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Background: With increasing constraints on healthcare resources, greater attention is being focused on improved resource utilization. Prior studies have demonstrated safety of same-day discharge following CIED implantation but are limited by vague protocols with long observation periods. In this study, we evaluate the safety of an expedited 2 hour same-day discharge protocol following CIED implantation. Methods: Patients undergoing CIED implantation at three centers between 2015 and 2021 were included. Procedural, demographic, and adverse event data were abstracted from the electronic health record. Patients were divided into same-day discharge (SDD) and delayed discharge (DD) cohorts. The primary outcome was complications including lead malfunction requiring revision, pneumothorax, hemothorax, lead dislodgement, lead perforation with tamponade, and mortality within 30 days of procedure. Outcomes were compared between the two cohorts using the χ2 test. Results: A total of 4543 CIED implantation procedures were included with 1557 patients (34%) in the SDD cohort. SDD patients were comparatively younger, were more likely to be male, and had fewer comorbidities than DD patients. Among SDD patients, the mean time to post-operative chest X-ray was 2.6 h. SDD had lower rates of complications (1.3% vs 2.1%, p = 0.0487) and acute care utilization post-discharge (9.6% vs 14.0%, p < 0.0001). There was no difference in the 90-day infection rate between the cohorts. Conclusions: An expedited 2 hour same-day discharge protocol is safe and effective with low rates of complications, infection, and post-operative acute care utilization. [ABSTRACT FROM AUTHOR]

The article describes the case of a 54-year-old man who underwent dual chamber pacemaker eight years ago because of symptomatic, high-grade atrioventricular block. Topics discussed include his electrocardiogram (EEG) during a routine visit to his cardiologist seven months later and algorithms designed to promote delivery of biventricular pacing during atrial tachycardia (AT/AF) in Medtronic cardiac resynchronization therapy (CRT) devices.

Background Cardiac resynchronization therapy (CRT) has been shown to benefit patients with heart failure and left bundle branch block (LBBB). However, CRT implantation is challenging when the superior venous access is not feasible. Case summary A 50-year-old man with a history of dilated cardiomyopathy and complete LBBB was referred to our hospital for CRT management. Angiography showed that the left and right brachiocephalic veins were occluded. Cardiac resynchronization therapy was finally implanted via the iliac vein. Follow-up echocardiography showed improved cardiac function, and the pacing system was functioning properly. Discussion The iliac vein access is feasible for CRT implantation with good stability, which can be a viable alternative to avoid unnecessary risk associated with thoracotomy and epicardial lead placement. [ABSTRACT FROM AUTHOR]

Aims Cardiac resynchronization therapy (CRT) is an established treatment for heart failure. There is contradictory evidence whether defibrillator capability improves prognosis in patients receiving CRT. We compared the survival of patients undergoing de novo implantation of a CRT with defibrillator (CRT-D) option and CRT with pacemaker (CRT-P) in a large health claims database. Methods and results Using health claims data of a major German statutory health insurance, we analysed patients with de novo CRT implantation from 2014 to 2019 without indication for defibrillator implantation for secondary prevention of sudden cardiac death. We performed age-adjusted Cox proportional hazard regression and entropy balancing to calculate weights to control for baseline imbalances. The analysis comprised 847 CRT-P and 2722 CRT-D patients. Overall, 714 deaths were recorded during a median follow-up of 2.35 years. A higher cumulative incidence of all-cause death was observed in the initial unadjusted Kaplan–Meier time-to-event analysis [hazard ratio (HR): 1.63, 95% confidence interval (CI): 1.38–1.92]. After adjustment for age, HR was 1.13 (95% CI: 0.95–1.35) and after entropy balancing 0.99 (95% CI: 0.81–1.20). No survival differences were found in different age groups. The results were robust in sensitivity analyses. Conclusion In a large health claims database of CRT implantations performed in a contemporary setting, CRT-P treatment was not associated with inferior survival compared with CRT-D. Age differences accounted for the greatest part of the survival difference that was observed in the initial unadjusted analysis. [ABSTRACT FROM AUTHOR]

This case series demonstrates 2 innovative approaches to successful coronary sinus lead placement in the setting of coronary sinus ostial atresia. Use of venous phase coronary angiography, a computed tomography scan with venous phase, or a left-sided upper extremity venogram may help reveal a variant anatomy and guide tool selection. (Level of Difficulty: Advanced.)

Abstract –: The benefits of CRT in select subsets of systolic heart failure patients with LBBB are proven. We prospectively evaluated conventional and newer echocardiographic parameters of left ventricular dyssynchrony in 35 patients who underwent CRT and were followed up after 6 months. Of the 33 surviving patients, 21 were echocardiographic responders and 24 were clinical responders. The parameters in clinical responders and non-responders were compared. The anatomic M Mode parameters of delays improved, while the radial strain and the mitral valve velocity time integral (MVVTI) did not show any significant change after CRT.

Abstract Background Usage of active fixation bipolar left ventricular (LV) leads represents an alternative approach to the more commonly used passive fixation quadripolar leads in cardiac resynchronization therapy (CRT). We compared a bipolar LV lead with a side screw for active fixation and passive fixation quadripolar LV leads. Methods Sixty‐two patients were before CRT implantations randomly allocated to receive a bipolar (n = 31) or quadripolar (n = 31) LV leads. Speckle‐tracking radial strain echocardiography was used to define the LV segment with latest mechanical activation as the target LV segment. The electrophysiological measurements and the capability to obtain a proximal position in a coronary vein placed over the target segment were assessed. Results Upon implantation, the quadripolar lead demonstrated a lower pacing capture threshold than the bipolar lead, but at follow‐up, there was no difference. There were no differences in the LV lead implant times or radiation doses. The success rate in reaching the target location was not significantly different between the two LV leads. Conclusions The pacing capture thresholds were low, with no significant difference between active fixation bipolar leads and quadripolar leads. Active fixation leads did not promote a more proximal location of the stimulating electrode or a higher grade of concordance to the target segment than passive fixation leads.

Blood culture-negative endocarditis (BCNE) poses significant diagnostic and therapeutic challenges and is associated with notable morbidity and mortality. When presented concurrently with other comorbidities, these challenges and the chances of morbidity and mortality significantly increase. This case presents right-sided BCNE accompanied by pulmonary cavitary lesions in a patient with a history of supraventricular tachycardias (SVT), a biventricular pacemaker and implantable cardioverter-defibrillator (BiV-ICD), alcohol use, and anticoagulant noncompliance. The patient missed follow-up appointments for six months after the death of his wife, leading to increased alcohol use and noncompliance with medications. During this period, his home monitoring device was offline. Once reconnected, it detected several episodes of SVT and ventricular tachycardia (VT), prompting a wellness check. He presented to the cardiology clinic with shortness of breath and a cough producing brown-tinged sputum. Evaluation revealed cavitary lesions in the lingula and left lower lobe, a vegetation on his tricuspid valve, and vegetations on his endocardial leads, despite negative blood cultures. Tuberculosis testing was negative, while sputum cultures were positive for Haemophilus influenzae. After ruling out other possible infectious causes of the cavitary lesions, septic emboli were suspected as the cause. Broad-spectrum antibiotics were begun and surgical intervention was done to replace the tricuspid valve and remove the endocardial leads. This procedure was complicated by fibrosis of the leads at the coronary sinus, necessitating their cutting at the superior vena cava and leaving them inside the patient until laser therapy could be performed for their removal. The patient's history of bradycardia and SVTs required the ongoing use of a pacemaker. Inventory discrepancy during the placement of the new pacemaker epicardial leads lead to complications warranting an alternative approach to lead implantation. A traditionally used epicardial lead was placed on the right ventricle for pacing, and an innovative technique was employed to place an endocardial lead on the right atrium epicardium for sensing. This case underscores the importance of thorough evaluation and collaborative management strategies to optimize outcomes for patients with concomitant cardiac and pulmonary pathologies, particularly in the context of underlying psychosocial stressors. Additionally, it demonstrates solutions to challenges that can arise during surgery and presents an alternative lead placement technique for physicians who have only one epicardial lead available after removing infected endocardial leads. This is illustrated by the innovative use of an endocardial lead as an epicardial sensing lead., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Coica et al.)

Atrioventricular node (AVN) ablation for atrial fibrillation (AF) is commonly performed in the cardiac catheterization laboratory often requiring patient immobility for accurate anatomical mapping and ablation. 1 Anesthetic management for AVN ablation can be accomplished via multiple modalities such as total intravenous anesthesia and jet ventilation, or deep sedation and analgesia. 1 Deep sedation is typically accompanied by deleterious sequelae such as hypotension, apnea, and respiratory depression. 1,2 This presents a significant challenge for the anesthesia professional as maintaining hemodynamic and respiratory stability requires judicious management in this high-risk patient population. 1 The following is a case study presenting the anesthetic management of an obese patient with multiple cardiac and respiratory comorbidities. [ABSTRACT FROM AUTHOR]

Background: Usage of active fixation bipolar left ventricular (LV) leads represents an alternative approach to the more commonly used passive fixation quadripolar leads in cardiac resynchronization therapy (CRT). We compared a bipolar LV lead with a side screw for active fixation and passive fixation quadripolar LV leads. Methods: Sixty‐two patients were before CRT implantations randomly allocated to receive a bipolar (n = 31) or quadripolar (n = 31) LV leads. Speckle‐tracking radial strain echocardiography was used to define the LV segment with latest mechanical activation as the target LV segment. The electrophysiological measurements and the capability to obtain a proximal position in a coronary vein placed over the target segment were assessed. Results: Upon implantation, the quadripolar lead demonstrated a lower pacing capture threshold than the bipolar lead, but at follow‐up, there was no difference. There were no differences in the LV lead implant times or radiation doses. The success rate in reaching the target location was not significantly different between the two LV leads. Conclusions: The pacing capture thresholds were low, with no significant difference between active fixation bipolar leads and quadripolar leads. Active fixation leads did not promote a more proximal location of the stimulating electrode or a higher grade of concordance to the target segment than passive fixation leads. [ABSTRACT FROM AUTHOR]

Aims While data from randomized trials suggest a declining incidence of sudden cardiac death (SCD) among heart failure patients, the extent to which such a trend is present among patients with cardiac resynchronization therapy (CRT) has not been evaluated. We therefore assessed changes in SCD incidence, and associated factors, in CRT recipients over the last 20 years. Methods and results Literature search from inception to 30 April 2018 for observational and randomized studies involving CRT patients, with or without defibrillator, providing specific cause-of-death data. Sudden cardiac death was the primary endpoint. For each study, rate of SCD per 1000 patient-years of follow-up was calculated. Trend line graphs were subsequently constructed to assess change in SCD rates over time, which were further analysed by device type, patient characteristics, and medical therapy. Fifty-three studies, comprising 22 351 patients with 60 879 patient-years of follow-up and a total of 585 SCD, were included. There was a gradual decrease in SCD rates since the early 2000s in both randomized and observational studies, with rates falling more than four-fold. The rate of decline in SCD was steeper than that of all-cause mortality, and accordingly, the proportion of deaths which were due to SCD declined over the years. The magnitude of absolute decline in SCD was more prominent among CRT-pacemaker (CRT-P) patients compared to those receiving CRT-defibrillator (CRT-D), with the difference in SCD rates between CRT-P and CRT-D decreasing considerably over time. There was a progressive increase in age, use of beta-blockers, and left ventricular ejection fraction, and conversely, a decrease in QRS duration and antiarrhythmic drug use. Conclusion Sudden cardiac death rates have progressively declined in the CRT heart failure population over time, with the difference between CRT-D vs. CRT-P recipients narrowing considerably. Open in new tab Download slide Open in new tab Download slide [ABSTRACT FROM AUTHOR]

Implantation of cardiac resynchronization therapy devices represents one of the more challenging and time-consuming procedures for the clinical electrophysiologist. This article reviews several strategies used to improve efficiency, safety, and effectiveness of cardiac resynchronization therapy implantation. The cornerstone of our strategy to improve efficiency, safety, and quality of cardiac resynchronization therapy implantation is the use of a telescoping guide system with high-quality venography. Competency in subclavian venoplasty and snaring techniques are essential to maintain efficiency and effectiveness during difficult cases. [ABSTRACT FROM AUTHOR]

Few cases of coincident takotsubo cardiomyopathy and complete heart block (CHB) have been reported. A 62-year-old woman presented with typical chest pain and was found to have CHB with a left ventricular ejection fraction of 35% and apical ballooning on ventriculogram. The patient was transvenously paced and a permanent biventricular pacemaker was placed when the CHB did not resolve. Repeat echocardiography 15 days after the event showed the ejection fraction to be 50%. This case highlights management strategies in this unique situation. [ABSTRACT FROM AUTHOR]

A 55‐year‐old woman presented with severe dyspnea during acceleration‐dependent left bundle branch block (LBBB). Metoprolol initially ameliorated symptoms by preventing the heart rate at which LBBB occurred. Over time LBBB presented at slower heart rates and the patient developed recurrent dyspnea during an activity that correlated with the development of LBBB on event monitors and exercise stress testing. A biventricular pacemaker was implanted, and the patient's symptoms remain resolved after a follow‐up of over 4 years. More research is needed to define the use of cardiac resynchronization therapy in patients with normal heart function. [ABSTRACT FROM AUTHOR]

The purpose of our research was to study features of development of dyssynchrony in patients with heart failure and different forms of ischemic heart disease, and also to estimate efficiency of cardiac resynchronization therapy. 125 patients with ischemic heart failure (including 17 patients, who were studied prior and within 1 week after biventricular pacing) were studied. Frequency of revealing dyssynchrony is connected with presence at patients an aberrant cardiac rhythm. After biventricular pacing we found significant positive dynamics of clinical and echocardiographic parameters in patients with heart failure.

Background: Prolongation of the baseline ECG PR interval is frequently encountered among cardiac resynchronization therapy (CRT) recipients. There are conflicting data regarding the association of a prolonged PR interval with long-term clinical outcome in this patient group.Objective: The purpose of this study was to compare clinical outcomes and response to CRT in patients with normal (<200 ms) vs prolonged (≥200 ms) baseline PR interval.Methods: In this study, 283 patients (normal PR interval: n = 158; prolonged PR interval: n = 125) with documented baseline intrinsic PR interval were followed for 3 years after CRT implantation. The study population consisted of 24.7% women (mean age 66 ± 13 years, left ventricular ejection fraction 24% ± 7%).Results: A Cox proportional hazard model identified baseline PR interval as a predictor of the composite end-point (all-cause mortality, heart failure hospitalization, left ventricular assist device implantation, and heart transplantation) in univariate analysis (hazard ratio [HR] 1.49, 95% confidence interval [CI] 1.02-2.17, P = .04) but not in multivariate analysis. It also predicted heart failure hospitalization in univariate (HR 1.6, 95% CI 1.1-2.4, P = .02) and multivariate analysis (HR 1.6, 95% CI 1.0-2.3, P = .03). A prolonged PR interval was associated with lower probability of reverse remodeling defined as ≥10% improvement in ejection fraction (64% vs 77%, P = .057), especially in patients with non-left bundle branch block ECG morphology (41% vs 68%, P = .03).Conclusion: Among patients with CRT, a prolonged baseline PR interval is an independent predictor of worse prognosis and lower probability of reverse remodeling, especially for patients with non-left bundle branch block morphology on ECG. [ABSTRACT FROM AUTHOR]

Background To explore the feasibility of a new method of achieving a permanent A-V block animal model. Methods 16 beagles were randomly divided into two groups based on the method of their preimplanted biventricular pacemakers. (1) In the first group (8 beagles), the A-V block model was achieved by ablating his-bundle potential at the site of the left ventricular superiorseptum, under the aortic sinus, through femoral artery. (2) In the second group (8 beagles), the A-V block model was achieved by ablating his-bundle potential at the triangle of Koch, through femoral vein. A complete A-V block model was achieved as a standard in this study. The success rates, intraoperative arrhythmias, operative and X-ray exposure time, intraoperative bleeding amount were assessed in this two groups, both animal models were followed up for four weeks and then fasted to monitor myocardial pathological changes. Results The success rate of the first group, which with fewer intraoperative arrhythmias, and less operative and X-ray exposure time, was significantly higher than the second group. Conclusions Compared with traditional animal method, our new method of ablating his-bundle potential at the left ventricle from the femoral artery has a higher success rate, fewer occurrence of malignant arrhythmias, and less operation and X-ray time. Thus, our new method should be preferred in the building of Permanent A-V Block Model. [ABSTRACT FROM AUTHOR]

Objective Implantation of biventricular devices (BiV) with a transvenous left ventricular lead is complex requiring a significant fluoroscopy time and radiation dose. In the United Kingdom, the Health Protection Agency (HPA) collects data regarding radiographic procedures and sets national diagnostic reference levels (DRL) at the 75th percentile of the distribution of doses for a wide range of procedures. Insufficient data were returned to the HPA to allow them to set DRL for BiV devices at the last publication in 2010. Due to the large variation in data available and small datasets for BiV procedures we aimed to collect a large dataset to guide standards for implantation. Methods We collected retrospective data (fluoroscopy time and radiation dose [DAP]) for new BiV devices for the three years 2009 - 2011 from three high volume tertiary centres in the North West of England. Databases were scrutinised to ensure the quality of the data. Results From a total of 1374 implants we identified data for 1319 patients for fluoroscopy time and 1316 for DAP. The mean fluoroscopy time for all three centres combined was 18.7±0.3 min. The 75th percentile fluoroscopy time for the combined data was 24.2 min. The mean DAP for the three centres combined was 25.1 ± 1.3 Gy cm².The 75th percentile DAP for the combined data was 27.7 Gy cm². Conclusions We present a large dataset of new biventricular device implants, based on the 75th percentile data we suggest a DRL of 24.2 min and 27.7 Gy cm². [ABSTRACT FROM AUTHOR]

Cardiac resynchronization therapy (CRT) improves measures of systolic function and clinical status. However, its effect on diastolic function is not well established. Commonly used parameters of diastolic function are measured from echocardiography, using pulse wave and tissue Doppler technologies, as well as timing and deformation data. Review of the existing studies that address the relationship between diastolic function and CRT shows conflicting data, but general trends can be deduced. Baseline elevated filling pressure appears to identify patients most likely to derive improvement in that particular parameter. Intrinsic relaxation does not appear to be significantly impacted by CRT. Generally, changes in diastolic properties after CRT appear to be linked to changes in systolic function. Specific therapy aimed at diastolic asynchrony is lacking, partly due to an unclear relationship between diastolic asynchrony and diastolic dysfunction, and the inability to specifically impact diastolic timing with a systolic intervention such as CRT. [ABSTRACT FROM AUTHOR]

Background: AV delay optimisation of biventricular pacing devices (cardiac resynchronisation therapy, CRT) is performed in trials and recommended by current guidelines. The Doppler echocardiographic iterative method is the most commonly recommended. Yet whether it can be executed reliably has never been tested formally. Methods: 36 multinational specialists, familiar with using the echocardiographic iterative method of CRT optimisation, were shown 20–40 sets of transmitral Doppler traces at 6–8 AV settings and asked to select the optimal AV delay. Unknown to the specialists, some Doppler datasets appeared in duplicate, allowing assessment of both inter and intra-specialist interpretation. Results: On the Kappa scale of agreement (1 = perfect agreement, 0 = chance alone), the agreement regarding optimal AV delay between specialists was poor (kappa=0.12±0.08). More importantly, agreement of specialists with themselves (i.e. viewing identical sets of traces, twice) was also poor, with Kappa=0.23±0.07 and mean absolute difference in optimum AV delay of 83ms between first and second viewing of the same traces. Conclusion: Iterative AV optimisation is not executed reliably by experts, even in an artificially simplified context where biological variability and variation in image acquisition are eliminated by use of identical traces. This cannot be blamed on insufficient skills of some experts or discordant methods of selecting the optimum, because operators also showed poor agreement with themselves when assessing the same trace. Instead, guidelines should retract any recommendation for this algorithm. Guideline-development processes might usefully begin with a rudimentary check on proposed algorithms, to establish at least minimal credibility. [ABSTRACT FROM AUTHOR]

Background: Patients with advanced heart failure bears bad prognosis, despite modern medical treatment year mortality rate spans from 30 up to 70%. Besides terminal heart failure the second most frequent cause is sudden death due to ventricular tachyarrhythmias as ventricular tachycardia and fibrillation. Ventricular fibrillation is very frequent cause of mortality of terminal heart failure especially in ischemic subgroup. Clinical studies have presented improvement of heart function by use of biventricular stimulation of patients with advanced heart failure and intraventricular conduction defects as left bundle branch block. Method very successfully improves acute hemodynamic parameters due to resynchronization of septal and lateral wall of left ventricle and improves economy of the heart contraction. Although these effects are present immediately after implantation they persist also through longer period. Method improves quality of life and also decreases mortality rate proved by clinical studies. Despite successful therapy mortality rate due to sudden death remains high. Implantable cardioverters defibrillators successfully prevent sudden cardiac death due to ventricular tachyarrhythmia. They are successful due to straightforward recognition of ventricular tachycardia or fibrillation and immediate electrical schock delivery. Cardiovertes defibrillators are successful in prevention of sudden cardiac death but they do not improve quality of life of heart failure patients like resynchronization therapy. Thus, combined therapy resynchronization and cardioverter defibrillator as a single implantable device has been developed.Conclusions: Due to very successful combined therapy the application of biventricular cardioverters defibrillators into clinical practice has increased. Implantation of biventricular cardioverter defibrillator is complex but very successful procedure. It is economically acceptable when proper indication has been stated. Large multicentric randomized clinical trials have proved better quality of life and reduced mortality rate in advanced heart failure patients especially when combined with cardioverter defibrillators.

Background: Use of rate adaptive atrioventricular (AV) delay remains controversial in patients with biventricular (Biv) pacing. We hypothesized that a shortened AV delay would provide optimal diastolic filling by allowing separation of early and late diastolic filling at increased heart rate (HR) in these patients. Methods: 34 patients (75 ± 11 yrs, 24 M, LVEF 34 ± 12%) with Biv and atrial pacing had optimal AV delay determined at baseline HR by Doppler echocardiography. Atrial pacing rate was then increased in 10 bpm increments to a maximum of 90 bpm. At each atrial pacing HR, optimal AV delay was determined by changing AV delay until best E and A wave separation was seen on mitral inflow pulsed wave (PW) Doppler (defined as increased atrial duration from baseline or prior pacemaker setting with minimal atrial truncation). Left ventricular (LV) systolic ejection time and velocity time integral (VTI) at fixed and optimal AV delay was also tested in 13 patients. Rate adaptive AV delay was then programmed according to the optimal AV delay at the highest HR tested and patients were followed for 1 month to assess change in NYHA class and Quality of Life Score as assessed by Minnesota Living with Heart Failure Questionnaire. Results: 81 AV delays were evaluated at different atrial pacing rates. Optimal AV delay decreased as atrial paced HR increased (201 ms at 60 bpm, 187 ms at 70 bpm, 146 ms at 80 bpm and 123 ms at 90 bpm (ANOVA F-statistic = 15, p = 0.0010). Diastolic filling time (P < 0.001 vs. fixed AV delay), mitral inflow VTI (p < 0.05 vs fixed AV delay) and systolic ejection time (p < 0.02 vs. fixed AV delay) improved by 14%, 5% and 4% respectively at optimal versus fixed AV delay at the same HR. NYHA improved from 2.6 ± 0.7 at baseline to 1.7 ± 0.8 (p < 0.01) 1 month post optimization. Physical component of Quality of Life Score improved from 32 ± 17 at baseline to 25 ± 12 (p < 0.05) at follow up. Conclusions: Increased heart rate by atrial pacing in patients with Biv pacing causes compromise in diastolic filling time which can be improved by AV delay shortening. Aggressive AV delay shortening was required at heart rates in physiologic range to achieve optimal diastolic filling and was associated with an increase in LV ejection time during optimization. Functional class improved at 1 month post optimization using aggressive AV delay shortening algorithm derived from echo-guidance at the time of Biv pacemaker optimization. [ABSTRACT FROM AUTHOR]

Heart failure (HF) remains an important heath care problem in the United States. With the aging of the US population, this trend is expected to continue. However, patients have also benefited from advances in pharmacologic and device-based therapies such as angiotensin-converting enzyme inhibitors, β-blockers, aldosterone blockers, and implantable cardioverter-defibrillators. More recently, cardiac resynchronization therapy (CRT) has become another important therapeutic option for treating heart failure due to systolic dysfunction. In this article, we review the physiologic basis for CRT, the clinical trials that support its efficacy, and the current indications for its use. We also examine key clinical questions regarding CRT still under research, including predictors of response. Finally, we look at the future of CRT and how its indications can be expanded to benefit more patients in the future. [ABSTRACT FROM AUTHOR]

Pacemaker implantation remains the only therapeutic option that improves morbidity and mortality for patients with symptomatic bradycardia. However, pacing from the right ventricular apex can induce dyssynchronous activation of the ventricles, increase sympathetic activation, cause abnormalities in myocardial perfusion, worsen cardiac output and endothelial function and may be associated with adverse cardiovascular outcomes. This article reviews the current knowledge on the pathophysiology of pacing-induced cardiovascular disease and current strategies to avoid and mitigate the adverse effects of right ventricular pacing. [ABSTRACT FROM AUTHOR]

Shoulder pain and disability ipsilateral to the implant site is a common complication of cardiac rhythm device implantation, yet very little has been published about this morbidity. We designed a study to assess the potential benefit of a simple exercise protocol in preventing shoulder pain postoperatively. Patients undergoing subcutaneous device implantation were randomized to one of two groups. The control group received standard instructions, whereas the exercise group was instructed on specific exercises aimed at strengthening or stretching the shoulder girdle, to be completed 3 days per week. Groups were postoperatively monitored for the development of shoulder discomfort and shoulder impingement by using physical examination and disability questionnaires. At 1 month, seven of 21 control patients reported developing shoulder pain or discomfort compared to one of 23 in the exercise group (P = 0.02). At 6 months, four of 23 control patients still reported worsening shoulder symptoms, compared to none in the exercise group (P = 0.11). In the control group, five of 19 patients developed a positive impingement test at 1 month, versus none in the exercise group (P = 0.01). Scores for the questionnaires designed to assess shoulder pain and dysfunction were worse in the control group. There were no activity-related complications in either group. Shoulder pain and disability occurs often following cardiac rhythm management device implantation. A simple exercise program aimed at strengthening the shoulder girdle is effective at preventing this complication. (PACE 2011; 1-7) [ABSTRACT FROM AUTHOR]

Impact of variability in the measured parameter is rarely considered in designing clinical protocols for optimization of atrioventricular (AV) or interventricular (VV) delay of cardiac resynchronization therapy (CRT). In this article, we approach this question quantitatively using mathematical simulation in which the true optimum is known and examine practical implications using some real measurements. We calculated the performance of any optimization process that selects the pacing setting which maximizes an underlying signal, such as flow or pressure, in the presence of overlying random variability (noise). If signal and noise are of equal size, for a 5-choice optimization (60, 100, 140, 180, 220 ms), replicate AV delay optima are rarely identical but rather scattered with a standard deviation of 45 ms. This scatter was overwhelmingly determined (ρ = −0.975, P < 0.001) by Information Content, $$ {\frac{\text{Signal}}{{{\text{Signal}} + {\text{Noise}}}}} $$, an expression of signal-to-noise ratio. Averaging multiple replicates improves information content. In real clinical data, at resting, heart rate information content is often only 0.2-0.3; elevated pacing rates can raise information content above 0.5. Low information content (e.g. <0.5) causes gross overestimation of optimization-induced increment in VTI, high false-positive appearance of change in optimum between visits and very wide confidence intervals of individual patient optimum. AV and VV optimization by selecting the setting showing maximum cardiac function can only be accurate if information content is high. Simple steps to reduce noise such as averaging multiple replicates, or to increase signal such as increasing heart rate, can improve information content, and therefore viability, of any optimization process. [ABSTRACT FROM AUTHOR]

Knowledge of the available sensing polarities in biventricular pacemakers is necessary for appropriate troubleshooting and avoiding possible pitfalls of cardiac resynchronization therapy programming, as illustrated through this case presentation. (PACE 2011; 34:e22-e25) [ABSTRACT FROM AUTHOR]

Cardiac resynchronization therapy aims at diminishing cardiac dyssynchrony in patients with heart failure. The effect of cardiac resynchronization therapy can be improved by optimization of the atrioventricular (AV) and interventricular (VV) delays. Currently, optimization of these pacing settings is mainly performed during resting conditions. This paper aims to objectively review the current literature about a rate-adaptive AV and VV delay in cardiac resynchronization therapy. The current evidence for a rate-adaptive AV and VV delay comprises only small nonrandomized studies on acute effects. The effect of exercise on the optimal AV delay was heterogeneous between studies. The optimal VV delay was influenced by exercise conditions in some, but not all patients. Possible explanations lie in the heterogeneous electrical and mechanical responses to exercise in patients with a complex disease such as heart failure with asynchronous contraction. Current evidence is insufficient to show the superiority of a rate-adaptive AV or VV delay in all CRT patients. Individualized exercise programming may be warranted in selected patients. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1307-1316, November 2010) [ABSTRACT FROM AUTHOR]

Cardiac resynchronization therapy by biventricular pacemaker/ICD implantation is a validated therapy for patients affected by heart failure with asynchrony of ventricular contraction. Considering the large number of parameters which play a role in cardiac resynchronization therapy, a comprehensive numerical model of cardiocirculatory system could be a useful tool to support clinical decisions. A variable elastance model of ventricles was updated to model the interventricular septum and to simulate the interventricular and the intraventricular desynchrony, and the effect of the biventricular stimulation. In addition, a numerical model of the biventricular pacemaker, which drives the beginning of the heart chambers and interventricular septum contraction, was also developed. In order to validate the model, five patients affected by dilated cardiomyopathy were analysed by echocardiography and electrocardiography before implantation, 24 h and 3 months after the implantation. The developed numerical model permits to reproduce clinical data and to estimate the trend of parameters that are difficult to measure (i.e. left ventricular systolic elastance). Furthermore, the model permits to study the effect of different biventricular pacemaker temporizations on hemodynamic variables. [ABSTRACT FROM AUTHOR]

Myxomas make up about 50% of benign cardiac neoplasms. The most common location is within the left atrium. At the initial stage they do not exhibit any specific clinical symptoms, so they are often diagnosed by accident or during examinations recommended for other reasons. Here we present a case of left atrium myxoma in a patient (a man, age 68 years) with a dual chamber pacemaker. The myxoma did not reveal any clinical symptoms and was discovered in echocardiography during routine diagnostic examination preceding pacemaker implantation. The literature search made by the authors showed that this is the first recorded case of myxoma in a patient after the implantation of a biventricular pacemaker. [ABSTRACT FROM AUTHOR]

Objectives: This study is a meta-analysis of prospective cohort studies comparing the impact of cardiac resynchronization therapy (CRT) for patients in atrial fibrillation (AF) and sinus rhythm (SR). Background: Although close to one-third of advanced heart failure patients exhibit AF, the impact of CRT in this group remains unclear. Methods: Prospective cohort studies comparing patients in normal SR and chronic AF treated with CRT were included. All studies reported death, New York Heart Association functional class, ejection fraction, 6-min walk test, and the Minnesota score or its equivalent as outcomes. Data sources included Ovid MEDLINE In-Process & Other Non-Indexed Citations, the Cochrane Central Register of Controlled Trials, the Database of Abstracts of Reviews of Effects, and the American College of Physicians Journal Club. Results: Of 2,487 reports identified, 5 studies following a total of 1,164 patients were included. Both AF and SR patients benefited significantly from CRT. Mortality was not significantly different at 1 year (relative risk ratio: 1.57, 95% confidence interval [CI]: 0.87 to 2.81). The New York Heart Association functional class improved similarly for both groups (−0.90 for SR patients, −0.84 for AF patients). SR patients showed greater relative improvement in the 6-min walk test (11.6 m greater, 95% CI: 10.4 to 12.8 m) and the Minnesota score (3.9 points less, 95% CI: 3.4 to 4.5 points) than AF patients. AF patients, however, achieved a small but statistically significant greater change in ejection fraction (0.39% greater change in ejection fraction, 95% CI: 0.22% to 0.55%). Conclusions: Patients in AF show significant improvement after CRT, with similar or improved ejection fraction as SR patients, but smaller benefits in regard to functional outcomes. [Copyright &y& Elsevier]

Aims: Little is known how patients with left ventricular hypertrabeculation/non-compaction (LVHT) and heart failure respond to cardiac resynchronization therapy (CRT). [ABSTRACT FROM PUBLISHER]

Background: Atrial flutter is a common cause of exacerbation of congestive heart failure (CHF). Typically, during atrial tachycardia, pacemakers, both dual and biventricular, are programmed to ignore atrial tracking. Virtually all current pacemakers and defibrillators use a programmable mode switch algorithm to switch between atrial tracking modes (DDD, DDDR) to nontracking modes (DDIR, DDI, VVI) during episodes of atrial tachycardia. Methods: In this report, we describe a novel method of atrioventricular (AV) pacemaker programming in four patients with atrial flutter and CHF who remained symptomatic postbiventricular pacemaker implantation. All patients had chronic atrial flutter upon interrogation; adjustment of AV delay and postventricular atrial refractory period (PVARP) was performed to enable sensing of every second to fourth atrial flutter beat by the atrial lead. Mode switch was turned “OFF” in all points, and lower and upper rate limits were set to 50 and 100 bpm. Once sequential early and late diastolic filling was seen on mitral inflow pulsed-wave (PW) Doppler, further adjustment of AV delay and PVARP was performed until the highest and broadest atrial velocity occurred on mitral inflow PW Doppler. Results: All patients developed improvement in aortic ejection duration and peak ejection velocity during AV optimization. Repeat ECG in these patients at 8 months, 7 days, 2 days, and 2 months postoptimization showed no change in P and QRS relationship. All patients developed improvement in CHF symptoms postbiv pacemaker optimization. Conclusion: In symptomatic patients with CHF and stable atrial flutter who have a biventricular pacemaker, atrial mechanical contribution to cardiac output can be achieved by adjusting PVARP and AV delay during echo-guided pacemaker programming. [ABSTRACT FROM AUTHOR]