Clinical and economic impact of multipoint left ventricular pacing: A comparative analysis from the Italian registry on multipoint pacing in cardiac resynchronization therapy (IRON-MPP).

INTRODUCTION: Early evidence suggests that multipoint left ventricular pacing (MPP) may improve response to cardiac resynchronization therapy (CRT). It is unknown whether this benefit is sustained and cost-effective. We used real-world data to evaluate long-term impact of MPP-ON clinical status, heart failure hospitalizations (HFH) and costs. METHODS: The Italian registry on multipoint left ventricular pacing is a prospective, multicenter registry of patients implanted with MPP-enabled CRT devices. For this analysis, clinical and echocardiographic data were collected through 24 months and compared between patients with (MPP-ON) or without (MPP-OFF) early MPP activation at implant. The total cost of each HFH was estimated with national Italian reimbursement rates. RESULTS: The study included 190 MPP-OFF and 128 MPP-ON patients with similar baseline characteristics. At 1 and 2 years, the MPP-ON group had lower rates of HFH vs MPP-OFF (1-year hazard ratio [HR]: 0.14, P = .0014; 2-year HR: 0.38, P = .009). The finding persisted in a subgroup of patients with consistent MPP activation through follow-up (1-year HR: 0.19; P = .0061; 2-year HR: 0.39, P = .022). Total HFH per-patient costs were lower in the MPP-ON vs the MPP-OFF group at 1 year (€101 ± 50 vs €698 ± 195, P < .001) and 2 years (€366 ± 149 vs €801 ± 203, P = .038). More MPP-ON patients had ≥5% improvement in ejection fraction (76.8% vs 65.4%, P = .025) and clinical composite score (66.7% vs 47.5%, P = .01). CONCLUSIONS: In this multicenter clinical study, early MPP activation was associated with a significant reduction in cumulative HFH and related costs after 1 and 2 years of follow-up.

Impact of multipoint pacing on projected battery longevity in cardiac resynchronization therapy. An IRON-MPP study sub-analysis.

BACKGROUND: Multipoint pacing (MPP) may improve clinical outcomes in patients with cardiac resynchronization therapy defibrillators (CRT-D), but its impact on battery longevity in a real-world population has not been investigated in large trials. OBJECTIVE: Compare projected battery longevity in CRT-D patients with and without MPP during long-term follow-up. METHODS: The Italian registry on multipoint left ventricular pacing (IRON-MPP) is a prospective, multicenter registry of patients implanted with MPP-capable CRT-D devices. Projected battery longevity during follow-up was compared for patients with MPP (MPP ON) vs single-site (MPP OFF) left ventricular pacing at CRT-D implantation. A sub-analysis excluded crossover patients with MPP activation or deactivation occurring after implantation. A second sub-analysis excluded patients with a right or left ventricular pacing amplitude >2.5 V. RESULTS: Out of 237 CRT-D patients (71 ± 9 years, 81% male) followed for 1.9 ± 0.8 years, 102 (43%) had MPP ON at implantation. Programmed atrial and ventricular outputs and percentage of pacing were similar between groups. MPP was associated with a 0.44 years reduction in projected battery longevity (P = .03) during long-term follow-up. Results were similar for the first and second sub-analyses, with a 0.57 years (P < .001) and 0.71 years (P < .001) reduction in projected longevity, respectively. CONCLUSION: In this long-term real-world registry, early MPP activation is associated with less than a 1-year reduction in projected battery life compared to single-site biventricular pacing.

Effect of lead design and pacing vector on electrical parameters of quadripolar coronary sinus leads: The RALLY-X4 study.

BACKGROUND: Various lead designs have been developed to accommodate different coronary sinus anatomies. Our objectives were to compare electrical parameters of straight and spiral left ventricular leads, to evaluate capture thresholds and impedances using different pacing vectors, and to study evolution of thresholds over time. METHODS: The RALLY-X4 study enrolled patients implanted with a lead from the Acuity X4 family (straight, spiral short, or spiral long). Electrical parameters (including capture thresholds from all 17 vectors) were measured at baseline and follow-up. RESULTS: Data from 795 patients who were successfully implanted were analyzed. Straight and spiral leads had similar proportions of patients with thresholds <2.5 V/0.4 ms using the distal electrode (61-65% of patients) or from at least one of the proximal (E2-E4) electrodes (81-83% of patients). Unipolar vectors had significantly lower thresholds and impedances than bipolar vectors, with similar measurements compared to extended bipolar configurations. Capture thresholds increased with more proximal electrodes for all leads. Over a mean follow-up of 1 year, a slight decrease in capture thresholds was observed. CONCLUSION: Straight and spiral quadripolar leads allow to obtain clinically acceptable capture thresholds from at least one of the proximal electrodes in >80% of patients. Pacing vectors significantly affect electrical parameters, with higher thresholds in more proximal electrodes and lower thresholds with unipolar and extended bipolar configurations. Capture thresholds slightly decreased over a mean follow-up of 1 year.

Patients with right bundle branch block and concomitant delayed left ventricular activation respond to cardiac resynchronization therapy.

Aims: Right bundle branch block (RBBB) typically presents with only delayed right ventricular activation. However, some patients with RBBB develop concomitant delayed left ventricular (LV) activation. Such patients may show a specific electrocardiographic (ECG) pattern resembling RBBB in the precordial leads in association with an insignificant S-wave in lateral limb leads (atypical RBBB). We therefore postulated that the ECG pattern of atypical RBBB might be able to identify a subgroup of patients likely to respond to cardiac resynchronization therapy (CRT). The purpose of this study was to assess the impact of RBBB ECG morphology on CRT response in patients with heart failure (HF). Methods and results: We evaluated the echocardiographic clinical response of 66 patients with RBBB treated with CRT and followed up for almost 2 years. The patients were divided electrocardiographically into 2 groups: 31 with typical RBBB and 35 with atypical RBBB. Responders were classified in terms of reduction in LV end-systolic volume index (ESVi) ≥ 15% or reduction in the New York Heart Association (NYHA) Class ≥ 1 or Packer score variation (NYHA response with no HF-related hospitalization events or death). The atypical RBBB group presented a longer LV activation time compared with the typical RBBB group (111.9 ± 17.6 vs. 73.2 ± 15.4 ms; P < 0.001). In the atypical and typical RBBB groups, respectively, 71.4% and 19.4% of patients were ESVi responders (P = 0.001) 74.3% and 32.3% were NYHA responders (P = 0.002); similarly, 71.4% and 29.0% of patients exhibited a 2-year Packer score of 0 (P = 0.002). Conclusion: Patients with atypical RBBB, which is a pattern highly suggestive of concomitant delayed LV conduction, may show a satisfactory response to CRT.

The economic impact of battery longevity in implantable cardioverter-defibrillators for cardiac resynchronization therapy: the hospital and healthcare system perspectives.

AIMS: Patients receiving cardiac resynchronization therapy defibrillators (CRT-Ds) are likely to undergo one or more device replacements, mainly for battery depletion. We assessed the economic impact of battery depletion on the overall cost of CRT-D treatment from the perspectives of the healthcare system and the hospital. We also compared devices of different generations and from different manufacturers in terms of therapy cost. METHODS AND RESULTS: We analysed data on 1792 CRT-Ds implanted in 1399 patients in 9 Italian centres. We calculated the replacement probability and the total therapy cost over 6 years, stratified by device generation and manufacturer. Public tariffs from diagnosis-related groups were used together with device prices and hospitalization costs. Generators were from 3 manufacturers: Boston Scientific (667, 37%), Medtronic (973, 54%), and St Jude Medical (152, 9%). The replacement probability at 6 years was 83 and 68% for earlier- and recent-generation devices, respectively. The need for replacement increased total therapy costs by more than 50% over the initial implantation cost for hospitals and by more than 30% for healthcare system. The improved longevity of recent-generation CRT-Ds reduced the therapy cost by ∼6% in both perspectives. Among recent-generation CRT-Ds, the replacement probability of devices from different manufacturers ranged from 12 to 70%. Consequently, the maximum difference in therapy cost between manufacturers was 40% for hospitals and 19% for the healthcare system. CONCLUSIONS: Differences in CRT-D longevity strongly affect the overall therapy cost. While the use of recent-generation devices has reduced the cost, significant differences exist among currently available systems.

Multipoint pacing via a quadripolar left-ventricular lead: preliminary results from the Italian registry on multipoint left-ventricular pacing in cardiac resynchronization therapy (IRON-MPP).

AIMS: This registry was created to describe the experience of 76 Italian centres with a large cohort of recipients of multipoint pacing (MPP) capable cardiac resynchronization therapy (CRT) devices. METHODS AND RESULTS: A total of 507 patients in whom these devices had been successfully implanted were enrolled between August 2013 and May 2015. We analysed: (i) current clinical practices for the management of such patients, and (ii) the impact of MPP on heart failure clinical composite response and on the absolute change in ejection fraction (EF) at 6 months. Multipoint pacing was programmed to 'ON' in 46% of patients before discharge. Methods of optimizing MPP programming were most commonly based on either the greatest narrowing of the QRS complex (38%) or the electrical delays between the electrodes (34%). Clinical and echocardiographic follow-up data were evaluated in 232 patients. These patients were divided into two groups according to whether MPP was programmed to 'ON' (n = 94) or 'OFF' (n = 138) at the time of discharge. At 6 months, EF was significantly higher in the MPP group than in the biventricular-pacing group (39.1 ± 9.6 vs. 34.7 ± 7.6%; P < 0.001). Even after adjustments, early MPP activation remained an independent predictor of absolute increase in LVEF of ≥5% (odds ratio 2.5; P = 0.001). At 6 months, an improvement in clinical composite score was recorded in a greater proportion of patients with MPP-ON than in controls (56 vs. 38%; P = 0.009). On comparing optimal MPP and conventional vectors, QRS was also seen to have decreased significantly (P < 0.001). CONCLUSION: This study provides information that is essential in order to deal with the expected increase in the number of patients receiving MPP devices in the coming years. The results revealed different practices among centres, and establishing the optimal programming that can maximize the benefit of MPP remains a challenging issue. Compared with conventional CRT, MPP improved clinical status and resulted in an additional increase in EF. CLINICAL TRIAL REGISTRATION: http://www.clinicaltrial.gov/. Unique identifier: NCT02606071.

Economic impact of remote monitoring after implantable defibrillators implantation in heart failure patients: an analysis from the EFFECT study.

AIMS: Heart failure (HF) patients with implantable cardioverter-defibrillators (ICD) require admissions for disease management and out-patient visits for disease management and assessment of device performance. These admissions place a significant burden on the National Health Service. Remote monitoring (RM) is an effective alternative to frequent hospital visits. The EFFECT study was a multicentre observational investigation aiming to evaluate the clinical effectiveness of RM compared with in-office visits standard management (SM). The present analysis is an economic evaluation of the results of the EFFECT trial. METHODS AND RESULTS: The present analysis considered the direct consumption of healthcare resources over 12-month follow-up. Standard tariffs were applied to hospitalizations, in-office visits and remote device interrogations. Economic comparisons were also carried out by means of propensity score (PS) analysis to take into account the lack of randomization in the study design. The analysis involved 858 patients with ICD or CRT-D. Of these, 401 (47%) were followed up via an SM approach, while 457 (53%) were assigned to RM. The rate of hospitalizations was 0.27/year in the SM group and 0.16/year in the RM group (risk reduction =0.59; P = 0.0004). In the non-adjusted analysis, the annual cost for each patient was €817 in the SM group and €604 in the RM group (P = 0.014). Propensity score analysis, in which 292 RM patients were matched with 292 SM patients, confirmed the results of the non-adjusted analysis (€872 in the SM group vs. €757 in the RM group; P < 0.0001). CONCLUSION: There is a reduction in direct healthcare costs of RM for HF patients with ICDs, particularly CRT-D, compared with standard monitoring. CLINICAL TRIAL REGISTRATION: http://clinicaltrials.gov/Identifier, NCT01723865.

Pitfalls in electrogram interpretation: Subcutaneous cardioverter defibrillator malfunction in Brugada syndrome.

A patient with Brugada syndrome implanted with subcutaneous implantable cardioverter defibrillator (S-ICD) had oversensing episodes treated with S-ICD shocks. Comparable artifacts were not evocable with S-ICD pocket manipulation. The fluoroscopy excluded S-ICD macroscopic damage. The device extraction revealed undamaged pulse generator and connector, but the lead was inappropriately tunneled under the sixth rib. Then the S-ICD malfunction was due to lead microscopic damage caused by the lead rubbing the rib surface.

Longevity of implantable cardioverter-defibrillators for cardiac resynchronization therapy in current clinical practice: an analysis according to influencing factors, device generation, and manufacturer.

AIMS: Device replacement at the time of battery depletion of implantable cardioverter-defibrillators (ICDs) may carry a considerable risk of complications and engenders costs for healthcare systems. Therefore, ICD device longevity is extremely important both from a clinical and economic standpoint. Cardiac resynchronization therapy defibrillators (CRT-D) battery longevity is shorter than ICDs. We determined the rate of replacements for battery depletion and we identified possible determinants of early depletion in a series of patients who had undergone implantation of CRT-D devices. METHODS AND RESULTS: We retrieved data on 1726 consecutive CRT-D systems implanted from January 2008 to March 2010 in nine centres. Five years after a successful CRT-D implantation procedure, 46% of devices were replaced due to battery depletion. The time to device replacement for battery depletion differed considerably among currently available CRT-D systems from different manufacturers, with rates of batteries still in service at 5 years ranging from 52 to 88% (log-rank test, P < 0.001). Left ventricular lead output and unipolar pacing configuration were independent determinants of early depletion [hazard ratio (HR): 1.96; 95% 95% confidence interval (CI): 1.57-2.46; P < 0.001 and HR: 1.58, 95% CI: 1.25-2.01; P < 0.001, respectively]. The implantation of a recent-generation device (HR: 0.57; 95% CI: 0.45-0.72; P < 0.001), the battery chemistry and the CRT-D manufacturer (HR: 0.64; 95% CI: 0.47-0.89; P = 0.008) were additional factors associated with replacement for battery depletion. CONCLUSION: The device longevity at 5 years was 54%. High left ventricular lead output and unipolar pacing configuration were associated with early battery depletion, while recent-generation CRT-Ds displayed better longevity. Significant differences emerged among currently available CRT-D systems from different manufacturers.

The axillary vein puncture for implantable cardiac defibrillator implantation: 14 years of experience. Analysis of the results.

BACKGROUND: Axillary vein puncture (AVP) is a valid alternative to Subclavan vein puncture for leads insertion in cardiac implantable electronic device implantation, that may reduce acute and delayed complications. Very few data are available about ICD recipients. A simplified AVP technique is described. METHODS: All the patients who consecutively underwent "de novo" ICD implantation, from March 2006 to December 2020 at the University of Verona, were considered. Leads insertion was routinely performed through an AVP, according to a simplified technique. Outcome and complications have been retrospectively analyzed. RESULTS: The study population consisted of 1711 consecutive patients. Out of 1711 patients, 38 (2.2%) were excluded because they were implanted with Medtronic Sprint Fidelis lead. Out of 1673 ICD implantations, 963 (57.6%) were ICD plus cardiac resynchronization therapy, 434 (25.9%) were dual-chamber defibrillators, and 276 (16.5%) were single-chamber defibrillators, for a total of 3879 implanted leads. The AVP success rate was 99.4%. Acute complications occurred in 7/1673 (0.42%) patients. Lead failure (LF) occurred in 20/1673 (1.19%) patients. Comparing the group of patients with lead failure with the group without LF, the presence of three leads inside the vein was significantly associated with LF, and the multivariate analysis confirmed three leads in place as an independent predictor of LF. CONCLUSION: AVP, according to our simplified technique, is safe, effective, has a high success rate, and a very low complication rate. The incidence of LF was exceptionally low. The advantages of AVP are maintained over time in a population of ICD recipients.

Non-alcoholic fatty liver disease is associated with an increased prevalence of atrial fibrillation in hospitalized patients with type 2 diabetes.

NAFLD (non-alcoholic fatty liver disease) and AF (atrial fibrillation) are two pathological conditions that are highly prevalent in developed countries and share multiple risk factors. The relationship between NAFLD and AF in Type 2 diabetes is currently unknown. We studied a hospital-based sample of 702 patients with Type 2 diabetes discharged from our Division of Endocrinology during 2007-2011. The diagnosis of AF was confirmed in affected participants on the basis of ECGs and medical history by experienced cardiologists. NAFLD was defined by ultrasonographic detection of hepatic steatosis in the absence of other liver diseases. Of the 702 hospitalized patients included in the study, 514 (73.2%) of them had NAFLD and 85 (12.1%) had persistent or permanent AF. NAFLD was associated with an increased risk of prevalent AF {OR (odds ratio), 3.04 [95% CI (confidence interval), 1.54-6.02]; P<0.001}. Adjustments for age, sex, systolic BP (blood pressure), HbA1c, (glycated haemoglobin), estimated GFR (glomerular filtration rate), total cholesterol, electrocardiographic LVH (left ventricular hypertrophy), COPD (chronic obstructive pulmonary disease), and prior history of HF (heart failure), VHD (valvular heart disease) or hyperthyroidism did not attenuate the association between NAFLD and AF [adjusted OR, 5.88 (95% CI, 2.72-12.7); P<0.001]. In conclusion, our results show that ultrasound-diagnosed NAFLD is strongly associated with an increased prevalence of persistent or permanent AF in patients with Type 2 diabetes, independently of several clinical risk factors for AF. The potential impact of NAFLD on AF deserves particular attention, especially with respect to the implications for screening and surveillance strategies in the growing number of patients with NAFLD.

Cardiac resynchronization therapy-defibrillator improves long-term survival compared with cardiac resynchronization therapy-pacemaker in patients with a class IA indication for cardiac resynchronization therapy: data from the Contak Italian Registry.

AIMS: In candidates for cardiac resynchronization therapy (CRT), the choice between pacemaker (CRT-P) and defibrillator (CRT-D) implantation is still debated. We compared the long-term prognosis of patients who received CRT-D or CRT-P according to class IA recommendations of the European Society of Cardiology (ESC) and who were enrolled in a multicentre prospective registry. METHODS AND RESULTS: A total of 620 heart failure patients underwent successful implantation of a CRT device and were enrolled in the Contak Italian Registry. This analysis included 266 patients who received a CRT-D and 108 who received a CRT-P according to class IA ESC indications. Their survival status was verified after a median follow-up of 55 months. During follow-up, 73 CRT-D and 44 CRT-P patients died (rate 6.6 vs. 10.4%/year; log-rank test, P = 0.020). Patients receiving CRT-P were predominantly older, female, had no history of life-threatening ventricular arrhythmias, and more frequently presented non-ischaemic aetiology of heart failure, longer QRS durations, and worse renal function. However, the only independent predictor of death from any cause was the use of CRT-P (hazard ratio, 1.97; 95% confidence interval, 1.21-3.16; P = 0.007). CONCLUSION: The implantation of CRT-D, rather than CRT-P, may be preferable in patients presenting with current class IA ESC indications for CRT. Indeed, CRT-D resulted in greater long-term survival and was independently associated with a better prognosis.

Correlation between epicardial adipose tissue and atrial fibrillation burden in coronary artery bypass graft surgery.

AIMS: Recent studies suggest an association between epicardial adipose tissue (EAT) and atrial fibrillation. The aim of the study is to evaluate the quantitative and qualitative characteristics of EAT in relation to atrial fibrillation burden after coronary artery bypass graft (CABG). METHODS: This prospective single-centre study included patients undergoing CABG. The patients underwent transthoracic echocardiography and collection of a bioptic sample containing right appendage and EAT during CABG for histological characterization. After surgery, clinical and telemetry data were collected. RESULTS: Fifty-six consecutive patients were enrolled. The mean postsurgical hospitalization was 7.9 ±â€Š3.7 days. Twenty-two patients had at least one episode of atrial fibrillation. In the atrial fibrillation group, there was a bigger atrial volume, a higher degree of diastolic disfunction, a thicker layer of EAT and an older median age in comparison with the group that did not develop it. EAT with a cut-off of 4 mm was a predictor of atrial fibrillation with an odds ratio (OR) of 1.49 (confidence interval (CI) 1.09-2.04), 73% of sensibility and 89% of specificity. From the histological analyses, the patients with atrial fibrillation had a significantly higher percentage of fibrosis. At univariate analysis, atrial volume [OR 1.05, CI 1.01-1.09, P = 0.022], E/A rate (OR 0.04, CI 0.02-0.72 P = 0.29), the percentage of fibrosis (OR 1.12, CI 1.00-1.25, P = 0.045) and age (OR 1.17, CI 1.07-1.28, P = 0.001) were predictors of atrial fibrillation. At multivariate analysis, atrial volume (P = 0.027), fibrosis (P = 0.003) and age (P = 0.039) were independent predictors of atrial fibrillation. CONCLUSION: Postcardiac surgical atrial fibrillation is frequent. EAT thickness, atrial volume, fibrosis and age are predictors of postcardiac surgical atrial fibrillation.

Prognostic significance of remotely monitored nocturnal heart rate in heart failure patients with reduced ejection fraction.

BACKGROUND: Elevated resting heart rate is a risk factor for cardiovascular events. OBJECTIVE: The purpose of this study was to investigate the clinical significance of nocturnal heart rate (nHR) and 24-hour mean heart rate (24h-HR) obtained by continuous remote monitoring (RM) of implantable devices. METHODS: We analyzed daily-sampled trends of nHR, 24h-HR, and physical activity in patients on ß-blocker therapy for chronic heart failure and with implantable cardioverter-defibrillators or cardiac resynchronization therapy defibrillators (CRT-Ds). Patients were grouped by average nHR and 24h-HR quartile during follow-up to estimate the respective incidence of nonarrhythmic death and device-treated ventricular tachycardia/fibrillation (VT/VF). RESULTS: The study cohort included 1330 patients (median age 69 years [interquartile range 61-77 years]; 41% [n = 550] with CRT-D; median follow-up 25 months [interquartile range 13-42 months]). Compared with patients in the lowest nHR quartile (≤57 beats/min) group, patients in the highest quartile group (>65 beats/min) had an increased risk of nonarrhythmic death (adjusted hazard ratio [AHR] 2.25; 95% confidence interval [CI] 1.13-4.50; P = .021) and VT/VF (AHR 1.98; 95% CI 1.40-2.79; P < .001) and were characterized by the lowest level of physical activity (P ≤ .0004 vs every other nHR quartiles). The highest 24h-HR quartile group (>75 beats/min) showed an increased risk of VT/VF (AHR 2.13; 95% CI 1.52-2.99; P < .001) and a weaker though significant association with nonarrhythmic mortality (AHR 1.80; 95% CI 1.00-3.22; P = .05) as compared with the lowest 24h-HR quartile group (≤65 beats/min). CONCLUSION: In remotely monitored patients with implantable cardioverter-defibrillator/CRT-D on ß-blocker therapy for heart failure, elevated heart rates (nHR >65 beats/min and 24h-HR >75 beats/min) were associated with increased mortality and VT/VF risk. nHR showed a stronger association than 24h-HR with worst prognosis and lowest physical activity.

Determinants of worse prognosis in patients with cardiac resynchronization therapy defibrillators. Are ventricular arrhythmias an adjunctive risk factor?

AIMS: Cardiac resynchronization therapy (CRT) is indicated in patients with systolic heart failure (HF), severe left ventricle (LV) dysfunction and interventricular dyssynchrony.In prospective observational research, we aimed to evaluate whether CRT-induced LV reverse remodelling and occurrence of ventricular arrhythmias (VT/VF) independently contribute to prognosis in patients with CRT defibrillators (CRT-D). METHODS: In 95 Italian cardiological centres, after a screening period of 6 months, patients were categorized according to VT/VF occurrence and CRT response, defined as LV end-systolic volume relative reduction >15% or LV ejection fraction absolute increase >5%. The main endpoint was death or HF hospitalizations. RESULTS: Among 1308 CRT-D patients (80% male, mean age 66 years), at 6 months, follow-up 71% were identified as CRT responders and 12% experienced appropriate VT/VF detections. The main endpoint was significantly and independently associated with previous myocardial infarction, New York Heart Association Class, VT/VF occurrence and with CRT response. CRT nonresponder patients who suffered VT/VF in the screening period had a risk of death or HF hospitalizations [HR = 7.82, 95% confidence interval (CI) = 3.95-15.48] significantly (P < 0.001) higher than CRT responders without VT/VF occurrence. This risk is mitigated without VT/VF occurrence (HR = 3.47, 95% CI = 2.03-5.91, P < 0.001) or in case of CRT response (HR = 3.11, 95% CI = 1.44-6.72, P = 0.004). CONCLUSION: Our data show that both CRT response and occurrence of VT/VF independently contribute to the risk of death or HF-related hospitalizations in CRT-D patients. Early VT/VF occurrence may be identified as a marker of disease severity than can be mitigated by CRT response both in terms of all-cause mortality and long-term VT/VF onset. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT00147290 and NCT00617175.

The Interplay of PR Interval and AV Pacing Delays Used for Cardiac Resynchronization Therapy in Heart Failure Patients: Association with Clinical Response in a Retrospective Analysis of a Large Observational Study.

Background. Cardiac resynchronization therapy (CRT) is a treatment for heart failure (HF) patients with prolonged QRS and impaired left ventricular (LV) systolic function. We aim to evaluate how the baseline PR interval is associated with outcomes (all-cause death or HF hospitalizations) and LV reverse remodeling (>15% relative reduction in LV end-systolic volume). Methods. Among 2224 patients with CRT defibrillators, 1718 (77.2%) had a device programmed at out-of-the-box settings (sensed AV delay: 100 ms and paced AV delay: 130 ms). Results. In this cohort of 1718 patients (78.7% men, mean age 66 years, 71.6% in NYHA class III/IV, LVEF = 27 ± 6%), echocardiographic assessment at 6-month follow-up showed that LV reverse remodeling was not constant as a function of the PR interval; in detail, it occurred in 56.4% of all patients but was more frequent (76.6%) in patients with a PR interval of 160 ms. In a median follow-up of 20 months, the endpoint of death or HF hospitalizations occurred in 304/1718 (17.7%) patients; in the multivariable regression analysis it was significantly less frequent when the PR interval was between 150 and 170 ms (hazard ratio = 0.79, 95% confidence interval (CI): 0.63−0.99, p = 0.046). The same PR range was associated with higher probability of CRT response (odds ratio = 2.51, 95% CI: 1.41−4.47, p = 0.002). Conclusions. In a large population of CRT patients, with fixed AV pacing delays, specific PR intervals are associated with significant benefits in terms of LV reverse remodeling and lower morbidity. These observational data suggest the importance of optimizing pacing programming as a function of the PR interval to maximize CRT response and patient outcome.

Cardiac resynchronization therapy or sequential pacing in failing Mustard?

The atrial switch (Mustard, Senning procedures) was one of the treatments of choice for repair of transposition of the great arteries from the early 1960s to the mid-1980s. A significant proportion of patients with atrial switch develops systemic (right) ventricular failure. A series of surgical therapeutic options exists to manage cardiac failure in this setting, and, more recently proposed, cardiac resynchronization therapy. We describe case report of a 30-year-old woman with congenital heart disease (CHD) and previous Mustard procedure who underwent upgrading from single chamber to dual-chamber pacemaker. The narrower native QRS did not correlate with a better synchrony status nor with a better cardiac output. Functional evaluation confirmed a better performance in DDD mode with short atrioventricular delay and broad QRS. Some echocardiographic and electrocardiographic parameters, such as ejection fraction and QRS duration, well established in adults' heart for selection of candidates to cardiac resynchronization therapy, are much less studied in CHD. Postoperative CHD may provide unique patterns of asynchrony with poorly predictable hemodynamic outcome.

Leadless pacemaker through tricuspid bioprosthetic valve: Early experience.

BACKGROUND: Leadless pacemaker (LP) therapy has been proved effective in cases where traditional transvenous right pacing (TRP) failed. TRP through a bioprosthetic tricuspid valve (BTV) has always been considered an unpreferable solution because of possible deleterious effect of permanent pacing leads on BTV function and specifically on tricuspid regurgitation (TR). Very limited data exist about the feasibility and safety of LP implantation in this setting. METHODS: We describe two cases of LP implantation through BTV in patients with failure of epicardial pacemaker implanted after cardiac surgery. The focus is on technical description of the procedure and on electrical and echocardiographic evaluation at implantation and at the follow-up. RESULTS: In both cases, skilled and careful handling of the delivery system as well as proper use of X-ray oblique views was determinant for atraumatic successful valve crossing. Likewise, an accurate selection of the deployment site inside the right ventricle, far enough from the valve to avoid valvular dysfunction, was important for successful implantation. Electrical parameters of LP were satisfying at implantation and at the follow-up. The echocardiogram after implantation and at the follow-up showed no mechanical interference of LP with prosthetic valve, no significant TR, and absence of significant changes in the biventricular function. CONCLUSION: Our data seem to support feasibility and safety of this type of procedure in skilled hands, allowing efficacious pacing without valvular dysfunction or right ventricular (RV) physiology impairment.