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BackgroundThe COMET-CTO trial was a randomized prospective study that assessed long-term follow-up in patients with chronic total occlusion (CTO) in coronary arteries treated with percutaneous coronary intervention (PCI) or with optimal medical therapy (OMT). During the 9-month follow-up, the incidence of major adverse cardiac events (MACE) did not differ between the two groups; no death or myocardial infarction (MI) was observed. There was a significant difference in quality of life (QoL), assessed by the Seattle Angina Questionnaire (SAQ), in favor of the PCI group. Here we report long-term follow-up results (56 ± 12 months).MethodsBetween October 2015 and May 2017, a total of 100 patients with CTO were randomized into two groups of 50 patients: PCI CTO or OMT group. The primary endpoint of the current study was the incidence of MACE defined as cardiac death, MI, and revascularization [PCI or coronary artery bypass graft (CABG)]. As the secondary exploratory outcome, we analyzed all the cause-mortality rate.ResultsOut of 100 randomized patients, 92 were available for long-term follow-up (44 in the PCI group and 48 in the OMT group). The incidence of MACE did not differ significantly between the two groups (p = 0.363). Individual components of MACE were distributed, respectively: cardiac death (OMT vs. PCI group, 6 vs. 3, p = 0.489), MI (OMT vs. PCI group, 1 vs. 0, p = 1), and revascularization (PCI: OMT vs. PCI group, 2 vs. 2, p = 1; CABG: OMT vs. PCI group, 1 vs. 1, p = 1). There was no significant difference between the two groups regarding the individual component of MACE. Six patients died from non-cardiac causes [five deaths were reported in the OMT group and one death in the PCI group (p = 0.206)]. Kaplan-Meier survival curves for MACE did not differ significantly between the study groups (log-rank 0.804, p = 0.370). Regarding the secondary exploratory outcome, a total of 15 patients died at 56 ± 12 months (11 in the OMT and 4 in the PCI group) (p = 0.093). The Kaplan-Meier survival curves for all-cause mortality rates did not differ significantly between the two groups (log rank 3.404, p = 0.065). There were no statistically significant differences between OMT and PCI groups in all five SAQ domains. There was a significant improvement in three SAQ domains in the PCI group: PL (p < 0.001), AF (p = 0.007), and QoL (p = 0.001).ConclusionAfter 56 ± 12 months of follow-up, the incidence of MACE, as well as QoL measured by SAQ, did not differ significantly between the PCI and OMT groups.

As the aging population continues to grow, so has the incidence of cardiovascular diseases, including bradycardia, with much of the burden falling on low- and middle-income countries (LMICs). Pacemaker therapy remains the only guideline-recommended therapy for symptomatic bradycardia, but due to the cost and expertise required for pacemaker implants, patients in LMICs have less access to pacemaker therapies. However, with the concerted effort of organizations (governments, non-governmental organizations, industry, and medical societies) strides can continue to be made in improving access to care. Governments play a role in extending health coverage to its citizens and improving their physical and digital healthcare infrastructure. Non-governmental organizations promote access and awareness through charity and advocacy programs. Industries can continue innovating technology that is both affordable and accessible. Medical societies provide guidelines for treatment and necessary educational and networking opportunities for physicians who serve in LMICs. All of these organizations have individual responsibilities and goals in expanding access to bradycardia therapy, which can be more easily realized by their continued collaboration., Competing Interests: Conflict of interest: All authors received consulting fees from Medtronic., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Bradycardia, a condition characterized by an abnormally slow heart rate, poses significant challenges in terms of diagnosis and treatment. While it is a concern world-wide, low- and middle-income countries (LMICs) face substantial barriers in accessing appropriate bradycardia therapy. This article aims to explore the global aetiology and incidence of bradycardia, compare the prevalence and management of the condition in high-income countries versus LMICs, identify the key reasons behind the disparities in access to bradycardia therapy in LMICs, and emphasize the urgent need to address these disparities to ensure equitable healthcare on a global scale., Competing Interests: Conflict of interest: None declared., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Aims: Selection of patients who are viable candidates for cardiac resynchronization therapy (CRT), prediction of the response to CRT as well as an optimal definition of a favorable response, all require further exploration. The purpose of this study was to evaluate the interplay between the prediction of the response to CRT and the definition of a favorable outcome., Methods: Seventy patients who received CRT were included. All patients met current guideline criteria for CRT. Forty-three echocardiographic parameters were evaluated before CRT and at 1, 3, 6, and 12 months. M-mode, 2D echocardiography, and Doppler imaging were used to quantify left ventricular (LV) systolic and diastolic function, mitral regurgitation, right ventricular systolic function, pulmonary artery pressure, and myocardial mechanical dyssynchrony. The following definitions of a favorable CRT response were used: left ventricular ejection fraction (LVEF) improvement more >5% acutely following CRT, LVEF improvement >20% at 12-month follow-up, and a LV end-systolic volume (LVESV) decrease >15% at 12-month follow-up., Results: For the LVEF improvement >5%, the best predictor was isovolumetric relaxation time (IVRT; P=.035). For improvement of LVEF >20%, the best predictors were left ventricular stroke index (LVSI; P=.044) and left ventricular fractional shortening (LVFS; P=.031). For the drop in left ventricular systolic volume (LVESV >15%), the best predictor was septal-to-lateral wall delay (ΔT) (P=.043, RR=1.023, 95% CI for RR=1.001-1.045)., Conclusion: The definition of a favorable CRT response influenced the optimal predictor variable(s). Standardization of defining a favorable response to CRT is needed to guide clinical decision making processes., (© 2017, Wiley Periodicals, Inc.)

Background: Heart failure (HF) is increasing in prevalence and is a major cause of morbidity and mortality despite advances in medical and device therapy. Autonomic imbalance, with excess sympathetic activation and decreased vagal tone, is an integral component of the pathophysiology of HF., Objectives: The INOVATE-HF (Increase of Vagal Tone in Heart Failure) trial assessed the safety and efficacy of vagal nerve stimulation (VNS) among patients with HF and a reduced ejection fraction., Methods: INOVATE-HF was a multinational, randomized trial involving 85 centers including patients with chronic HF, New York Heart Association functional class III symptoms and ejection fraction ≤40%. Patients were assigned to device implantation to provide VNS (active) or continued medical therapy (control) in a 3:2 ratio. The primary efficacy endpoint was composite of death from any cause or first event for worsening HF., Results: Patients (n = 707) were randomized and followed up for a mean of 16 months. The primary efficacy outcome occurred in 132 of 436 patients in the VNS group, compared to 70 of 271 in the control group (30.3% vs. 25.8%; hazard ratio: 1.14; 95% confidence interval: 0.86 to 1.53; p = 0.37). During the trial, the estimated annual mortality rates were 9.3% and 7.1%, respectively (p = 0.19). Quality of life, New York Heart Association functional class, and 6-min walking distance were favorably affected by VNS (p < 0.05), but left ventricular end-systolic volume index was not different (p = 0.49)., Conclusions: VNS does not reduce the rate of death or HF events in chronic HF patients. (INcrease Of VAgal TonE in CHF [INOVATE-HF]; NCT01303718)., (Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: In the majority of patients with a wide QRS complex and heart failure resistant to optimal medical therapy, cardiac resynchronization therapy (CRT) leads to reverse ventricular remodeling and possibly to changes in cardiac collagen synthesis and degradation. We investigated the relationship of biomarkers of myocardial collagen metabolism and volumetric response to CRT., Methods: We prospectively studied 46 heart failure patients (mean age 61±9 years, 87% male) who underwent CRT implantation. Plasma concentrations of amino-terminal propeptide type I (PINP), a marker of collagen synthesis, and carboxy-terminal collagen telopeptide (CITP), a marker of collagen degradation, were measured before and 6 months after CRT. Response to CRT was defined as 15% or greater reduction in left ventricular end-systolic volume at 6-month follow-up., Results: Baseline PINP levels showed a negative correlation with both left ventricular end-diastolic volume (r=-0.51; p=0.032), and end-systolic diameter (r=-0.47; p=0.049). After 6 months of device implantation, 28 patients (61%) responded to CRT. No significant differences in the baseline levels of PINP and CITP between responders and nonresponders were observed (p>0.05 for both). During follow-up, responders demonstrated a significant increase in serum PINP level from 31.37±18.40 to 39.2±19.19 μg/L (p=0.049), whereas in non-responders serum PINP levels did not significantly change (from 28.12±21.55 to 34.47± 18.64 μg/L; p=0.125). There were no significant changes in CITP levels in both responders and non-responders (p>0.05)., Conclusions: Left ventricular reverse remodeling induced by CRT is associated with an increased collagen synthesis in the first 6 months of CRT implantation., Competing Interests: The authors stated that they have no conflicts of interest regarding the publication of this article.

Background: Magnetic resonance imaging (MRI) can be safely performed in patients with magnetic resonance (MR)-conditional pacemaker systems but remains relatively contraindicated with non-MR-conditional pacemaker systems., Objective: The purpose of this study was to evaluate the safety of MRI without positioning restrictions in patients with an MR-conditional pacemaker and currently a non-MR-conditional Medtronic CapSureFix Novus 5076 lead(s)., Methods: The study randomized 266 patients in a 2:1 ratio to the MRI group (177 patients) or to the control group (89 patients). At 9-12 weeks postimplant, the MRI group underwent MRI at 1.5 T. Primary end points were MRI-related complication-free rate and noninferiority of the MRI group compared to the control group with regard to the proportion of patients with an increase of ≤0.5 V in right atrial (RA) and right ventricular (RV) pacing capture thresholds from immediately before MRI to 1-month after MRI., Results: No MRI-related complications occurred in 156 MRI-scanned patients who were followed through 1-month post-MRI. Differences in the proportion of patients with ≤0.5 V pacing capture threshold changes from pre-MRI to 1-month post-MRI were minimal between the groups for RA (proportions of 100% in both groups; a P value cannot be calculated) and RV leads (proportions of 99.3% in the MRI group and 100% in the control group; noninferiority test, P < .0001). Proportions of patients with acceptable sensing amplitude changes from pre-MRI to 1-month post-MRI were also similar between the 2 groups for RA and RV leads (noninferiority test, P < .0001 and P = .0004, respectively). No arrhythmias occurred during MRI., Conclusion: MRI scans can be performed safely without positioning restrictions in patients with Medtronic CapSureFix Novus 5076 leads connected to an MR-conditional pacemaker., (Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Aims: The aim of the study was to assess the value of coronary flow reserve (CFR) for predicting improvement of left ventricular function after cardiac resynchronization therapy (CRT)., Methods and Results: Study population included 40 patients (mean age 58 ± 9 years) with heart failure (ejection fraction 25, 7 ± 5, 4%) and QRS duration of 158 ± 22 ms, planned for CRT. Before and after CRT implantation, CFR was measured non-invasively during hyperaemia induced with adenosine. Responders were defined by decrease in end-systolic volume ≥15%. Follow-up echocardiography and CFR measurements were obtained after 6 months. At baseline there was no significant difference in left ventricular ejection fraction (LVEF), QRS duration, 6 min walk test distance and coronary flow velocity at rest between responder (n = 26) vs. non-responder group (n = 14, P = ns). Before CRT implantation, responders compared with non-responders, showed a greater increase in coronary flow velocity during hyperaemia, and consequently higher CFR: 2.41 ± 0.60 vs. 1.61 ± 0.45 (P = 0.001). There was significant correlation between CFR before CRT implantation and LVEF after 6 months (r = 0.545, P = 0.001). End-diastolic, end-systolic left ventricular diameter, and CFR before CRT were predictors of LV functional improvement. By multivariate analysis, only CFR before CRT was independent predictor of left ventricular recovery in the follow-up period (P = 0.001)., Conclusion: Our results demonstrate that preserved CFR in patients with dilated cardiomyopathy is predictive of left ventricular improvement after CRT implantation., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.)

Introduction: In this study, we sought to determine whether myocardial contractile reserve (CR) assessed by dobutamine stress echocardiography (DSE) can identify patients who experience nearly complete normalization of left ventricular (LV) function after the implantation of a cardiac resynchronization therapy (CRT) pacemaker., Material and Methods: The study group consisted of 55 consecutive patients with non-ischemic dilated cardiomyopathy, LV ejection fraction (LVEF) < 35%, and prolonged QRS complex duration, who were scheduled for CRT pacemaker implantation. The DSE (20 µg/kg/min) was performed in all patients. The CR assessment was based on a change in the wall motion score index (ΔWMSI) and ΔLVEF during DSE. Super-response was defined as an increase in LVEF to > 50% and reduction in left ventricular end-systolic dimension to < 40 mm 12 months following the CRT implantation., Results: A total of 7 patients (12.7%) were identified as super-responders to CRT. When compared to non-super-responders, these patients had significantly higher values of the dobutamine-induced change in ΔWMSI (1.031 ±0.120 vs. 0.49 ±0.371, p < 0.01), and ΔEF (17.9 ±2.2 vs. 8.8 ±6.2, p < 0.01). Receiver operating characteristic analysis showed that dobutamine-induced changes in ΔWMSI ≥ 0.7 and ≥ 14% for ΔEF are the best discriminators for a super-response. Patients with ΔWMSI ≥ 0.7 and ΔEF ≥ 14% are significantly less often hospitalized (p < 0.01) for worsening of heart failure during 28.5 ±3.0 months of the follow-up., Conclusions: Contractile reserve assessed by DSE can identify patients with dilated cardiomyopathy who are likely to experience near normalization of LV function following CRT.

Introduction: A purely subcutaneous implantable cardioverter defibrillator (ICD) requires higher energy but may be an effective alternative to transvenous ICDs to deliver lifesaving therapies., Objective: To identify combinations of anteroposterior subcutaneous shock pathways and waveforms with defibrillation efficacy comparable to transvenous ICDs., Methods: Defibrillation testing was performed in 141 patients temporarily implanted with an active can emulator and subcutaneous coil electrodes. The patients were subdivided into 5 groups within 2 study phases. In all groups, a posterior electrode was positioned with its tip close to the spine. In the first study phase, 2 different can locations were evaluated: (1) an inframammary pocket (IM-1-750), or (2) a conventional infraclavicular pocket (IC-1-750). In both cases, a 70 J biphasic shock was used (peak voltage 750 V; 270 μF capacitance). In the second phase, configuration IC-1-750 was enhanced by the addition of a second (parasternal) subcutaneous electrode (IC-2-750). Furthermore, the effects of a different 70 J shock waveform (1,000 V, 160 μF) were evaluated for configurations IM-1-750 and IC-2-750 (becoming IM-1-1000 and IC-2-1000)., Results: The proportion of patients satisfying a defibrillation safety margin test of 2 consecutive successes at ≤50 J was 74%, 11%, and 44%, respectively, for the IM-1-750, IC-1-750, and IC-2-750 configurations, and 93% and 86% for the IM-1-1000 and IC-2-1000 configurations., Conclusions: Defibrillation efficacy comparable to that of a transvenous system was achieved with an anteroposterior subcutaneous ICD configuration, with 160 μF capacitance, 1,000 V, and 70 J output. An infraclavicular pocket location becomes feasible if a parasternal subcutaneous coil is added., (© 2014 Wiley Periodicals, Inc.)

Background: Acute studies have suggested that left ventricular pacing (LVP) may have benefits over biventricular pacing (BVP). The adaptive cardiac resynchronization therapy (aCRT) algorithm provides LVP synchronized to produce fusion with the intrinsic activation when the intrinsic atrioventricular (AV) interval is normal. The randomized double-blind adaptive cardiac resynchronization therapy trial demonstrated noninferiority of the aCRT algorithm compared to echocardiography-optimized BVP (control)., Objective: To examine whether synchronized LVP (sLVP) resulted in better clinical outcomes., Methods: First, stratification by percent sLVP (%sLVP) and multivariate Cox proportional hazards model was used to assess the relationship between %sLVP and clinical outcomes. Second, outcomes were compared between patients in the aCRT arm (n = 318) and control patients (n = 160) stratified by intrinsic AV interval at randomization., Results: In the aCRT arm, %sLVP ≥50% (n = 142) was independently associated with a decreased risk of death or heart failure hospitalization (hazard ratio 0.49; 95% confidence interval 0.28-0.85; P = .012) compared with %sLVP <50% (n = 172). A greater proportion of patients with %sLVP ≥50% improved in Packer's clinical composite score at 6-month (82% vs. 68%; P = .002) and 12-month (80% vs. 62%; P = .0006) follow-ups compared to controls. In the subgroup with normal AV (n = 241), there was a lower risk of death or heart failure hospitalization (hazard ratio 0.52; 95% confidence interval 0.27-0.98; P = .044) with the aCRT algorithm. A greater proportion of patients in the aCRT arm improved in the clinical composite score at 6-month (81% vs. 69%; P = .041) and 12-month (77% vs. 66%; P = .076) follow-ups compared to controls., Conclusions: Higher %sLVP was independently associated with superior clinical outcomes. In patients with normal AV conduction, the aCRT algorithm provided mostly sLVP and demonstrated better clinical outcomes compared to echocardiography-optimized BVP., (Copyright © 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: In patients with sinus rhythm and normal atrioventricular conduction, pacing only the left ventricle with appropriate atrioventricular delays can result in superior left ventricular and right ventricular function compared with standard biventricular (BiV) pacing., Objective: To evaluate a novel adaptive cardiac resynchronization therapy ((aCRT) algorithm for CRT pacing that provides automatic ambulatory selection between synchronized left ventricular or BiV pacing with dynamic optimization of atrioventricular and interventricular delays., Methods: Patients (n = 522) indicated for a CRT-defibrillator were randomized to aCRT vs echo-optimized BiV pacing (Echo) in a 2:1 ratio and followed at 1-, 3-, and 6-month postrandomization., Results: The study met all 3 noninferiority primary objectives: (1) the percentage of aCRT patients who improved in their clinical composite score at 6 months was at least as high in the aCRT arm as in the Echo arm (73.6% vs 72.5%, with a noninferiority margin of 12%; P = .0007); (2) aCRT and echo-optimized settings resulted in similar cardiac performance, as demonstrated by a high concordance correlation coefficient between aortic velocity time integrals at aCRT and Echo settings at randomization (concordance correlation coefficient = 0.93; 95% confidence interval 0.91-0.94) and at 6-month postrandomization (concordance correlation coefficient = 0.90; 95% confidence interval 0.87-0.92); and (3) aCRT did not result in inappropriate device settings. There were no significant differences between the arms with respect to heart failure events or ventricular arrhythmia episodes. Secondary end points showed similar benefit, and right-ventricular pacing was reduced by 44% in the aCRT arm., Conclusions: The aCRT algorithm is safe and at least as effective as BiV pacing with comprehensive echocardiographic optimization., (Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Objectives: The aim of this study was to assess the performance of echocardiographic parameters to predict response to cardiac resynchronization therapy (CRT)., Background: CRT reduces morbidity and mortality due to the proper selection of candidates for CRT., Methods: The 12-month trial was performed on 70 optimally medicated patients with standard inclusion criteria: NYHA class III or IV heart failure, left ventricular ejection fraction (LVEF) ≤ 35%, and QRS ≥ 120 ms. All parameters were evaluated by conventional and tissue Doppler-based methods. Indicator of positive CRT response was more than 20% in improvement of LVEF., Results: LVEF increased >20% in 42 patients. Out of 43 tested baseline echocardiographic parameters, 12 showed statistical difference between responders and nonresponders. Out of these 12 parameters, six (LVSV, LVSI, LVFS, RVd, VPMR, and PISA) had modest to moderately good ability to predict LVEF response with sensitivity ranging from 62.2% to 82.4%, and specificity ranging from 56.5% to 81.2%. For those parameters, the area under the receiver-operating characteristic curve for positive response to CRT was ≤0.76. Multivariate regression analysis resulted in selection of LVSI and LVFS as possible predictive independent parameters for a good response. The cutoff value for LVSI was 38.7 mL/m(2) (P = 0.045) and for LVFS was 13% (P = 0.032)., Conclusions: Contribution of LVSI and LVFS is to be confirmed in larger trials. Simplicity of their assessment by conventional echocardiography could be an argument for adding them to the inclusion criteria for CRT in severe heart failure patients., (© 2011, Wiley Periodicals, Inc.)

Aims: In chronic heart failure (CHF), reduced vagal activity correlates with increased mortality and acute decompensation. Experimentally, chronic vagus nerve stimulation (VNS) improved left ventricular (LV) function and survival; clinically, it is used for the treatment of drug-refractory epilepsy. We assessed safety and tolerability of chronic VNS in symptomatic CHF patients, using a novel implantable nerve stimulation system. The secondary goal was to obtain preliminary data on clinical efficacy., Methods and Results: This multi-centre, open-label phase II, two-staged study (8-patient feasibility phase plus 24-patient safety and tolerability phase) enrolled 32 New York Heart Association (NYHA) class II-IV patients [age 56 ± 11 years, LV ejection fraction (LVEF) 23 ± 8%]. Right cervical VNS with CardioFit (BioControl Medical) implantable system started 2-4 weeks after implant, slowly raising intensity; patients were followed 3 and 6 months thereafter with optional 1-year follow-up. Overall, 26 serious adverse events (SAEs) occurred in 13 of 32 patients (40.6%), including three deaths and two clearly device-related AEs (post-operative pulmonary oedema, need of surgical revision). Expected non-serious device-related AEs (cough, dysphonia, and stimulation-related pain) occurred early but were reduced and disappeared after stimulation intensity adjustment. There were significant improvements (P < 0.001) in NYHA class quality of life, 6-minute walk test (from 411 ± 76 to 471 ± 111 m), LVEF (from 22 ± 7 to 29 ± 8%), and LV systolic volumes (P = 0.02). These improvements were maintained at 1 year., Conclusions: This open-label study shows that chronic VNS in CHF patients with severe systolic dysfunction may be safe and tolerable and may improve quality of life and LV function. A controlled clinical trial appears warranted.

Aims: Little is known about the incidence of paroxysmal atrial tachycardias (PAT) in patients with heart failure (HF). The availability of cardiac resynchronization therapy (CRT) devices with extended diagnostics for AT enables continuous monitoring of PAT episodes. The aim of the study was to assess the incidence over time of PAT in HF patients treated with CRT., Methods and Results: Consecutive patients in NYHA functional class III or IV despite optimal drug therapy, QRS duration > or = 130 ms, left ventricular ejection fraction < or = 35%, and left ventricular end-diastolic dimension > or = 55 mm were eligible for enrolment. Patients with permanent or persistent atrial fibrillation (AF) were not included in the study. The first follow-up examination was performed 2 weeks after implantation, to optimize atrial sensing and CRT. Subsequent follow-up examinations were carried out 15 and 28 weeks after implantation, to collect the telemetric data. A total of 173 patients (67 +/- 11 years, M 116) were enrolled. Complete arrhythmia monitoring data were available from 120 patients over a mean follow-up of 183 +/- 23 days. Atrial tachycardia episodes were detected through telemetry in 25 of 120 patients (21%) during at least one follow-up examination. Atrial tachycardia episodes were recorded in 29 and 17% (P = NS) of patients with and without previous history of AF, respectively., Conclusion: More than 20% of the overall HF patient population treated with CRT suffer PAT episodes. Paroxysmal atrial tachycardia may interfere with response to CRT. Therefore, telemetric data may be relevant to drive the appropriate therapy in each patient.

Background: Managed Ventricular Pacing (MVP) and Search AV+ (SAV+) are two pacing algorithms designed to reduce ventricular pacing. MVP promotes conduction by operating in AAI/R mode with backup ventricular pacing during atrioventricular block (AVB). SAV+ operates in DDD/R mode with a nominal AV extension of 290 ms during atrial sensing and 320 ms during atrial pacing. The reduction in ventricular pacing was compared with these two algorithms in pacemaker patients., Methods: The EnRhythm and EnPulse clinical studies assessed the percentage of ventricular pacing (%VP) after 1 month. Each patient's AVB status was assigned using the following hierarchical categories: persistent third-degree AVB (p3AVB), episodic third-degree AVB (e3AVB), second-degree AVB (2AVB), first-degree AVB (1AVB), and no AVB (nAVB). The%VP was tabulated for each AVB status category., Results: Data were available from 322 patients of whom 129 received DDD(R) pacing with the MVP algorithm activated and 193 patients with DDD(R) pacing and the SAV+ function activated, each for a month period. MVP resulted in a significantly lower median%VP than SAV+ in all AVB categories except for p3AVB: nAVB (0.3 vs 2.9, P < 0.0001), 1AVB (0.9% vs 80.6%, P < 0.0001), 2AVB (37.6 vs 99.3, P< 0.002), e3AVB (1.2 vs 42.2, P = 0.02), p3AVB (98.9 vs 100, P = 1.00)., Conclusion: MVP resulted in a greater reduction in%VP than SAV+ across all patient groups except persistent third-degree AV block. The greatest reduction in%VP was observed in patients with mildly impaired AV conduction.

Aims: Unnecessary right ventricular pacing has deleterious effects and becomes more significant when cumulative percent ventricular pacing (Cum%VP) exceeds 40% of time. The Managed Ventricular Pacing (MVP) mode has been shown to significantly reduce the percent ventricular pacing compared to the DDD/R mode. This study assessed the percent of ventricular pacing in a standard pacemaker population programmed to MVP and for which patients it is possible to achieve a Cum%VP < or = 40%., Methods and Results: Unselected, consecutive patients were implanted with a dual chamber pacemaker with a mean follow-up period of 76 days. The Cum%VP was calculated from device diagnostics between pre-hospital discharge (PHD) and the 1-month post implant visit. The median Cum%VP of 107 patients (age 67.2 +/- 14 years; 53% male) who were programmed to MVP was 3.9%. The median Cum%VP was 1.4% in patients with sinus node disease (SND) and 28.8% in patients with AV block (AVB). Cum%VP < or = 40% was observed in 72% of all patients, in 50% of AVB patients, and in 86% of SND patients., Conclusion: The MVP mode is capable of achieving a low percent of ventricular pacing in a standard pacemaker population with SND and AVB. In addition, 72% of patients in MVP mode demonstrated Cum%VP < or = 40%.

Background: In patients requiring permanent pacing, preservation of intrinsic ventricular activation is preferred whenever possible. The Search AV+ (SAV+) algorithm in Medtronic EnPulsetrade mark dual-chamber pacemakers can increase atrioventricular (AV) intervals to 320 ms in patients with intact or intermittent AV conduction. This prospective, multicenter study compared the percentage of ventricular pacing with and without AV interval extension., Methods: Among 197 patients enrolled in the study, the percentage of ventricular-paced beats was evaluated via device diagnostics at the 1-month follow-up. Patient cohorts were defined by clinician assessment of conduction via a 1:1 AV conduction test at the 2-week follow-up. The observed percentage of ventricular pacing with SAV + ON and the predicted percentage of ventricular pacing with SAV + OFF were determined from the SAV + histogram data for the period between the 2-week and 1-month follow-up visits., Results: Of 197 patients, 110 (55.8%) had intact 1:1 AV conduction, of which 109 had 1-month data. SAV + remained ON in 99/109 patients; 10 patients had intrinsic A-V conduction intervals beyond SAV + nominal and therefore SAV + disabled. The mean percentage of ventricular pacing in the 109 patients was SAV+ ON = 23.1% (median 3.7%) versus SAV + OFF = 97.2% (median 99.7%). In 87 patients without 1:1 AV conduction, SAV + was programmed OFF in 6, automatically disabled in 52, and remained ON in 29. In 8 of these patients, 80-100% reduction in ventricular pacing was observed with SAV + ON., Conclusion: The Search AV+ algorithm in the EnPulse pacemaker effectively promotes intrinsic ventricular activation and substantially reduces unnecessary ventricular pacing.

Background: The Medtronic EnPulse pacemaker incorporates the new atrial capture management (ACM) algorithm to automatically measure atrial capture thresholds and subsequently manage atrial pacing outputs., Objectives: The purpose of this study was to evaluate the clinical performance of ACM., Methods: Two hundred patients with an indication for a dual-chamber pacemaker underwent implantation. ACM thresholds and manually measured atrial pacing thresholds were assessed at follow-up visits. Clinical equivalence was defined as the ACM-measured threshold being within -0.25 V to +0.5 V of the manually measured threshold. The clinician analyzed all ACM measurements performed in-office for evidence of proarrhythmia., Results: All 200 implanted patients had a 1-month visit, and validated manual and in-office ACM threshold data were available for 123 patients. The ACM threshold was 0.595 +/- 0.252 V, and the manual threshold was 0.584 +/- 0.233 V. The mean difference was 0.010 V with a 95% confidence interval of (-0.001, 0.021). The mean difference over all visits was 0.011 V. For all patients, the individual threshold differences were within the range of clinical equivalence at all visits. No atrial arrhythmias were observed during 892 ACM tests in 193 patients., Conclusion: This study demonstrated that the ACM algorithm is safe, accurate, and reliable over time. ACM was demonstrated to be clinically equivalent to the manual atrial threshold test in all patients at 1 month and over the entire follow-up period of up to 6 months. ACM ensures atrial capture, may save time during follow-up, and can be used to manage atrial pacing outputs.

There are more than 20 years of experience with implantation of defibrillator devices in humans and the procedure is an important therapeutic option for patients at high risk of life-threatening ventricular arrhythmias. The incidence of new defibrillator implantation has gradually increased, being used even in children, (1) although pediatric use is associated with several complications, especially with epicardial systems,(2) including fracture of the subcutaneous patch,(3-5) mainly because of growth.(3) We present a case of subcutaneous patch electrode fracture in the left axillary pectoral region of a patient who needed the patch for effective defibrillation, and we discuss the methods of treatment.

Background: In patients in whom syncopal episodes are mainly caused by occasional drops in heart rate, Sudden Rate Drop intervention feature intends to provide high rate intervention pacing. New Vitatron Medical B.V. pacemaker system Clarity DDDR, provides AN option FOR recognizing Sudden Rate Drop and responding by intervention pacing until it detects the recovering., Material and Methods: In patients with carotid sinus syndrome it is possible to provoke this situation BY sinus carotidus massage. We have implanted 10 of these devices in our center, 2 of which in patients with hypersensitive carotid sinus syndrome. In both patients, we activated sudden rate drop intervention on DDD mode pacing and applied protocol for testing the necessary level of Sudden Rate Drop Intervention Rate. Both patients gave their informed consent to be submitted to this testing. Pacemaker software assumes rate intervention level of 110 bpm. We tested our patients for rate levels of 90 and 110 bpm. Massaging the carotid sinus during 5 seconds, we provoked Sudden Rate Drop Intervention 10 times, in each patient, 5 times at intervention rate of 90 and 5 times at 110 bpm. Patients were unaware of the programmed intervention rate and were merely expected to report any different sensations experienced during the testing., Results: In all 20 tests, pacemaker responded to sudden rate drop elicited by carotid sinus massage (100%), which was verified by selected event recordings. After the massage, neither of the patients registered any sensations at sudden rate drop intervention rate level of 90 bpm in a total od 10 tests (100%), while 8 out of 10 massages at 110 bpm intervention rate provoked palpitations (80%). On the grounds of this testing, we concluded that lowering of Sudden Rate Drop Intervention Rate Level from 110 BPM to 90 BPM does not affect the reliability of system reaction, but changes patient's awareness of heart beats., Conclusion: As a final conclusion, it should be said that basic prerogatives of a pacing system: safety and efficacy with minimal energy consumption, and in this case, quality of life option that a patients practically does not feel intervention when it occurs, are all met.