Influence Of Cardiac Resynchronization Therapy Research Articles

The influence of cardiac resynchronization therapy on subjective and objective parameters of sleep, and their association with the function of the autonomous nervous system.

IntroductionCardiac resynchronization therapy (CRT) was a breakthrough in the treatment of heart failure, but data regarding the effect of this therapy on numerous disorders associated with heart failure are limited.AimTo assess the impact of CRT on sleep breathing disorders, and to determine the relationship between the changes in the autonomous nervous system and sleep disorders after CRT.Material and methodsThe study included 55 patients with chronic heart failure stable for at least last 3 months, in New York Heart Association (NYHA) class III or IV despite optimal medical therapy, with a reduced left ventricular ejection fraction (LVEF) ≤ 35%, QRS complex duration ≥ 120 ms, and sinus rhythm. Before and 3 months after implementation of CRT echocardiography, 6-minute walk test (6MWT), polysomnography with the Pittsburgh Sleep Quality Index (PSQI) questionnaire and the Epworth Sleepiness Scale (ESS) were performed. Also baroreflex sensitivity (BRS) was evaluated.ResultsAfter implementation of CRT, the values of the apnea-hypopnea index (AHI), apnea index (AI), and central and mixed apnea indexes (CAI, MAI) were statistically significantly reduced. The strongest negative correlations were demonstrated for changes in CAI and changes in BRS. An improvement in sleep quality, daytime sleepiness, LVEF, NYHA class, and 6MWT was observed and was the most strongly associated with the improvement in CAI, too.ConclusionsCRT has a beneficial effect on subjective and objective features of sleep, as well as on the function of the autonomous nervous system. In addition, patients with heart failure and coexisting central sleep apnea may benefit most from this therapy.

Evaluation of the influence of cardiac resynchronization therapy on sleep apnea syndrome

Many studies have shown a high prevalence of sleep apnea syndrome (SAS), whether obstructive sleep apnea (OSA) or central sleep apnea (CSA) in heart failure patients (HF). Very few data exit about HF patients with cardiac resynchronization therapy (CRT). In this study, we will determine the prevalence of SAS in this population and study the influence of CRT about SAS. A prospective open-label, single-center, non-interventional, cohort-type study was conducted at Reims University Hospital between 1st January and 31st August 2016. All patients implanted with CRT device without known SAS were included. Screening polysomnography was performed before and 6 months after implantation. Primary endpoint was the incidence of SAS and secondary endpoint was the evaluation of the impact of CRT on SAS. During the study period, 31 patients were implanted with a CRT device: 10 were already known having SAS and 5 did not give their consent. At M0, 100% of the 16 included patients were diagnosed having SAS, with 69% severe OSAS. All were treated by CPAP according to guidelines. At 6 months, after 48 h CPAP washout, no independent significant influence of CRT on the Apnea-Hypopnea Index (AHI) was demonstrated (37 ± 19 vs 60 ± 12, P = 0.0625). An improvement in HF parameters was observed (NYHA class (−1, P = 0.0195), QRS width (−26 ms, P = 0.0002) and LVEF (+9.5%, P = 0.0039)). At 6 months, the CRT response rate was high with significant NYHA class and LVEF improvement in 79 and 57% patients respectively. SAS (especially OSA) is frequent in HF patients eligible for CRT and mostly under-diagnosed. The lack of improvement of the AHI by the CRT alone and the existence of a specific treatment of the OSAS improving morbi-mortality, maintaining a very good response rate to the CRT invite to screen this population.

Influence of cardiac resynchronization therapy on oxidative stress markers in patients with chronic heart failure.

The aim of the study was to assess changes of substances of oxidative stress in patients treated with cardiac resynchronization therapy (CRT). The study comprised 51 patients with median age of 66 years. The presence, severity, and changes of oxidative stress during CRT were assessed and expressed as malondialdehyde (MDA) concentration in plasma or in red blood cells. Antioxidant activity was assessed by the activity of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) in red blood cells. The concentration and activities were analyzed directly prior to implantation, 2-5 days after the procedure and after 6 months. Follow-up (6 months) included clinical, echocardiographic and implanted device assessments. During the follow-up, 14% patients died. The median percentage of biventricular pacing was 99.29%. After 6 months 88% of patients improved NYHA, 12% remained as non-responders. Left ventricular ejection fraction increased from median 21.5% to 29% (p < 0.05). Left ventricular end-diastolic diameter decreased significantly from a median of 69.5 mm to 63 mm (p < 0.05). After a 6-month study, MDA plasma concentration and the activity levels of each antioxidant enzymes (CAT, SOD, GPx) showed a statistically significant reduction (p < 0.05). Changes concerning MDA concentrations in red blood cells remained statistically insignificant. Resynchronization effect oxidative stress by reducing plasma concentration of MDA, CAT, SOD and GPX.

The influence of cardiac resynchronization therapy on molecular pathways in pathophysiology of heart failure

The influence of cardiac resynchronization therapy on molecular pathways in pathophysiology of heart failure

Impact of Cardiac Resynchronization Therapy on Exercise Performance, Functional Capacity, and Quality of Life in Systolic Heart Failure With QRS Prolongation: COMPANION Trial Sub-Study

Background A total of 405 participants in the Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure trial were prospectively enrolled in an exercise sub-study designed to study the influence of cardiac resynchronization therapy (CRT) on measures of exercise capacity, functional capacity, and quality of life (QOL). Methods and Results Substudy eligibility included New York Heart Association (NYHA) functional Class III or IV heart failure, left ventricular ejection fraction ≤0.35, QRS interval of ≥120 ms, normal sinus rhythm, a heart failure hospitalization (or equivalent) within 1 year, a peak VO 2 ≤22 mL ·kg ·min, the ability to walk 150 to 425 meters in 6 minutes, forced expiratory volume in 1 second/forced vital capacity ≥50%, and no clinical indication for a pacemaker or implantable cardioverter-defibrillator. Patients were randomized in a 1:4 ratio to optimal medical therapy (OPT) or to OPT plus CRT. Cardiopulmonary exercise testing (peak VO 2 and 6-minute walk distance [6MWD]) and assessment of NYHA functional class and QOL were assessed at baseline and at 3 and 6 months of assigned therapy. There was no significant improvement in peak VO 2 at 6 months in the CRT group compared with the OPT group (+0.63 mL ·kg ·min) by unadjusted analysis ( P = .05) or by analyses adjusted for missing data. Thus the primary end point of the study was not met. There was significantly greater improvement in the 6MWD in the CRT group compared with the OPT group at both 3 and 6 months by both statistical methods ( P ≤ .045). Likewise, a greater proportion of CRT patients improved by 1 or more NYHA functional classes ( P < .01) at 3 months and had better QOL scores ( P < .01) at 3 and 6 months compared with the OPT patients. Baseline peak VO 2 predicted clinical events (time to death, time to death or first hospitalization, or time to death and first heart failure hospitalization: P < .05) in CRT participants. Conclusion CRT patients with moderate to advanced symptoms of systolic heart failure and prolonged QRS intervals benefit from the addition of CRT to OPT in terms of exercise capacity, functional status, and QOL. CRT should be considered standard therapy in this select group of heart failure patients.

It's the metabolism, stupid! Why electrophysiologists should be interested in biomarkers of heart failure

Cardiac resynchronization therapy (CRT) has emerged as a new standard in the treatment of patients with moderate-to-advanced heart failure and ventricular dyssynchrony. The recently actualized ESC/AHA/ACC heart failure guidelines have classified CRT as a class I indication in patients with reduced ejection fraction and ventricular dyssynchrony (QRS width ≥ 120 ms) who remain symptomatic (NYHA III–IV) despite optimal medical therapy to improve symptoms, hospitalizations, and mortality.1 These criteria have been derived mainly from data of the COMPANION2 and CARE-HF3 trials. So far, so good. Why should we be interested in the influence of CRT on the release of neurohormone markers such as brain natriuretic peptide (BNP)? BNP is a hormone co-secreted with the inactive aminoterminal pro-BNP, i.e. NT-pro-BNP, from the ventricles in response to increase of left ventricular wall stress. Thus, levels of BNP or NT-pro-BNP in the serum are elevated in patients with both systolic and diastolic heart failure. At first sight, it seems rather self-evident that a treatment such as CRT which has been shown to lead to long-term reduction in left … Corresponding author. Tel: +49 521 5813401; fax: +49 521 5813498. E-mail address : christoph.stellbrink{at}sk-bielefeld.de

The Impact of Cardiac Resynchronization Therapy on Ventricular Tachycardia/Fibrillation: An Analysis from the Combined Contak‐CD and InSync‐ICD Studies

To determine the potential influence of cardiac resynchronization therapy (CRT) on the frequency and types of ventricular arrhythmia (VA) in patients with an indication for the implantable cardioverter-defibrillator (ICD), we performed a retrospective electrogram (EGM) analysis of stored VA events from the two largest CRT-ICD trials. Previous reports suggest that CRT might promote polymorphic VT (PVT), while a beneficial effect of CRT on ventricular function might reduce the frequency of monomorphic VT (MVT). Theoretically, a balanced effect produces no change in overall VA. We analyzed stored EGMs from patients in the Contak-CD and Insync-ICD studies receiving appropriate therapy for VA. EGM inspection distinguishes MVT and PVT using morphologic criteria rather than cycle length classification alone. Of 1,041 subjects entering the two trials, 880 were randomized CRT (N = 439) or control (N = 441). We were able to analyze 840 EGMs in 150 patients with VA, including 678 MVT episodes and 162 PVT episodes. These events were distributed among 68 patients with active CRT (390 MVT vs 111 PVT) and 82 patients assigned to control (288 MVT compared to 51 PVT). The apparent increase in PVT episodes in the CRT group is not significant and can be explained by a disproportionate number of episodes in a few patients. We were unable to identify clinical variables predictive of PVT during CRT. CRT is not associated with a measurable increase in the incidence of PVT, or in a reduction in MVT in the combined InSync-ICD and Contak-CD populations.

Central but not obstructive sleep apnea can be influenced by cardiac resynchronisation therapy

Rationale: This study investigates the influence of cardiac resynchronization therapy (CRT) on sleep disordered breathing (SDB) in patients with severe chronic heart failure (CHF). Methods and Results: A total of 100 consecutive patients with CHF eligible for CRT (NYHA class III, LBBB, QRS width 150 ms, EF 35%, LVEDD 60 mm) were screened for SDB using cardiorespiratory polygraphy (Embletta®) before device implantation. Mean age 64.8 9.8 years, CAD n 42, DCM n 54, valvular heart disease n 4, mean EF 25.7 6.8%, mean VO2peak 13.4 4.8 ml/kg/min, mean QRS width 185 18 ms. Central sleep apnea (CSA) was documented in 39 patients (39%) and obstructive sleep apnea (OSA) in 34 patients (34%). Only 27 patients (27%) had normal results during cardiorespiratory polygraphy. Twenty-two patients with CSA (central apnea index 15/hr) and 8 patients with OSA were reinvestigated 12 24 weeks after biventricular pacemaker implantation for apnea-hypopnea-index (AHI), NYHA classification, and peak oxygen uptake. Eleven patients demonstrated a significant improvement of CSA by CRT: AHI 32.0 vs 10.8, p 0.0001, EF (23.1 vs 27.8%, p 0.026), NYHA (2.9 vs 2.1 p 0.0002), and oxygen uptake (13.7 vs 17.4, p 0.01). In contrast, CSA remained unchanged in the other 11 patients (AHI 33.9/hr vs 30.7/hr, ns). All nonresponders were also nonresponders with respect to CRT (neither improvement of NYHA, EF nor of oxygen uptake after 3 months of CRT). OSA was not influenced by CRT (AHI 14.0 versus 12.0, p ns), despite good clinical response to CRT (NYHA 3.1 versus 2.3; VO2peak 13.7 versus 17.6 ml/kg/min, p 0.02). Conclusion: In appr. 50 % of patients with CRT, a short term improvement of heart failure symptoms and parameters correlates with a marked improvement in central sleep apnea. In patients who do not show a clinical improvement during the first 3 months of CRT, CSA does also not improve, which supports CSA being a marker for the severity of CHF. In contrast OSA is not influenced by CRT. Because of its pathophysiologic and prognostic significance and the availability of modern treatment options, cardiorespiratory screening should be routinely implemented in the evaluation of CRT patients.

Heart rate variability behaviour during cardiac resynchronization therapy

The influence of cardiac resynchronization therapy (CRT) on heart rate variability (HRV) and therefore on autonomic nervous system in the heart has been discussed recently. Purpose of the study to assess the behaviour of HRV parameters in patients (pts) with chronic heart failure (CHF) treated with CRT therapy in three months follow-up. Methods The study group consisted of 17 pts (3F,14M, aged 53±9 years) with CHF at NYHA class III, EF<35% and significant systolic dyssynchrony of the left ventricle in whom BIV pacemakers InSyncIII (Medtronic) were implanted. HRV “time domain” parameters were calculated based on 24-hour digital Holter monitoring which was performed: before the procedure (I), 3-4(II) days after, 1(III), and 3(IV) months after BIV implantation. View this table: Conclusions The decrease of HRV immediately after BIV implantation and the tendency of HRV improvement during CRT therapy in three months follow-up are observed. CRT therapy may improve the autonomic tone in the heart.