RESUMEN

Arrhythmia is an extremely common finding in patients receiving cardiac resynchronisation therapy (CRT). Despite this, in the majority of randomised trials testing CRT efficacy, patients with a recent history of arrhythmia were excluded. Most of our knowledge into the management of arrhythmia in CRT is therefore based on arrhythmia trials in the heart failure (HF) population, rather than from trials dedicated to the CRT population. However, unique to CRT patients is the aim to reach as close to 100% biventricular pacing (BVP) as possible, with HF outcomes greatly influenced by relatively small changes in pacing percentage. Thus, in comparison to the average HF patient, there is an even greater incentive for controlling arrhythmia, to achieve minimal interference with the effective delivery of BVP. In this review, we examine both atrial and ventricular arrhythmias, addressing their impact on CRT, and discuss the available evidence regarding optimal arrhythmia management in this patient group. We review pharmacological and procedural-based approaches, and lastly explore novel ways of harnessing device data to guide treatment of arrhythmia in CRT.

RESUMEN

Background: Some patients with cardiac resynchronisation therapy (CRT) experience super-response (LVEF improvements to ≥50%). At generator exchange (GE), downgrading (DG) from CRT-defibrillator (CRT-D) to CRT-pacemaker (CRT-P) could be an option for these patients on primary prevention ICD indication and no required ICD therapies. Long-term data on arrhythmic events in super-responders is scarce. Methods: CRT-D patients with LVEF improvement to ≥50% at GE were identified in four large centres for retrospective analysis. Mortality, significant ventricular tachyarrhythmia and appropriate ICD-therapy were determined, and patient analysis was split into two groups (downgraded to CRT-P or not). Results: Sixty-six patients (53% male, 26% coronary artery disease) on primary prevention were followed for a median of 129 months [IQR: 101-155] after implantation. 27 (41%) patients were downgraded to CRT-P at GE after a median of 68 [IQR: 58-98] months (LVEF 54% ± 4%). The other 39 (59%) continued with CRT-D therapy (LVEF 52% ± 6%). No cardiac death or significant arrhythmia occurred in the CRT-P group (median follow-up (FU) 38 months [IQR: 29-53]). Three appropriate ICD-therapies occurred in the CRT-D group [median FU 70 months (IQR: 39-97)]. Annualized event-rates after DG/GE were 1.5%/year and 1.0%/year in the CRT-D group and the whole cohort, respectively. Conclusions: No significant tachyarrhythmia were detected in the patients downgraded to CRT-P during follow-up. However, three events were observed in the CRT-D group. Whilst downgrading CRT-D patients is an option, a small residual risk for arrhythmic events remains and decisions regarding downgrade should be made on a case-by-case basis.

RESUMEN

BACKGROUND: Leadless pacemakers preclude the need for permanent leads to pace endocardium. However, it is yet to be determined whether a leadless pacemaker of a similar design to those manufactured for the right ventricle (RV) fits within the left ventricle (LV), without interfering with intracardiac structures. METHODS: Cardiac computed tomography scans were obtained from 30 patients indicated for cardiac resynchronisation therapy upgrade. The mitral valve annulus, chordae tendineae, papillary muscles and LV endocardial wall were marked in the end-diastolic frame. Intracardiac structures motions were tracked through the cardiac cycle. Two pacemaker designs similar to commercially manufactured leadless systems (Abbott's Nanostim LCP and Medtronic's Micra TPS) as well as theoretical designs with calculated optimal dimensions were evaluated. Pacemakers were virtually placed across the LV endocardial surface and collisions between them and intracardiac structures were detected throughout the cycle. RESULTS: Probability maps of LV intracardiac structures collisions on a 16-segment AHA model indicated possible placement for the Nanostim LCP, Micra TPS, and theoretical designs. Thresholding these maps at a 20% chance of collision revealed only about 36% of the endocardial surface remained collision-free with the deployment of Micra TPS design. The same threshold left no collision-free surface in the case of the Nanostim LCP. To reach at least half of the LV endocardium, the volume of Micra TPS, which is the smaller design, needed to be decreased by 41%. CONCLUSION: Due to the presence of intracardiac structures, placement of leadless pacemakers with dimensions similar to commercially manufactured RV systems would be limited to apical regions.

Asunto(s)

RESUMEN

AIMS: To evaluate whether peripheral circulatory 'remodelling' as measured by changes in vascular compliance and in markers of nitric oxide signalling contributes to patient response to cardiac resynchronization therapy (CRT). METHODS AND RESULTS: Effects of CRT were evaluated in 33 patients pre-procedure and 6 months post-procedure. Peak oxygen consumption, 6 min walk distance, New York Heart Association class, and quality of life score were evaluated. Augmentation index and its interactions with nitric oxide (NO) were evaluated by applanation tonometry. Platelet NO responsiveness and content of thioredoxin-interacting protein were assessed. Plasma concentrations of N-terminal proBNP, asymmetric and symmetric dimethylarginine (SDMA), high sensitivity C-reactive protein, catecholamines, and matrix metalloproteinases-2 and -9 were assessed. Despite significant improvement in 6 min walk distance (P = 0.005), New York Heart Association class (P < 0.001), quality of life (P = 0.001), and all echocardiographic parameters post-CRT, there were no significant changes in augmentation index measurements, thioredoxin-interacting protein content, and platelet NO response. Significant falls in N-terminal proBNP (P = 0.008) and SDMA (P = 0.013; independent of renal function) occurred. Falls in SDMA predicted reduction in high-sensitivity C-reactive protein (P = 0.04) and increases in peak oxygen consumption (P = 0.04). There were no correlations between changes in echocardiographic parameters and those in vascular function. CONCLUSIONS: These data suggest that the beneficial effects of CRT over 6 months are independent of any change in peripheral NO-related signalling. However, there is evidence that suppression of inflammation occurs, and its magnitude predicts extent of clinical improvement.

Asunto(s)

RESUMEN

PURPOSE: To determine the prognostic implications of changes towards hyponatremia at varying time-points in the treatment of patients undergoing cardiac resynchronisation therapy (CRT). METHODS: A retrospective series of 249 patients was studied from 2002 to 2013. The population was categorized on the basis of serum sodium profile at baseline, at 1 month and at 6 month follow up visits following successful CRT implantation. The composite endpoint was all-cause mortality and heart failure hospitalisation (defined by the need for intravenous diuretic therapy) following CRT implantation. RESULTS: A total of 249 patients (67.8±12.5 years; NYHA class III/IV 75; LVEF 27.2±8.8%) were followed up for a median of 5.5 years. Hyponatremia at baseline, 1 month or 6 months follow up did not predict the composite endpoint. 26% of patients showed hyponatremia at baseline prior to CRT implantation, while it was present in 19.9% of patients 1 month (p=0.003) and in 16% (p<0.001) 6 months after CRT implantation. There was a significantly worse outcome for those patients who developed hyponatremia 6 months after CRT implantation. In multivariate analysis, the intake of loop diuretics (HR 1.76 [1.04-2.95], p=0.03) and renal impairment (urea>7.0mmol/l) (HR 1.61 [1.05-2.46], p=0.03) at baseline were associated with an increased risk of unplanned heart failure hospitalisation and all-cause mortality after CRT implantation. CONCLUSIONS: A change towards hyponatremia when observed 6 months after CRT implantation may predict a worse clinical outcome. Additionally, renal impairment and higher diuretic doses are associated with an increased risk of mortality in the population analysed.

Asunto(s)

RESUMEN

BACKGROUND: Complex cardiac rhythm management device (CRMD) therapy provides an important treatment option for people at risk of sudden cardiac death. Despite the survival benefit, device implantation is associated with significant physical and psychosocial concerns presenting considerable challenges for the decision-making process surrounding CRMD implantation for patients and physicians. AIMS: The purpose of this scoping review was to explore what is known about how adult (>16 years) patients make decisions regarding implantation of CRMD therapy. METHODS: Published, peer reviewed, English language studies from 2000 to 2016 were identified in a search across eight healthcare databases. Eligible studies were concerned with patient decision-making for first time device implantation. Quality assessment was completed using the mixed methods appraisal tool for all studies meeting the inclusion criteria. RESULTS: The findings of eight qualitative and seven quantitative studies, including patients who accepted or declined primary or secondary sudden cardiac death prevention devices, were clustered into two themes: knowledge acquisition and the process of decision-making, exposing similarities and distinctions with the treatment decision-making literature. CONCLUSION: The review revealed some insight in to the way patients approach decision-making but also exposed a lack of clarity and research activity specific to CRMD patients. Further research is recommended to support the development and application of targeted decision support mechanisms.

Asunto(s)