Twelve-month efficacy of second-generation cryoballoon ablation for atrial fibrillation performed at community hospitals: results of the German register on cryoballoon ablation in local hospitals (regional).

BACKGROUND: The 12-month follow-up (F/U) efficacy of CBA PVI performed at community hospitals for treatment of symptomatic paroxysmal and persistent atrial fibrillation (AF) is unknown. This study determined the 12-month efficacy of pulmonary vein isolation (PVI) using cryoballoon ablation (CBA) performed at community hospitals with limited annual case numbers. METHODS: This registry study included 983 consecutive patients (pts) from 19 hospitals, each with an annual procedural volume of < 100 PVI procedures/year. Pts underwent CBA PVI for paroxysmal AF (n = 520), persistent AF (n = 423), or redo PVI (n = 40). The primary endpoint was frequency of documented recurrent AF, the occurrence of atrial flutter or tachycardia following a 90-day period after the index ablation and up to 12 months. The frequency of repeat ablation was determined. RESULTS: Isolation of all PVs was documented in 98% of pts at the end of the procedure. Twelve-month F/U data could be obtained in 916 pts. A 24-h ECG registration was performed in 641 pts (70.0%); in 107 pts (16.7%) of them, recurrent AF was documented. The primary endpoint was met in 193 F/U pts (21.1%). It occurred in 80/486 F/U pts with paroxysmal AF (16.4%), and in 107/390 F/U pts with persistent AF (27.4%). Redo PVI was performed in 71 pts (7.8%), and atrial flutter ablation was performed in 12 pts (1.4%). CONCLUSIONS: CBA PVI for paroxysmal or persistent AF can be performed at community hospitals with adequate rates of 12-month symptom freedom and arrhythmia recurrence. The study was registered at the German register of clinical studies (DRKS00016504).

Safety and acute efficacy of cryoballoon ablation for atrial fibrillation at community hospitals.

AIMS: Pulmonary vein isolation (PVI) using cryoballoon ablation (CBA) is an established procedure for treating symptomatic paroxysmal and persistent atrial fibrillation (AF). The safety and efficacy of PVI performed at community hospitals are unknown. We aimed to determine the safety and acute efficacy of PVI using CBA performed at community hospitals with limited annual case numbers. METHODS AND RESULTS: This registry study included 1004 consecutive patients who had PVI performed for symptomatic paroxysmal (n = 563) or persistent AF (n = 441) from January 2019 to September 2020 at 20 hospitals. Each hospital performed fewer than 100 CBA-PVI procedures/year according to local standards. Procedural data, efficacy, and complication rates were determined. The mean number of CBA procedures performed/year at each centre was 59 ± 25. The average procedure time was 90.1 ± 31.6 min and the average fluoroscopy time was 19.2 ± 11.4 min. Isolation of all pulmonary veins was documented in 97.9% of patients. The most frequent reason for not achieving complete isolation was development of phrenic nerve palsy. No hospital deaths were observed. Two patients (0.2%) suffered a clinical stroke. Pericardial effusion occurred in six patients (0.6%), two of whom (0.2%) required pericardial drainage. Vascular complications occurred in 24 patients (2.4%), two of whom (0.2%) required vascular surgery. Phrenic nerve palsy occurred in 48 patients (4.8%) and persisted up to hospital discharge in six patients (0.6%). CONCLUSION: Pulmonary vein isolation procedures for paroxysmal or persistent AF using CBA can be performed at community hospitals with high acute efficacy and low complication rates.

Hemodynamic monitoring by intracardiac impedance measured by cardiac resynchronization defibrillators: Evaluation in a controlled clinical setting (BIO.Detect HF II study).

BACKGROUND: In patients with cardiac resynchronization therapy defibrillators (CRT-Ds), intracardiac impedance measured by dedicated CRT-D software may be used to monitor hemodynamic changes. We investigated the relationship of hemodynamic parameters assessed by intracardiac impedance and by echocardiography in a controlled clinical setting. METHODS: The study enrolled 68 patients (mean age, 66 ± 9 years; 74% males) at 12 investigational sites. The patients had an indication for CRT-D implantation, New York Heart Association class II/III symptoms, left ventricular ejection fraction 15%-35%, and a QRS duration ≥150 ms. Two months after a CRT-D implantation, hemodynamic changes were provoked by overdrive pacing. Intracardiac impedance was recorded at rest and at four pacing rates ranging from 10 to 40 beats/min above the resting rate. In parallel, echocardiography measurements were performed. We hypothesized that a mean intra-individual correlation coefficient (rmean) between stroke impedance (difference between end-systolic and end-diastolic intracardiac impedance) measured by CRT-D and the aortic velocity time integral (i.e., stroke volume) determined by echocardiography would be significantly larger than 0.65. RESULTS: The hypothesis was evaluated in 40 patients with complete data sets. The rmean was 0.797, with a lower confidence interval bound of 0.709. The study hypothesis was met (p = 0.007). A stepwise reduction of stroke impedance and stroke volume was observed with increasing heart rate. CONCLUSIONS: Intracardiac impedance measured by implanted CRT-Ds correlated well with the aortic velocity time integral (stroke volume) determined by echocardiography. The impedance measurements bear potential and are readily available technically, not requiring implantation of additional material beyond standard CRT-D system.

Fracture of an S-ICD lead after two prior transvenous lead-related complications with conventional defibrillators.

Six months after subcutaneous implantable cardioverter defibrillator (S-ICD) implantation a 26-year-old Brugada patient presented because of a beeping tone emitted by his device. Chest X-ray displayed two functionless transvenous shock leads and the S-ICD system with a lead fracture. During lead revision procedure, extensive preparation of the lead from unexpectedly firm surrounding fibrous tissue encapsulating the lead was necessary before it could be removed, and a new shock lead could be implanted. This is the first report of an S-ICD lead exchange due to very early lead fracture and unexpectedly severe fibrous tissue hampering surgical lead extraction.

First interventional exchange of a left transvenous phrenic nerve stimulation lead from the novel remede system.

The remede system is a novel fully implantable transvenous phrenic nerve stimulation (TPNS) device developed to treat central sleep apnea. No information is published on how to explant or replace its leads. An eighty-one year-old had a fractured lead and we removed it over a wire. However, unbreachable resistances occurred with a new lead deployed over the enclosed wire and interventional endovascular techniques were performed to reimplant a new fully functioning system. This first report demonstrates TPNS lead exchange is possible but can be challenging. Interventional maneuvers and techniques, including balloon angioplasty, can facilitate this procedure.

Long-term development of radiation exposure, fluoroscopy time and contrast media use in daily routine in cryoballoon ablations after implementation of intracardiac echocardiography and other radioprotective measures: experiences from a large single-centre cohort.

PURPOSE: The concern of higher radiation exposure during cryoballoon ablation (CBA) compared with radiofrequency ablation for atrial fibrillation (AF) was raised before. Previously, we compared CBA plus intracardiac echocardiography (ICE) to our former standard approach without ICE. A substantial reduction of radiation exposure without compromising safety or outcome was observed. We now investigate if at all and possibly to which amount radiation reduction can be achieved with growing experience. METHODS: We retrospectively analysed procedure time, dose area product (DAP), fluoroscopy time (FT) and contrast media (CM) use for all patients receiving CBA between 2013 and 2017 for AF. RESULTS: In 1131 procedures, procedure time decreased significantly between 2013 and 2017 (2013 111 ± 26 min, 2017 99 ± 25 min, p = 0.005). DAP halved between 2013 and 2014 without further significant decline (2013 1428 ± 1276 cGycm2, 2014 725 ± 551 cGycm2, p < 0.001). FT demonstrated a constant decrease from 2013 to 2017 (2013 11.7 ± 5.5 min, 2017 5.1 ± 3.5 min, p < 0.001). CM use did not show a significant reduction comparing 2013 to 2017 (2013 62 ± 19 ml, 2017 59 ± 18 ml, 2013/2017 p = 0.584). CONCLUSION: Given the imminent negative effects of radiation, every effort should be undertaken for its reduction. Feasible protocols can be kept simple by technical changes as reducing frame rates and basic radiation reduction strategies such as collimation, but ICE might add additional benefit. With growing experience and awareness of radioprotection, DAP and FT as low as or lower than in radiofrequency ablations seem possible.

Interventional techniques to increase implantation success of transvenous phrenic nerve stimulation for central sleep apnea treatment.

PURPOSE: Central sleep apnea (CSA) is a highly common comorbidity in heart failure (HF) patients and is known to deteriorate quality of life and prognosis. Effective treatment options are scarce. Transvenous phrenic nerve stimulation (PNS) has been shown to be effective and safe in CSA treatment in HF. However, lead implantation may be difficult or fail due to anatomical or technical challenges. We report novel and innovative approaches applying different interventional techniques to enhance PNS implantation success, allowing otherwise missing CSA treatment. METHODS: Twenty-seven consecutive HF patients (86% male, mean age: 69 ± 11 years; reduced left ventricular ejection fraction in 16 patients (57%)) were included in this study who were unable to tolerate or had contraindications for mask-based therapy. We evaluated PNS total implantation success, procedural characteristics, and feasibility and success rates of intravascular interventions to facilitate PNS lead implantation in otherwise ineffective procedures. RESULTS: Seven lead implantation attempts (24%) required additional intravascular interventional action to facilitate successful implantation, mainly consisting of balloon angioplasties to allow optimal PNS lead placement. Two procedures remained unsuccessful and two patients underwent a second procedure due to stimulation side effects and lead fracture respectively. All over, no complications resulted from application of interventional techniques to achieve a 93% implantation success rate. CONCLUSION: Transvenous PNS lead placement for CSA treatment can be difficult and challenging. However, interventional intravascular techniques markedly increase implantation success and thereby allow application of this therapy for effective CSA treatment in most patients without additional complications.

Pulmonary vein isolation and beyond: Predictive value of vagal reactions in second-generation cryoballoon ablation for the outcome of persistent atrial fibrillation.

BACKGROUND: Cryoballoon ablation (CBA) is gaining increasing acceptance in the treatment of persistent (per) atrial fibrillation (AF). The cardiac autonomic nervous system plays a pivotal role in the regulation of AF. OBJECTIVE: We evaluated the impact of vagal reactions (VRs), as a surrogate marker for autonomic nervous system modulation, on the outcome of CBA in patients (pts) with perAF. METHODS: A total of 250 consecutive pts (mean age 63.9 ± 10.0 years; 175 pts, 70% male) undergoing primary second-generation CBA for perAF were studied. VRs were defined as bradycardia <40 beats/min, asystole, or higher-degree atrioventricular block. Follow-up visits at 3, 6, and 12 months included 7-day Holter electrocardiograms. RESULTS: VRs were recorded in 61 pts (24%). These pts showed a significantly reduced recurrence rate of AF (5%) than did those without VRs (log-rank, P < .01). Univariate Cox regression analyses confirmed VRs as a strong predictor of AF-free survival (hazard ratio [HR] 0.10; P < .01). Female sex (HR 1.71; P = .02), preprocedural tachycardia (HR 1.01; P = .01), and AF (HR 1.75; P = .01) before CBA at admission were revealed as predictors of AF recurrence. Multivariate regression model calculation solely identified VRs (HR 0.11; 95% confidence interval 0.03-0.34; P < .01) and male sex (HR 0.57; 95% confidence interval 0.36-0.89; P = .01) as independent predictors of AF-free survival. CONCLUSION: VR is an independent predictor of AF-free survival after CBA for perAF.

How to implant a phrenic nerve stimulator for treatment of central sleep apnea?

BACKGROUND: Central sleep apnea (CSA) is a breathing disorder caused by the intermittent absence of central respiratory drive. Transvenous phrenic nerve stimulation is a new therapeutic option, recently approved by the FDA , for the treatment of CSA. OBJECTIVE: To describe the technique used to implant the transvenous phrenic nerve stimulation system (the remede System, Respicardia, Inc). METHODS: The remede System is placed in the pectoral region, typically on the right side. A single stimulation lead is placed in either the left pericardiophrenic vein (PPV) or the right brachiocephalic vein (RBC). A sensing lead is placed into the azygous vein to detect respiration. RESULTS: In the remede System Pivotal trial, 147 of 151 (97%) patients were successfully implanted with the system. Sixty-two percent of stimulation leads were placed in the PPV and 35% in the RBC. Mean procedure time was 2.7 ± 0.8 hours and 94% of patients were free from implant-related serious adverse events through 6 months. CONCLUSION: In patients with CSA, transvenous phrenic nerve stimulation is an effective and safe therapy with an implant procedure similar to that of cardiac implantable electronic devices.

Hemoptysis as a side effect of cryoballoon pulmonary vein isolation in atrial fibrillation: a retrospective case-control study.

PURPOSE: Hemoptysis and pulmonary hemorrhage are rarely described as complications of cryoballoon ablation for pulmonary vein isolation (CB PVI). This study evaluated a large cohort to determine the frequency and risk factors for manifestation of these complications and assess the clinical relevance of hemoptysis after CB PVI. METHODS: Seven hundred fifteen consecutive patients (351 female) from a single-center database were evaluated to identify those who developed hemoptysis after CB PVI. RESULTS: A total of 31 patients with hemoptysis (4.3%; 2 female, age 60.5 ± 11.5 years) were matched with a control group (n = 31). Hemoptysis developed within 72 h after CB PVI. Cases versus controls had significantly lower ablation temperatures in the right inferior pulmonary vein (PV) (- 56.2 ± 26.6 vs - 49.1 ± 13.2 °C; p = 0.004) and left inferior PV (- 56.4 ± 11.9 vs - 47.2 ± 7.6 °C; p = 0.001). A trend to lower temperatures not reaching the level of significance was also found for the superior PV. All other procedural parameters were not significantly different between cases and controls. Although pre-procedural hemoglobin levels were comparable, post-procedural hemoglobin was lower in cases versus controls (12.9 ± 1.6 vs 13.7 ± 1.5 g/dL; p < 0.05). Twenty-six patients presenting with hemoptysis underwent chest CT scan, which showed perivenous infiltration at either the right (n = 23) or left inferior PV (n = 2) or no infiltrate (n = 1). No negative long-term effects were reported after 3, 6, and 12 months' follow-up. CONCLUSIONS: Post-procedural hemoptysis after CB PVI is a relatively frequent finding and was associated with low freezing temperatures and pulmonary tissue infiltration predominantly located at the right inferior PV. Hemoptysis resolved without long-term sequelae.

Shock efficacy of single and dual coil electrodes-new insights from the NORDIC ICD Trial.

Aims: Dual coil (DC) electrodes are preferred to single coil (SC) electrodes because of an assumed higher shock efficacy. However, DC-electrodes may be associated with an increased difficulty and risk of lead extraction. We aimed to compare SC- and DC-electrodes with respect to the first shock efficacy (FSE) after implantable cardioverter defibrillator (ICD) implantation. Methods and results: One thousand and seventy-seven patients of the NORDIC ICD trial were randomly assigned to first time ICD implantation with or without defibrillation (DF) testing. The electrode configuration was determined before randomization. One thousand and sixty-seven patients eventually received an ICD, 516 (48.4%) with a SC- and 551 (51.6%) with a DC-electrode. DC-electrodes were preferentially selected in older patients, renal failure, atrial fibrillation, dual chamber, Cardiac Resynchronization Therapy (CRT) devices, angiotensin-converting-enzyme (ACE) inhibitors/angiotensin (AT) receptor blockers and without Sotalol. However, the preference of the investigational site was dominant over clinical parameters. The DF energy at the final electrode position was higher in SC-electrodes (adjusted difference +1.15 J; P = 0.005; only patients tested). Less patients with DC-electrodes required intra-operative system reconfiguration (adjusted difference -3.9; P = 0.046; only patients tested). Using mixed logistic regression, the FSE was 92.6% in SC- and 97.8% in DC-electrodes (adjusted odds ratio 4.3 (95% confidence interval [1.9, 9.8]; P < 0.001)). Conclusion: Dual coil-electrode selection mainly depends on the preference of the investigational site and seems to be preferred in older patients, renal failure, atrial fibrillation, dual chamber, and CRT devices. Patients with DC-electrodes required less intraoperative system reconfigurations. Dual coil-electrodes provided a substantially higher FSE during follow-up. Mortality rates were not significantly different in patients with DC- and SC-electrodes.

Second generation cryoballoon ablation for persistent atrial fibrillation: an updated meta-analysis.

BACKGROUND: Catheter ablation is an established treatment option for patients with symptomatic atrial fibrillation (AF). The cornerstone of AF ablation is pulmonary vein isolation (PVI). The second-generation cryoballoon (2G-CB) has shown non-inferiority to radiofrequency (RF) ablation in paroxysmal AF in several trials. Growing evidence suggests that 2G-CB is also effective in patients with persistent AF (perAF). The aim of this study was to summarize and analyze available data on safety and mid-term (≥ 12 months) efficacy of PVI using 2G-CB in patients with perAF. METHODS: We did a search in PubMed, Web of Science, Cochrane Library, and clinicaltrials.gov in December 2016 for studies of 2G-CB ablation for perAF. Studies reporting clinical success rates at a follow-up (FU) of ≥ 12 months were included. Success was defined as freedom from any atrial arrhythmia lasting > 30 s after an initial blanking period of 3 months. Acute success and complication rates were also assessed. Data were analyzed applying random-effects model. RESULTS: A total of 917 patients from 11 studies meeting study inclusion criteria were analyzed. After a mean FU of 16.7 ± 3.0 months, 68.9% were free from recurrences [95% confidence interval (CI) 63.4-74.7%]. Overall acute success rate was 99.7% (95% CI 99.2-100%). Complications occurred in 5.5% (95% CI 2.4-9.6%). Vascular access complications were the most frequent 3.3% (95% CI 1.5-5.6%). The rate of phrenic nerve palsy/injury was 2.09% (95% CI 0.8-3.9%). No death, stroke or myocardial infarction was reported. CONCLUSION: The 2G-CB seems to be safe and effective in the treatment of perAF in the mid-term.

Predominant obstructive or central sleep apnea in patients with atrial fibrillation: influence of characterizing apneas versus apneas and hypopneas.

OBJECTIVE/BACKGROUND: Sleep-disordered breathing (SDB) is common in patients with atrial fibrillation (Afib). Although a high proportion of respiratory events are hypopneas, previous studies have only used apneas to differentiate obstructive (OSA) from central (CSA) sleep apnea. This study investigated the impact of using apneas and hypopneas versus apneas only to define the predominant type of SDB in Afib patients with preserved ejection fraction. PATIENTS/METHODS: This retrospective analysis was based on high-quality cardiorespiratory polygraphy (PG) recordings (07/2007-03/2016) that were re-analyzed using 2012 American Academy of Sleep Medicine criteria, with differentiation of apneas and hypopneas as obstructive or central. Classification of predominant (>50% of events) OSA and CSA was defined based on apneas only (OSAAI and CSAAI) or apneas and hypopneas (OSAAHI and CSAAHI). SDB was defined as an apnea-hypopnea index ≥5/h. RESULTS: A total of 211 patients were included (146 male, age 68.7 ± 8.5 y). Hypopneas accounted for >50% of all respiratory events. Based on apneas only, 46% of patients had predominant OSA and 44% had predominant CSA. Based on apneas and hypopneas, the proportion of patients with OSA was higher (56%) and that with CSA was lower (36%). In the subgroup of patients with moderate to severe SDB (AHI ≥ 15/h), the proportion with predominant CSA was 55.2% based on apneas only versus 42.1% with apneas and hypopneas. CONCLUSIONS: In hospitalized patients with Afib and SDB, use of apneas and hypopneas versus apneas alone had an important influence on the proportion of patients classified as having predominant OSA or CSA.

Additional electrodes on the Quartet™ LV lead provide more programmable pacing options than bipolar and tripolar equivalents.

AIMS: The aim of this study was to evaluate any benefits to the number of viable pacing vectors and maximal spatial coverage with quadripolar left ventricular (LV) leads when compared with tripolar and bipolar equivalents in patients receiving cardiac resynchronization therapy (CRT). METHODS AND RESULTS: A meta-analysis of five previously published clinical trials involving the Quartet™ LV lead (St Jude Medical, St Paul, MN, USA) was performed to evaluate the number of viable pacing vectors defined as capture thresholds ≤2.5 V and no phrenic nerve stimulation and maximal spatial coverage of viable vectors in CRT patients at pre-discharge (n = 370) and first follow-up (n = 355). Bipolar and tripolar lead configurations were modelled by systematic elimination of two and one electrode(s), respectively, from the Quartet lead. The Quartet lead with its four pacing electrodes exhibited the greatest number of pacing vectors per patient when compared with the best bipolar and the best tripolar modelled equivalents. Similarly, the Quartet lead provided the highest spatial coverage in terms of the distance between two furthest viable pacing cathodes when compared with the best bipolar and the best tripolar configurations (P < 0.05). Among the three modelled bipolar configurations, the lead configuration with the two most distal electrodes resulted in the highest number of viable pacing vectors. Among the four modelled tripolar configurations, elimination of the second proximal electrode (M3) resulted in the highest number of viable pacing options per patient. There were no significant differences observed between pre-discharge and first follow-up analyses. CONCLUSION: The Quartet lead with its four electrodes and the capability to pace from four anatomical locations provided the highest number of viable pacing vectors at pre-discharge and first follow-up visits, providing more flexibility in device programming and enabling continuation of CRT in more patients when compared with bipolar and tripolar equivalents.

Long-Term Experience with First-Generation Implantable Neurostimulation Device in Central Sleep Apnea Treatment.

BACKGROUND: Sleep-disordered breathing (SDB) and Cheyne-Stokes respiration (CSR) are associated with shorter survival in patients with heart failure. A novel treatment method for this patient group is unilateral phrenic nerve stimulation by the remede® system (Respicardia Inc., Minnetonka, MN, USA), a transvenously implantable neurostimulation device, which has recently been studied in a large randomized, controlled trial. Previous literature has shown efficacy and safety of the treatment with this first-generation device, but hardly any data are available on long-term clinical parameters, the remede® device's battery lifetime, device exchangeability, lead position stability, surgical accessibility, and manageability. METHODS: We performed remede® device replacements in consecutive patients for battery depletion, and documented clinical parameters, longevity, operation procedure, complications, and difficulties. RESULTS: All patients were on neurostimulation treatment by phrenic nerve neurostimulation when device replacement became necessary. Apnea-hypopnea index (from 45 ± 4/h to 9 ± 4/h), oxygen-desaturation index (from 35 ± 7/h to 7 ± 6/h), and time spent with oxygen saturation of <90% (T < 90% from 5 ± 7% to 0 ± 0%) were improved and improvements remained constant throughout the 4-year follow-up. Mean battery life was 4.2 ± 0.2 years and mean replacement procedure time was 25 ± 5.1 minutes. Apart from conventional X-ray documentation of stable lead positions in a long-term setting, no radiation or contrast dye usage was needed and no major complications occurred. In addition, clinical exercise capacity and sleepiness symptoms improved. CONCLUSIONS: Novel remede® device shows sustained therapy efficacy and safety in terms of stable lead positions over 4 years. Long-term phrenic nerve neurostimulation therapy for central SDB/CSR appears feasible in a clinical routine setting.

Reduction of radiation exposure in cryoballoon ablation procedures: a single-centre study applying intracardiac echocardiography and other radioprotective measures.

AIMS: The population treated with cryoballoon (CB) ablation is relatively young, and radiation protection is of major importance. We aimed to demonstrate that radiation exposure can be markedly reduced by intracardiac echocardiography (ICE) and optimized settings of the X-ray system. METHODS AND RESULTS: We analysed 100 patients undergoing CB pulmonary vein isolation (PVI) for treatment of paroxysmal atrial fibrillation. In 50 consecutive patients (25 male, 59 ± 13 years; Group 1), we used ICE, skipped PV angiography prior to CB inflation, and avoided fluoroscopy whenever possible. Furthermore, we reduced the frame rate, minimized distance between patient and detector, and consequently applied collimation. These patients were compared with 50 similar preceding patients in Group 2 (29 male, 61 ± 12 years). Total fluoroscopy time was reduced from 18 ± 6 min in Group 2 to 12 ± 5 min in Group 1 (P < 0.001). Moreover, the dose area product was significantly lower (1555 ± 1219 vs. 4935 ± 2094 cGycm2, P < 0.001), total freezing time was significantly shortened (1855 ± 399 vs. 2121 ± 756 s, P = 0.031), and contrast media use was significantly reduced (66 ± 25 vs. 109 ± 27 mL, P < 0.001). At the same time, total procedure duration and complication rates did not differ significantly between both groups. After a 12 months follow-up, a similar percentage of patients was free from recurrences (74% in Group 1 vs. 78% in Group 2, P = 0.640). CONCLUSION: Radiation exposure in CB PVI can be markedly reduced without prolonging procedure times, affecting the outcome or complication rates. Moreover, ICE seems to shorten total freezing time.

Phrenic nerve stimulation for the treatment of central sleep apnea.

OBJECTIVES: The aim of this study was to evaluate chronic, transvenous, unilateral phrenic nerve stimulation to treat central sleep apnea (CSA) in a prospective, multicenter, nonrandomized study. BACKGROUND: CSA occurs predominantly in patients with heart failure and increases the risk for morbidity and mortality. Established therapies for CSA are lacking, and those available are limited by poor patient adherence. METHODS: Fifty-seven patients with CSA underwent baseline polysomnography followed by transvenous phrenic nerve stimulation system implantation and follow-up. Feasibility was assessed by implantation success rate and therapy delivery. Safety was evaluated by monitoring of device- and procedure-related adverse events. Efficacy was evaluated by changes in the apnea-hypopnea index at 3 months. Quality of life at 6 months was evaluated using a sleepiness questionnaire, patient global assessment, and, in patients with heart failure at baseline, the Minnesota Living With Heart Failure Questionnaire. RESULTS: The study met its primary end point, demonstrating a 55% reduction in apnea-hypopnea index from baseline to 3 months (49.5 ± 14.6 episodes/h vs. 22.4 ± 13.6 episodes/h of sleep; p < 0.0001; 95% confidence interval for change: -32.3 to -21.9). Central apnea index, oxygenation, and arousals significantly improved. Favorable effects on quality of life and sleepiness were noted. In patients with heart failure, the Minnesota Living With Heart Failure Questionnaire score significantly improved. Device- or procedure-related serious adverse events occurred in 26% of patients through 6 months post therapy initiation, predominantly due to lead repositioning early in the study. Therapy was well tolerated. Efficacy was maintained at 6 months. CONCLUSIONS: Transvenous, unilateral phrenic nerve stimulation appears safe and effective for treating CSA. These findings should be confirmed in a prospective, randomized, controlled trial. (Chronic Evaluation of Respicardia Therapy; NCT01124370).

Left ventricular three-dimensional quadripolar lead acute clinical study: the LILAC study.

AIMS: This multicenter acute clinical study was designed to verify novel three-dimensional (3D) quadripolar lead designs that can achieve ≤2.5 V average pacing capture threshold (PCT) not only at the apex, but also at the base of the left ventricle with phrenic nerve stimulation (PNS) avoidance for cardiac resynchronization. METHODS: During the implant procedure, up to two different left ventricular investigational leads were introduced and tested in the same target coronary vein based on the coronary sinus venogram in a wedged and unwedged position. Adverse events were collected in 30 days following the procedure. RESULTS: Eighty-seven leads were tested in 50 patients. When the best performing spiral electrode was chosen from each lead testing, the average of the best PCT on spiral in a wedged position was similar to the unwedged position (1.7 ± 1.5 V vs 1.9 ± 1.5 V, P = ns) and was similar to the wedged tip electrode average PCT (1.7 ± 1.5 V vs 1.6 ± 1.6 V, P = ns). In the majority of patients (89-96%), pacing was achievable in a mid-basal ventricular location without PNS. CONCLUSIONS: This acute study demonstrated that a 3D quadripolar spiral lead design can achieve acceptable PCTs and avoid PNS without repositioning the lead at implant in the vast majority of patients. It also demonstrated that this lead design can achieve mid-basal ventricular stimulation with low PCT and good acute stability.

Risk for ventricular fibrillation in peripartum cardiomyopathy with severely reduced left ventricular function-value of the wearable cardioverter/defibrillator.

AIMS: The true incidence of life-threatening ventricular tachyarrhythmic events and the risk of sudden cardiac death in the early stage of peripartum cardiomyopathy (PPCM) are still unknown. We aimed to assess the usefulness of the wearable cardioverter/defibrillator (WCD) to bridge a potential risk for life-threatening arrhythmic events in patients with early PPCM, severely reduced left ventricular ejection fraction (LVEF) and symptoms of heart failure. METHODS AND RESULTS: Twelve consecutively admitted women with PPCM were included in this single-centre, prospective observational study between September 2012 and September 2013. Patients with LVEF ≤35% were considered to use the WCD for 3 months or even 6 months when considered necessary for LVEF recovery. Nine of the 12 women had a severely reduced LVEF (mean 18.3%) at the time of study enrollment; seven women received a WCD, while two patients refused to wear a WCD. During a median WCD follow-up of 81 days (range 25-345 days), we observed a total of four events of ventricular fibrillation with appropriate and successful WCD shocks in three of the seven women receiving a WCD. No syncope or sudden arrhythmic deaths occurred in women not using the WCD during a median follow-up of 12 months (range 5-15 months). All women showed impressive improvement of LVEF during follow-up. CONCLUSION: PPCM patients with severely reduced LVEF have an elevated risk for ventricular tachyarrhythmias early after diagnosis. Therefore, use of the WCD should be considered in all women with early-stage PPCM and severely reduced LVEF during the first 6 months after initiation of heart failure therapy.