Left Atrial Volume and the Benefit of Cardiac Resynchronization Therapy in the MADIT-CRT Trial

N-terminal pro atrial natriuretic peptide as a prognostic marker of cardiac resynchronization therapy recipients

Background

Although the dynamic changes of atrial natriuretic peptide (ANP) expressions in a failing heart are well-documented, the clinical implications of detailed measurements of each ANP molecular form processed from proANP remain unclear.

Methods

Patients screening was conducted on patients who were eligible for cardiac resynchronization therapy (CRT) between 2014 and 2019 in our institution. Blood samples and echocardiographic parameters were collected on the day before and six months after implantation. Total ANP, proANP, and N-terminal fragment of proANP (NT-proANP) were examined as predictive biomarkers for cardiac death, left ventricular assist device implantation, and heart failure hospitalization following CRT implantation.

Results

A total of 86 subjects (mean age 70 years, 64 males) who underwent successful CRT implantation were enrolled. Plasma levels of total ANP, proANP, and NT-proANP were not normally distributed [25.8 pM (interquartile range: 11.1-53.1), 2.2 pM (1.0-5.4), and 4.1 nM (2.4-7.1), respectively]. Over a median follow-up of 2.7 years, 31 patients (2 deaths and 29 heart failure hospitalizations) reached the endpoints. Among the different ANP forms, only NT-proANP emerged as an independent predictor of the composite outcome (adjusted odds ratio of 2.542 in those with levels above vs. below the median, 95 % confidence interval 1.151-5.615, p = 0.021). NT-proANP levels were associated with left atrial volume and left diastolic functional parameters and decreased in response to echocardiographic improvements at six months post-implantation (16 ± 44 % decrease in responders vs 18 ± 60 % increase in non-responders, p = 0.005).

Conclusion

Pre-implantation NT-proANP levels could serve as a predictive factor for clinical outcomes in recipients of CRT.

Cardiac Resynchronization Therapy and Left Atrial Remodeling: A Novel Insight?

Cardiac resynchronization therapy (CRT) restores ventricular dyssynchrony, improving left ventricle (LV) systolic function, symptoms, and outcome in patients with heart failure, systolic dysfunction, and prolonged QRS interval. The left atrium (LA) plays tremendous roles in maintaining cardiac function, being often inflicted in various cardiovascular diseases. LA remodeling implies structural-dilation, functional-altered phasic functions, and strain and electrical-atrial fibrillation remodeling. Until now, several important studies have approached the relationship between LA and CRT. LA volumes can predict responsiveness to CRT, being also associated with improved outcome in these patients. LA function and strain parameters have been shown to improve after CRT, especially in those who were positive responders to it. Further studies still need to be conducted to comprehensively characterize the impact of CRT on LA phasic function and strain, and, also, in conjunction with its impact on functional mitral regurgitation and LV diastolic dysfunction. The aim of this review was to provide an overview of current available data regarding the relation between CRT and LA remodeling.

The saga of dyssynchrony imaging: Are we getting to the point

Cardiac resynchronisation therapy (CRT) has an established role in the management of patients with heart failure, reduced left ventricular ejection fraction (LVEF < 35%) and widened QRS (>130 msec). Despite the complex pathophysiology of left ventricular (LV) dyssynchrony and the increasing evidence supporting the identification of specific electromechanical substrates that are associated with a higher probability of CRT response, the assessment of LVEF is the only imaging-derived parameter used for the selection of CRT candidates.

This review aims to (1) provide an overview of the evolution of cardiac imaging for the assessment of LV dyssynchrony and its role in the selection of patients undergoing CRT; (2) highlight the main pitfalls and advantages of the application of cardiac imaging for the assessment of LV dyssynchrony; (3) provide some perspectives for clinical application and future research in this field.

Conclusion

the road for a more individualized approach to resynchronization therapy delivery is open and imaging might provide important input beyond the assessment of LVEF.

Left atrial reverse remodeling predicts long-term survival after cardiac resynchronization therapy

BACKGROUND

Left ventricular (LV) reverse remodeling has been identified as a strong predictor of long-term survival in patients receiving CRT. Interestingly, CRT induces reverse remodeling in the left atrium (LA) as well. It is currently unknown to what extent LA reverse remodeling is correlated to long-term survival after CRT. This study aims to assess the long-term prognostic value of left atrium (LA) reverse remodeling in patients undergoing cardiac resynchronization therapy (CRT).

METHODS

Baseline and 3-months follow-up echocardiograms after CRT implantation were prospectively assessed to determine changes in left ventricular end-systolic volume (LVESV), left ventricular ejection fraction (LVEF), left atrial volume (LAV), and left atrial reservoir strain (LAS_r). Multivariate Cox regression analysis was performed to identify predictors for long-term survival.

RESULTS

In our study population of 99 patients with a mean follow-up of 6.3 ± 2.1 years, 43 patients (43%) reached the end-point of all-cause mortality. More extensive LA reverse remodeling, as measured by a relative increase in LAS_r, was observed in survivors compared to non-survivors (43 [29-64] % vs. 8 [2-28] %, P < 0.001, respectively). After multivariate analysis, delta LAS_r remained the only significant predictor of mortality [HR per 5%: 0.90 (0.86-0.95); AUC 0.78 (0.68-0.88)].

CONCLUSION

An increase in LAS_r is associated with favorable long-term outcome after CRT. The observed clinical importance of LA reverse remodeling after CRT asks for further validation in larger prospective cohorts.

Improvement in quality of life and cardiac function after catheter ablation for asymptomatic persistent atrial fibrillation

BACKGROUND

Catheter ablation (CA) for atrial fibrillation (AF) is widely performed. However, the indication for CA in patients with asymptomatic persistent AF is still controversial.

METHODS

Among 259 consecutive patients who were hospitalized for initial CA of AF, a total of 45 patients who had asymptomatic persistent AF were retrospectively analyzed. Quality of life (QOL) before and 1 year after CA was evaluated, and changes in the cardiac function over 5 years after CA were also examined. QOL was assessed using the AF QOL questionnaire (AFQLQ) developed by the Japanese Heart Rhythm Society. In addition, cardiac function was assessed by measuring the plasma B-type natriuretic peptide (BNP) level, left ventricular ejection fraction (LVEF), left atrial diameter (LAD) with transthoracic echocardiogram, and left atrial (LA) volume with computed tomography (CT).

RESULTS

The AFQLQ significantly improved after CA in terms of "symptom frequency" and "activity limits and mental anxiety." The plasma BNP level, LVEF, and LAD significantly improved in the first 3 months after the first CA, with no significant changes thereafter (from 149.0 pg/dL [95% confidence intervals {CI}, 114.5-183.5 pg/dL] to 49.8 pg/dL [95% CI, 26.5-70.1], P < .0001; from 60.8% [95% CI, 58.1%-63.6%] to 65.0% [95% CI, 62.6-67.4], P = .001; and from 41.3 mm [95% CI, 39.7-42.9] to 36.8 [95% CI, 34.5-39.1 mm], P < .0001, respectively). LA volume revealed LA reverse remodeling after CA.

CONCLUSION

Improvement in the QOL and cardiac function after CA of asymptomatic persistent AF was revealed. Asymptomatic persistent AF should be appropriately treated by CA.

Predictors of rhythm outcomes after cardiac resynchronization therapy in atrial fibrillation patients: When should we use an atrial lead?

BACKGROUND

Cardiac resynchronization therapy (CRT) is widely used in atrial fibrillation (AF) patients and could impact rhythm stability.

HYPOTHESIS

We aimed to identify predictors of sinus rhythm (SR) stability or AF progression in a real-word cohort of CRT-AF patients.

METHODS

From 330 consecutive implantable cardioverter-defibrillator implantations due to ischemic or dilated cardiomyopathy, 65 (20%) patients with AF history (paroxysmal, n = 32) underwent a CRT implantation with an atrial electrode and were regularly followed every 4-6 months. Rhythm restoration was attempted for most AF patients based on symptoms, biventricular pacing (BP), and lack of thrombi.

RESULTS

After 33 months, 18 (28%) patients progressed to permanent mode switch (MS≥99%) and 20 (31%) patients had stable SR (MS < 1%). Logistic regression showed that history of persistent AF (OR: 8.01, 95%CI: 2.0-31.7, p = .003) is associated with higher risk of permanent MS. In persistent AF patients, a bigger left atrium (OR: 1.2 per mm, 95%CI: 1.03-1.4, p = .025) and older age (OR: 1.15 per life-year, 95%CI: 1.01-1.3, p = .032) were predictors of future permanent MS. Paroxysmal AF at implantation (OR: 5.96, 95%CI: 1.6-21.9, p = .007) and increased BP (OR: 1.4 per 1%, 95%CI: 1.05-1.89, p = .02) were associated with stable SR. In persistent AF patients, stable SR correlated with higher BP (98 ± 2 vs. 92 ± 8%, p < .001).

CONCLUSION

In patients with AF undergoing CRT implantation, persistent AF, LA dilatation and advanced age relate to future permanent MS (AF), whereas high BP promotes SR stability. These findings could facilitate the management of CRT-AF patients and guide therapy in order to maximize its effect on rhythm.

Association Between Subcutaneous Implantable Cardioverter Defibrillator Preimplantation Screening and the Response to Cardiac Resynchronization Therapy

Background and Objectives

Preimplantation QRS-T morphology screening (TMS) is a composite tool for selecting subcutaneous implantable cardioverter defibrillator (S-ICD) candidates. However, its role in predicting the patient's response to cardiac resynchronization therapy (CRT) is uncertain.

Methods

A total of 55 consecutive de novo CRT candidates were enrolled between January 2016 and March 2017. Electrocardiogram (ECG) and TMS were performed before and soon after implantation. The ECG parameters were recorded, including QRS duration and morphology (such as ΔQRS_Index, QTc during biventricular pacing mode [BiV pacing QTc], and QRS/T ratio during biventricular pacing mode [BiV pacing QRS/T ratio]). TMS monitored three sensory vectors of the S-ICD. Six months after implantation, the responses to CRT were evaluated.

Results

Thirty-nine patients (70.9%) passed the TMS during biventricular pacing mode. At the six-month follow-up, the number of responders and super-responders was significantly higher in the passing group than in the non-passing group (responders: 31/39 [79.5%] vs. 5/16 [31.3%], p<0.001; super-responders: 9/39 [23.1%] vs. 1/16 [6.3%], p=0.020). The super-response rate was higher among patients who passed all three vectors than among those who passed 1 or 2 vectors (3 vs. 2 vectors, p=0.018; 3 vs. 1 vector, p=0.003). A smaller left atrial diameter, vectors that passed TMS during biventricular pacing mode, and larger ΔQRS_Index values were independently associated with good CRT response.

Conclusions

Our study demonstrated that patients on CRT who pass the TMS during biventricular pacing mode are more likely to respond and super-respond to CRT.

Left ventricular response after cardiac resynchronization therapy is related to early left atrial volume reduction

BACKGROUND/AIMS

The current study aimed to elucidate a time-course change in left atrial volume after cardiac resynchronization therapy (CRT) and to verify factors associated with left atrial volume reduction (LAVR) and its prognostic implications.

METHODS

The records of 97 patients were retrospectively reviewed after CRT. Echocardiographic data were analyzed at baseline before CRT, at early follow-up (FU) (≤ 1 year, median 6 months), and at late FU (median 30 months). Left ventricular volume response (LVVR) was defined as 15% reduction in left ventricular (LV) end-systolic volume (ESV). LAVR was classified into two groups by the median value at early FU: LAVR (≥ 7.5%) and no LAVR (< 7.5%).

RESULTS

LV ESV index continuously decreased from baseline to early FU and from early FU to late FU (106.1 ± 47.4 mL/m2 vs. 87.6 ± 51.6 mL/m2 vs. 72.5 ± 57.1 mL/m2). LA volume index decreased from baseline to early FU, but there were no reductions thereafter (51.8 ± 21.9 mL/m2 vs. 45.1 ± 19.6 mL/m2 vs. 44.9 ± 23.0 mL/m2). The only echocardiographic factor associated with LAVR was change in E velocity (odds ratio [OR], 1.04; p = 0.002). Early LAVR (OR, 10.05; p = 0.002) was an independent predictor for late LVVR.

CONCLUSION

LAVR was related to reduction in E velocity, suggesting its relation with optimization of LV filling pressure. Early LAVR was a predictor for LVVR to CRT in long-term FU.

Is extensive atrial fibrosis in the setting of heart failure associated with a reduced atrial fibrillation burden?

Atrial fibrillation (AF) affects 10-50% of patients with chronic heart failure (HF) and is associated with poor long-term prognosis. AF is commonly associated with atrial structural remodeling (ASR), principally characterized by atrial dilatation and fibrosis. However, the occurrence of AF in the full spectrum of ASR encountered in patients with HF is poorly defined. Experimental studies have presented evidence that extensive ASR can be accompanied with a reduced burden of AF, secondary to a prominent depression of atrial excitability. This reduction in AF burden is associated with severe atrial fibrosis rather than with dilatation. Clinical studies of patients with HF point to the possibility that advanced ASR is associated with a less frequent AF occurrence than moderate ASR. Our goal in this review is to introduce the hypothesis that AF is less likely to occur in severe versus moderate atrial ASR in the setting of HF and that it is severe atrial fibrosis-associated depression of atrial excitability that reduces AF burden.

Left atrial volume and cardiovascular outcomes in systolic heart failure: effect of antithrombotic treatment

AIMS

Left atrium (LA) dilation is associated with adverse cardiovascular (CV) outcomes. Blood stasis, thrombus formation and atrial fibrillation may occur, especially in heart failure (HF) patients. It is not known whether preventive antithrombotic treatment may decrease the incidence of CV events in HF patients with LA enlargement. We investigated the relationship between LA enlargement and CV outcomes in HF patients and the effect of different antithrombotic treatments.

METHODS AND RESULTS

Two-dimensional echocardiography with LA volume index (LAVi) measurement was performed in 1148 patients with systolic HF from the Warfarin versus Aspirin in Reduced Ejection Fraction (WARCEF) trial. Patients were randomized to warfarin or aspirin and followed for 3.4 ± 1.7 years. While the primary aim of the trial was a composite of ischaemic stroke, death, and intracerebral haemorrhage, the present report focuses on the individual CV events, whose incidence was compared across different LAVi and treatment subgroups. After adjustment for demographics and clinical covariates, moderate or severe LA enlargement was significantly associated with total death (hazard ratio 1.6 and 2.7, respectively), CV death (HR 1.7 and 3.3), and HF hospitalization (HR 2.3 and 2.6) but not myocardial infarction (HR 1.0 and 1.4) or ischaemic stroke (1.1 and 1.5). The increased risk was observed in both patients treated with warfarin or aspirin. In warfarin-treated patients, a time in therapeutic range >60% was associated with lower event rates, and an interaction between LAVi and time in therapeutic range was observed for death (P = 0.034).

CONCLUSIONS

In patients with systolic HF, moderate or severe LA enlargement is associated with death and HF hospitalization despite treatment with antithrombotic medications. The possibility that achieving a more consistent therapeutic level of anticoagulation may decrease the risk of death requires further investigation.

Current role of echocardiography in cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) is an established treatment for patients with heart failure and left ventricular systolic dysfunction. Patients are usually assessed by echocardiography, which provides a number of anatomical and functional information used for cardiac dyssynchrony assessment, prognostic stratification, identification of the optimal site of pacing in the left ventricle, optimization of the CRT device, and patient follow-up. Compared to other cardiac imaging techniques, echocardiography has the advantage to be non-invasive, repeatable, and safe, without exposure to ionizing radiation or nefrotoxic contrast. In this article, we review current evidence about the role of echocardiography before, during, and after the implantation of a CRT device.

Mid-regional pro-atrial natriuretic peptide to predict clinical course in heart failure patients undergoing cardiac resynchronization therapy

Aims

Cardiac resynchronization therapy (CRT) induces reverse cardiac remodelling in heart failure (HF), but many patients receiving CRT remain non-responders. This study assessed the role of amino-terminal-pro-B-type natriuretic peptide (NT-proBNP), mid-regional-pro-atrial natriuretic peptide (MR-proANP), and mid-regional-pro-adrenomedullin (MR-proADM) at the time of device implantation to predict favourable clinical course (CRT response and/or risk of MACE) in HF patients receiving CRT.

Methods and results

A total of 137 HF patients were prospectively included. Blood was drawn from the coronary sinus (CS) at CRT implantation, and from a peripheral vein (PV) simultaneously and after 6 months. Clinical CRT response at 6 months and major adverse cardiovascular events (MACE) at 2 years were assessed. Baseline PV-levels of MR-proANP (202 vs. 318 pmol/L, P = 0.009) and MR-proADM (843 vs. 1112 pmol/L, P = 0.02) were lower in CRT responders compared with non-responders. At 6 months, CRT responders showed a decrease in MR-proANP levels, compared with an increase in non-responders (-32 vs. +7 pmol/L, P = 0.02). During the same period, NT-proBNP decreased by a similar way in responders and non-responders, while MR-proADM was unchanged in both groups. High baseline MR-proANP, either in PV (OR 0.41, 95% CI 0.24-0.71, P = 0.002) or CS (OR 0.32, 95% CI 0.15-0.70, P = 0.005) was associated with reduced likelihood of CRT response. Furthermore, PV and CS levels of NT-proBNP, MR-proANP, and MR-proADM were all associated with increased risk of 2-year MACE (all P < 0.01).

Conclusion

Mid-regional-pro-atrial natriuretic peptide may assist prediction of clinical course in HF patients undergoing CRT implantation. Low circulating MR-proANP at the time of device implantation is associated with CRT response and more favourable outcome.

Clinical Implications of Complete Left-Sided Reverse Remodeling With Cardiac Resynchronization Therapy: A MADIT-CRT Substudy

BACKGROUND

Clinical implications of complete left-sided reverse remodeling due to cardiac resynchronization therapy with a defibrillator (CRT-D), defined as reduction in both left ventricular end-systolic volume (LVESV) and left atrial volume (LAV), are unknown.

OBJECTIVES

This study aimed to evaluate the rate and predictive value of complete left-sided reverse remodeling on heart failure (HF) and death events in CRT-D patients with left bundle branch block (LBBB) enrolled in MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy).

METHODS

The study population comprised 533 CRT-D patients with LBBB, 212 (40%) with complete left-sided reverse remodeling (above-median change in both LAV and LVESV), 115 (22%) with discordant reverse remodeling (above-median change in only LAV or LVESV), and 206 (38%) with lesser reverse remodeling (below-median LAV and LVESV change). The primary endpoint was HF or death; secondary endpoints included HF alone and death alone during long-term follow-up.

RESULTS

Patients with complete left-sided reverse remodeling had a significantly lower rate of HF or death than those with discordant reverse remodeling or lesser reverse remodeling (p < 0.001). Multivariate Cox proportional hazard models consistently showed a decreased risk for HF and death in patients with complete reverse remodeling compared with discordant reverse remodeling or lesser reverse remodeling (hazard ratio: 0.66 per each group; 95% CI: 0.50 to 0.85; p = 0.002). This finding was similar for HF alone and death alone.

CONCLUSIONS

In MADIT-CRT, >20% of CRT-D patients exhibited discordant reverse remodeling in the left ventricle and the left atrium. CRT-D patients with LBBB and complete left-sided reverse remodeling had a significantly lower risk of HF and death, HF alone, and death alone during long-term follow-up than patients with discordant or lesser reverse remodeling. (MADIT-CRT: Multicenter Automatic Defibrillator Implantation With Cardiac Resynchronization Therapy [MADIT-CRT]; NCT00180271).

Position paper for management of elderly patients with pacemakers and implantable cardiac defibrillators: Groupe de Rythmologie et Stimulation Cardiaque de la Société Française de Cardiologie and Société Française de Gériatrie et Gérontologie

Despite the increasingly high rate of implantation of pacemakers (PMs) and implantable cardioverter defibrillators (ICDs) in elderly patients, data supporting their clinical and cost-effectiveness in this age stratum are ambiguous and contradictory. We reviewed the data regarding the applicability, safety and effectiveness of conventional pacing, ICDs and cardiac resynchronization therapy (CRT) in elderly patients. Although periprocedural risk may be slightly higher in the elderly, the implantation procedure for PMs and ICDs is still relatively safe in this age group. In older patients with sinus node disease, the general consensus is that DDD pacing with the programming of an algorithm to minimize ventricular pacing is preferred. In very old patients presenting with intermittent or suspected atrioventricular block, VVI pacing may be appropriate. In terms of correcting potentially life-threatening arrhythmias, the effectiveness of ICD therapy is similar in older and younger individuals. However, the assumption of persistent ICD benefit in the elderly population is questionable, as any advantageous effect of the device on arrhythmic death may be attenuated by higher total non-arrhythmic mortality. While septuagenarians and octogenarians have higher annual all-cause mortality rates, ICD therapy may remain effective in selected patients at high risk of arrhythmic death and with minimum comorbidities despite advanced age. ICD implantation among the elderly, as a group, may not be cost-effective, but the procedure may reach cost-effectiveness in those expected to live more than 5-7years after implantation. Elderly patients usually experience significant functional improvement after CRT, similar to that observed in middle-aged patients. Management of CRT non-responders remains globally the same, while considering a less aggressive approach in terms of reinterventions (revision of left ventricular [LV] lead placement, addition of a right ventricular or LV lead, LV endocardial pacing configuration). Overall, physiological age, general status and comorbidities rather than chronological age per se should be the decisive factors in making a decision about device implantation selection for survival and well-being benefit in elderly patients.

Analyses of inappropriate shocks in a Spanish ICD primary prevention population: Predictors and prognoses

BACKGROUND

ICDs have been demonstrated to be highly effective in the primary prevention of sudden death, but inappropriate shocks (IS) occur frequently and represent one of the most important adverse effects of ICDs. The aim of this study was to analyze IS and identify the clinical predictors and prognostic implications of ISs in a real-world primary prevention ICD population.

METHODS

This multicenter retrospective study was performed in 13 centers with experience in the field of ICD implantation (at least 30 per year) and ICD follow-up in Spain. All consecutive patients who underwent ICD implantation for primary prevention between January 2008 and May 2014 were included.

RESULTS

One-thousand-sixteen patients were included, and 4 (0.39%) were lost to follow-up. Two-hundred-seventeen (21.4%) patients suffered from shock; 69 (6.8%) of these patients experienced IS, and 154 (15.4%) experienced appropriate shocks (AS). Age (<65 years, hazard ratio (HR) 2.588 [95% CI 1.282-5.225]; p=0.008), history of atrial fibrillation (HR 2.252 [95% CI 1.230-4.115]; p=0.009), non-ischemic myocardiopathy (HR 2.258 [95% CI 1.090-4.479]; p=0.028), and cardiac resynchronization therapy (HR 0.385 [95% CI 0.200-0.740]; p=0.004) were identified as IS predictors in a multivariate analysis. IS was not associated with rehospitalization due to heart failure, myocardial infarction, cardiovascular mortality or all-cause mortality.

CONCLUSIONS

This analysis of our national registry identified the independent IS predictors of age, atrial fibrillation history and cardiac resynchronization therapy and suggests that ISs are not linked to poorer clinical endpoints.