upgrade cardiac resynchronisation therapy: a multicentre experience

BACKGROUND

The clinical safety and consequences of upgrade procedures compared with de novo cardiac resynchronisation therapy (CRT) implantation in heart failure remain unclear. The present study aimed to assess clinical and procedural consequences of patients undergoing CRT upgrade as compared to de novo CRT implantations.

METHODS

In this prospective cohort study, two subgroups were considered as the study population as (1) de novo group that CRT was considered on optimised medical treatment with heart failure of NYHA functional class from II to IV, left ventricular ejection fraction (LVEF) of ≤35%, and QRS width of >130 ms and (2) upgrade group including the patients with previously implantable cardioverter defibrillator (ICD) with the indications for upgrading to CRT. The two groups were compared regarding the changes in clinical outcome and echocardiography parameters.

RESULTS

The procedure was successful in 95.9% of patients who underwent CRT upgrade and 100% of those who underwent de novo CRT implantation. It showed a significant improvement in LVEF, severity of mitral regurgitation and NYHA functional classification, without any difference between the two study groups. Overall procedural related complications were reported in 10.8% and 3.8% (p = .093) and cardiac death in 5.4% and 2.5% (p = .360), respectively, with no overall difference in postoperative outcome between the two groups.

CONCLUSIONS

Upgrading to CRT is a safe and effective procedure regarding improvement of functional class, left ventricular function status and post-procedural outcome.

Location, Location, Location: A Pilot Study to Compare Electrical with Echocardiographic-Guided Targeting of Left Ventricular Lead Placement in Cardiac Resynchronisation Therapy

Introduction: Cardiac resynchronisation therapy is ineffective in 30-40% of patients with heart failure with reduced ejection fraction. Targeting non-scarred myocardium by selecting the site of latest mechanical activation using echocardiography has been suggested to improve outcomes but at the cost of increased resource utilisation. The interval between the beginning of the QRS complex and the local LV lead electrogram (QLV) might represent an alternative electrical marker. Aims: To determine whether the site of latest myocardial electrical and mechanical activation are concordant. Methods: This was a single-centre, prospective pilot study, enrolling patients between March 2019 and June 2021. Patients underwent speckle-tracking echocardiography (STE) prior to CRT implantation. Intra-procedural QLV measurement and R-wave amplitude were performed in a blinded fashion at all accessible coronary sinus branches. Pearson's correlation coefficient and Cohen's Kappa coefficient were utilised for the comparison of electrical and echocardiographic parameters. Results: A total of 20 subjects had complete data sets. In 15, there was a concordance at the optimal site between the electrically targeted region and the mechanically targeted region; in four, the regions were adjacent (within one segment). There was discordance (≥2 segments away) in only one case between the two methods of targeting. There was a statistically significant increase in procedure time and fluoroscopy duration using the intraprocedural QLV strategy. There was no statistical correlation between the quantitative electrical and echocardiographic data. Conclusions: A QLV-guided approach to targeting LV lead placement appears to be a potential alternative to the established echocardiographic-guided technique. However, it is associated with prolonged fluoroscopy and overall procedure time.

The Emerging Role of Left Bundle Branch Area Pacing for Cardiac Resynchronisation Therapy

Cardiac resynchronisation therapy (CRT) reduces the risk of heart failure-related hospitalisations and all-cause mortality, as well as improving quality of life and functional status in patients with persistent heart failure symptoms despite optimal medical treatment and left bundle branch block. CRT has traditionally been delivered by implanting a lead through the coronary sinus to capture the left ventricular epicardium; however, this approach is associated with significant drawbacks, including a high rate of procedural failure, phrenic nerve stimulation, high pacing thresholds and lead dislodgement. Moreover, a significant proportion of patients fail to derive any significant benefit. Left bundle branch area pacing (LBBAP) has recently emerged as a suitable alternative to traditional CRT. By stimulating the cardiac conduction system physiologically, LBBAP can result in a more homogeneous left ventricular contraction and relaxation, thus having the potential to improve outcomes compared with conventional CRT strategies. In this article, the evidence supporting the use of LBBAP in patients with heart failure is reviewed.

Transvenous lead extraction, factors affecting procedural difficulty

BACKGROUND

A complex transvenous lead extraction (TLE) procedure could be associated with lower success and higher complication rates in inexperienced hands. In this study, we aim to assess the factors that determine procedural difficulty in TLE.

METHODS

We retrospectively studied 200 consecutive patients undergoing TLE in a single referral centre from June 2020 to December 2021. Lead extraction difficulty was assessed by the success of simple manual traction with or without a locking stylet, the need for advanced extraction tools and the number of tools required to extract the lead. Logistic and linear regression analyses were used to determine the factors independently affecting these 3 parameters.

RESULTS

363 leads were extracted from 200 patients (79% males, mean age 66.85 years). The indication for TLE was device-related infection in 51.5%. Multivariate analysis revealed the lead indwelling time to be the only factor affecting the 3 parameters of difficulty. Passive fixation leads and dual coil leads increased procedural difficulty by affecting 2 parameters each. Factors that affected one parameter included infected leads, coronary sinus leads, older age of the patient and a history of valvular heart disease, all associated with a simpler procedure. Right ventricular leads were associated with a more complex one.

CONCLUSION

The most important factor that increased TLE procedural difficulty was a longer lead indwelling time, followed by passive fixation and dual-coil leads. Other contributing factors were the presence of infection, coronary sinus leads, older patients, a history of valvular heart disease and right ventricular leads.

Leadless Pacing: Therapy, Challenges and Novelties

Leadless pacing is a rapidly growing field. Initially designed to provide right ventricular pacing for those who were contraindicated for conventional devices, the technology is growing to explore the potential benefit of avoiding long-term transvenous leads in any patient who requires pacing. In this review, we first examine the safety and performance of leadless pacing devices. We then review the evidence for their use in special populations, such as patients with high risk of device infection, patients on haemodialysis, and patients with vasovagal syncope who represent a younger population who may wish to avoid transvenous pacing. We also summarise the evidence for leadless cardiac resynchronisation therapy and conduction system pacing and discuss the challenges of managing issues, such as system revisions, end of battery life and extractions. Finally, we discuss future directions in the field, such as completely leadless cardiac resynchronisation therapy-defibrillator devices and whether leadless pacing has the potential to become a first-line therapy in the near future.

Automatic daily remote monitoring in heart failure patients implanted with a cardiac resynchronisation therapy-defibrillator: a single-centre observational pilot study

INTRODUCTION

The impact of remote monitoring (RM) on clinical outcomes in heart failure (HF) patients with cardiac resynchronisation therapy-defibrillator (CRT-D) implantation is controversial. This study sought to evaluate the performance of an RM follow-up protocol using modified criteria of the PARTNERS HF trial in comparison with a conventional follow-up scheme.

MATERIAL AND METHODS

We compared cardiovascular (CV) mortality (primary endpoint) and hospitalisation events for decompensated HF, and the number of ambulatory in-office visits (secondary endpoint) in CRT-D implanted patients with automatic RM utilising daily transmissions (RM group, n = 45) and conventional follow-up (CFU group, n = 43) in a single-centre observational study.

RESULTS

After a median follow-up of 25 months, a significant advantage was seen in the RM group in terms of CV mortality (1 vs. 6 death event, p = 0.04), although RM follow-up was not an independent predictor for CV mortality (HR = 0.882; 95% CI: 0.25-3.09; p = 0.845). Patient CV mortality was independently influenced by hospitalisation events for decompensated HF (HR = 3.24; 95% CI: 8-84; p = 0.022) during follow-up. We observed significantly fewer hospitalisation events for decompensated HF (8 vs. 29 events, p = 0.046) in the RM group. Furthermore, a decreased number of total (161 vs. 263, p < 0.01) and unnecessary ambulatory in-office visits (6 vs. 19, p = 0.012) were seen in the RM group as compared to the CFU group.

CONCLUSIONS

Follow-up of CRT-D patients using automatic RM with daily transmissions based on modified PARTNERS HF criteria enabled more effective ambulatory interventions leading indirectly to improved CV survival. Moreover, RM directly decreased the number of HF hospitalizations and ambulatory follow-up burden compared to CRT-D patients with conventional follow-up.

Clinical Utility of HeartLogic, a Multiparametric Telemonitoring System, in Heart Failure

Telemonitoring through multiple variables measured on cardiac devices has the potential to improve the follow-up of patients with heart failure. The HeartLogic algorithm (Boston Scientific), implemented in some implantable cardiac defibrillators and cardiac resynchronisation therapy, allows monitoring of the nocturnal heart rate, respiratory movements, thoracic impedance, physical activity and the intensity of heart tones, with the aim of predicting major clinical events. Although HeartLogic has demonstrated high sensitivity for the detection of heart failure decompensations, its effects on hospitalisation and mortality in randomised clinical trials has not yet been corroborated. This review details how the HeartLogic algorithm works, compiles available evidence from clinical studies, and discusses its application in daily clinical practice.

Left atrial volume index predicts response to cardiac resynchronisation therapy: a systematic review and meta-analysis

INTRODUCTION

In responders, cardiac resynchronisation therapy (CRT) results in improved left ventricular (LV) function and reduced atrial arrhythmia. The aim of this meta-analysis was to assess the potential relationship between the left atrium (LA) volume and CRT response.

MATERIAL AND METHODS

We systematically searched all electronic databases up to August 2018 in order to select clinical trials and observational studies that assessed the predictive value of LA volume index (LAVI) of CRT response. Left ventricular end-systolic volume (LVESV) reduction ≥ 15 ml and/or LV ejection fraction (EF) increase ≥ 10% were the documented criteria for positive CRT response.

RESULTS

A total of 2191 patients recruited in 10 studies with mean follow-up duration of 10.5 months were included in this meta-analysis. The pooled analysis showed that CRT responders had lower baseline LAVI compared to non-responders, with a weighted mean difference (WMD) of -5.89% (95% CI: -9.47 to -3.22, p < 0.001). At follow-up, LAVI fell in the CRT responders (WMD -4.36%, 95% CI: -3.54 to -5.17, p < 0.001) compared to non-responders (WMD 1.45 %, 95% CI: -0.75 to 3.65, p = 0.20). The mean change of LAVI in the CRT responders was related to the fall in LVESV, β = -1.02 (-1.46 to -0.58), p < 0.001 and the increase in LVEF, β = 2.02 (1.86 to 4.58), p = 0.001. A baseline LAVI < 34 ml/m² predicted CRT response with summary sensitivity 0.80% (0.53-0.95), specificity 0.74% (0.53-0.89), and odds ratio > 11.

CONCLUSIONS

Baseline LAVI predicts CRT response, and its reduction reflects devise-related LA remodelling. These results emphasis the role of LAVI assessment as an integral part of cardiac function response to CRT.

Quadripolar Passive Fixation Leads in Cardiac Resynchronisation Therapy

Background: Bipolar active fixation (BipolarAFL) and quadripolar passive fixation left-ventricular leads (QuadPFL) have been designed to reduce the risk of phrenic nerve stimulation (PNS), enable targeted left-ventricular pacing, and overcome problems of difficult coronary venous anatomy and lead dislodgment. This study sought to report the long-term safety and performance of a BipolarAFL, Medtronic Attain Stability 20066, compared to QuadPFL. Methods: We performed a single-operator retrospective analysis of 81 patients receiving cardiac resynchronization therapy (CRT) (36 BipolarAFL, 45 QuadPFL). Immediate implant data and electrical and clinical data during follow-up (FU) were analyzed. Results: BipolarAFL has been chosen in patients with significantly larger estimated vein diameter (at the lead tip: 7.2 ± 4.1 Fr vs. 4.1 ± 2.3 Fr, p < 0.001) without significant time difference until the final lead position was achieved (BipolarAFL: 20.9 ± 10.5 min, vs. QuadPFL: 18.9 ± 8.9 min, p = 0.35). At 12 month FU no difference in response rate to CRT was recorded between BipolarAFL and QuadPFL according to left ventricular end-systolic volume (61.1 vs. 60.0%, p = 0.82) and New York Heart Association (66.7 vs. 62.2%, p = 0.32). At median FU of 48 months (IQR: 44-54), no lead dislodgment occurred in both groups but a significantly higher proportion of PNS was recorded in QuadPFL (13 vs. 0%, p < 0.05). Electrical parameters were stable during FU in both groups without significant differences. Conclusion: BipolarAFL can be implanted with ease in challenging coronary venous anatomy, shows excellent electrical performance and no difference in clinical outcome compared to QuadPFL.

Usefulness of telemedicine devices in patients with severe heart failure with implanted cardiac resynchronisation therapy system during two years of observation

BACKGROUND

Heart failure (HF) remains a disease with poor prognosis. Telemonitoring is a medical service aimed at remote monitoring of patients.

AIM

The study aimed to identify the clinical relevance of non-invasive telemonitoring devices in HF patients.

METHODS

Sixty patients 66.1 (11) years, left ventricular ejection fraction (LVEF) 26.3 (6.8)% underwent cardiac resynchronisation therapy (CRT) implantation. They were randomly allocated to the control (standard medical care) or study (standard medical care + telemonitoring device) group. During follow‑up (24 months) the patients' physiological data (body mass, blood pressure, electrocardiogram) were provided by patients in the study group on a daily basis. The data were transferred to themonitoring centre and consulted by cardiologist. Transthoracic echocardiography and 6‑minute walk test were performed before and 24 months after CRT implantation.

RESULTS

During the two-year observation, the composite endpoint (death or HF hospitalisation) occurred in 21 patients, more often in the control group (46.8% vs. 21.4%; P<0.03). Inunivariate analysis: the use of telemetry (hazard ratio [HR], 0.2; 95% confidence interval [CI], 0.07-0.7; P=0.004), thepresence of coronary heart disease (HR, 41.4; 95% CI, 3.1-567.7; P=0.005), hypertension (HR, 0.24; 95% CI, 0.07-0.90; P = 0.035) and patient's body mass (HR, 0.36; 95% CI, 0.14-0.92; P = 0.03) were related with the occurrence of the composite endpoint.

CONCLUSIONS

The use of a telemonitoring device in CRT recipients improved theprognosis in2-year observation and contributed to the reduction of HF hospitalisation.

Physiology and Practicality of Left Ventricular Septal Pacing

Left ventricular septal pacing (LVSP) and left bundle branch pacing (LBBP) have been introduced to maintain or correct interventricular and intraventricular (dys)synchrony. LVSP is hypothesised to produce a fairly physiological sequence of activation, since in the left ventricle (LV) the working myocardium is activated first at the LV endocardium in the low septal and anterior free-wall regions. Animal studies as well as patient studies have demonstrated that LV function is maintained during LVSP at levels comparable to sinus rhythm with normal conduction. Left ventricular activation is more synchronous during LBBP than LVSP, but LBBP produces a higher level of intraventricular dyssynchrony compared to LVSP. While LVSP is fairly straightforward to perform, targeting the left bundle branch area may be more challenging. Long-term effects of LVSP and LBBP are yet to be determined. This review focuses on the physiology and practicality of LVSP and provides a guide for permanent LVSP implantation.

Improvement of electrical synchrony in cardiac resynchronization therapy using dynamic atrioventricular delay programming and multipoint pacing

BACKGROUND

Optimization of cardiac resynchronization therapy (CRT) is often time-consuming and therefore underused in a clinical setting. Novel device-based algorithms aiming to simplify optimization include a dynamic atrioventricular delay (AVD) algorithm (SyncAV, Abbott) and multipoint pacing (MPP, Abbott). This study examines the acute effect of SyncAV and MPP on electrical synchrony in patients with newly and chronically implanted CRT devices.

METHODS

Patients with SyncAV and MPP enabled devices were prospectively enrolled during implant or scheduled follow-up. Blinded 12-lead electrocardiographic acute measurements of QRS duration (QRSd) were performed for intrinsic QRSd (Intrinsic), bi-ventricular pacing (BiV), MPP, BiV with SyncAV at default offset 50 ms (BiVSyncAV_def ), BiV with SyncAV at patient-specific optimised offset (BiVSyncAV_opt ), MPP with SyncAV at default offset 50 ms (MPPSyncAV_def ), and MPP with SyncAV at patient-specific optimised offset (MPPSyncAV_opt ).

RESULTS

Thirty-three patients were enrolled. QRSd for Intrinsic, BiV, MPP, BiVSyncAV_def , BiVSyncAV_opt , MPPSyncAV_def , MPPSyncAV_opt were 160.4 ± 20.6 ms, 141.0 ± 20.5 ms, 130.2 ± 17.2 ms, 121.7 ± 20.9 ms, 117.0 ± 19.0 ms, 121.2 ± 17.1 ms, 108.7 ± 16.5 ms respectively. MPPSyncAV_opt led to greatest reduction of QRSd relative to Intrinsic (-31.6 ± 11.1%; p < .001), showed significantly shorter QRSd compared to all other pacing configurations (p < .001) and shortest QRSd in every patient. Shortening of QRSd was not significantly different between newly and chronically implanted devices (-51.6 ± 14.7 ms vs. -52.7 ± 21.9 ms; p = .99).

CONCLUSION

SyncAV and MPP improved acute electrical synchrony in CRT. Combining both technologies with patient-specific optimization resulted in greatest improvement, regardless of time since implantation. Whats new Novel device-based algorithms like a dynamic AVD algorithm (SyncAV, Abbott) and multipoint pacing (MPP, Abbott) aim to simplify CRT optimization. Our data show that a combination of patient tailored SyncAV optimization and MPP results in greatest improvement of electrical synchrony in CRT measured by QRS duration, regardless if programmed in newly or chronically implanted devices. This is the first study to our knowledge to examine a combination of these device-based algorithms. The results help understanding the ideal ventricular excitation in heart failure.

How to Implant His Bundle and Left Bundle Pacing Leads: Tips and Pearls

Cardiac pacing is the treatment of choice for the management of patients with bradycardia. Although right ventricular apical pacing is the standard therapy, it is associated with an increased risk of pacing-induced cardiomyopathy and heart failure. Physiological pacing using His bundle pacing and left bundle branch pacing has recently evolved as the preferred alternative pacing option. Both His bundle pacing and left bundle branch pacing have also demonstrated significant efficacy in correcting left bundle branch block and achieving cardiac resynchronisation therapy. In this article, the authors review the implantation tools and techniques to perform conduction system pacing.

Multipoint pacing for cardiac resynchronisation therapy in patients with heart failure: A systematic review and meta-analysis

INTRODUCTION

Multipoint pacing (MPP) has been proposed as an effective way to improve cardiac resynchronisation therapy (CRT) response. We performed a systematic review and meta-analysis evaluating the efficacy of CRT delivered via MPP compared to conventional CRT.

METHODS

A literature search was performed from inception to January 2021 for studies in Medline, Embase and Cochrane databases, comparing MPP to conventional CRT with a minimum of 6 months follow-up. Randomised and nonrandomised studies were assessed for relevant efficacy data including echocardiographic (left ventricular end systolic volume [LVESV] and ejection fraction) or functional changes (New York Heart Association [NYHA] class/Clinical Composite Score). Subgroup analyses were performed by study design and programming type.

RESULTS

A total of 7 studies with a total of 1390 patients were included in the final analysis. Overall, MPP demonstrated greater echocardiographic improvement than conventional CRT in nonrandomised studies (odds ratio [OR]: 5.33, 95% confidence interval [CI]: [3.05-9.33], p < .001), however, was not significant in randomised studies (OR: 1.86, 95% CI: [0.91-3.79], p = .086). There was no significant difference in LVESV reduction >15% (OR: 1.96, 95% CI: [0.69-5.55], p = .20) or improvement by ≥1 NYHA class (OR: 2.49, 95% CI: [0.74-8.42], p = .141) when comparing MPP to conventional CRT. In a sub analysis, MPP programmed by widest anatomical separation (MPP-AS) signalled greater efficacy, however, only 120 patients were included in this analysis.

CONCLUSION

Overall MPP was more efficacious in nonrandomised studies, and not superior when assessed in randomised studies. There was considerable heterogeneity in study design making overall interpretation of results challenging. Widespread MPP programming in all CRT patients is currently not justified. Further large, randomised studies with patient-specific programming may clarify its effectiveness.

Conduction System Pacing for Cardiac Resynchronisation

Conduction system pacing (CSP) is a technique of pacing that involves implantation of permanent pacing leads along different sites of the cardiac conduction system and includes His bundle pacing and left bundle branch pacing. There is an emerging role for CSP to achieve cardiac resynchronisation in patients with heart failure with reduced ejection fraction and inter-ventricular dyssynchrony. In this article, the authors review these strategies for resynchronisation and the available data on the use of CSP in overcoming dyssynchrony.

Myocardial strain characteristics at different interventricular pacing timings: implications for device programming and long-term clinical outcomes in patients with cardiac resynchronisation therapy

AIMS

Response to cardiac resynchronisation therapy (CRT) in patients with heart failure depends on the degree of correction of electromechanical dyssynchrony between the left and right ventricles (LV, RV). It is not known whether chronic programming of interventricular (VV) intervals based on characterisation of myocardial strain at different pacing intervals performed acutely would have better long-term clinical outcomes. We hence aimed to evaluate this relationship between speckle tracking strain patterns and rates at different VV intervals and long-term clinical outcomes of programmed VV pacing in patients with CRT in a prospective, longitudinal follow-up study.

METHODS

We assessed echocardiographic effects, myocardial strain patterns and rates in acute settings at VV intervals; 'LV Off', 'VV0', 'VV60' and 'RV Off' to provide 'RV-only', 'simultaneous BiV', 'sequential LV-RV' and 'LV-only' pacing respectively in 338 patients (age, 67.5 ± 10.3 years; male, 70%) with CRT. Thereafter, devices were programmed chronically to VV60, and long-term clinical outcomes were assessed.

RESULTS

With VV0, VV60 and LV only pacing, LVEF improved to 33.6 ± 12.3%, 40.0 ± 11.4% and 42.6 ± 11.2%, respectively, from 23.7 ± 10.2% at baseline (p < .001). Incremental improvement in strain occurred with VV0, VV60 and LV only pacing; greatest with LV only pacing. At 1 year, 23% patients had NYHA III-IV compared to 96% at baseline (p < .001).

CONCLUSIONS

In patients with CRT, different VV timings show significant differences in acute myocardial strain patterns and rates, and LVEF. These changes are markedly favourable with LV-only and sequential LV-RV pacing, the latter with chronic programming also results in long-term clinical improvement.

Economic evaluation of a dedicated cardiac resynchronisation therapy preassessment clinic

Introduction

Patient evaluation before cardiac resynchronisation therapy (CRT) remains heterogeneous across centres and it is suspected a proportion of patients with unfavourable characteristics proceed to implantation. We developed a unique CRT preassessment clinic (CRT PAC) to act as a final review for patients already considered for CRT. We hypothesised that this clinic would identify some patients unsuitable for CRT through updated investigations and review. The purpose of this analysis was to determine whether the CRT PAC led to savings for the National Health Service (NHS).

Methods

A decision tree model was made to evaluate two clinical pathways; (1) standard of care where all patients initially seen in an outpatient cardiology clinic proceeded directly to CRT and (2) management of patients in CRT PAC.

Results

244 patients were reviewed in the CRT PAC; 184 patients were eligible to proceed directly for implantation and 48 patients did not meet consensus guidelines for CRT so were not implanted. Following CRT, 82.4% of patients had improvement in their clinical composite score and 57.7% had reduction in left ventricular end-systolic volume ≥15%. Using the decision tree model, by reviewing patients in the CRT PAC, the total savings for the NHS was £966 880. Taking into consideration the additional cost of the clinic and by applying this model structure throughout the NHS, the potential savings could be as much as £39 million.

Conclusions

CRT PAC appropriately selects patients and leads to substantial savings for the NHS. Adopting this clinic across the NHS has the potential to save £39 million.

Pacing at accelerated heart rate during echocardiography-guided atrioventricular optimisation following cardiac resynchronisation therapy

Introduction

Although echo-guided atrioventricular optimisation (AVO) is standardly performed at rest, this approach may not provide optimal AV synchrony during daily activities.

Material and methods

The AVO protocol at one of two hospital campuses had been modified to be performed while pacing at an accelerated heart rate. We tested if this approach would improve the yield from AVO compared to the other campus, where AVO was performed at the intrinsic sinus rate.

Results

Between campuses, no significant differences were seen in demographics, chamber sizes, left ventricular ejection fraction, and diastolic function grade. Those having AVO at C2 were more likely to demonstrate “fusion prone” physiology (36% vs. 9%; p = 0.006) and were more likely to display either “truncation- or fusion-prone” physiology (58% vs. 27%; p = 0.007).

Conclusions

When AVO was performed at an accelerated heart rate, patients with “truncation-prone” or “fusion-prone” physiology were identified more readily.

His-Purkinje Conduction System Pacing: State of the Art in 2020

Conduction system pacing involves directly stimulating the specialised His-Purkinje cardiac conduction system with the aim of activating the ventricles physiologically, in contrast to the dyssynchronous activation produced by conventional myocardial pacing. Since the first report of permanent His bundle pacing (HBP) in 2000, the stylet-driven technique of its earliest incarnation has been superseded by a more successful stylet-less approach. Widespread uptake has led to a much greater evidence base. Single-centre observational studies have now been supported by large multicentre, international registries, mechanistic studies and the first randomised controlled trials. New evidence has elucidated mechanisms of HBP and illustrated the nature and magnitude of its potential benefits for preventing pacing-induced cardiomyopathy and correcting bundle branch block. Left bundle branch pacing (LBBP) is a newer technique in which the lead is fixed deep into the left side of the intraventricular septum to allow capture of the left bundle, distal to the His bundle. LBBP holds promise as a method for physiological pacing that overcomes some of the fixation, threshold and sensing challenges of HBP. In this state-of-the-art review of His-Purkinje conduction system pacing, the authors assess recent evidence and current practice and explore emerging and future directions in this rapidly evolving field.

Pacemaker-mediated tachycardia in a dual-lead CRT-D: What is the mechanism?

A 73-year-old gentleman with dilated cardiomyopathy, left bundle branch block and a left ventricular (LV) ejection fraction of 20% was implanted with two LV leads in a tri-ventricular cardiac resynchronisation therapy defibrillator (CRT-D) trial. As a part of the trial he was programmed with fusion-based CRT therapy with dual LV lead only pacing. The patient presented to local heart failure service 12 years after implant, after a positive response to CRT therapy, with increase in fatigue, shortness of breath and bilateral pitting oedema. The patient sent a remote monitoring transmission that suggested loss of capture on one of the LV leads. This coupled with atrial ectopics was producing a high burden of pacemaker-mediated tachycardia (PMT) that was not seen when both LV leads had been capturing. What is the mechanism for this? Dual LV-lead tri-ventricular leads have been shown to have variable improvements in CRT response but with an increased complexity of implant procedure. This is the first case report of PMT-induced heart failure exacerbation in a tri-ventricular device following loss of LV capture of one lead.

Exclusively cephalic venous access for cardiac resynchronisation: A prospective multi-centre evaluation

BACKGROUND

Small series has shown that cardiac resynchronisation therapy (CRT) can be achieved in a majority of patients using exclusively cephalic venous access. We sought to determine whether this method is suitable for widespread use.

METHODS

A group of 19 operators including 11 trainees in three pacing centres attempted to use cephalic access alone for all CRT device implants over a period of 8 years. The access route for each lead, the procedure outcome, duration, and complications were collected prospectively. Data were also collected for 105 consecutive CRT device implants performed by experienced operators not using the exclusively cephalic method.

RESULTS

A new implantation of a CRT device using exclusively cephalic venous access was attempted in 1091 patients (73.6% male, aged 73 ± 12 years). Implantation was achieved using cephalic venous access alone in 801 cases (73.4%) and using a combination of cephalic and other access in a further 180 (16.5%). Cephalic access was used for 2468 of 3132 leads implanted (78.8%). Compared to a non-cephalic reference group, complications occurred less frequently (69/1091 vs 12/105; P = .0468), and there were no pneumothoraces with cephalic implants. Procedure and fluoroscopy duration were shorter (procedure duration 118 ± 45 vs 144 ± 39 minutes, P < .0001; fluoroscopy duration 15.7 ± 12.9 vs 22.8 ± 12.2 minutes, P < .0001).

CONCLUSIONS

CRT devices can be implanted using cephalic access alone in a substantial majority of cases. This approach is safe and efficient.

Persistent left superior vena cava accompanying repaired tetralogy of Fallot: Does it pose a challenge for device implantation?

Persistent left superior vena cava is a thoracic venous return anomaly. Tetralogy of Fallot is one of the most common congenital anomalies seen with persistent left superior vena cava. We are presenting a successful cardiac resynchronisation therapy device implantation in a patient with repaired tetralogy of Fallot and persistent left superior vena cava combination which has not been previously reported in the literature.

Body composition in heart failure and the impact of cardiac resynchronisation therapy: a proof-of-concept study

Aims

Body composition (BC) is known to alter in heart failure. Cardiac resynchronisation therapy (CRT) improves left ventricular geometry but the impact on BC is unknown. Our aim was to evaluate BC in these patients before and after CRT implantation.

Methods

Prospective proof-of-concept pilot study of heart failure patients undergoing CRT between September 2014 and December 2015. Assessments performed pre-CRT and post-CRT (6 weeks and 6 months) were: BC parameters (using air-displacement plethysmography), New York Heart Failure classification for assessing symptom severity, echocardiography to assess left ventricular geometry, electrocardiography, Minnesota Heart Failure Questionnaire and N-terminal probrain natriuretic peptide (NT-pro-BNP). Repeated measures analysis of variance was performed to assess relative change over time and potential correlations.

Results

Twenty-five patients were recruited; mean-age (±SD) was 73.4±10.0 years, 23 males, 18 CRT defibrillators (remainder CRT pacemakers), 16 had ischaemic aetiology, 6 diabetics, 17 with left bundle-branch morphology on ECG and 10 had atrial fibrillation. Significant inverse correlations were observed in the first 6 weeks following CRT between fat mass and left ventricular end-diastolic volume (r=−0.69, p<0.01) and NT-pro-BNP and fat mass (r=0.41, p=0.05). No significant differences were noted over 6 months. There was an observed trend towards reduced fat mass in the first 6 weeks post-CRT implant driven by non-responders. There was no significant difference between responders and non-responders in BC over 6 months.

Conclusion

This is the first study to observe interplay between BC and cardiac geometry/function following CRT; a trend in overall fat mass reduction was noted following CRT and merits further study.

Chest radiographs of cardiac devices (Part 1): Cardiovascular implantable electronic devices, cardiac valve prostheses and Amplatzer occluder devices

Several new innovative cardiac devices have been created over the last few decades. Chest radiographs (CXRs) are the most common imaging investigations undertaken because of their value in evaluating the cardiorespiratory system. It is important for the interpreting radiologist to not only identify these iatrogenic objects but also to assess for their accurate placement, as well as for any complications related to their placement, which may be seen either on the immediate post-procedural CXR or on a follow-up CXR.

Update in Cardiac Pacing

Initial efforts to artificially stimulate the heart were borne out of a necessity to prevent catastrophic bradycardic events. The initial pacemaker systems were large, bulky external devices. However, advancements in technology allowed for the development of internally powered, fully implantable devices. Further advancements resulted in more complex, programmable devices, but the overall systems have remained largely unchanged for more than 50 years. The most recent advancements in the field have represented fundamental paradigm shifts in both pacemaker design and the approach to cardiac pacing. These efforts have focused on reducing and eliminating hardware to reduce the risk of complications and to focus on improving cardiac efficiency to improve clinical outcomes. In this article, the authors explore these advances including leadless pacemaker systems, permanent His bundle pacing and advances in the field of cardiac resynchronisation therapy.

Cardiac Resynchronisation Therapy and Cellular Bioenergetics: Effects Beyond Chamber Mechanics

Cardiac resynchronisation therapy is a cornerstone in the treatment of advanced dyssynchronous heart failure. However, despite its widespread clinical application, precise mechanisms through which it exerts its beneficial effects remain elusive. Several studies have pointed to a metabolic component suggesting that, both in concert with alterations in chamber mechanics and independently of them, resynchronisation reverses detrimental changes to cellular metabolism, increasing energy efficiency and metabolic reserve. These actions could partially account for the existence of responders that improve functionally but not echocardiographically. This article will attempt to summarise key components of cardiomyocyte metabolism in health and heart failure, with a focus on the dyssynchronous variant. Both chamber mechanics-related and -unrelated pathways of resynchronisation effects on bioenergetics – stemming from the ultramicroscopic level – and a possible common underlying mechanism relating mechanosensing to metabolism through the cytoskeleton will be presented. Improved insights regarding the cellular and molecular effects of resynchronisation on bioenergetics will promote our understanding of non-response, optimal device programming and lead to better patient care.

Implantable Cardiac Electronic Devices in the Elderly Population

The use of cardiac implantable electronic devices in the management of patients with heart rhythm conditions is well established. As the population ages, the use of cardiac implantable electronic devices in the elderly is likely to increase. This review provides a summary of the indications, implantation considerations and pragmatic advice on how to approach the use of these devices in this group of patients.

Adverse Consequences of Right Ventricular Apical Pacing and Novel Strategies to Optimize Left Ventricular Systolic and Diastolic Function

Several studies have focused on the deleterious consequences of Right Ventricular Apical (RVA) pacing on Left Ventricular (LV) function, mediated by pacing-induced ventricular dyssyn-chrony. Therapeutic strategies to reduce the detrimental consequences of RVA pacing have been pro-posed, that includes upgrading of RVA pacing to Cardiac Resynchronization Therapy (CRT), alterna-tive Right Ventricular (RV) pacing sites, minimal ventricular pacing strategies, as well as atrial-based pacing. In developing countries, single chamber RV pacing still constitutes a majority of cases of permanent pacing, and assessment of the optimal RV pacing site is of paramount importance. In chronically-paced patients, it is crucial to maintain as close and normal LV physiological function as possible, by minimizing ventricular dyssynchrony, reducing the chances for heart failure and other complications to develop. This review provides an analysis of the deleterious immediate and long-term consequences of RVA pacing, and the most recent available evidence regarding improvements in pacing options and strategies to optimize LV diastolic and systolic function. Furthermore, the place of advanced echocardiography in the identification of patients with pacing-induced LV dysfunction, the potential role of a new predictor of LV dysfunction in RV-paced subjects, and the long- term out-comes of patients with RV septal pacing will be explored

Outcomes of patients with heart failure after primary prevention ICD unit generator replacement

OBJECTIVE

Data describing outcomes after implantable cardioverter-defibrillator (ICD) unit generator replacement in patients with heart failure (HF) with primary prevention devices are limited.

METHOD

Data on patients with HF who underwent primary prevention ICD/cardiac resynchronisation therapy-defibrillator (CRT-D) implantation from 2007 until mid-2015 who subsequently received unit generator replacement were analysed. Outcomes assessed were mortality, appropriate ICD therapy and shock, and procedural complications.

RESULTS

61 of 385 patients with HF with primary prevention ICD/CRT-D undergoing unit generator replacement were identified. Follow-up period was 1.8±1.5 years after replacement. 43 (70.5%) patients had not received prior appropriate ICD therapy prior to unit replacement. The cumulative risks of appropriate ICD therapy at 1, 3 and 5 years after unit replacement in those without prior ICD therapy were 0%, 6.2% and 50% compared with 6.2%, 59.8% and 86.6%, respectively (p=0.005) in those with prior ICD therapies. No predictive factors associated with appropriate ICD therapy after replacement could be identified. 41 (32.8%) patients no longer met guideline indications at the time of unit replacement but risks of subsequent appropriate ICD interventions were not different compared with those who continued to meet primary prevention ICD indications.The 5-year mortality risk after unit replacement was 18.4% and there were high procedural complication rates (9.8%).

CONCLUSION

No predictive marker successfully stratified patients no longer needing ICD support prospectively. Finding such a marker is important in decision-making about device replacement particularly given the concerns about the complication rates. These factors should be considered at the time of ICD unit replacement.

Contractility surrogates derived from three-dimensional lead motion analysis and prediction of acute haemodynamic response to CRT

Background

Patient-specific left ventricular (LV) lead optimisation strategies with immediate feedback on cardiac resynchronisation therapy (CRT) effectiveness are needed. The purpose of this study was to compare contractility surrogates derived from biventricular lead motion analysis to the peak positive time derivative of LV pressure (dP/dt_max) in patients undergoing CRT implantation.

Methods

Twenty-seven patients underwent CRT implantation with continuous haemodynamic monitoring. The right ventricular (RV) lead was placed in apex and a quadripolar LV lead was placed laterally. Biplane fluoroscopy cine films facilitated construction of three-dimensional RV–LV interlead distance waveforms at baseline and under biventricular pacing (BIVP) from which the following contractility surrogates were derived; fractional shortening (FS), time to peak systolic contraction and peak shortening of the interlead distance (negative slope). Acute haemodynamic CRT response was defined as LV ∆dP/dt_max ≥ 10 %.

Results

We observed a mean increase in dP/dt_max under BIVP (899±205 mm Hg/s vs 777±180 mm Hg/s, p<0.001). Based on ΔdP/dt_max, 18 patients were classified as acute CRT responders and nine as non-responders (23.3%±10.6% vs 1.9±5.3%, p<0.001). The baseline RV–LV interlead distance was associated with echocardiographic LV dimensions (end diastole: R=0.61, p=0.001 and end systole: R=0.54, p=0.004). However, none of the contractility surrogates could discriminate between the acute CRT responders and non-responders (ΔFS: −2.5±2.6% vs − 2.0±3.1%, p=0.50; Δtime to peak systolic contraction: −9.7±18.1% vs −10.8±15.1%, p=0.43 and Δpeak negative slope: −8.7±45.9% vs 12.5±54.8 %, p=0.09).

Conclusion

The baseline RV–LV interlead distance was associated with echocardiographic LV dimensions. In CRT recipients, contractility surrogates derived from the RV–LV interlead distance waveform could not discriminate between acute haemodynamic responders and non-responders.

Protocol-driven remote monitoring of cardiac resynchronization therapy as part of a heart failure disease management strategy

BACKGROUND

Cardiac resynchronisation therapy (CRT) is an established treatment for heart failure (HF) with reduced ejection fraction. CRT devices are equipped with remote monitoring functions, which are pivotal in the detection of device problems, but may also facilitate disease management. The aim of this study was to provide a comprehensive overview of the clinical interventions taken based on remote monitoring.

METHODS

This is a single centre observational study of consecutive CRT patients (n = 192) participating in protocol-driven remote follow-up. Incoming technical- and disease-related alerts were analysed together with subsequently triggered interventions.

RESULTS

During 34 ± 13 months of follow-up, 1372 alert-containing notifications were received (2.53 per patient-year of follow-up), comprising 1696 unique alerts (3.12 per patient-year of follow-up). In 60%, notifications resulted in a phone contact. Technical alerts constituted 8% of incoming alerts (0.23 per patient-year of follow-up). Rhythm (1.43 per patient-year of follow-up) and bioimpedance alerts (0.98 per patient-year of follow-up) were the most frequent disease-related alerts. Notifications included a rhythm alert in 39%, which triggered referral to the emergency room (4%), outpatient cardiology clinic (36%) or general practitioner (7%), or resulted in medication changes (13%). Sole bioimpedance notifications resulted in a telephone contact in 91%, which triggered outpatient evaluation in 8% versus medication changes in 10%. Clinical outcome was excellent with 97% 1-year survival.

CONCLUSIONS

Remote CRT follow-up resulted in 0.23 technical- versus 2.64 disease-related alerts annually. Rhythm and bioimpedance notifications constituted the majority of incoming notifications which triggered an actual intervention in 22% and 15% of cases, respectively.

Coronary sinus ostial atresia with persistent left superior caval vein in a patient with congenitally corrected transposition of the great arteries

We present a case of a 57-year-old man with congenitally corrected transposition of great vessels who was found to have coronary ostial atresia with cranial flow through left superior vena cava on CT with contrast injection in coronary tributaries. As such, he was ineligible for cardiac resynchronization therapy.

Significant mitral regurgitation as a predictor of long-term prognosis in patients receiving cardiac resynchronisation therapy

BACKGROUND

Cardiac resynchronisation therapy (CRT) has been shown to reduce functional mitral regurgitation, although the relationship between significant mitral regurgitation (SMR) and the clinical prognosis of CRT remains uncertain.

AIM

We sought to investigate the association of baseline SMR with long-term outcomes in patients undergoing CRT.

METHODS

A total of 296 consecutive patients undergoing CRT were enrolled. SMR was quantified by colour Doppler in all patients at baseline and defined as level ≥ 3 on the severity scale. The primary endpoints included all-cause death, heart failure hospitalisation (HFH), and heart transplantation, and the secondary endpoints were response to CRT and New York Heart Association (NYHA) class III or IV six months after CRT implantation.

RESULTS

The mean age was 59 ± 11 years, and 202 (68.2%) patients were male. Among all patients, 124 (41.9%) presented with baseline SMR. Over a mean follow-up of 4.17 ± 3.16 years, there were 53 (17.9%) cases of all-cause death, 41 (13.8%) cases of HFH, and four (1.4%) cases of heart transplantation. SMR was positively associated with primary endpoint events (hazard ratio [HR] 1.602, 95% confidence interval [CI] 1.083-2.371, p = 0.019), HFH (HR 3.567, 95% CI 1.763-7.219, p < 0.001) and NYHA class III or IV (HR 2.101, 95% CI 1.313-3.363, p = 0.002). After adjusting for multiple factors, we found that SMR (HR 1.785, 95% CI 1.091-2.920, p = 0.021), ischaemic heart disease (HR 1.628, 95% CI 1.062-2.494, p = 0.025), and the lack of use of spironolactone (HR 2.044, 95% CI 1.040-4.017, p = 0.038) were independent predictors of primary endpoints, and SMR remained an independent predictor of HFH (HR 4.622, 95% CI 1.955-10.923, p < 0.001).

CONCLUSIONS

Significant mitral regurgitation before CRT implantation was strongly associated with long-term poor progno-sis. SMR was positively associated with HFH rather than all-cause death and CRT response.

Are changes in heart rate, observed during dobutamine stress echocardiography, associated with a response to cardiac resynchronisation therapy in patients with severe heart failure? Results of a multicentre ViaCRT study

BACKGROUND

According to current European Society of Cardiology guidelines for the diagnosis and treatment of heart failure (HF), cardiac resynchronisation therapy (CRT) is indicated in patients suffering from HF with reduced ejection fraction (EF) with significantly widened QRS complexes. The presence of vital myocardium proven by dobutamine stress echocardiography (DSE) is considered as a good prognostic factor for responsiveness to this treatment. Chronotropic incompetence is, on the other hand, a known factor of unfavourable outcome in HF.

AIM

The aim of this study was to analyse the relationship between heart rate (HR) response during DSE and resultant changes in echocardiographic parameters determined prior to CRT and six weeks post-implantation of the CRT system.

METHODS

The study included 72 men and 25 women with chronic HF and markedly deteriorated left ventricular (LV) sys-tolic function (EF < 35%). Low-dose DSE was performed prior to the CRT system implantation. Baseline echocardiographic parameters determined before CRT were compared to those measured six weeks after implantation.

RESULTS

Implantation of the CRT system resulted in an improvement of LV systolic function. DSE showed a significant in-crease in HR, by 16.3 bpm on average. Patients with the least prominent increase in HR during DSE (< 7 bpm) presented with significantly greater end-diastolic LV dimension and volume, as well as with significantly lower EF than the subjects with the most evident increase in HR (> 24 bpm). Improvement in EF at six weeks was associated with lower baseline HR and its greater absolute and relative increase during DSE. Greater absolute increase in HR during DSE was also associated with more prominent decrease in systolic/diastolic LV volumes.

CONCLUSIONS

Patients with better chronotropic response during DSE show significant improvement in LV parameters determined by echocardiography within six weeks of CRT. Chronotropic response to pharmacologic stress test may serve as a predictive factor in patients qualified for CRT.

Overview of implantable cardioverter defibrillator and cardiac resynchronisation therapy in heart failure management

Clinical trials have established the benefits of implantable cardioverter defibrillators (ICDs) and cardiac resynchronisation therapy (CRT) in the treatment of heart failure patients. As adjuncts to guideline-directed medical therapy, ICDs confer mortality benefits from sudden cardiac arrest, while CRT reduces mortality, hospitalisation rates and improves functional capacity. This review discusses the use of ICDs and CRT devices in heart failure management, outlining the evidence supporting their use, indications and contraindications.

Long-term complications, reoperations and survival following cardioverter-defibrillator implant

OBJECTIVE

Implantable cardioverter-defibrillators (ICDs) reduce risk of death in select populations, but are also associated with harms. We aimed to characterise long-term complications and reoperation rate.

METHODS

We assessed the rate, cumulative incidence and predictors of long-term reoperation and survival using a prospective, multicentre registry serving British Columbia in Canada, a universal single payer healthcare system with 4.5 million residents. 3410 patients (mean 63.3 years, 81.7% male) with new primary (n=1854) or secondary prevention (n=1556) ICD implant from 2003 to 2012 were followed for a median of 34 months (single chamber n=1069, dual chamber n=1905, biventricular n=436). Independent predictors of adverse outcomes were defined using Cox regression models.

RESULTS

The overall reoperation rate was 12.0% per patient-year, and less for single vs dual vs biventricular ICDs (9.1% vs 12.5% vs 17.8% per patient-year, respectively). The Kaplan-Meier complication estimates (excluding generator end of life) at 1, 3 and 5 years were respectively: single chamber 10.2%, 16.2% and 21.6%; dual 11.7%, 19.1% and 27.4% and biventricular 15.9%, 22.2% and 24.7%. Cardiac resynchronisation therapy had the highest rate of early lead complications, but lower long-term need for upgrade. Device complexity, age and atrial fibrillation were key determinants of complications. Overall mortality at 1, 3 and 5 years was 5.4%, 17.4% and 32.7%, respectively. In younger patients, observed 5-year survival approached the expected survival in the general population (relative survival ratio=0.96 (0.90-0.98)). With increasing age, observed survival steadily declined relative to expected.

CONCLUSIONS

In a prospective registry capturing all procedures, complication and reoperation rates following de novo ICD implantation were high. Shared decision making must carefully consider these factors.

Chronic heart failure part 2: treatment and management

Chronic heart failure is a common and complex clinical syndrome that results from impaired cardiac relaxation or contraction. There have been considerable advances in the management of chronic heart failure; however, the mortality rate remains high. Patients with chronic heart failure may experience multiple debilitating symptoms, such as fatigue, pain, and peripheral oedema. However, breathlessness may be considered the most debilitating symptom. The management of chronic heart failure aims to improve the patient's quality of life by reducing symptoms and supporting the patient to manage their condition. Treatment of patients with chronic heart failure may involve a combination of pharmacological therapy, device implantation and cardiac rehabilitation. This is the second of two articles on chronic heart failure. Part 1 discussed the pathophysiology of chronic heart failure, its causes, assessment, signs and symptoms. Part 2 outlines the treatment and management of patients with the condition, including pharmacological strategies, device implantation, lifestyle modification, cardiac rehabilitation and palliative care.

Highlights of the 2016 European Society of Cardiology Guidelines on Heart Failure

The European Society of Cardiology guidelines for the diagnosis and treatment of heart failure (HF) was updated in 2016. In this article, highlights of the updates made based on new findings and practical recommendations are presented. The 2016 guidelines include definitions and criteria for diagnosing the different types of HF. In addition, a newly developed algorithm is proposed for treating particularly symptomatic HF with reduced ejection fraction, including the use of the angiotensin-converting enzyme inhibitors, beta-blockers, mineralocorticoid receptor antagonists and the angiotensin receptor neprilysin inhibitor sacubitril/valsartan. Further evidence is required for some aspects of the diagnosis and treatment of HF, but these guidelines will prove useful for decision making in this setting.

Key Lessons from the ELECTRa Registry in the Modern Era of Transvenous Lead Extraction

The implantation rate of cardiac electronic devices has grown over the past decades. The number of treated patients has increased in parallel with the complexity of the patient population treated, being older, frailer, having more complex devices (in particular, cardiac resynchronisation therapy) and presenting with a greater comorbidity burden. As a consequence, there is a rising number of related implanted system complications, including malfunction and infection. Thus, the demand for transvenous lead extraction (TLE) has also substantially increased. To identify the indication to TLE by various operators and centres, techniques used to perform TLE, and the safety and efficacy of the current clinical practice of TLE, a large prospective registry has been started in Europe - the European Lead Extraction Controlled (ELECTRa) Registry. The key findings of the ELECTRa Registry are discussed in the present review and placed in the context of previous knowledge. The ELECTRa Registry confirms that the TLE procedure is a safe and effective treatment, with an acceptable risk-benefit ratio that is comparable with other well-known cardiological invasive procedures. Of course, TLE is accompanied by potential life-threatening complications; the vast majority of these can be managed by an experienced multidisciplinary team. Multiple factors predict complications, including patient/lead profile, centre experience and procedure volumes, which may suggest caution when accepting a patient for TLE.

Is There a Future for Remote Cardiac Implantable Electronic Device Management?

In the era of communication technology, remote monitoring has been a paradigm shift in the way patients with cardiac implantable electronic devices are managed. It has been endorsed by scientific societies and is being increasingly adopted in the clinical setting. Despite the various advantages associated with this strategy, data on improved clinical outcome are still sparse. The recently published study on the remote management of heart failure using implanted devices and formalised follow-up procedures, which turned out to be negative, has cast doubt on whether remote monitoring should still be used. This article provides a critical appraisal of the study, and discusses the issue of remote data management.

The Prognostic Role of Tissue Characterisation using Cardiovascular Magnetic Resonance in Heart Failure

Despite significant advances in heart failure diagnostics and therapy, the prognosis remains poor, with one in three dying within a year of hospital admission. This is at least in part due to the difficulties in risk stratification and personalisation of therapy. The use of left ventricular systolic function as the main arbiter for entrance into clinical trials for drugs and advanced therapy, such as implantable defibrillators, grossly simplifies the complex heterogeneous nature of the syndrome. Cardiovascular magnetic resonance offers a wealth of data to aid in diagnosis and prognostication. The advent of novel cardiovascular magnetic resonance mapping techniques allows us to glimpse some of the pathophysiological mechanisms underpinning heart failure. We review the growing prognostic evidence base using these techniques.

Gender-related differences in coronary venous anatomy: a potential basis for various response to cardiac resynchronisation therapy

BACKGROUND AND AIM

We hypothesised that small differences in the anatomy of the coronary venous tree might be one of the factors responsible for the differences in the response for cardiac resynchronisation depending on a patient's gender.

METHODS

Cardiac computed tomography scans with retrospective gating were performed on 315 subjects (aged 58.3 ± 11.6 years; 117 women) according to the clinical criteria. The standard protocol for coronary arteries was used during scanning. Additional reconstructions that were focused on the coronary veins during post processing were used to analyse the data. Gender-related anatomical variants were identified.

RESULTS

The average of 3.6 ± 1.4 veins per case were visualised. The posterolateral vein was visualised more frequently in men than in women (p < 0.05). Eight variants were identified as being more frequent - they were found in 237 out of 315 cases (75.24%). Those variants occurred in 95 (81.19%) of the women and in 142 (71.72%) of the men, p = 0.080. Six variants occurred more frequently in women; however, the differences were not significant.

CONCLUSIONS

In women a more frequent presence of favourable coronary vein variants in the target area for cardiac resynchronisation can be seen. Anatomical findings may help to explain why women more frequently respond to cardiac resyn-chronisation therapy compared to men.

Pacing and Defibrillators in Complex Congenital Heart Disease

Device therapy in the complex congenital heart disease (CHD) population is a challenging field. There is a myriad of devices available, but none designed specifically for the CHD patient group, and a scarcity of prospective studies to guide best practice. Baseline cardiac anatomy, prior surgical and interventional procedures, existing tachyarrhythmias and the requirement for future intervention all play a substantial role in decision making. For both pacing systems and implantable cardioverter defibrillators, numerous factors impact on the merits of system location (endovascular versus non-endovascular), lead positioning, device selection and device programming. For those with Fontan circulation and following the atrial switch procedure there are also very specific considerations regarding access and potential complications. This review discusses the published guidelines, device indications and the best available evidence for guidance of device implantation in the complex CHD population.

Retrospective application of Program to Access and Review Trending iNformation and Evaluate coRrelation to Symptoms in patients with Heart Failure criteria for the remote management of patients with cardiac resynchronisation therapy

Aim The Program to Access and Review Trending iNformation and Evaluate coRrelation to Symptoms in patients with Heart Failure (PARTNERS HF) trial elaborated a multiparametric model for prediction of acute decompensation in advanced heart failure patients, based on periodical in office data download from cardiac resynchronisation devices. In this study, we evaluated the ability of the PARTNERS HF criteria to detect initial decompensation in a population of moderate heart failure patients under remote monitoring. Methods We retrospectively applied the PARTNERS HF criteria to 1860 transmissions from 104 patients (median follow up 21 months; range 1-67 months), who were enrolled in our programme of telemedicine after cardiac resynchronisation therapy. We tested the ability of a score based on these criteria to predict any acute clinical decompensation occurring in the 15 days following a transmission. Results In 441 cases, acute heart failure was diagnosed after the index transmission. The area under the curve (AUC) of the score for the diagnosis of acute decompensation was 0.752 (confidence interval (CI) 95% 0.728-0.777). The best score cut-off was consistent with the results of PARTNERS HF: with a score ≥2, sensitivity was 75% and specificity 68%. The odds ratio for events was 6.24 (CI 95% 4.90-7.95; p < 0.001). Conclusions When retrospectively applied to remote monitoring transmissions and arranged in a score, PARTNERS HF criteria could identify HF patients who subsequently developed acute decompensation. These results warrant prospective studies applying PARTNERS HF criteria to remote monitoring.

Clinical utility of speckle-tracking echocardiography in cardiac resynchronisation therapy

Cardiac resynchronisation therapy (CRT) can profoundly improve outcome in selected patients with heart failure; however, response is difficult to predict and can be absent in up to one in three patients. There has been a substantial amount of interest in the echocardiographic assessment of left ventricular dyssynchrony, with the ultimate aim of reliably identifying patients who will respond to CRT. The measurement of myocardial deformation (strain) has conventionally been assessed using tissue Doppler imaging (TDI), which is limited by its angle dependence and ability to measure in a single plane. Two-dimensional speckle-tracking echocardiography is a technique that provides measurements of strain in three planes, by tracking patterns of ultrasound interference ('speckles') in the myocardial wall throughout the cardiac cycle. Since its initial use over 15 years ago, it has emerged as a tool that provides more robust, reproducible and sensitive markers of dyssynchrony than TDI. This article reviews the use of two-dimensional and three-dimensional speckle-tracking echocardiography in the assessment of dyssynchrony, including the identification of echocardiographic parameters that may hold predictive potential for the response to CRT. It also reviews the application of these techniques in guiding optimal LV lead placement pre-implant, with promising results in clinical improvement post-CRT.

Day by day telemetric care of patients treated with cardiac resynchronisation therapy: first Polish experience

BACKGROUND

Due to the recent rapid increase in the number of patients implanted with pacemakers, cardioverter-defibrillators (ICD), and cardiac resynchronisation therapy devices (CRT), conventional monitoring at specialist clinics is becoming increasingly difficult. The development of technology has enabled remote device monitoring with the use of teletransmission systems.

AIM

To assess the effectiveness of transmission and the possibility of using telemetric data for further clinical management of patients with heart failure (HF) treated with CRT-D.

METHODS

The analysis included 305 consecutive patients with chronic HF, New York Heart Association functional classes II-IV, treated with the use of CRT-D by Biotronik or Medtronic in the years 2006-2012. The patients received transmitters, enabling the remote monitoring of the implanted device from the patients' houses. Scheduled reports were automatically sent every month. The triggers for pre-specified emergency alert transmissions were as follows: ventricular tachycardia (VT) or ventricular fibrillation (VF) episodes, CRT-D intervention, ventricular extrasystoles > 110/h, any episode of atrial fibrillation (AF), atrial flutter (AFL) or supraventricular tachycardia, mean heart rate (HR) during, mean 24-h HR, CRT pacing < 95%, Elective Replacement Indicator, or End Of Service and device malfunction. The all-cause mortality of the study population has been assessed at the end of the follow-up period (mean of 20.5 months).

RESULTS

Devices manufactured by Biotronik were provided to 71% of the study population, while 29% received devices by Medtronic. In 97.3% of cases, the monitors were wireless, fully automatic, and capable of immediate data transmission whenever a pre-specified alert notification was fulfilled. The analysis of long-term outcomes revealed that all-cause mortality of the whole study population was 13%. The effectiveness of report transmission was 98%. During follow-up a total of 31,198 transmissions were received and analysed, which constituted, on average, 4.9 transmissions per patient per month. Among analyses, 30% were reports generated by scheduled remote follow-ups, and 70% were caused by unscheduled device alerts. Correct functioning of the system was confirmed; the quality of the received data was 100%. In 63.9% of patients, decisions based on the information obtained from telemonitoring reports were made to modify the therapy, refer the patients to cardiology or electrophysiology clinics, or hospitalise them urgently. The most common medical reaction was device reprogramming (46.8%). Pharmacotherapy was modified in 33.7% of patients: beta-blocker dose increase (25.9%), anticoagulant treatment inclusion (15.7%), amiodarone inclusion (1.9%), or digoxin inclusion (4.5%). The remaining medical responses were referring patients for atrioventricular junction ablation (8.1%), VT ablation (2.9%), or AF/AFl ablation (1.6%).

CONCLUSIONS

Remote monitoring of implantable devices is feasible, safe, and effective in supervising patients with CRT-D devices. Daily-based remote monitoring of a large population of HF patients allows continuous "triage" of high-risk patients and selection of individuals who require urgent intervention.

Outcomes in Women Undergoing Electrophysiological Procedures

The number of invasive electrophysiological procedures is steadily increasing in Western countries, as the age of the population increases and technologies advance. In recent years, gender-related differences in cardiac rhythm disorders have been increasingly appreciated, which can potentially have a great impact on the outcomes of invasive electrophysiological procedures. Among supraventricular arrhythmias, women have a higher incidence of atrioventricular nodal re-entrant tachycardia and a significantly lower incidence of atrioventricular re-entrant tachycardia compared with males, and present to ablation procedures later and after having failed more antiarrhythmic drugs. The results of catheter ablation of atrial fibrillation in women have been reported worse than in men. This finding is possibly due to a later referral of females to ablation procedures, who present older and with a higher incidence of long-standing persistent atrial fibrillation. With regard to cardiac device implantation procedures, a smaller survival benefit from prophylactic implantable cardioverter defibrillator (ICD) implantation has been shown in women, essentially due to gender-specific differences in the clinical course of patients with severe left ventricular dysfunction, with women dying predominantly from non-arrhythmic causes. On the other side, the clinical outcome of cardiac resynchronisation therapy seems to be more favourable in women, who experience a greater degree of reverse left ventricular remodelling and a striking decrease of heart failure events or mortality after biventricular pacing. This review will summarise the available evidence on gender-related differences in outcomes of invasive electrophysiological procedures.

Predictors of functional mitral regurgitation improvement during a short-term follow-up after cardiac resynchronisation therapy

BACKGROUND AND AIM

The study was undertaken to assess the predictive role of myocardial contractile reserve for functional mitral regurgitation (FMR) improvement after cardiac resynchronisation therapy (CRT), and to define other predictors of FMR improvement (FMRI) and the impact of FMRI on left ventricular (LV) reverse remodelling.

METHODS AND RESULTS

Among 90 patients in whom echocardiography was performed one day before and six weeks after CRT implantation, 66 with at least FMR(2+) in a four-point scale (mean age 64 ± 10 years, mean LV ejection fraction [LVEF] 25.7 ± 6%, ischaemic aetiology 48%) were included. FMRI was defined as the reduction of the FMR severity by at least one grade. The patients were divided into groups: A with FMRI (n = 30) and B without FMRI (n = 36). Contractile reserve was evaluated using low-dose dobutamine stress-echo before CRT implantation and was defined as a relative improvement in LVEF of more than 20% and segmental contractility improvement. Reverse remodelling was defined as the reduction of the LV end-systolic volume (LVESV) by at least 15%. Cox regression multivariate analysis revealed the following predictors for FMRI: contractile reserve preserved in more than three segments with an OR = 5.7 (95% CI 1.81-17.97, p = 0.005, sensitivity 65.5%, specificity 72.2%, AUC = 0.727) and LV end-diastolic diameter ≤ 74 mm with an OR = 2.09 (95% CI 0.75-5.78, p < 0.05, sensitivity 80.0%, specificity 47.2%, AUC = 0.632). FMRI was associated with greater reduction of LVESV (p = 0.002), greater increase in LVEF (p < 0.001) and higher incidence of the LV reverse remodelling (p < 0.001).

CONCLUSIONS

Preserved contractile reserve and lesser degree of LV dilation were predictive factors of short-term FMR improvement after CRT implantation. FMR improvement was associated with higher incidence of the LV reverse remodelling early, already in the six weeks after CRT implantation.