Dual-chamber Implantable Cardioverter-defibrillator Research Articles

A case study of a 59-year-old male with a cardiac variant of Anderson–Fabry disease

Anderson–Fabry disease is a rare X-linked lysosomal storage disorder caused by deficiency of the enzyme alpha-galactosidase A, affecting around 1 in 100,000 births. Waste products build up within cells throughout the body, affecting the heart, nervous system, skin, eyes and kidneys. In the cardiac variant, Anderson–Fabry disease the effects are limited to the heart, causing left-ventricular hypertrophy (LVH), valve defects and conduction abnormalities. Involvement of the heart contributes to morbidity and premature death because of increased prevalence of heart failure, arrhythmia and strokes. Utilising a case study of a 59-year-old male with the cardiac variant of Anderson–Fabry disease, this article discusses the treatment options available, including dual chamber pacing and implantable cardioverter defibrillator (ICD) therapy, in line with American Heart Association/American College of Cardiology (AHA/ACC) guideline criteria. Additionally research into enzyme replacement therapy (ERT) suggests treatment can reverse damage and prevent further damage occurring, therefore the use of ERT and its effectiveness in this case is also discussed.

Do cardiologists follow the European guidelines for cardiac pacing and resynchronization therapy? Results of the European Heart Rhythm Association survey.

The purpose of this European Heart Rhythm Association (EHRA) EP wire survey was to evaluate the implementation of the current guidelines for cardiac pacing and cardiac resynchronization therapy (CRT) in Europe. A total of 48 centres replied to the survey, 34 of them (71%) were university hospitals. All responding centres implement CRT in patients with classical indications, i.e. sinus rhythm, New York Heart Association (NYHA) functional class II, III, or ambulatory IV, left ventricular ejection fraction (LVEF) 35%, and left bundle-branch block (LBBB) with QRS duration >150 ms, while 31 centres (67%) would implant a CRT device in patients with the same characteristics but with a non-LBBB pattern. Forty-one centres (89%) would also implant CRT in patients with sinus rhythm, NYHA Class II, III, or ambulatory IV, LVEF <35%, and LBBB with QRS duration between 120 and 150 ms, while only eight centres (17%) would implant the device in patients with the same characteristics but with a non-LBBB pattern. In patients with LVEF <35% and QRS duration below 120 ms, the majority of the centres (80%) would implant a single- or dual-chamber implantable cardioverter-defibrillator, but in nine cases (20%) no device was considered to be indicated. The results of this survey showed a good adherence to some of the current recommendations. Still some reluctance exists when offering the device therapy to patients with QRS duration in the lower range.

Role of atrial fibrillation burden in assessing thromboembolic risk.

Stroke represents the most devastating complication of atrial fibrillation (AF). Our understanding of the pathophysiology of thromboembolism in patients with AF remains incomplete, and as such, our assessment and management of this risk is imperfect. Current guidelines regard the risk of thromboembolism as independent of the frequency or duration of AF.1 Paradoxically, standard practice in the pericardioversion period considers thromboembolic risk to accrue after 48 hours of AF.1 This recommendation, however, is based on limited data, including an observational study of 357 patients which demonstrated that the risk of thromboembolic events was <1% in patients with AF lasting <48 hours who cardioverted without prolonged anticoagulation therapy or a transesophageal echocardiogram.2 No strong randomized control trial data exist to specifically support a 48-hour safety cut-off, and recent data suggest that the duration of AF associated with a significantly increased risk of stroke may in fact be less.3–8 The emergence of technology to allow absolute quantification of the frequency and duration, or burden, of AF offers the opportunity to refine our assessment and management of thromboembolic risk associated with AF. It has been 200 years since William Wood described a ball thrombus in the left atrium of a patient with mitral stenosis9 and 170 years since Virchow identified the critical components required for thrombus formation.10 It took until 1930 for Harvey and Levine to first declare that “auricular fibrillation definitely increases the incidence of auricular thrombosis” in an autopsy series of patients with mural thrombi.11 Uncertainty as to whether nonrheumatic AF resulted in stroke continued for the next 40 plus years until Wolfe and colleagues, in their landmark analysis using the Framingham population data, identified a 5.6-fold increased risk of stroke in patients with chronic nonvalvular AF.12 With time it would become …

Abstract 16317: Cost-Effectiveness of Bi-Ventricular Pacemakers vs. RV Pacemakers and Bi-Ventricular Defibrillators vs. Dual Chamber Defibrillators in Patients With Atrioventricular Block and Systolic Dysfunction: All-Patient and Subgroup Analyses From the BLOCK-HF Clinical Trial

BACKGROUND: The cost-effectiveness (C-E) of biventricular (BiV) pacing compared to right ventricular (RV) pacing in patients with a pacing indication due to atrioventricular (AV) block and EF &lt; 50% is unknown. Material differences may exist between the C-E of BiV pacemakers (BiV-P) vs. RV and BiV defibrillators (BiV-D) vs. dual chamber ICDs, the latter when patients independently have an ICD indication. METHODS: Patient-level data from the BLOCK-HF trial were used. Statistical models were used to predict all-cause mortality, NYHA distribution over time, and NYHA-specific HF-related healthcare utilization (HCU) rates. Analyses were undertaken separately for BiV/RV (All-Patient), BiV-P/IPG and BiV-D/ICD. RESULTS: HCU rates in NYHA Classes I/II were lower than Classes III/IV and consistently reduced with BiV devices. Predicted life expectancy in the “All-Patient” analysis was 6.78 years with RV devices and 7.52 with BiV ones (a 10.8% increase). More BiV patients were predicted to remain in, or improve to, Classes I/II, if alive. In the “All-Patient” analysis, BiV offered patients 0.41 more Quality-Adjusted Life Years (QALYs) compared to RV, at an additional cost of $12,537 (Incremental C-E Ratio “ICER” $30,860.16/QALY Gained). Within the clinical co-variate subgroups of the “All-Patient” analysis, the highest ICER observed was $43,687.59 (NYHA Class I Patients). Within the device-based subgroups, BiV-D patients were projected to benefit more (0.84 years gained) than BiV-P ones (0.49 years) CONCLUSIONS: BiV reduces HCU rates compared with RV, offering survival benefits and slowing HF progression. The “All-Patient” ICER was $30,860.16/QALY Gained and ICERs were consistently below the conventional US acceptability threshold ($50,000/QALY Gained). The additional cost associated with offering BiV devices to patients with AV block and systolic dysfunction appears justified by the expected benefits across both device types.

Do patients with heart failure and right bundle branch block need biventricular pacing? A case of significant QRS narrowing by right ventricular pacing alone

We report the case of a 56-year-old male with ischemic cardiomyopathy, severe left ventricular dysfunction and right bundle branch block (RBBB) with a wide QRS duration (180ms) who received dual-chamber implantable cardioverter–defibrillator for primary prevention of sudden death. After having placed the right ventricular lead in the middle of the inter-ventricular septum, a significant narrowing of QRS duration was observed, thus obtaining “de facto” a cardiac resynchronization therapy (CRT). This type of cardiac pacing could be an alternative to conventional CRT with left ventricular pacing in patients with wide QRS due to RBBB. The long-term effects of this RV only pacing strategy with ICD in patients with heart failure yet remain to be determined.

Defibrillation lead placement using a transthoracic transatrial approach in a case without transvenous access due to lack of the right superior vena cava

A 65-year-old woman with a history of syncope was diagnosed with hypertrophic cardiomyopathy. She had previously undergone mastectomy of the left breast owing to breast cancer. Holter electrocardiogram (ECG) and monitor ECG revealed sick sinus syndrome (Type II) and non-sustained ventricular tachycardia. Sustained ventricular tachycardia and ventricular fibrillation were induced in an electrophysiological study. Although the patient was eligible for treatment with a dual chamber implantable cardioverter defibrillator (ICD), venography revealed lack of the right superior vena cava (R-SVC). Lead placement from the left subclavian vein would have increased the risk of lymphedema owing to the patient׳s mastectomy history. Consequently, the defibrillation lead was placed in the right ventricle by direct puncture of the right auricle through the tricuspid valve. The atrial lead was sutured to the atrial wall, and the postoperative course was unremarkable. Defibrillation lead placement using a transthoracic transatrial approach can be an alternative method in cases where a transvenous approach for lead placement is not feasible.

Optimal pacing for right ventricular and biventricular devices: minimizing, maximizing, and right ventricular/left ventricular site considerations.

The results from numerous clinical studies provide guidance for optimizing outcomes related to RV or biventricular pacing in the pacemaker and ICD populations. (1) Programming algorithms to minimize RV pacing is imperative in patients with dual-chamber pacemakers who have intrinsic AV conduction or intermittent AV conduction block. (2) Dual-chamber ICDs should be avoided in candidates without an indication for bradycardia pacing. (3) Alternate RV septal pacing sites may be considered at the time of pacemaker implantation. (4) Biventricular pacing may be beneficial in some patients with mild LV dysfunction. (5) LV lead placement at the site of latest LV activation is desirable. (6) Programming CRT systems to achieve biventricular/LV pacing >98.5% is important. (7) Protocols for AV and VV optimization in patients with CRT are not recommended after device implantation but may be considered for CRT nonresponders. (8) Novel algorithms to maximize the benefit of CRT are in evolution further.

Reduced Risk for Inappropriate Implantable Cardioverter-Defibrillator Shocks With Dual-Chamber Therapy Compared With Single-Chamber Therapy: Results of the Randomized OPTION Study

ObjectivesThe OPTION (Optimal Anti-Tachycardia Therapy in Implantable Cardioverter-Defibrillator Patients Without Pacing Indications) trial sought to compare long-term rates of inappropriate shocks, mortality, and morbidity between dual-chamber and single-chamber settings in implantable cardioverter-defibrillators (ICDs) patients. BackgroundThe use of dual-chamber ICDs potentially allows better discrimination of supraventricular arrhythmias and thereby reduces inappropriate shocks. However, it may lead to detrimental ventricular pacing. MethodsThis prospective multicenter, single-blinded trial enrolled 462 patients with de novo primary or secondary prevention indications for ICD placement and with left ventricular ejection fractions ≤40% despite optimal tolerated pharmacotherapy. All patients received atrial leads and dual-chamber defibrillators that were randomized to be programmed either with dual-chamber or single-chamber settings. In the dual-chamber setting arm, the PARAD+ algorithm, which differentiates supraventricular from ventricular arrhythmias, and SafeR mode, to minimize ventricular pacing, were activated. In the single-chamber setting arm, the acceleration, stability, and long cycle search discrimination criteria were activated, and pacing was set to VVI 40 beats/min. Ventricular tachycardia detection was required at rates between 170 and 200 beats/min, and ventricular fibrillation detection was activated above 200 beats/min. ResultsDuring a follow-up period of 27 months, the time to the first inappropriate shock was significantly longer in the dual-chamber setting arm (p = 0.012, log-rank test), and 4.3% of patients in the dual-chamber setting group compared with 10.3% in the single-chamber setting group experienced inappropriate shocks (p = 0.015). Rates of all-cause death or cardiovascular hospitalization were 20% for the dual-chamber setting group and 22.4% for the single-chamber setting group and satisfied the pre-defined margin for equivalence (p < 0.001). ConclusionsTherapy with dual-chamber settings for ICD discrimination combined with algorithms for minimizing ventricular pacing was associated with reduced risk for inappropriate shock compared with single-chamber settings, without increases in mortality and morbidity. (Optimal Anti-Tachycardia Therapy in Implantable Cardioverter-Defibrillator [ICD] Patients Without Pacing Indications [OPTION]; NCT00729703)

THERE IS NO DIFFERENCE IN LONGEVITY OF IMPLANTABLE CARDIOVERTER-DEfiBRILLATORS BETWEEN MANUFACTURERS

BackgroundIncreased implantable cardioverter defibrillator (ICD) longevity decreases the risk of generator change thus reducing cost and the associated morbidity. We sought to evaluate the longevity of Bi-ventricular (Bi-V), dual chamber and single chamber ICDs from British Columbia’s ICD registry, analyzing the 3 largest vendors: Medtronic, St. Jude Medical and Boston Scientific.MethodsAll BC patients aged 20 or older, who underwent ICD implants or generator replacement with Medtronic, St. Jude Medical, or Boston Scientific devices between 01 January 2004 and 31 December 2012 were included. The longevity of device was estimated by the Kaplan-Meier method. Data regarding shocks and pacing parameters is being collected, but was not available for this analysis.Results4711 patients (3835 male; 876 female, age 63.7±13.0 years) underwent 5602 ICD insertions (3502 primary implants; 2100 generator changes). Inserted generators were Medtronic (4452; 79.47%), St. Jude Medical (976; 17.42%) and Boston Scientific (174; 3.11%). Implanted devices were predominantly dual chamber (45.25%), with a lesser proportion of single chamber (27.56%) and Bi-V (27.19%) devices. The overall median ICD longevity was 6.56 years (5.07, 8.89). There was no difference in longevity by manufacturer. There was a significant difference in the longevity by device type (Single chamber: 7.72 (5.99, 9.11); Dual chamber: 6.49 (5.47, 7.83); Bi-V: 5.00 (4.06, 6.45), p < 0.0001).ConclusionView Large Image Figure ViewerDownload (PPT) BackgroundIncreased implantable cardioverter defibrillator (ICD) longevity decreases the risk of generator change thus reducing cost and the associated morbidity. We sought to evaluate the longevity of Bi-ventricular (Bi-V), dual chamber and single chamber ICDs from British Columbia’s ICD registry, analyzing the 3 largest vendors: Medtronic, St. Jude Medical and Boston Scientific. Increased implantable cardioverter defibrillator (ICD) longevity decreases the risk of generator change thus reducing cost and the associated morbidity. We sought to evaluate the longevity of Bi-ventricular (Bi-V), dual chamber and single chamber ICDs from British Columbia’s ICD registry, analyzing the 3 largest vendors: Medtronic, St. Jude Medical and Boston Scientific. MethodsAll BC patients aged 20 or older, who underwent ICD implants or generator replacement with Medtronic, St. Jude Medical, or Boston Scientific devices between 01 January 2004 and 31 December 2012 were included. The longevity of device was estimated by the Kaplan-Meier method. Data regarding shocks and pacing parameters is being collected, but was not available for this analysis. All BC patients aged 20 or older, who underwent ICD implants or generator replacement with Medtronic, St. Jude Medical, or Boston Scientific devices between 01 January 2004 and 31 December 2012 were included. The longevity of device was estimated by the Kaplan-Meier method. Data regarding shocks and pacing parameters is being collected, but was not available for this analysis. Results4711 patients (3835 male; 876 female, age 63.7±13.0 years) underwent 5602 ICD insertions (3502 primary implants; 2100 generator changes). Inserted generators were Medtronic (4452; 79.47%), St. Jude Medical (976; 17.42%) and Boston Scientific (174; 3.11%). Implanted devices were predominantly dual chamber (45.25%), with a lesser proportion of single chamber (27.56%) and Bi-V (27.19%) devices. The overall median ICD longevity was 6.56 years (5.07, 8.89). There was no difference in longevity by manufacturer. There was a significant difference in the longevity by device type (Single chamber: 7.72 (5.99, 9.11); Dual chamber: 6.49 (5.47, 7.83); Bi-V: 5.00 (4.06, 6.45), p < 0.0001). 4711 patients (3835 male; 876 female, age 63.7±13.0 years) underwent 5602 ICD insertions (3502 primary implants; 2100 generator changes). Inserted generators were Medtronic (4452; 79.47%), St. Jude Medical (976; 17.42%) and Boston Scientific (174; 3.11%). Implanted devices were predominantly dual chamber (45.25%), with a lesser proportion of single chamber (27.56%) and Bi-V (27.19%) devices. The overall median ICD longevity was 6.56 years (5.07, 8.89). There was no difference in longevity by manufacturer. There was a significant difference in the longevity by device type (Single chamber: 7.72 (5.99, 9.11); Dual chamber: 6.49 (5.47, 7.83); Bi-V: 5.00 (4.06, 6.45), p < 0.0001). Conclusion

Increased Long‐Term Mortality in Patients with Cardiovascular Implantable Electronic Device Infections

Device infection is associated with increased mortality in patients receiving cardiovascular implantable electronic device (CIED) therapy. However, long-term mortality associated with CIED infections has not been systematically analyzed in larger studies. This study sought to determine the long-term mortality associated with CIED infection in a large cohort of Medicare beneficiaries. We used a retrospective study design to analyze 3-year mortality in 200,219 Medicare fee-for-service patients admitted for CIED generator implantation, replacement, or revision between January 1, 2007 and December 31, 2007. Multivariate analysis adjusting for age, sex, race, and 28 comorbidities was performed to determine the relative risk (RR) of death in the 12 quarters following CIED infection. Patients with CIED infection, compared to device recipients without infection, had increased mortality that persisted for at least 3 years after the admission quarter for all device types: pacemakers (PMs: 53.8% vs 33%; P < 0.001), implantable cardioverter defibrillator (ICD: 47.7% vs 31.6%; P < 0.001), and cardiac resynchronization therapy-defibrillator (CRT-D: 50.8% vs 36.5%; P < 0.001). After adjusting for patient demographics and comorbidities, significantly increased RR of death following CIED infection persisted for at least 3 years following PM infection, and for at least 2 years with single- and dual-chamber ICD infection. CIED recipients who develop device infection have increased, device-dependent, long-term mortality even after successful treatment of infection. The etiology of this persistent increased risk of death associated with CIED infection is unknown and merits further investigation.

Implant-based multiparameter telemonitoring of patients with heart failure (IN-TIME): a randomised controlled trial

An increasing number of patients with heart failure receive implantable cardioverter-defibrillators (ICDs) or cardiac resynchronisation defibrillators (CRT-Ds) with telemonitoring function. Early detection of worsening heart failure, or upstream factors predisposing to worsening heart failure, by implant-based telemonitoring might enable pre-emptive intervention and improve outcomes, but the evidence is weak. We investigated this possibility in IN-TIME, a clinical trial. We did this randomised, controlled trial at 36 tertiary clinical centres and hospitals in Australia, Europe, and Israel. We enrolled patients with chronic heart failure, NYHA class II-III symptoms, ejection fraction of no more than 35%, optimal drug treatment, no permanent atrial fibrillation, and a recent dual-chamber ICD or CRT-D implantation. After a 1 month run-in phase, patients were randomly assigned (1:1) to either automatic, daily, implant-based, multiparameter telemonitoring in addition to standard care or standard care without telemonitoring. Investigators were not masked to treatment allocation. Patients were masked to allocation unless they were contacted because of telemonitoring findings. Follow-up was 1 year. The primary outcome measure was a composite clinical score combining all-cause death, overnight hospital admission for heart failure, change in NYHA class, and change in patient global self-assessment, for the intention-to-treat population. The trial is registered with ClinicalTrials.gov, number NCT00538356. We enrolled 716 patients, of whom 664 were randomly assigned (333 to telemonitoring, 331 to control). Mean age was 65·5 years and mean ejection fraction was 26%. 285 (43%) of patients had NYHA functional class II and 378 (57%) had NYHA class III. Most patients received CRT-Ds (390; 58·7%). At 1 year, 63 (18·9%) of 333 patients in the telemonitoring group versus 90 (27·2%) of 331 in the control group (p=0·013) had worsened composite score (odds ratio 0·63, 95% CI 0·43-0·90). Ten versus 27 patients died during follow-up. Automatic, daily, implant-based, multiparameter telemonitoring can significantly improve clinical outcomes for patients with heart failure. Such telemonitoring is feasible and should be used in clinical practice. Biotronik SE & Co. KG.

Generator replacement is associated with an increased rate of ICD lead alerts.

Lead malfunction is an important cause of morbidity and mortality in patients with an implantable cardioverter-defibrillator (ICD). We have shown that the failure of recalled high-voltage leads significantly increases after ICD generator replacement. However, generator replacement has not been recognized as a predictor of lead failure in general. The purpose of this study is to assess the effect of ICD generator exchange on the rate of ICD lead alerts. A time-dependent Cox proportional hazards model was used to analyze a database of remotely monitored ICDs. The model assessed the impact of generator exchange on the rate of lead alerts after ICD generator replacement. The analysis included 60,219 patients followed for 37 ± 19 months. The 5-year lead survival was 99.3% (95% confidence interval 99.2%-99.4%). Of 60,219 patients, 7458 patients (12.9%) underwent ICD generator exchange without lead replacement. After generator replacement, the rate of lead alerts was more than 5-fold higher than in controls with leads of the same age without generator replacement (hazard ratio 5.19; 95% confidence interval 3.45-7.84). A large number of lead alerted within 3 months of generator replacement. Lead alerts were more common in patients with single- vs dual-chamber ICDs and in younger patients. Sex was not associated with lead alerts. Routine generator replacement is associated with a 5-fold higher risk of lead alert compared to age-matched leads without generator replacement. This suggests the need for intense surveillance after generator replacement and the development of techniques to minimize the risk of lead damage during generator replacement.

Rationale and design of the MONITOR-ICD study: A randomized comparison of economic and clinical effects of automatic remote MONITORing versus control in patients with Implantable Cardioverter Defibrillators

Implantable cardioverter defibrillator (ICD) remote follow-up and ICD remote monitoring (RM) are established means of ICD follow-up. The reduction of the number of in-office visits and the time to decision is proven, but the true clinical benefit is still unknown. Cost and cost-effectiveness of RM remain leading issues for its dissemination. The MONITOR-ICD study has been designed to assess costs, cost-effectiveness, and clinical benefits of RM versus standard-care follow-up in a prospective multicenter randomized controlled trial. Patients indicated for single- or dual-chamber ICD are eligible for the study and are implanted an RM-capable Biotronik ICD (Lumax VR-T or Lumax DR-T; Biotronik SE & Co KG, Berlin, Germany). Implantable cardioverter defibrillator programming and alert-based clinical responses in the RM group are highly standardized by protocol. As of December 2011, recruitment has been completed, and 416 patients have been enrolled. Subjects are followed-up for a minimum of 12months and a maximum of 24months, ending in January 2013. Disease-specific costs from a societal perspective have been defined as primary end point and will be compared between RM and standard-care groups. Secondary end points include ICD shocks (including appropriate and inappropriate shocks), cardiovascular hospitalizations and cardiovascular mortality, and additional health economic end points. The MONITOR-ICD study will be an important randomized RM study to report data on a primary economic end point in 2014. Its results on ICD shocks will add to the currently available evidence on clinical benefit of RM.

A prospective randomized trial of single- or dual-chamber implantable cardioverter-defibrillators to minimize inappropriate shock risk in primary sudden cardiac death prevention.

Dual-chamber implantable cardioverter-defibrillators (ICDs) may improve specificity and reduce the risk of inappropriate shocks, and enhance atrial arrhythmia (AT/AF) detection to permit stroke prevention compared with single-chamber ICDs, but at additional expense and risk. Patients (n = 100) receiving primary prevention ICDs at two USA and two Israeli centres were randomized to dual-chamber or single-chamber devices between December 2008 and December 2010 and were followed for 1 year. Programming in both groups included: delayed detection to avoid therapy for non-sustained episodes; high detection cut-off rates to avoid treating slower, better tolerated arrhythmias; minimized right ventricular pacing; and routine use of supraventricular-ventricular tahcycardia discriminators and antitachycardia pacing. The primary outcome was the proportion of patients with inappropriate shocks. One patient in each group (2%) received inappropriate shocks (P = 1.00). Death occurred in two patients in the single-chamber arm, and in none of the patients in the dual-chamber arm (P = 0.15). New AT/AF was detected in 12 patients (24%) in the dual-chamber group, vs. no patients in the single-chamber group (P < 0.001). Among US participants, the mean cost of dual- vs. single-chamber ICD implantation was $16 579 vs. $14 249, respectively (P < 0.001); there was no difference in the quality of life (EQ-5D index difference 0.013, P = 0.769; EQ VAS difference 3.3, P = 0.49). When optimal programming is utilized, inappropriate shocks are rare in primary prevention patients with both single- and dual-chamber ICDs. The routine use of dual-chamber ICDs increases the expense without reducing inappropriate shocks or improving the quality of life at 1 year. clinicaltrials.gov Identifier: NCT00787800.

Single versus dual chamber implantable cardioverter defibrillator for the avoidance of inappropriate shocks - results from the OPTION trial

Introduction Implantable Cardioverter Defibrillators (ICD) are considered to be the treatment of choice for primary and secondary prevention of sudden cardiac death. However, the therapy is burdened by inappropriate ICD shocks (for example for supraventricular tachyarrhythmias) which reduce patient’s quality of life and acceptance of the device, although dual chamber (DC) ICD have access to atrial and ventricular information for tachyarrhythmia discrimination. Recent studies have failed to show a clear benefit in reducing inappropriate shocks by these devices [1-3]. But adequately powered trials with a long-term follow-up are scarce.

Current implantable cardioverter-defibrillator programming in Europe: the results of the European Heart Rhythm Association survey.

The purpose of this European Heart Rhythm Association (EHRA) survey was to examine the current practice on the choice of implantable cardioverter-defibrillator (ICD) type, use of defibrillation testing, and ICD programming for detection and therapy of ventricular arrhythmias. In accordance with recent guidelines and the results of observational studies, the majority of EHRA research network centres reported a high utilization rate of dual-chamber ICDs in the presence of symptomatic and asymptomatic sinus node dysfunction, biventricular ICD in high-degree atrioventricular block and QRS duration <120 ms, and a limited use of defibrillation testing either in primary and secondary prevention settings. Activation of the long ventricular tachycardia (VT) detection window, slow VT zone, antitachycardia pacing before shock for slow and fast VT, and atrial tachyarrhythmia discrimination were considered useful in ICD programming for the majority of patients.

Implantable cardioverter defibrillator system with floating atrial sensing dipole: a single-center experience.

The concept of a single-lead dual-chamber implantable cardioverter defibrillator (ICD) with floating sensing atrial dipole has been proven safe and functional. We report a single-center experience with this ICD system; the major focus of the work is on the recorded atrial activation and its stability on a medium term follow-up. Thirteen patients received a DX ICD (BIOTRONIK SE & Co, Berlin, Germany) with the Linox Smart S DX(ProMRI) ICD lead; the implantation data were reported. Daily P- and R-wave sensing amplitude was collected and followed up during 200 days; their coefficient of variance (CV) was calculated. In addition, all the atrial and ventricular high-rate episodes were analyzed. The total x-ray exposure time was 3.9 ± 1.8 minutes. The overall mean sensing was 4.2 ± 1.9 mV for P wave and 12.9 ± 4.5 mV for R wave. The CV was significantly higher for the P-wave amplitude than for the R-wave one (0.25 ± 0.11 vs 0.08 ± 0.06; P < 0.001). A total of 27 high ventricular rate episodes were recorded and correctly discriminated by the device. Fifty-six high atrial rate episodes were recorded, 49 were true arrhythmic events. The single-lead ICD system with floating atrial dipole provides reliable atrial sensing amplitude over time. The physician, without the implantation of an additional lead, has the atrial information that may be used for the discrimination of supraventricular tachyarrhythmia/ventricular tachycardia, for the early detection of atrial fibrillation episodes and for the evaluation of changes in the patient's heart status.

Superior vena cava syndrome in a 37-year-old woman with a cardioverter-defibrillator.

A 37-year-old woman was admitted to the cardiology department because of a clinical suspicion of superior vena cava (SVC) syndrome. This suspicion was based on anamnesis of decreased physical effort tolerance with recurrent facial and eyelid oedema, resistant to an antiallergic treatment. At the age of 16, the patient had been diagnosed as having hypertrophic obstructive cardiomyopathy. After one year, a dual-chamber pacemaker was implanted to decrease the maximum left ventricular outflow tract gradient. Sixteen years later, an implantable cardioverter-defibrillator (ICD) was implanted as primary sudden cardiac death (SCD) prevention due to the following risk factors: recurrent non-sustained ventricular tachycardia, persistent massive interventricular septum hypertrophy, and a family history of SCD. The former pacemaker unit was removed, but the two leads were left with distal tips localised in the right atrium and right ventricle and proximally cut off and secured in the area of the primary pacemaker cavity. The implantation of a dual-chamber ICD was complicated by pneumothorax. Next, in order to verify the diagnosis of SVC syndrome, phlebography of the intrathoracic venous system was performed. This confirmed the obstruction of both left and right subclavian vein, as well as of the SVC (Figs. 1, 2). This caused a collateral circulation through the thoracic wall venous system to develop. Additionally, all four leads of both the former and the current implantable devices were visualised, two of them being actively fixated in the right atrium and the right ventricle (Fig. 3). In transthoracic echocardiography, there was no thrombus visible in the right heart cavities and the echoes of hyperechogenic atrial and ventricular leads were visualised (Fig. 4). Due to the final diagnosis of SVC thrombosis, antithrombotic treatment was initiated — starting with a therapeutic dose of low molecular weight heparin followed by a vitamin K antagonist with target international normalised ratio ranged 2.5–3.0. In conclusion, redundant leads of electrotherapy devices left in the venous system can generate significant health complications. Careful consideration of indications for electrotherapy devices implantation may help prevent future complications, especially in young patients.

Pulmonary fluid overload monitoring in heart failure patients with single and dual chamber defibrillators

Heart failure has a relevant healthcare impact. Monitoring of pulmonary fluid overload (PFO), measured by intrathoracic impedance, has been proposed to alert to heart failure worsening before symptoms become patent. The aim of our research was to evaluate whether PFO diagnostics reduce heart failure hospitalizations in heart failure patients receiving single-chamber or dual-chamber implantable cardioverter-defibrillator (ICD) for primary prevention of sudden death. Twenty-five Italian cardiological centers prospectively followed 221 ICD patients (86% men, 66 ± 11 years, 79% New York Heart Association II and left ventricular ejection fraction 28 ± 5%), of whom 123 received an ICD with PFO monitoring (diagnostics group) and 98 an ICD without such a diagnostics (control group). The association of each patient to a group was assigned a priori, independently of patients' characteristics but based on regional device allocation policies. Patient clinical characteristics and observation period were similar between groups. In a mean follow-up of 17 ± 11 months, heart failure hospitalizations or emergency-room admissions occurred in eight (7%) patients of the diagnostics group and in 16 of the control group (16%; P = 0.02), with an incidence, measured by Kaplan-Meier analysis, of 23% at 2 years and 34% at 3 years in patients of the control group compared with 8% at 2 and 3 years in patients of the diagnostics group (Log rank test P = 0.044). Our data show that in heart failure patients receiving single-chamber or dual-chamber ICD, the use of intrathoracic impedance monitoring is associated with a significant reduction of heart failure hospitalizations. Our results support the hypothesis that PFO diagnostics improve the likelihood of timely detection of heart failure worsening.

COMPLETE HEART BLOCK AND SUBARACHNOID HEMORRHAGE: WHAT'S THE LINK?

Cardiac involvement of sarcoidosis occurs in 25% of patients. The most common manifestation is complete heart block (CHB) from granulomatous infiltration of the conduction system. A dual-chamber implantable cardioverter-defibrillator (ICD) is implanted for pacing and primary prevention of sudden