Long-Term Technical Performance of the Osypka QT-5® Ventricular Pacemaker Lead.

BACKGROUND: Lead-associated complications and technical issues in patients with cardiac implantable electronic devices are common but underreported in the literature. METHODS: All patients undergoing implantation of the Osypka QT-5® ventricular lead at the University Clinic St. Pölten between 1 January 2006 and 31 December 2012 were retrospectively analyzed (n = 211). Clinical data including pacemaker follow-up examinations and the need for lead revisions were assessed. Kaplan-Meier analysis to estimate the rate of lead dysfunction during long-term follow-up was conducted. RESULTS: Patients were followed for a median of 5.2 years (interquartile range (IQR) 2.0-8.7). R-wave sensing properties at implantation, compared to last follow-up, remained basically unchanged: 9.9 mV (IQR 6.8-13.4) and 9.6 mV (IQR 5.6-12.0), respectively). Ventricular pacing threshold significantly increased between implantation (0.5 V at 0.4 ms; IQR 0.5-0.8) and the first follow-up visit (1.0 V at 0.4 ms; IQR 0.8-1.3; p < 0.001) and this increase persisted throughout to the last check-up (0.9 V at 0.4 ms; IQR 0.8-1.2). Impedance significantly declined from 1142 Ω (IQR 955-1285) at implantation to 814 Ω (IQR 701-949; p < 0.001) at the first check-up, followed by a further decrease to 450 Ω (IQR 289-652; p < 0.001) at the last check-up. Overall, the Osypka QT-5® ventricular lead was replaced in 36 patients (17.1%). CONCLUSIONS: This report shows an unexpected high rate of technical issues of the Osypka QT-5® ventricular lead during long-term follow-up.

Clinical safety of ProMRI implantable cardioverter-defibrillator systems during head and lower lumbar magnetic resonance imaging at 1.5 Tesla.

Magnetic resonance imaging (MRI) has long been contraindicated in patients with implanted pacemakers, defibrillators, and cardiac resynchronisation therapy (CRT) devices due to the risk of adverse effects through electromagnetic interference. Since many recipients of these devices will have a lifetime indication for an MRI scan, the implantable systems should be developed as 'MRI-conditional' (be safe for the MRI environment under predefined conditions). We evaluated the clinical safety of several Biotronik ProMRI ('MRI-conditional') defibrillator and CRT systems during head and lower lumbar MRI scans at 1.5 Tesla. The study enrolled 194 patients at 22 sites in Australia, Canada, and Europe. At ≥9 weeks after device implantation, predefined, non-diagnostic, specific absorption rate (SAR)-intensive head and lower lumbar MRI scans (total ≈30 minutes per patient) were performed in 146 patients that fulfilled pre-procedure criteria. Three primary endpoints were evaluated: freedom from serious adverse device effects (SADEs) related to MRI and defibrillator/CRT (leading to death, hospitalisation, life-threatening condition, or potentially requiring implanted system revision or replacement), pacing threshold increase, and sensing amplitude decrease, all at the 1-month post-MRI clinical visit. No MRI-related SADE occurred. Lead values remained stable, measured in clinic and monitored daily by the manufacturer home monitoring technology.

Long-term performance of an atrial lead capable of accelerometer based detection of cardiac contractility in patients receiving cardiac resynchronisation therapy.

OBJECTIVES: To evaluate the long-term performance of the SonRtip atrial lead. BACKGROUND: To optimize atrioventricular and interventricular timing and thereby potentially improving cardiac resynchronization therapy (CRT) responder rates, a lead integrated technology and a cardioverter/defibrillator-based algorithm measuring peak endocardial acceleration have been introduced. Long-term performance of the atrial lead (SonRtip PS55D, Sorin/MicroPort CRM, Italy) embedded with such a sensor has not been reported so far. METHODS: Between 2012 and 2018, 143 patients underwent implantation of the SonRtip atrial lead in four Austrian medical centers. Conventional bipolar atrial leads implanted during the same period in 526 patients receiving CRT were used as control cohort. RESULTS: Among 669 patients included in the study, 10 (1.5%) showed increased atrial pacing thresholds and/or decreased atrial sensing amplitudes and/or sudden increase in atrial lead impedance (above 3000 Ω) after an uneventful early postoperative period. Seven (70%) of the malfunctioning leads were SonRtip leads (p <0.001). Lead replacement was needed in 4.2% of SonRtip leads (six out of 143) and in 0.38% of all other conventional atrial leads (two out of 526) (p <0.001). Because of unaltered atrial sensing properties, a wait and see strategy was chosen in two patients-one of them with a SonRtip lead. The implanted atrial lead in the latter person experienced a sudden increase in pacing threshold (4V/0.35ms). CONCLUSIONS: While short-term safety and stable technical performance of the SonRtip atrial lead could be confirmed, our study found an unexpectedly high malfunction rate over a longer follow-up period.

Clinical safety of the ProMRI implantable cardioverter-defibrillator systems during head and lower lumbar magnetic resonance imaging at 3 T: results of the ProMRI 3T ENHANCED Master study.

AIMS: There have been no published studies on the safety of magnetic resonance imaging (MRI) at 3 Tesla (3 T) in patients with MRI-conditional implantable cardioverter-defibrillators (ICDs). The aim of this study was to assess clinical safety of the Biotronik ProMRI ICD system during non-diagnostic head and lower lumbar scans under 3 T MRI conditions. METHODS AND RESULTS: The study enrolled 129 patients at 12 sites in Australia, Singapore, and Europe. Predefined head and lower lumbar MR scans (total duration ≈30 min) were performed in 112 patients. Three primary endpoints were evaluated from the pre-MRI to the 1-month post-MRI visit: (i) freedom from serious adverse device effects (SADEs) related to MRI (hypothesized to be >90%); (ii) pacing threshold invariance for all leads (geometric mean of the patient-wise ratios for 1 month vs. pre-MRI was hypothesized to be <1.07); and (iii) sensing amplitude invariance (geometric mean of the ratios was hypothesized to be >0.993). No MRI-related SADE occurred (SADE-free rate 100%, 95% confidence interval 95.98-100%). Pacing threshold and sensing amplitudes fulfilled the invariance hypotheses with high statistical significance (P < 0.0013). No threshold increase >0.5 V or sensing amplitude decrease by >50% was observed (secondary endpoints). Lead impedances, battery capacity, and detection and treatment of arrhythmias by ICDs were not affected by MRI scans. CONCLUSION: The head and lower lumbar scans under specific 3 T MRI conditions were safe in the investigated MR-conditional ICD systems. There was no evidence of harm to the patients or any negative influence of the MRI scan on the implanted systems.

A detailed view on pacemaker lead parameters remotely transmitted after magnetic resonance.

BACKGROUND: The purpose of this study was to analyze potential influences of magnetic resonance (MR) on the course of automatically device-based assessed lead parameters remotely transmitted in patients who were implanted with MR-conditional permanent pacemakers (PMs) and who had nondiagnostic brain and lumbar spine MR (1.5T) within the ProMRI single center pilot study. METHODS: The ProMRI study evaluated the feasibility of the Evia PMs with Safio S leads (Biotronik SE&Co KG, Berlin, Germany) in the MR environment. All patients were equipped with remote monitoring on the day of MR. Atrial (RA) und ventricular (RV) lead parameters (sensing, pacing capture threshold [PCT], pacing impedance) were automatically assessed and remotely transmitted on a daily or event-triggered basis for 3 months post MR. Remotely transmitted data were normalized for potential differences between at-daytime (in-office) and at-night-time (remotely) assessed parameters using the 1-month follow-up data for each patient. Confidence intervals of continuous data were calculated day-wise with one sample t-tests of post-MR/pre-MR differences, respectively. RESULTS: A total of 2,428 data sets (mean 80 ± 20 per patient) were transmitted. Mean values for the different lead parameters were (RA/RV) 3.3 ± 2.0/14.4 ± 6.9 mV for sensing, 0.65 ± 0.17/0.78 ± 0.23 V/0.4 ms for PCT, and 516 ± 60/607 ± 47 Ω for pacing impedance. No significant differences were found compared with pre-MR measurements. No atrial PCT increases ≥0.5 V compared with pre-MR were observed, and in only one patient the ventricular PCT increased by ≥0.5 V from day 76 post-MR, presumably based on new antiarrhythmic therapy with amiodarone. CONCLUSION: Our analyses of automatically assessed and remotely transmitted PM lead parameters after MR show that sensing amplitudes, PCTs, and pacing impedances are not affected in a clinically relevant way by MR.

Reel syndrome in an ICD with DF4 connector.

This is the first case report about a patient implanted with a DF4 lead suffering from reel syndrome. The reel syndrome may occur due to a ratchet mechanism where the device generator creates torque on a lead fixed at the fixation sleeve. Theoretically, this is less likely to occur in DF4 connectors due to their higher stiffness.

Safe performance of magnetic resonance of the heart in patients with magnetic resonance conditional pacemaker systems: the safety issue of the ESTIMATE study.

BACKGROUND: No published data exist about the safety of diagnostic magnetic resonance (MR) of the heart performed in a larger series of patients implanted with MR conditional pacemakers (PM). The purpose of our study is to analyse safety and potential alterations of electrical lead parameters in patients implanted with the EnRhythm/Advisa MRI SureScan PM with 5086MRI leads (Medtronic Inc.) during and after MR of the heart at 1.5 Tesla. METHODS: Patients enrolled in this single center pilot study who underwent non-clinically indicated diagnostic MR of the heart were included in this analysis. Heart MR was performed for analyses of potential changes in right and left ventricular functional parameters under right ventricular pacing at 80 and 110 bpm. Atrial/ventricular sensing, atrial/ventricular pacing capture threshold [PCT], and pacing impedances were assessed immediately before, during, and immediately after MR, as well at 3 and 15 months post MR. RESULTS: Thirty-six patients (mean age 69 ± 13 years; high degree AV block 18 [50%]) underwent MR of the heart. No MR related adverse events occurred during MR or thereafter. Ventricular sensing differed significantly between the FU immediately after MR (10.3 ± 5.3 mV) and the baseline FU (9.8 ± 5.3 mV; p < 0.05). Despite PCT [V/0.4ms] was not significantly different between the FUs (baseline: 0.84 ± 0.27; in-between MR scans: 0.82 ± 0.27; immediately after MR: 0.84 ± 0.24; 3-month: 0.85 ± 0.23; 15-month: 0.90 ± 0.67; p = ns), 7 patients (19%) showed PCT increases by 100% (max. PCT measured: 1.0 V) at the 3-month FU compared to baseline. RV pacing impedance [Ω/5V] differed significantly at the FU in-between MR scans (516 ± 47), and at the 15-month FU (482 ± 58) compared to baseline (508 ± 75). CONCLUSION: The results of our study suggest MR of the heart to be safe in patients with the MR conditional EnRhythm/Advisa system, albeit although noticeable but clinically irrelevant ventricular PCT changes were observed.

Implantable defibrillators with enhanced detection algorithms: detection performance and safety results from the PainFree SST study.

BACKGROUND: Implantable defibrillators (ICD) are highly effective in reducing arrhythmia-related mortality. ICD shock therapy has been shown to increase psychological distress, health care utilization, and is associated with increased mortality. The Protecta ICDs (Medtronic Inc., Minneapolis, MN, USA) have algorithms designed to reduce unnecessary and inappropriate shock therapy. METHODS AND RESULTS: The PainFree SmartShock™ Technology (PainFree SST) study is a prospective, multicenter, clinical trial with two consecutive phases, a premarket phase safety study and a postmarket phase effectiveness study. We report the results of the PainFree SST safety study. The premarket phase aimed to investigate safety in the first year postimplant, and to determine if the novel algorithms (T-wave discrimination, right ventricular lead noise discrimination and confirmation+) affect appropriate ventricular fibrillation (VF) detection. Patients (total: n = 246 [male 78%, mean age 63 year, primary prevention indication in 76%]) were implanted either with a Protecta XT dual-chamber ICD (n = 114 [46%]) or a defibrillator with cardiac resynchronization therapy (n = 132 [54%]). Appropriate VF detection was measured during VF induction at implantation when the novel algorithms were programmed ON. A two-second delay in VF detection was classified as clinically significant. No delay in VF detection was observed with all algorithms programmed ON. No unanticipated serious adverse device effects occurred during first year postimplant. CONCLUSION: The results of the premarket phase of the PainFree SST trial demonstrate the safety of the Protecta XT defibrillators. Detection of induced VF was not delayed with SmartShock™ algorithms ON.

Benefit of immediate beta-blocker therapy on mortality in patients with ST-segment elevation myocardial infarction.

OBJECTIVES: Despite the recommendations to initiate ß-blockade to all patients with an ST-segment elevation myocardial infarction, data concerning the timing of the administration of ß-blockers are controversially discussed. In view of these controversies, we analyzed the effect of immediate vs. delayed ß-blockade on all-cause mortality of patients with ST-segment elevation myocardial infarction in the Lower Austrian Myocardial Infarction Network. DESIGN: Nonrandomized, prospective observational cohort study. SETTING: Myocardial infarction network including the out-of-hospital emergency services, five primary-care hospitals and a percutaneous coronary intervention-capable hospital in the western part of Lower Austria. PATIENTS: The data of all patients with ST-segment elevation myocardial infarction defined according to the American Heart Association criteria and treated according to the treatment protocol of the network were consecutively collected. For the purpose of survival analyses, the baseline survival time was set to 48 hours after the first electrocardiogram, and in all patients with recurrent MI within the observational period, only the first MI was regarded. INTERVENTIONS: The treatment protocol recommended either the immediate oral administration of 2.5 mg bisoprolol (within 30 min after the first electrocardiogram) or 24 hours after acute myocardial infarction (delayed ß-blockade). MEASUREMENTS AND MAIN RESULTS: In total, out of the 664 patients with ST-segment elevation myocardial infarction, 343 (n = 52%) received immediate ß-blockade and 321 (48%) received delayed ß-blockade. The probability of any death (baseline survival time: 48 hours after first electrocardiogram; 640 patients) was 19.2% in the delayed treatment group and 10.7% in the immediate treatment group (p = 0.0022). Also the probability of cardiovascular mortality was significantly lower in the immediate ß-blocker treatment group (immediate treatment group: 9 (5.2%); delayed treatment group: 30 (13.4%); p = 0.0002). Multivariable Cox regression analysis identified immediate ß-blocker therapy to be independently protective against death of any cause (odds ratio: 0.55, p = 0.033). CONCLUSION: Immediate ß-blocker administration in the emergency setting is associated with a reduction of all-cause and cardiovascular mortality in patients with ST-segment elevation myocardial infarction and seems to be superior to a delayed ß-blockade in our patient cohort.

T-wave integral: an electrocardiographic marker discriminating patients with arrhythmogenic right ventricular cardiomyopathy from patients with right ventricular outflow tract tachycardia.

AIMS: Clinical and electrocardiographic (ECG) presentation of patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) and idiopathic right ventricular outflow-tract tachycardia (RVOT) may be similar. The aim of the study was to assess the validity and utility of T-wave integral measurement as an ECG discriminator of patients with ARVC and RVOT using a body surface mapping (BSM). METHODS AND RESULTS: A 120-channel BSM with quantitative signal analysis of the T-wave integral was performed in 10 patients with ARVC. Results were compared with those obtained from 13 patients with RVOT and a control group of 12 healthy subjects (controls). Age, body mass index, and QRS-axis on surface ECG were not significantly different between the groups. Arrhythmogenic right ventricular cardiomyopathy patients showed a significantly negative T-wave integral in the right lower anterior region of the torso when compared with RVOT (P < 0.001). There was no statistically significant difference between RVOT patients and controls. At a cut-off level of -0.3 mV ms, sensitivity and specificity were 83% [area under curve (AUC) 0.85 ± 0.04 for the comparison of ARVC and RVOT]. These differences were pronounced in ARVC patients with a plakophlin-2 mutation (P < 0.001). CONCLUSION: Quantitative analysis of the BSM T-wave integral in distinct anatomical regions discriminates ARVC patients from RVOT patients and controls and may serve as an additional diagnostic tool.

Monocenter feasibility study of the MRI compatibility of the Evia pacemaker in combination with Safio S pacemaker lead.

BACKGROUND: The purpose of this study was to evaluate the feasibility of the magnetic resonance (MR) conditional pacemaker (PM) system (Evia SR-T and DR-T with Safio S leads) under MR conditions. METHODS: Patients with standard PM indications and Evia PM were eligible for enrollment in this single center prospective non-randomized pilot study. Patients underwent MR of the brain and lower lumbar spine at 1.5 Tesla. Atrial (RA) und ventricular (RV) lead parameters (sensing, pacing threshold [PTH], pacing impedance) were assessed immediately before (baseline follow-up [FU]) and immediately after MRI (1st FU), after 1 month (2nd FU) and 3 months (3rd FU). The effect of MR on serious adverse device effect (SADE) free-rate, on atrial and ventricular sensing (AS/VS; mV) and atrial (RA) and ventricular (RV) pacing thresholds (PTH; V/0.4 ms) were investigated between baseline and 2nd FU. Continuous variables are expressed as mean ± SD and were compared using paired Student's t-test. A p < 0.05 was considered significant. RESULTS: Thirty-one patients were enrolled. One patient had to be excluded because of an enrollment violation. Therefore, data of 30 patients (female 12 [40%], age 73 ± 12 years, dual chamber PM 15 [50%]) were included in this analysis. No MR related SADE occurred. Lead measurements were not statistically different between the baseline FU and the 2nd FU (AS/VS at baseline 3.2 ± 2.1/15.0 ± 6.0, at 2nd FU 3.2 ± 2.1/14.9 ± 6.5; p = ns. RA-PTH/RV-PTH at baseline 0.68 ± 0.18/0.78 ± 0.22, at 2nd FU 0.71 ± 0.24/0.78 ± 0.22; p = ns). The presence of the permanent pacemakers led to MR imaging artifacts on diffusion weighted sequences of the brain, but did not affect other sequences (e.g. FLAIR and T2 weighted spin-echo images). CONCLUSION: The use of the MR conditional Evia PM in a MR environment under predefined conditions is feasible. No MR related SADEs nor clinically relevant changes in device functions occurred.

Cardiac sympathetic dysfunction in genotyped patients with arrhythmogenic right ventricular cardiomyopathy and risk of recurrent ventricular tachyarrhythmias.

UNLABELLED: Patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) typically present with ventricular tachyarrhythmias preferentially triggered by an elevated sympathetic tone. Previous studies demonstrated an impairment of the presynaptic catecholamine reuptake as assessed by (123)I-labeled norepinephrine analog on metaiodobenzylguanidine ((123)I-MIBG) SPECT. Mutations in the gene encoding for plakophilin-2 (PKP-2) are the most common cause of autosomal dominant ARVC (ARVC-9). In this study, we investigated the potential role of adrenergic dysfunction on the arrhythmia profile in patients with ARVC and correlated these findings with the causative genotype. METHODS: (123)I-MIBG SPECT was performed for 42 patients with definite ARVC (10 women, 32 men; mean age ± SD, 43 ± 14 y). Images were acquired at 4 h after injection and analyzed for regional (123)I-MIBG uptake in a standardized 33-segment polar map. Results were compared with those obtained from 10 control subjects (5 women, 5 men; mean age ± SD, 43 ± 12 y). RESULTS: An abnormal tracer uptake was detected in 25 patients with ARVC (59%). The extents of right ventricular dilation and regional wall motion abnormalities as well as electrocardiographic markers of de- or repolarization were not significantly different between patients with normal and abnormal (123)I-MIBG SPECT findings. However, during long-term follow-up of 11.9 ± 4.1 y, patients with abnormal (123)I-MIBG SPECT findings experienced life-threatening ventricular tachyarrhythmias significantly more often (22/25 patients [88%]) and independent of the extent of right ventricular dysfunction than those with a normal sympathetic innervation (6/17 patients [35%]; P < 0.0005). Mutations in PKP-2 were identified in 17 patients (40%) but were not correlated with the degree of adrenergic dysfunction. CONCLUSION: In patients with ARVC, an impairment of adrenergic innervation independent of the underlying genotype is associated with a higher incidence for future recurrences of ventricular tachyarrhythmias. This finding may suggest a potential role of (123)I-MIBG SPECT for individualized risk stratification in ARVC patients and asymptomatic PKP-2 mutation carriers alike.

A 2-year survey of treatment of acute atrial fibrillation in an ED.

OBJECTIVE: Pharmacologic cardioversion of atrial fibrillation (AF) is a reasonable mode of treatment if the arrhythmia is of recent onset. Results concerning the response rates of different drugs, respectively, in daily clinical practice and data with regard to the parameters associated with successful cardioversion are not very prevalent. METHODS: Three-hundred seventy-six patients who were admitted to the emergency department with acute AF and a duration of shorter than 48 hours were enrolled into the AF registry. RESULTS: The most effective drugs were flecainide and ibutilide (95% and 76%). Low response rates were observed with amiodarone (36%) and the individual use of digoxin or diltiazem (19% and 18%). Factors associated with a successful cardioversion were a lower blood pressure on admission (P = .002), a shorter time interval between the onset of AF and admission to the ED (P = .003), and adherence to treatment guidelines (P < .0001). CONCLUSION: The use of flecainide and ibutilide is associated with a much higher rate of cardioversion than other drugs we studied.

Explantation of implantable defibrillator leads using open heart surgery or percutaneous techniques.

BACKGROUND: To remove failing or infected implantable cardioverter defibrillator leads, percutaneous techniques and open heart surgery are two common approaches. However, well-defined indications for either technique are not available. We summarize our experience with implantable cardioverter defibrillator system explantation using open heart surgery and percutaneous lead removal. METHODS: A total of 1,391 transvenously introduced implantable cardioverter defibrillator systems were implanted during the analyzed time interval from January 1995 to June 2005 in our institution. In 21 patients (1.5%), open heart surgery for implantable cardioverter defibrillator lead and generator explantation was applied (group A), and in 53 patients (3.8%), a percutaneous lead removal was possible (group B). The log-rank test was used to calculate differences in survival between both patient groups, and the Student's t test was applied for differences in nonlethal complications. RESULTS: The 30-day, 6-month, 12-month, and 5-year survival rates were 91%, 91%, 81%, and 71%, respectively, for group A patients, and 100%, 100%, 94%, and 78%, respectively, for group B patients, which was not statistically different (p = 0.11). After open heart surgery, survival was comparable for cases with lead removal because of lead infection and those with lead malfunction (p = 0.28); however, patients with open heart surgery had a longer hospital stay (p = 0.03). Student's t test revealed no statistical difference in nonlethal complications between both patient groups (p = 0.37). CONCLUSIONS: As open heart surgery yielded similar results with regard to survival and complications, implantable cardioverter defibrillator lead removal using extracorporeal circulation may be well justified as a last therapeutic option, eg, in case of large bacterial vegetations.

[ICD lead defects: diagnosis and therapeutical options]. / Diagnostik und Therapie von ICD-Elektrodendefekten.

The number of cardioverter/defibrillator (ICD) implantations has been steadily increasing; thus, ICD lead-associated complications are an important issue. No clear recommendations for the diagnosis and management are available. This article gives an overview of how to diagnose and manage an ICD lead defect. Possible therapeutic options are discussed by reviewing the literature.

Two different therapeutic strategies in ICD lead defects: additional combined lead versus replacement of the lead.

OBJECTIVES: Implantation of an additional HV-P/S lead versus extraction of the defective HV-P/S lead and implantation of a new one is one possible therapeutic approach in cases of a defective high-voltage pace/sense lead (HV-P/S). No information is available on potential differences in clinical outcome in these different approaches. METHODS: Between January 2000 and February 2006, 86 patients with HV-P/S lead defect received either an additional transvenous HV-P/S lead (n = 33, group 1) or the HV-P/S lead was replaced (n = 53, group 2). The duration of the initially implanted leads was significantly different in the two groups (7.4 +/- 2.9; group 1 and 4.1 +/- 3.4 years; group 2). The outcome of these two groups of patients was retrospectively analyzed. RESULTS: Seventy-three patients [85%] survived until the end of follow-up of 29 +/- 15 (group 1) and 33 +/- 21 (group 2) months (P = ns), respectively. Thirteen patients died: six in group 1 and seven in group 2 (P = ns). Fourteen patients experienced perioperative complications (group 1: six; group 2: eight; P = ns). ICD system-related complications occurred in 22 patients (group 1: seven; group two: 15; P = ns). The event-free cumulative survival of patients with additional and replaced HV-P/S lead for postoperative events (including death) after 1, 2, and 3 years was 82%, 70%, 70%, and 86%, 81%, 66%, respectively (P = 0.93). CONCLUSIONS: Implantation of an additional HV-P/S lead or replacement of the HV-P/S lead in case of HV-P/S lead failure is statistically not different concerning mortality and morbidity. There are no predictors for further lead defects. Implantation of an additional HV-P/S lead should not be recommended in young patients or patients with greater likelihood of living many years. Predictors for death were an age over 70 years and renal insufficiency.

Reduction of ventricular tachyarrhythmia by treatment of atrial fibrillation in ICD patients with dual-chamber implantable cardioverter/defibrillators capable of atrial therapy delivery: the REVERT-AF Study.

AIMS: The purpose of this prospective, randomized, multicentre study was to investigate whether the incidence of ventricular tachyarrhythmia can be reduced in standard implantable cardioverter/defibrillator (ICD) patients by implanting a dual-chamber ICD capable of atrial therapy delivery. METHODS AND RESULTS: A Jewel AF or GEM III AT ICD (Medtronic Inc., Minneapolis, MN, USA) was implanted in 122 patients (62.3 +/- 10.5 years; 84.4% male; coronary artery disease 71.3%; left ventricular ejection fraction 39.7 +/- 13.6%; secondary ICD indication 91%). Overall, 31.2% of the patients had paroxysmal atrial fibrillation (AF)/atrial tachycardia (AT) before ICD implantation (n = 38). Implantable cardioverter/defibrillator therapies for AT/AF were activated and de-activated every 3 months in a cross-over study design. The mean follow-up was 18.5 +/- 7.7 months (6.29 +/- 2.2 cross-over/patient). Overall, there were 684 episodes of ventricular tachyarrhythmias in 48.4% of patients (n = 59). In 33.6% of patients (n = 41), 532 supraventricular tachyarrhythmias occurred. Activation of ICD therapies for AT/AF did not result in a reduction of ventricular tachyarrhythmias (P = 0.92). Patients with monomorphic ventricular tachycardias (mVTs) as index arrhythmia for ICD implantation or inducible mVTs in the electrophysiological study had the highest probability of recurrences of ventricular tachyarrhythmias. CONCLUSION: For patients with standard indications for ICD therapy and no indication for cardiac pacing, a dual-chamber ICD capable of atrial tachyarrhythmia treatment offers no benefit concerning a reduction of ventricular tachyarrhythmias.

Near fatal arrhythmia induction by an implantable cardioverter defibrillator.

Sudden death among implantable cardioverter defibrillator (ICD) recipients is well known. The underlying mechanism remains unclear in most cases. One possible mechanism is an accidentally induced arrhythmia by the ICD itself. This report describes for the first time a case of a life-threatening ventricular arrhythmia induced by a specific algorithm for ventricular arrhythmia reconfirmation before shock delivery in a fourth-generation ICD.

Incidence of complications in patients with implantable cardioverter/defibrillator who receive additional transvenous pace/sense leads.

BACKGROUND: Implantation of an additional pace/sense (P/S) lead is commonly used in patients with implantable cardioverter/defibrillators (ICDs) to overcome P/S defects of integrated defibrillation leads (HV-P/S leads). No information is available about the clinical outcome and the incidence of complications in these patients. METHODS: Retrospective analysis was performed in 151 patients (125 male, age 54.9 +/- 13.6 years, LVEF 48.1 +/- 17.8%, CAD in 86 [57%], DCM in 24 [16%], ARVCM in 11 [7%]) who received an additional P/S lead between 1990 and 2002 (54 patients with abdominal and 97 patients with pectoral ICD system). Statistical analysis was done using Kaplan-Meier survival curves. RESULTS: The average follow-up (FU) after implantation of the additional P/S lead was 43 +/- 27 months. In total 117 patients [77.5%] remain implanted; 22 patients died due to cardiac-related reasons. After a FU of 23 +/- 23 months, 43 patients [28.5%] experienced lead-related problems after implantation of the additional P/S lead: oversensing in 23 [53.5%], insulation defect in 3 [7.0%], fracture in 1 [2.3%], system infection in 4 [9.3%], and defect of the HV-P/S lead in 6 [14.0%] patients. The event-free cumulative survival of the additional P/S lead after 1, 2, and 5 years was 87.0%, 79.8%, and 59.4%, respectively (for pectoral leads: 89.6%, 82.0%, and 60.0%, respectively). CONCLUSIONS: Implantation of an additional P/S lead in case of failure of an HV-P/S lead is safe. However, it is associated with a substantial rate of complications during FU. Therefore, extraction of damaged defibrillation leads instead of implantation of P/S leads should be favored.

Comparison of induced and spontaneous atrial tachyarrhythmias in patients with a history of spontaneous atrial tachyarrhythmias.

INTRODUCTION: This retrospective study investigated whether induced episodes could be used to predict the morphology of future spontaneous atrial episodes. METHODS: Eighty-two patients (64 +/- 12 years; 77% male; CAD in 60%; left ventricular ejection fraction 45 +/- 16%) with a history of atrial tachycardia or atrial fibrillation (AT/AF) were implanted with a dual-chamber implantable cardioverter defibrillator (ICD) and followed for 6 months. A total of 224 episodes of induced and spontaneous AT/AF were classified into type I, II, and III according to the method of Israel et al. and then compared based on average cycle length (CL) and atrial amplitude. Episodes were also grouped as "pace-terminable" or "nonpace-terminable" based on the CL definition of Gillis et al. RESULTS: The analysis of 121 induced episodes (from 80 patients) and 103 spontaneous episodes (from 43 patients) showed that within each arrhythmia type, there were no significant differences in CL or mean amplitude between induced and spontaneous episodes. Additional analysis of patients that had both induced and spontaneous episodes (n = 41) showed 78% had at least one spontaneous episode that matched the induced episode. Fifty-seven percent of spontaneous episodes were considered to be pace-terminable based on CL. CONCLUSIONS: Our data suggest that there is no significant difference between induced and spontaneous episodes of AT/AF of the same type. The majority of patients had at least one spontaneous episode of the same type as the induced episode, showing that induced atrial arrhythmias may be useful in predicting the morphology of future spontaneous episodes and in identifying patients potentially benefiting from atrial antitachycardia pacing.