Arritmias ventriculares en superrespondedores a la terapia de resincronización cardiaca

Utility of Computed Tomography to Predict Ventricular Arrhythmias in Patients With Nonischemic Cardiomyopathy Receiving Cardiac Resynchronization Therapy

The residual risk of ventricular arrhythmia (VA) after cardiac resynchronization therapy (CRT) implantation in patients with nonischemic cardiomyopathy (NICM) remains difficult to evaluate. The impact of left ventricular (LV) wall thickness (WT) measured using computed tomography (CT) on the occurrence of VA after CRT implantation has never been investigated. In this pilot study, we examined the association of LV WT and the occurrence of VA in NICM patients receiving CRT. Thirty three patients with NICM scheduled for CRT underwent preprocedural CT. Reduced LV WT was defined as WT <6 mm and quantified as a percentage of total LV area. The end point was the occurrence of VA episode during 2-years follow-up after CRT implantation. During the 2-years follow-up, a total of 37 VA episodes occurred in 6 (18.2%) patients. Patients with VA exhibited significantly higher NT-pro BNP level before CRT implantation. Additionally, CT analysis showed that patients with VA had a higher percentage of total LV with reduced WT compared with those free from VA (49.5% vs 25.8%, respectively; p = 0.005). In multivariable analysis, the total percentage of LV area with WT <6 mm was the only predictor of VA (odds ratio 1.07 [1.00 to 1.14]; p = 0.047). Receiver-operator curves analysis for total percentage of LVWT <6 mm demonstrated that an optimal cut-off value of 40% differentiated patients at risk of VA. In conclusion, LVWT evaluated using cardiac CT is an independent predictor of VA in NICM patients implanted with CRT. Patients with a total percentage of LVWT <6 mm ≥40% are especially at high risk of VA after CRT implantation.

Heart Failure Duration Combined with Left Atrial Dimension Predicts Super-Response and Long-Term Prognosis in Patients with Cardiac Resynchronization Therapy Implantation

Background

Response to cardiac resynchronization therapy (CRT) varies significantly among patients. This study aimed to identify baseline characteristics that could predict super-response to CRT and to evaluate the long-term prognosis in super-responders.

Methods

We retrospectively reviewed the data of 73 consecutive patients who received CRT. Patients were considered as super-responders after 6-month follow-up when NYHA class reduction to I or II combined with left ventricular ejection fraction (LVEF) ≥ 50% was observed. Patients were divided into super-responders group and non-super-responders group. All-cause mortality or hospitalization for heart failure (HF) was referred to the combined end point.

Results

17 (23.3%) patients were super-responders. HF duration, left atrial dimension (LAD), and left bundle branch block (LBBB) were independent predictors of super-response to CRT. The combination of HF duration and LAD could provide more robust prediction of super-response than standalone HF duration (0.899 versus 0.789, Z = 2.207, P = 0.027) or standalone LAD (0.899 versus 0.775, Z = 2.487, P = 0.013). super-responders had excellent LV reverse remodeling. The cumulative incidences of combined end point were significantly lower in the super-responders group, LAD ≤ 42mm group, and combination of HF duration ≤ 48 months and LAD ≤ 42mm group. LBBB remained associated with a lowered risk of the combined end point (HR: 0.19, 95% CI: 0.07-0.57, P = 0.003), whereas LAD was associated with a raised risk of the combined end point (HR: 1.09, 95% CI: 1.02-1.17, P = 0.014).

Conclusions

HF duration, LAD, and LBBB independently predicted super-response. The combination of HF duration and LAD makes more robust prediction of CRT super-response. Super-responders had excellent LV reverse remodeling and decreased the incidences of the combined end point. LBBB and LAD were independently associated with the combined end point.

Very long-term survival and late sudden cardiac death in cardiac resynchronization therapy patients

Aims

The very long-term outcome of patients who survive the first few years after receiving cardiac resynchronization therapy (CRT) has not been well described thus far. We aimed to provide long-term outcomes, especially with regard to the occurrence of sudden cardiac death (SCD), in CRT patients without (CRT-P) and with defibrillator (CRT-D).

Methods and results

A total of 1775 patients, with ischaemic or non-ischaemic dilated cardiomyopathy, who were alive 5 years after CRT implantation, were enrolled in this multicentre European observational cohort study. Overall long-term mortality rates and specific causes of death were assessed, with a focus on late SCD. Over a mean follow-up of 30 months (interquartile range 10–42 months) beyond the first 5 years, we observed 473 deaths. The annual age-standardized mortality rates of CRT-D and CRT-P patients were 40.4 [95% confidence interval (CI) 35.3–45.5] and 97.2 (95% CI 85.5–109.9) per 1000 patient-years, respectively. The adjusted hazard ratio (HR) for all-cause mortality was 0.99 (95% CI 0.79–1.22). Twenty-nine patients in total died of late SCD (14 with CRT-P, 15 with CRT-D), corresponding to 6.1% of all causes of death in both device groups. Specific annual SCD rates were 8.5 and 5.8 per 1000 patient-years in CRT-P and CRT-D patients, respectively, with no significant difference between groups (adjusted HR 1.0, 95% CI 0.45–2.44). Death due to progressive heart failure represented the principal cause of death (42.8% in CRT-P patients and 52.6% among CRT-D recipients), whereas approximately one-third of deaths in both device groups were due to non-cardiovascular death.

Conclusion

In this first description of very long-term outcomes among CRT recipients, progressive heart failure death still represented the most frequent cause of death in patients surviving the first 5 years after CRT implant. In contrast, SCD represents a very low proportion of late mortality irrespective of the presence of a defibrillator.

Can cardiac resynchronization therapy be used as a tool to reduce sudden cardiac arrest risk?

Patients with cardiomyopathy and reduced left ventricular (LV) ejection fraction are at risk of heart failure (HF) symptoms and sudden cardiac arrest (SCA). In selected HF patients, cardiac resynchronization therapy (CRT) provides LV reverse remodeling and improves the cellular and molecular function. However controversial results have been published regarding the effect of CRT on the residual ventricular arrhythmia risk. Indeed, the decrease in SCA risk is inconsistent and some factors strongly influence the residual post implantation arrhythmic risk. Conversely, proarrhythmic effect of CRT has been previously described. In this review we aim to describe the relationship between CRT implantation and the SCA risk decrease and discuss the patients who only require cardiac resynchronization therapy-pacemaker and those who need a concomitant implantable cardioverter defibrillator.

Cardiac resynchronization therapy pacemakers versus defibrillators in older non-ischemic cardiomyopathy patients

Introduction

With the recent publication of the negative DANISH trial, the mortality benefit of the implantable cardioverter-defibrillator (ICD) has been put in question in patients with non-ischemic cardiomyopathy (NICM). Because a majority of patients in DANISH receive cardiac resynchronization therapy (CRT) devices, we investigated in the present study the survival of recipients of CRT pacemakers (CRT-P) versus CRT ICDs (CRT-D) in a cohort of older (≥75 years) NICM patients at our institution.

Methods

A total of 135 NICM patients with CRT device were identified (42 with CRT-P and 93 with CRT-D) and were followed to the endpoint of all-cause mortality. Overall survival was compared between the CRT-P and CRT-D groups with adjustment for differences in baseline characteristics.

Results

Over a median follow-up of 46 months from the time of CRT device implantation, there were 54 total deaths (40%): 14 in the CRT-P (33%) and 40 in the CRT-D (43%) groups. Overall, CRT-P recipients had similar unadjusted mortality compared to CRT-D recipients (hazard ratio [HR] 1.04, 95% confidence interval [CI] 0.56–1.93), and this remained unchanged after adjusting for unbalanced covariates (HR 0.95, 95% CI 0.47–1.89) including left ventricular ejection fraction, used of angiotensin converting enzyme inhibitors/angiotensin receptor blockers, and the Charlson comorbidity index.

Conclusion

Our data support that in older NICM patients with CRT devices, the addition of ICD therapy does not improve survival.

Cardiac resynchronization is pro-arrhythmic in the absence of reverse ventricular remodelling: a systematic review and meta-analysis

Aims

Cardiac resynchronization therapy (CRT) has been shown to reduce mortality and heart failure (HF) hospitalization but its effects on the rate of ventricular arrhythmias (VAs) appears to be neutral. We hypothesize that CRT with LV epicardial stimulation is inherently pro-arrhythmic and increases VA rates in the absence of reverse ventricular remodelling while conferring an anti-arrhythmic effect in mechanical responders.

Methods and results

In this systematic review and meta-analysis, we considered retrospective cohort, prospective cohort, and randomized controlled trials comparing VA rates between cardiac resynchronization therapy-defibrillator (CRT-D) non-responders, CRT-D responders and those with implantable cardioverter-defibrillator (ICD) only. Studies were eligible if they defined CRT-D responders using a discrete left ventricular volumetric value as assessed by any imaging modality. Studies were identified through searching electronic databases from their inception to July 2017. We identified 2579 citations, of which 23 full-text articles were eligible for final analysis. Our results demonstrated that CRT-D responders were less likely to experience VA than CRT-D non-responders, relative risk (RR) 0.49 [95% confidence interval (CI) 0.41-0.58, P < 0.01] and also less than patients with ICD only: RR 0.59 (95% CI 0.50-0.69, P < 0.01). However, CRT-D mechanical non-responders had a greater likelihood of VA compared with ICD only, RR 0.76 (95% CI 0.63-0.92, P = 0.004).

Conclusion

CRT-D non-responders experienced more VA than CRT-D responders and also more than those with ICD only, suggesting that CRT with LV epicardial stimulation may be inherently pro-arrhythmic in the absence of reverse remodelling.

Cardiac resynchronization therapy is associated with a reduction in ICD therapies as it improves ventricular function

BACKGROUND

Repeated implantable cardioverter-defibrillator (ICD) therapies cause myocardial damage and, thus, an increased risk of arrhythmias and mortality.

HYPOTHESIS

Cardiac resynchronization therapy-defibrillator (CRT-D) reduces the number of appropriate therapies in patients with left ventricular dysfunction (left ventricular ejection fraction [LVEF] <50%).

METHODS

The retrospective study involved 175 consecutive patients (mean age, 64.6 ±10.4 years; 86.9% males) with reduced LVEF of 27.9% ±7.6% treated with an ICD (56.6%) or CRT-D (43.4%), according to standard indications, between January 2009 and July 2014. Devices were placed for either primary (54.3%) or secondary prevention (45.7%). Mean follow-up was 2.5 ±1.5 years. Predictors of first appropriate therapy were assessed using Cox regression analysis.

RESULTS

Forty-four (25.1%) patients received ≥1 appropriate therapy. Although patients treated with CRT-D had lower LVEF and poorer New York Heart Association class, CRT-D patients with LVEF improvement >35% at the end of follow-up had a significantly lower risk of receiving a first appropriate therapy relative to those with an ICD (adjusted hazard ratio: 0.24, 95% confidence interval: 0.07-0.83, P = 0.025), independently of ischemic cardiomyopathy, baseline LVEF, and secondary prevention. There were no differences in mortality between the ICD and the CRT-D groups.

CONCLUSIONS

Although patients receiving CRT-D had a worse clinical profile, they received fewer device therapies in comparison with those receiving an ICD. This reduction is associated with a significant improvement in LVEF.

Characteristics and prognosis of heart failure with improved compared with persistently reduced ejection fraction: A systematic review and meta-analyses

Aims We assessed the clinical characteristics and prognosis of chronic heart failure patients with improved ejection fraction (HFIEF) compared with persistently reduced ejection fraction (HFpREF) after evidence-based therapy. Methods and results We performed a meta-analysis including 24 eligible observational studies comparing 2663 HFIEF (≥5% left ventricular ejection fraction (LVEF) improvement) versus 8355 HFpREF patients who received recommended drug therapy, cardiac resynchronization therapy and/or intracardiac defibrillator. LVEF was assessed at baseline and reassessed after 19 ± 19 months. The primary endpoints were all-cause mortality and appropriate shocks. The mean duration of follow-up was 39 ± 12 months. Among HFIEF patients, LVEF improved 16.3 percentage points (95% confidence interval 15.9-16.6, p < 0.0001). Compared with HFpREF patients, HFIEF patients had a comparable mean age (60.9 years vs. 62.4 years, p = 0.11), were more often women (33% vs. 25%), had a higher prevalence of non-ischaemic heart failure (58% vs. 53%), less diabetes (27% vs. 28%), higher systolic blood pressure (127.5 ± 9 vs. 122 ± 12 mmHg) and lower left ventricle end-diastolic diameter (64.1 ± 3.7 vs. 67.4 ± 4.9 mmHg), all p-values < 0.05. Absolute risk of all-cause mortality was lower in HFIEF (5.8%) compared with HFpREF (17.5%) with a risk ratio of 0.34 (95% confidence interval 0.28-0.41), p < 0.001. Risk of appropriate shocks was significantly lower in HFIEF versus HFpREF (risk ratio 0.58 (95% confidence interval 0.46-0.74), p < 0.001). Conclusion In heart failure patients, we identified several baseline characteristics in favour of an improved LVEF, in response to evidence based therapy. Patients with improved LVEF had significantly lower risks of mortality and appropriate shocks compared with patients with persistently reduced LVEF.

Predicting Ventricular Arrhythmias in Cardiac Resynchronization Therapy: The Impact of Persistent Electrical Dyssynchrony

BACKGROUND

Although response to cardiac resynchronization therapy (CRT) has been conventionally assessed with left ventricular volume reduction, ventricular arrhythmias (ventricular tachycardia/ventricular fibrillation [VT/VF]) are of critical importance associated with unfavorable outcomes even in the "superresponders" to therapy. We evaluated the predictors of VT/VF and the association of residual dyssynchrony during follow-up.

METHODS

Ninety-five patients receiving CRT were followed-up for 9 ± 3 months. Post-CRT dyssynchrony was defined as a prolonged QRS duration (QRSd) for persistent electrical dyssynchrony (ED), and a Yu index ≥ 33 ms for persistent mechanical dyssynchrony. The first VT/VF episode, including nonsustained VT detected on device interrogation and/or appropriate antitachycardia pacing or shock for VT/VF, were the end points of the study.

RESULTS

Forty-five patients who reached the study end points had significantly lower mean ΔQRS (baseline QRSd - post-CRT QRSd) values than those without VT/VF (-20.8 ± 28.9 ms vs -6.6 ± 30.7 ms, P = 0.022). Both the baseline and post-CRT QRSds, along with the Yu index values, were not different in two groups. Patients with VT/VF were statistically more likely to have persistent ED (38% vs 9%, P = 0.021). Kaplan-Meier curves showed that a negative ΔQRS was associated with a higher incidence of VT/VF during follow-up (P = 0.016). A multivariate Cox model revealed that QRS prolongation was an independent predictor of VT/VF after CRT (P = 0.029).

CONCLUSIONS

A negative ΔQRS, also called persistent ED, is associated with VT/VF. Narrowest possible QRSd might be a reliable goal of both implantation and optimization of devices to reduce arrhythmic events after CRT.

Reduced appropriate implantable cardioverter-defibrillator therapy after cardiac resynchronization therapy-induced left ventricular function recovery: a meta-analysis and systematic review

AIMS

For patients undergoing cardiac resynchronization therapy (CRT) with implantable cardioverter-defibrillator (ICD; CRT-D), the effect of an improvement in left ventricular ejection fraction (LVEF) on appropriate ICD therapy may have significant implications regarding management at the time of ICD generator replacement.

METHODS AND RESULTS

We conducted a meta-analysis to determine the effect of LVEF recovery following CRT on the incidence of appropriate ICD therapy. A search of multiple electronic databases identified 709 reports, of which 6 retrospective cohort studies were included (n = 1740). In patients with post-CRT LVEF ≥35% (study n = 4), the pooled estimated rate of ICD therapy (5.5/100 person-years) was significantly lower than patients with post-CRT LVEF <35% [incidence rate difference (IRD): -6.5/100 person-years, 95% confidence interval (95% CI): -8.8 to -4.2, P < 0.001]. Similarly, patients with post-CRT LVEF ≥45% (study n = 4) demonstrated lower estimated rates of ICD therapy (2.3/100 person-years) compared with patients without such recovery (IRD: -5.8/100 person-years, 95% CI: -7.6 to -4.0, P < 0.001). Restricting analysis to studies discounting ICD therapies during LVEF recovery (study n = 3), patients with LVEF recovery (≥35 or ≥45%) had significantly lower rates of ICD therapy compared with patients without such recovery (P for both <0.001). Patients with primary prevention indication for ICD, regardless of LVEF recovery definition, had very low rates of ICD therapy (0.4 to 0.8/100-person years).

CONCLUSION

Recovery of LVEF post-CRT is associated with significantly reduced appropriate ICD therapy. Patients with improvement of LVEF ≥45% and those with primary prevention indication for ICD appear to be at lowest risk.