patients, this hypothesis should be formally tested in a prospective, randomized multicentre trial. Show less
