Elevated Defibrillation Threshold Research Articles

EFFICACY AND SAFETY OF THE SUBCUTANEOUS IMPLANTABLE CARDIOVERTER-DEFIBRILLATOR IN PATIENTS WITH AND WITHOUT OBESITY: A META-ANALYSIS

The subcutaneous implantable cardioverter-defibrillator (S-ICD) has emerged as an alternative to transvenous systems for preventing sudden cardiac death. However, concerns have been raised regarding its efficacy and safety in obese individuals. This meta-analysis aims to evaluate the efficacy and safety of the S-ICD in patients with obesity by assessing the relationship between body mass index (BMI) and clinical outcomes. A comprehensive search of multiple databases was conducted for English-language peer-reviewed studies reporting clinical outcomes in S-ICD recipients with (BMI ≥30 kg/m2) and without obesity (BMI <30 kg/m2). Data on pre-implantation screening failure, defibrillation testing, complications, appropriate and inappropriate shocks, and survival were analysed using standard random-effect meta-analytical techniques. Twenty-nine studies involving 20,486 patients were included. There was no statistically significant difference in the mean BMI values of patients with failed or successful preimplantation screening (mean difference -0.60 kg/m2, 95% CI -2.06 to 0.86). Obesity was associated with higher rates of failed defibrillation testing at ≤65J (OR 2.16, 95% CI 1.39-3.35), and mal-/suboptimal positioning occurred more frequently in obese compared to non-obese patients (OR 3.37, 95% CI 1.76-6.44). Increased BMI as a continuous variable (per increase in 1 kg/m2 BMI) was associated with elevated defibrillation thresholds (OR 1.05, 95% CI 1.03-1.08), a higher risk of complications (HR 1.04, 95% CI 1.02-1.05), a trend towards increased number of appropriate shocks (HR 1.02, 95% CI 1.00-1.04), and no significant increase in the risk for inappropriate shocks (HR 1.01, 95% CI 0.99-1.03). This meta-analysis underscores the importance of considering obesity in S-ICD implantation decisions. While S-ICD remains effective in obese patients, attention to potential technical challenges and higher complication rates is warranted.

Additional coils mitigate elevated defibrillation threshold in right-sided implantable cardioverter defibrillator generator placement: a simulation study.

The standard implantable cardioverter defibrillator (ICD) generator (can) is placed in the left pectoral area; however, in certain circumstances, right-sided cans may be required which may increase defibrillation threshold (DFT) due to suboptimal shock vectors. We aim to quantitatively assess whether the potential increase in DFT of right-sided can configurations may be mitigated by alternate positioning of the right ventricular (RV) shocking coil or adding coils in the superior vena cava (SVC) and coronary sinus (CS). A cohort of CT-derived torso models was used to assess DFT of ICD configurations with right-sided cans and alternate positioning of RV shock coils. Efficacy changes with additional coils in the SVC and CS were evaluated. A right-sided can with an apical RV shock coil significantly increased DFT compared to a left-sided can [19.5 (16.4, 27.1) J vs. 13.3 (11.7, 19.9) J, P < 0.001]. Septal positioning of the RV coil led to a further DFT increase when using a right-sided can [26.7 (18.1, 36.1) J vs. 19.5 (16.4, 27.1) J, P < 0.001], but not a left-sided can [12.1 (8.1, 17.6) J vs. 13.3 (11.7, 19.9) J, P = 0.099). Defibrillation threshold of a right-sided can with apical or septal coil was reduced the most by adding both SVC and CS coils [19.5 (16.4, 27.1) J vs. 6.6 (3.9, 9.9) J, P < 0.001, and 26.7 (18.1, 36.1) J vs. 12.1 (5.7, 13.5) J, P < 0.001]. Right-sided, compared to left-sided, can positioning results in a 50% increase in DFT. For right-sided cans, apical shock coil positioning produces a lower DFT than septal positions. Elevated right-sided can DFTs may be mitigated by utilizing additional coils in SVC and CS.

Ineffective implantable cardioverter-defibrillator shocks among patients on continuous left ventricular assist device support: Clinical characteristics and management.

BackgroundPlacement of a left ventricular assist device (LVAD) has been described to compromise implantable cardioverter-defibrillator (ICD) defibrillation threshold (DFT). Elevated DFT will have negative consequences and increases the risk of ineffective ICD shocks, morbidity, and mortality. DFT testing is not routinely performed in clinical practice, despite this fact.ObjectiveWe describe the clinical characteristics of 7 LVAD patients who presented with multiple ineffective ICD shocks, along with the management strategy in such patients.MethodsSeven patients (5 male, mean age 52.2 ± 9 years, 85.7% nonischemic cardiomyopathy) with an ICD in situ who progressed to NYHA class IV, ACC/AHA stage D chronic systolic congestive heart failure who underwent successful LVAD implantation presented to our institution in the setting of ventricular tachyarrhythmia and ineffective ICD shocks. Six patients underwent implantation of azygos and subclavian coils with subsequent DFT testing. The remaining patient was made comfort care.ResultsFive patients had successful DFT testing with azygos (n = 4) and subclavian (n = 1) defibrillation coil implantation. One patient had unsuccessful DFT testing despite evaluation of multiple shock vectors. There were no major or minor vascular complications in any of the cases. There were no procedural-related deaths.ConclusionThis case series highlights the need for a systematic approach to management of ICDs and DFT testing in LVAD patients. The addition of new shock vectors with azygos and subclavian coil implantation may reduce DFT, shock burden, morbidity, and mortality.

Coronary vein defibrillator coil placement in patients with high defibrillation thresholds.

BackgroundElevated defibrillation threshold (DFT) occurs in 2%‐6% of patients undergoing implantable cardioverter defibrillator (ICD) implantation. Adding a defibrillation coil in the coronary sinus (CS) or its branches can result in substantial reductions in the mean DFT. However, data regarding acute success and long‐term stability remain lacking. We report our experience with this bailout strategy.MethodsPatients with elevated DFT at implantation (safety margin at implantation <10 J) and those with failed ICD shocks for ventricular arrhythmias (VA) referred for high DFT underwent placement of an additional defibrillation coil in the CS. DFT testing was performed at the completion of the implantation procedure. External potentially reversible factors were excluded. High‐output devices were systematically used.ResultsFour patients with high DFT at implantation and two with several failed shock attempts underwent placement of a defibrillation coil in the CS. Mean age was 41.8 (23‐78). They presented a mean LVEF of 21% (15‐30), QRS‐complex duration of 109.8 milliseconds (87‐168), body surface area of 1.96 m2 (1.45‐2.58), and a mean R wave of 16.3 mV (8‐27). Defibrillation coil implantation in the CS (final shocking configuration of right ventricle as anode and left ventricle (LV) plus can as cathode) was associated with successful DFT testing in all. Three patients had a concomitant LV lead for biventricular pacing. During a mean follow‐up of 54.67 months (10‐118), two patients experienced successful ICD shocks for VA (one of them also presented inappropriate shocks because of the fast conducting atrial fibrillation).ConclusionsPositioning of a defibrillation coil in the CS can result in a substantial reduction in mean DFT and associates with optimal long‐term stability.

Predictors of Elevated Defibrillation Threshold with the Subcutaneous Implantable Cardioverter-defibrillator.

There are limited data regarding defibrillation thresholds (DFTs) for the subcutaneous implantable cardioverter-defibrillator (S-ICD), and factors associated with elevated DFTs remain incompletely understood. The objective of this study was to determine the factors associated with elevated DFTs in patients undergoing S-ICD implantation. A retrospective cross-sectional analysis of all patients undergoing S-ICD implantation at our institution between 2013 and 2016 who underwent step-down DFT testing was performed. Factors associated with a higher DFT were analyzed. In total, 56 patients (mean age: 49.3 ± 13.1 years, mean left ventricular ejection rate: 31.1% ± 13.7%) underwent S-ICD implantation in the study period. Full DFT testing was performed in 31 of the 56 patients (55%), with an average DFT of 46.4 joules (J) ± 25.9 J found among this cohort. The DFT was > 65 J in five of the 31 patients (16%). A high DFT was associated with increased body mass index (BMI) (37.7 kg/m2 versus 29.4 kg/m2; p = 0.02) and either increased septal or posterior wall thickness (1.5 cm versus 1.0 cm; p = 0.0003 and 1.4 cm versus 1.1 cm; p= 0.003, respectively). Patients with high DFTs also had higher failed shock impedance values (138 Ω versus 71 Ω; p = 0.005). Renal failure did not appear to affect DFT (51.4 J versus 51.7 J; p = 0.99). BMI, body surface area (BSA), and septal and posterior left ventricular wall thickness predicted elevated DFT on univariate analysis, although findings were not significant with multivariate analysis due to the small sample size. Thus, elevated S-ICD DFT appears to be associated with increased BMI, BSA, and septal or posterior wall thickness. In contrast, dialysis-dependent renal failure is not associated with elevated DFT. Further investigation is necessary in order to better characterize and predict which patients are at-risk for high DFTs.

Implantable cardioverter–defibrillator therapy in hypertrophic cardiomyopathy: A SIMPLE substudy

Patients with hypertrophic cardiomyopathy (HCM) are considered to be at high risk for elevated defibrillation thresholds, periprocedural complications, and failed appropriate shocks. The purpose of this study was to determine the value of defibrillation testing (DT) in HCM patients undergoing implantable cardioverter-defibrillator (ICD) insertion. Defibrillation thresholds, perioperative complications, and long-term outcomes were compared between patients with HCM and those with ischemic cardiomyopathy (ICM) or dilated cardiomyopathy (DCM) enrolled in the SIMPLE (Shockless IMPLant Evaluation) trial (Clinialtrials.gov Identifier: NCT00800384). In patients with HCM, outcomes were also compared between those randomized to DT vs no DT. Adequate defibrillation safety margin without system change was achieved in 46 of 52 (88.5%) HCM and 948 of 1047 (90.5%) ICM/DCM patients (P = .63). Perioperative complications occurred in 1 of 52 (1.9%) HCM patients with DT compared to 67 of 1047 (6.4%) ICM/DCM patients with DT (P = .37) or 3 of 42 (7.1%) HCM patients without DT (P = .32). During follow-up, there was no significant difference between HCM vs ICM/DCM patients in terms of all-cause mortality (adjusted hazard ratio [HR] 1.02, 95% confidence interval [CI] 0.45-2.34), composite of arrhythmic death or failed appropriate shock (adjusted HR 0.33, 95% CI 0.04-2.42), inappropriate shocks (adjusted HR 1.64, 95% CI 0.69-3.89), or system complications (adjusted HR 1.93, 95% CI 0.88-4.27). All-cause mortality (HR 0.26, 95% CI 0.03-2.20), appropriate (HR 0.24, 95% CI 0.03-2.05), and inappropriate shocks (HR 2.13, 95% CI 0.51-8.94) were similar in HCM patients without or those with DT. We did not find any difference in intraoperative defibrillation efficacy, perioperative complications, and long-term outcomes between patients with HCM and those with ICM/DCM. DT did not improve intraoperative or clinical shock efficacy in HCM patients.

Higher defibrillation threshold in methamphetamine cardiomyopathy patients with implantable cardioverter-defibrillator

IntroductionIdentification of patients with an increased risk of high defibrillation thresholds (DFTs) is important in planning implantable cardioverter-defibrillator (ICD) procedures. Clinical observations have suggested that patients with methamphetamine cardiomyopathy (MACMP) have significantly elevated defibrillation thresholds. We hypothesized that MACMP patients would have higher DFT thresholds than controls and would require procedural changes during ICD implantation to accommodate higher thresholds. MethodsWe identified consecutive patients with MACMP undergoing ICD implantation at the academic center from 2003 to 2007. We then compared DFTs against age-and sex-matched controls. ResultsThe MACMP (n = 10) group showed significantly increased DFT thresholds (23.7 ± 6.7 J) compared with age and sex-matched controls (14.5 ± 4.6 J, p < 0.005). Additionally, patients with MACMP had evidence of more severe congestive heart failure, with increased B-type natrieutic protein (BNP) levels (1173 ± 784 vs 260 ± 349, p = 0.02) and decreased left ventricular ejection fraction (LVEF) (17.8 ± 9.4 vs 35.9 ± 15.2, p = 0.02). MACMP patients required high output devices than controls (50% versus 0%, p = 0.03). Differences between groups remained significant despite adjusting for LVEF. ConclusionsPlanning for ICD implantation should take into consideration a history of methamphetamine abuse, mandating DFT testing and empiric consideration of high output devices for such patients.

Wszczepialne kardiowertery-defibrylatory — czy test skuteczności defibrylacji jest jeszcze potrzebny?

Test defibrylacji (DT) od ponad 20 lat stanowil integralną cześc procedury implantacji wszczepialnych kardiowerterow- -defibrylatorow (ICD). Indukcja migotania komor w czasie DT ma na celu potwierdzenie adekwatnego marginesu bezpieczenstwa pomiedzy maksymalną energią generowaną przez ICD, a energią defibrylacji wymaganą dla przerwania zagrazających zyciu arytmii komorowych. Aktualnie postep technologiczny sprawil, ze skutecznośc kliniczna terapii antyarytmicznej ICD siega 90% co wplywa na staly trend do rezygnacji z wykonywania DT. Tematem artykulu są aktualne pytania związane z problemem podwyzszonego progu defibrylacji (DFT) oraz koniecznością i bezpieczenstwem dalszego rutynowego wykonywania DT.

The relationship between defibrillation threshold and total mortality

The relationship between the defibrillation threshold (DFT) and total mortality is unclear. A university hospital prospectively maintained implantable defibrillator (ICD) database identified 508 patients who underwent ICD implantation and had DFT testing performed at implant. Patients were placed in one of three groups based on the implant DFT (high (≥20 J), moderate (19-11 J), or low DFT (≤10 J)). Sixty-seven patients had a high DFT, 216 had a moderate DFT, and 225 had a low DFT. The mean left ventricular ejection fraction (LVEF) was 0.25, 0.28, and 0.30 in the high, moderate, and low DFT groups, respectively, (p = 0.04). There were significantly more patients with a subcutaneous electrode in the high DFT group (p < 0.001), more patients taking amiodarone (p < 0.001), and more patients on oral anticoagulation (p = 0.04). There were a total of 140 deaths during the follow-up period (mean 3.2 ± 1.7 years). There were 24 deaths in the high DFT group (35.8%), 62 in the moderate DFT group (28.7%), and 54 in the low DFT group (24.0%) (p = 0.05). Implant DFT was a significant predictor of mortality (p = 0.01), as was age, LVEF (p < 0.001), CAD (p = 0.01), amiodarone use (p = 0.02), and hematoma at implant (p = 0.01). An elevated DFT was an independent predictor of mortality after controlling for all significant univariate variables (p = 0.004). A high-implant DFT predicts an adverse prognosis, even when an adequate ICD safety margin is present.

Transvenous placement of the subcutaneous coil electrode to reduce elevated defibrillation thresholds: an alternative to an azygous or subcutaneous coil

Purpose: Despite waveform optimization, high output devices, dual coil electrodes (DCE) or the addition of a standard (Medtronic Transvene) proximal coil (TVCE) high defibrillation thresholds (DFT) continue to be a problem in patients with implantable cardioverter defibrillator (ICD). Placement of a coil electrode (Medtronic 6996) posterior in the subcutaneous (SQ) tissue (SQCE) reduces DFTs but requires a second procedure in many centers and is not readily applicable to a right-sided implant. Placement of a TVCE in the azygous vein or coronary sinus can be challenging and may be extremely difficult/dangerous to extract. We present an alternative approach to high DFT's by transvenous rather than SQ placement of the SQCE. Methods: Between Sept 2009 and May 2012, eight patients with high DFT's (mean ≥ 35.3 SD ± 2.7) despite a DCE (proximal coil surface area {SA} 860 mm2) or addition of a TVCE (SA 125 mm2) who had a SQCE (SA 500 mm2) placed in the left innominate/SVC (7 left-sided implants) or azygos vein (1 right-sided implant). After connecting the SQCE to the proximal port, the generator was implanted in the subcutaneous space and DFT's repeated. Results: The mean age was 63±16 years (range 30-79) with 3 females and 1 right-sided implant. The initial ICD lead was dual coiled in seven with the addition of a TVCE in one. After removal of the plastic tip, the subcutaneous coil electrode was positioned in the left innominate/SVC (n=7) and the azygos vein (n=1) for the right-sided implant. The mean DFT was reduced from > 35.3 J ± 2.7 to ≤ 20.3 J ± 4.9 (p=0.003) and the high voltage lead impedance reduced from 41.5±16.7 to 31.1±6.8 Ω (p = 0.2) There were no perioperative complications such as lead dislodgements, fractures, infections or sensing problems noted till last follow up. One patient expired from progressive congestive heart failure one year after the implant. None of the patients have had a spontaneous arrhythmic episode and there were no inappropriate therapies recorded since implant till last follow up. Conclusion: Despite a lower SA than the proximal coil of a DCE, transvenous placement of the SQCE in the left innominate/SVC reduces high DFT's below that seen with a dual coil system and does not require a second procedure. For right-sided implants, azygos placement of the subcutaneous coil may be preferred than the conventional transvenous coil for reducing DFT's.

第20回 心臓性急死研究会 著明な除細動閾値高値を示した心室細動蘇生の1例

第20回 心臓性急死研究会 著明な除細動閾値高値を示した心室細動蘇生の1例

Predictors of High Defibrillation Threshold in the Modern Era

High defibrillation threshold (DFT) is a clinical problem in 1-8% of implantable cardioverter-defibrillator implants. Some clinicians and investigators question whether the benefits of routine DFT testing outweigh the risks. Identification of the predictors of elevated DFT may allow selective application of DFT testing. However, the clinical characteristics of patients with high DFT in the modern era have not been well-defined. All patients who underwent DFT testing in our institution during an 8-year period were reviewed for this retrospective study. High DFT was defined as less than a 10-J safety margin on initial testing. For each case, the two cases preceding and two cases following by the same implanter were selected as controls. Of the 2,138 patients who underwent DFT testing, 48 (2.2%) met criteria for high DFT. Compared to 192 control patients, patients with high DFT were more likely to be younger (P = 0.004), have nonischemic cardiomyopathy (P = 0.036), have a longer QRS interval (P = 0.026), and have a left ventricular ejection fraction (LVEF) ≤ 0.25 (P = 0.013). On multivariate analysis, only younger age (P = 0.016) and LVEF ≤ 0.25 (P = 0.010) remained statistically significant predictors of elevated DFT. High DFT was identified in 2.2% of ICD implants in our institution in recent years. Although younger age and depressed LVEF predicts this problem, elevated DFT occurred in patients of all ages and ejection fractions. Elimination of routine DFT testing appears to be premature given the prevalence and unpredictability of elevated DFT.

Elevated Defibrillation Threshold Despite Programmable Tilt, Pulse Width, or Implant of Subcutaneous Coil: Role of Higher Energy Devices

The value of defibrillation threshold testing (DFT) has been debated in recent years, especially with developments in the technology of manufactured defibrillators, most of which are capable of delivering high energies (35 Joules [J]) and have programmable features such as tilt percentage and pulse width duration that increase the efficiency of biphasic shocks. The following is an unusual case of elevated DFT despite all attempts of invasive and noninvasive approaches--it highlights the importance of performing DFT testing particularly when implantable cardioverter defibrillator is indicated for secondary prevention of sudden cardiac death and the need for devices capable of delivering higher energies >35 J.

Defibrillation Thresholds in Hypertrophic Cardiomyopathy

Defibrillation threshold (DFT) testing is performed in part to ensure an adequate safety margin for the termination of spontaneous ventricular arrhythmias. Left ventricular mass is a predictor of high DFTs, so patients with hypertrophic cardiomyopathy (HCM) are often considered to be at risk for increased defibrillation energy requirements. However, there are little prospective data addressing this issue. To assess DFTs in patients with HCM and evaluate the clinical predictors of elevated DFTs. Eighty-nine consecutive patients with HCM and 600 control patients with ischemic or nonischemic cardiomyopathy underwent a uniform modified step-down DFT testing protocol. DFT was compared between the control and HCM populations. Predictors of elevated DFT were evaluated in the HCM group. There was no difference in DFT between HCM and control groups (10.4 ± 5.8 J vs 11.2 ± 5.6 J, respectively). Among patients with HCM, clinical parameters such as left ventricular ejection fraction, interventricular septal thickness, left ventricular mass, and QRS duration were not predictive of an elevated DFT. Only 3 patients (3.4%) with HCM had a DFT >20 J. Patients with HCM do not have elevated DFTs as compared to more typical populations undergoing implantable cardioverter-defibrillator implant; high-energy devices or complex lead systems are not needed routinely in this population.

Defibrillation threshold decrease with the supradiaphragmatic extracardiac implantable cardioverter-defibrillator implantation technique

Despite advances in implantable cardioverter-defibrillator (ICD) technology, the optimal ICD implantation technique for pediatric patients has not yet been established. One increasingly used option is totally extracardiac implantation. However, concern exists about the high defibrillation threshold (DFT) at the moment of implantation or during follow-up. We report the case of a 3-year-old boy with repetitive syncopal idiopathic ventricular tachycardia episodes treated with ICD implantation using the extracardiac technique. Changing device position from abdominal to a supradiaphragmatic, solved unsafe elevated discharge impedance and DFT during follow-up.

Does defibrillation threshold increase as left ventricular ejection fraction decreases?

AimsAdvanced cardiac disease, entailing more hypertrophy, fibrosis, scarring, dilatation and conduction delays, poses the question of whether defibrillation thresholds (DFTs) increase as left ventricular ejection fraction (LVEF) decreases. This question has been approached indirectly or insufficiently in previous studies. In this study we add and expand on our previous work, stratifying DFT for various LVEF ranges.Methods and resultsThis retrospective analysis included DFT data from three acute, multicentre, randomized studies that included 230 ICD/CRT-D patients. All DFTs were obtained with the SVC coil turned ON and with pulse-width optimized waveforms based on a 3.5 ms membrane time constant. As the LVEF decreased, DFT estimates increased from 395.2 ± 115 V for LVEF ≥ 46% to 425.8 ± 117.6 V for LVEF ≤ 25%. However, these changes in DFT estimates were very minor and not statistically significant. Only 3% of the patients in this population had an elevated DFT of >20 J.ConclusionThis analysis shows that over a very broad range of LVEF, DFT changes minimally (approximately 1 J), if at all. Our results are consistent with previous studies that demonstrated no difference in the DFT estimates: (a) between patient groups receiving ICD (typically higher LVEF) vs. CRT-D (typically lower LVEF) and (b) between patient groups receiving a device for primary prevention indications (typically lower LVEF) vs. secondary prevention indications (typically higher LVEF).

Effect of cardiogenic pulmonary edema on defibrillation efficacy

Cardiogenic pulmonary edema is a common concomitant of heart failure. Clinical studies have shown that patients with heart failure have elevated defibrillation thresholds, but the underlying mechanism is still largely not understood. By aid of an anatomically realistic finite difference model of the thorax, this study aims to explore whether cardiogenic pulmonary edema could be a possible factor contributing to defibrillation threshold elevation. Simulation results demonstrate that defibrillation efficacy is compromised as pulmonary edema progresses.

The Azygos Defibrillator Lead for Elevated Defibrillation Thresholds: Implant Technique, Lead Stability, and Patient Series

Conventional insertion of implantable cardioverter-defibrillator (ICD) includes an evaluation of the defibrillation threshold (DFT). Implanting an ancillary defibrillation lead in the azygos vein has been introduced as a therapeutic option in patients with "high" DFT. This study reports the efficacy and stability of azygos defibrillation coils implanted for elevated DFTs. This is a retrospective review of seven consecutive patients with right and left pectoral, single- and dual-chamber, and biventricular ICDs and elevated DFTs, in whom an azygos defibrillation coil was introduced. Addition of an azygos defibrillator lead achieved a satisfactory safety margin during single energy defibrillation efficacy testing in four out of seven patients, with success at maximum device output in two patients. No satisfactory safety margin was achieved in the remaining patient, despite the further addition of a subcutaneous defibrillation coil. No change in lead position was observed over a mean radiographic follow-up of 8 months. No complications were noted during a mean follow-up of 14 months, including no deaths, and no ICD shocks. Implanting a defibrillation coil into the azygos vein is feasible and safe. In a majority of patients with failed defibrillation efficacy testing, adding an azygos coil achieves success on repeat testing. Therefore, this technique is one option for lowering the defibrillation threshold in patients who fail DFT testing of their ICD.

Portadores de CDI com limiar de desfibrilação elevado: evolução clínica e alternativas terapêuticas

The ideal programming of the implantable cardioverter defibrillator (ICD) shock energy should be at least 10J above the defibrillation threshold (DFT), requiring alternative techniques when the DFT is elevated. To assess the clinical behavior of ICD patients with DFT>25J and the efficacy of the chosen therapy. Patients who had undergone ICD implantation between Jan/00 and Aug/04 (prospective database) and presented intraoperative DFT>25J were selected. The analyzed variables were: clinical characteristics, LVEF, rescue of arrhythmic events from ICD and causes of deaths. among 476 patients, 16 (3.36%) presented DFT>25J. The mean age was 56.5 years, and 13 patients (81%) were men. According to the baseline cardiomyopathy, 09 patients had Chagas' disease, 04 had ischemic cardiomyopathy and 03 had idiopathic cardiomyopathy. Mean LVEF was 0.37 and amiodarone was used by 94% of the patients. Mean follow-up (FU) period was 25.3 months. DFT was higher than maximum energy shock (MES) in 2 patients and it was necessary to implant an additional shock electrode (array). It was programmed MES in ventricular fibrillation zone of ICD therapy in the other patients. In the FU, 03 patients had 67 successful appropriate shock therapies (AST). There were 05 noncardiac and 02 heart failure deaths. The patients who died showed higher DFT levels (p=0.044) without correlation with death because there wasn't unsuccessful AST. In this cohort of ICD patients, the occurrence of elevated DFT (>25J) was low, leading to alternative therapies. There was an association with severe ventricular dysfunction, although without correlation to the causes of death.

Increased Complication Rates of Cardiac Rhythm Management Devices in ESRD Patients

Patients with end-stage renal disease (ESRD) have a high incidence of sudden cardiac death and may benefit from implantable cardioverter defibrillators (ICDs). However, ESRD also may predispose patients to device-related complications, potentially offsetting some of the benefits of prophylactic ICD placement. The purpose of this study is to compare the incidence of complications after cardiac rhythm management device (CRMD) implantation in patients with and without ESRD. An observational study was performed on 41 patients with ESRD and 123 controls without ESRD who had a CRMD (permanent pacemaker or ICD) implanted at a single institution from 1998 to 2005. Controls were matched for age, sex, type of device, and calendar year of device implantation. Primary and secondary end points were any complication and complications requiring intervention, respectively. 23 complications occurred in 16 of 41 patients with ESRD (39%) versus 13 complications in 13 of 123 matched controls (11%; P < 0.001). Major complications occurred in 29% of patients with ESRD versus 5% of controls (P < 0.001), whereas minor complications occurred in 17% and 6%, respectively (P < 0.03). Hematoma, thrombosis, and device-related complications, including elevated defibrillation thresholds, were more common in patients with ESRD (P < 0.05 for all), and there also was a nonsignificant trend toward greater infection risk (P = 0.1). There were no fatal complications in either group. Patients with ESRD had greater complication rates after CRMD implantation compared with matched controls, but these complications did not result in death. These results should be considered when evaluating patients with ESRD for prophylactic CRMD implantation, but do not support withholding such therapy.