Relationship Between Acute Improvement in Left Ventricular Function to 6-Month Outcomes After Cardiac Resynchronization Therapy in Patients With Chronic Heart Failure

Acute recoordination rather than functional hemodynamic improvement determines reverse remodelling by cardiac resynchronisation therapy

PURPOSE

Cardiac resynchronisation therapy (CRT) improves left ventricular (LV) function acutely, with further improvements and reverse remodelling during chronic CRT. The current study investigated the relation between acute improvement of LV systolic function, acute mechanical recoordination, and long-term reverse remodelling after CRT.

METHODS

In 35 patients, LV speckle tracking longitudinal strain, LV volumes & ejection fraction (LVEF) were assessed by echocardiography before, acutely within three days, and 6 months after CRT. A subgroup of 25 patients underwent invasive assessment of the maximal rate of LV pressure rise (dP/dt_max,) during CRT-implantation. The acute change in dP/dt_max, LVEF, systolic discoordination (internal stretch fraction [ISF] and LV systolic rebound stretch [SRSlv]) and systolic dyssynchrony (standard deviation of peak strain times [2DS-SD18]) was studied, and their association with long-term reverse remodelling were determined.

RESULTS

CRT induced acute and ongoing recoordination (ISF from 45 ± 18 to 27 ± 11 and 23 ± 12%, p < 0.001; SRS from 2.27 ± 1.33 to 0.74 ± 0.50 and 0.71 ± 0.43%, p < 0.001) and improved LV function (dP/dt_max 668 ± 185 vs. 817 ± 198 mmHg/s, p < 0.001; stroke volume 46 ± 15 vs. 54 ± 20 and 52 ± 16 ml; LVEF 19 ± 7 vs. 23 ± 8 and 27 ± 10%, p < 0.001). Acute recoordination related to reverse remodelling (r = 0.601 and r = 0.765 for ISF & SRSlv, respectively, p < 0.001). Acute functional improvements of LV systolic function however, neither related to reverse remodelling nor to the extent of acute recoordination.

CONCLUSION

Long-term reverse remodelling after CRT is likely determined by (acute) recoordination rather than by acute hemodynamic improvements. Discoordination may therefore be a more important CRT-substrate that can be assessed and, acutely restored.

Time to left ventricular reverse remodeling after cardiac resynchronization therapy: Better late than never

INTRODUCTION

Left ventricular reverse remodeling (LVRR), defined as reduction of end-diastolic and end-systolic dimensions and improvement of ejection fraction, is associated with the prognostic implications of cardiac resynchronization therapy (CRT). The time course of LVRR remains poorly characterized. Nevertheless, it has been suggested that it occurs ≤6 months after CRT.

OBJECTIVE

To characterize the long-term echocardiographic and clinical evolution of patients with LVRR occurring >6 months after CRT and to identify predictors of a delayed LVRR response.

METHODS

A total of 127 consecutive patients after successful CRT implantation were divided into three groups according to LVRR response: Group A, 19 patients (15%) with LVRR after >6 months (late LVRR); Group B, 58 patients (46%) with LVRR before 6 months (early LVRR); and Group C, 50 patients (39%) without LVRR during follow-up (no LVRR).

RESULTS

The late LVRR group was older, more often had ischemic etiology and fewer patients were in NYHA class ≤II. Overall, group A presented LVRR between group B and C. This was also the case with the percentage of clinical response (68.4% vs. 94.8% vs. 38.3%, respectively, p<0.001), and hospital readmissions due to decompensated heart failure (31.6% vs. 12.1% vs. 57.1%, respectively, p<0.001). Ischemic etiology (OR 0.044; p=0.013) and NYHA functional class <III (OR 0.056; p=0.063) were the variables with the highest predictive value for late LVRR.

CONCLUSIONS

Late LVRR has better clinical and echocardiographic outcomes than no LVRR, although with a suboptimal response compared to the early LVRR population. Ischemic etiology and NYHA functional class <III are predictors of late LVRR.

Factors associated with improvement in ejection fraction in clinical practice among patients with heart failure: findings from IMPROVE HF

BACKGROUND

Available data suggest that improvement in left ventricular ejection fraction (LVEF) is a major predictor of improved survival in heart failure (HF). Although certain factors are associated with improvements in LVEF in select patients with HF enrolled in clinical trials, relatively little is known about such factors among patients in clinical practice. This study evaluated changes in LVEF and associated factors in outpatients with systolic HF or post-myocardial infarction with reduced LVEF during 24 months of follow-up.

METHODS

IMPROVE HF is a prospective evaluation of a practice-based performance improvement intervention implemented at outpatient cardiology/multispecialty practices to increase use of guideline-recommended care for eligible patients. Data were analyzed by patient groups based on absolute improvement in LVEF (<0%, 0-≤10%, and >10%) from baseline to 24 months and by change in LVEF as a continuous variable.

RESULTS

A total of 3,994 patients from 155 of 167 practices were eligible for analysis. The overall mean LVEF increased from 25.8% at baseline to 32.3% (+6.4%) at 24 months (P < .001), and 28.6% of patients had a >10% improvement in ejection fraction (from 24.5% to 46.2%, 92% relative improvement). Age, race, and practice setting were similar between the 3 LVEF improvement groups. Multivariate analysis revealed female sex, no prior myocardial infarction, nonischemic HF etiology, and no digoxin use were associated with >10% improvement in LVEF.

CONCLUSIONS

Among patients with HF receiving care in cardiology/multispecialty practices participating in a performance measure intervention, surviving, and having repeat LVEF assessment, close to one third of patients had a >10% improvement in LVEF at 24 months. These findings indicate that HF is not always a progressive disease and that differentiation of the heterogeneous HF phenotypes may set the stage for future research and therapeutic targets.