Developing a risk score to predict mortality in the first year after implantable cardioverter defibrillator implantation: Data from the Israeli ICD Registry.

INTRODUCTION: Life expectancy of less than 1 year is usually a contraindication for implantable cardioverter defibrillator (ICD) implantation. The aim was to identify patients at risk of death during the first year after implantation. METHODS AND RESULTS: Data were derived from a prospective Israeli ICD Registry. Two groups of patients were compared, those who died and those who were alive 1 year after ICD implantation. Factors associated with 1-year mortality were identified on a derivation cohort. A risk score was established and validated. A total of 2617 patients have completed 1 year of follow-up after ICD or cardiac resynchronization therapy defibrillator (CRT-D) implantation. Age greater than 75 years (hazard ratio [HR], 2.7; 95% confidence interval [95% CI], 1.6 to 4.4), atrial fibrillation (AF; HR, 1.9; 95% CI, 1.12 to 3.17), chronic lung disease (HR, 2.0; 95% CI, 1.1 to 3.76), anemia (HR, 2.3; 95% CI, 1.3 to 3.93) and chronic renal failure (CRF; HR, 3.4; 95% CI, 1.74 to 6.6) were independent risk factors for 1-year mortality. We propose a simple AAACC ("triple A double C") score for prediction of 1-year mortality after ICD implantation: Age greater than 75 years (3 points(pts)), anemia (2 pts), AF (1 pt), CRF (3 pts) and chronic lung disease (1 pt). Mortality risk increased with rising number of points (from 1% with 0 pts to 12.5% with >4 pts). The risk score was evaluated with receiver operating characteristic curve and the area under the curve of the validation curve is 0.71 (95% CI, 0.66 to 0.76). CONCLUSIONS: Age greater than 75, AF, chronic lung disease, anemia, and CRF were independent risk factors for 1-year mortality. AAACC risk score identifies patients at high risk of death during 1 year after ICD implantation.

High-grade atrioventricular block in patients with acute myocardial infarction. Insights from a contemporary multi-center survey.

High-grade atrioventricular block (HAVB) is a frequent complication of acute myocardial infarction (AMI) and is associated with increased morbidity and mortality. We aimed to evaluate the incidence, predictors, and prognostic significance of HAVB in a contemporary cohort of patients with AMI, in the recent era of early reperfusion. Patients with acute coronary syndromes (n=11,487) during the years 2000-2010 were included. Patients were divided into two groups: with HAVB (n=308, 2.7%) and without HAVB (n=11,179, 97.3%). The incidence of HAVB decreased from 4.2% in 2000 to 2.1% in 2010 (p for trend<0.01). Patients with HAVB were more likely to develop in-hospital complications. Independent predictors of developing HAVB were older age, ST-elevation myocardial infarction (STEMI), smoking and Killip class≥2 on admission. 30-day and 1-year mortality rates were significantly higher in the HAVB as compared to the non-HAVB group (24% vs. 4.9%, p<0.01, 33.5% vs. 10%, p<0.01, respectively). Multivariable logistic regression analysis revealed that, HAVB was associated with increased 30-day (OR - 3.97; 95% CI - 1.96-8.04) and 1-year mortality risk (HR - 2.02; 95% CI - 1.3-3.1). Similar estimates were obtained for STEMI and non-STEMI (NSTEMI). In conclusion, although the incidence of HAVB decreased over the last decade, the associated morbidity and mortality are still high in these patients despite early reperfusion therapy.

Gender-Related Differences in Outcomes of Patients with Cardiac Resynchronization Therapy.

BACKGROUND: Gender-related differences (GRD) exist in the outcome of patients with cardiac resynchronization therapy (CRT). OBJECTIVES: To assess GRD in patients who underwent CRT. METHODS: A retrospective cohort of 178 patients who were implanted with a CRT in a tertiary center 2005-2009 was analyzed. Primary outcome was 1 year mortality. Secondary endpoints were readmission and complication rates. RESULTS: No statistically significant difference was found in 1 year mortality rates (14.6% males vs. 11.8% females, P = 0.7) or in readmission rate (50.7% vs. 41.2%, P = 0.3). The complication rate was only numerically higher in women (14.7% vs. 5.6%, P = 0.09). Men more often had CRT-defibrillator (CRT-D) implants (63.2% vs. 35.3%, P = 0.003) and had a higher rate of ischemic cardiomyopathy (79.2% vs. 38.2%, P < 0.001). There was a trend to higher incidence of ventricular fibrillation/ventricular tachycardia in men before CRT implantation (29.9% vs. 14.7%, P = 0.07%). A higher proportion of men upgraded from implantable cardioverter defibrillator (ICD) to CRT-D, 20.8% vs. 8.8%, P = 0.047. On multivariate model, chronic renal failure was an independent predictor of 1 year mortality (hazard ratio [HR] 3.6; 95% confidence interval [95%CI] 1.4-9.5), CRT-D had a protective effect compared to CRT-pacemaker (HR 0.3, 95%CI 0.12-0.81). CONCLUSIONS: No GRD was found in 1 year mortality or readmission rates in patients treated with CRT. There was a trend toward a higher complication rate in females. Men were implanted more often with CRT-D and more frequently underwent upgrading of ICD to CRT-D.

Arrhythmic Events in Brugada Syndrome: A Nationwide Israeli Survey of the Clinical Characteristics, Treatment; and Long-Term Follow-up (ISRABRU-VF).

BACKGROUND: Limited information exists about detailed clinical characteristics and management of the small subset of Brugada syndrome (BrS) patients who had an arrhythmic event (AE). OBJECTIVES: To conduct the first nationwide survey focused on BrS patients with documented AE. METHODS: Israeli electrophysiology units participated if they had treated BrS patients who had cardiac arrest (CA) (lethal/aborted; group 1) or experienced appropriate therapy for tachyarrhythmias after prophylactic implantable cardioverter defibrillator (ICD) implantation (group 2). RESULTS: The cohort comprised 31 patients: 25 in group 1, 6 in group 2. Group 1: 96% male, mean CA age 38 years (range 13-84). Nine patients (36%) presented with arrhythmic storm and three had a lethal outcome; 17 (68%) had spontaneous type 1 Brugada electrocardiography (ECG). An electrophysiology study (EPS) was performed on 11 patients with inducible ventricular fibrillation (VF) in 10, which was prevented by quinidine in 9/10 patients. During follow-up (143 ± 119 months) eight patients experienced appropriate shocks, none while on quinidine. Group 2: all male, age 30-53 years; 4/6 patients had familial history of sudden death age < 50 years. Five patients had spontaneous type 1 Brugada ECG and four were asymptomatic at ICD implantation. EPS was performed in four patients with inducible VF in three. During long-term follow-up, five patients received ≥ 1 appropriate shocks, one had ATP for sustained VT (none taking quinidine). No AE recurred in patients subsequently treated with quinidine. CONCLUSIONS: CA from BrS is apparently a rare occurrence on a national scale and no AE occurred in any patient treated with quinidine.

Yield of left ventricular dyssynchrony by gated SPECT MPI in patients with heart failure prior to implantable cardioverter-defibrillator or cardiac resynchronization therapy with a defibrillator: Characteristics and prediction of cardiac outcome.

BACKGROUND: Mechanical left ventricular dyssynchrony (MLVD) might contribute in the therapeutic decision-making in patients with heart failure (HF) prior to cardiac resynchronization therapy (CRT). Our aim was to assess MLVD in patients with HF prior to implantable cardioverter-defibrillator (ICD) compared to patients with CRT-D. METHODS: In a prospective study, patients with LVEF ≤ 35% who were scheduled for ICD or CRT-D, underwent gated SPECT myocardial perfusion imaging with technetium 99m sestamibi within 3 months prior procedure. MLVD was measured by phase analysis. RESULTS: The study cohort consisted of 143 patients, 71 with ICD and 72 with CRT-D. Age 68.3 ± 11 and LVEF 24 ± 6%. Phase standard deviation (SD) was 62.5 ± 18 and 59.7 ± 20 (P = NS), respectively. During follow-up of 23.7 ± 12.1 months, there were 10 vs 14 cardiac death in ICD and CRT-D, respectively (P = NS), hospitalization for HF, in 34 vs 53 (P < .001). In multivariate analysis, Phase SD was the independent predictor for cardiac death [HR 2.66 (95% CI 1.046-6.768), P = .04]. Kaplan-Meier curves of phase SD of 60° significantly identified ICD patients with and without cardiac deaths and hospitalization for HF exacerbation. CONCLUSIONS: MLVD by phase SD can identify patients with cardiac events and predict cardiac death in patients treated with ICD.

Syncope in Primary Prevention Implantable Cardioverter Defibrillator Implantation.

BACKGROUND: Syncope prognosis varies widely: 1 year mortality may range from 0% in the case of vasovagal events up to 30% in the presence of heart disease. OBJECTIVES: To assess the outcomes and prognosis of patients with implantable cardiac defibrillator (ICD) and indication of primary prevention and compare patients presenting with or without prior syncope. METHODS: We reviewed the charts of 75 patients who underwent ICD implantation with the indication of primary prevention and history of syncope and compared them to a control group of 80 patients without prior syncope. We assessed the number of ventricular tachycardia (VT), ventricular fibrillation (VF), shock, anti-tachycardia pacing (ATP), and death in each group during the follow-up. RESULTS: Mean follow-up was 893 days (810-976, 95% confidence interval) (no difference between groups). Patients with prior syncope had a higher ejection fraction (EF) (35.5 ± 12.6 vs. 31.4 ± 8.76, P = 0.02), more episodes of VT (21.3% vs. 3.8%, P = 0.001) and VF (8% vs. 0%, P = 0.01) and also received more electric shocks (18.7% vs. 3.8%, P = 0.004) and ATP (17.3% vs. 6.2%, P = 0.031). There were no differences in inappropriate shocks (6.7% vs. 5%, P = 0.74), in cardiovascular mortality (cumulative 5 year estimate 29.9% vs. 32.2% P = 0.97) and any death (cumulative 5 year estimate 38.1% vs. 48.9% P = 0.18) during the follow-up. CONCLUSIONS: Syncopal patients before ICD implantation seem to have more episodes of VT/VF and shock or ATP. No mortality differences were observed.

Characteristics and outcomes of diabetic patients with an implantable cardioverter defibrillator in a real world setting: results from the Israeli ICD registry.

AIMS: There are limited data regarding the effect of diabetes mellitus (DM) on the risks of both appropriate and inappropriate implantable cardioverter defibrillator (ICD) therapy. The present study was designed to compare the outcome of appropriate and inappropriate ICD therapy in patients with or without DM. METHODS AND RESULTS: The risk of a first appropriate ICD therapy for ventricular tachyarrhythmias (including anti tachycardia pacing and shock) was compared between 764 DM and 1346 non-DM patients enrolled in the national Israeli ICD registry. We also compared the risks of inappropriate ICD therapy, and death or cardiac hospitalization between diabetic and non-diabetic patients. Diabetic patients were older, were more likely to have ischemic cardiomyopathy, lower ejection fraction, atrial fibrillation, and other co-morbidities. The 3-year cumulative incidence of appropriate ICD therapy was similar in the DM and non-DM groups (12 and 13%, respectively, p = 0.983). Multivariate analysis showed that DM did not affect the risk of appropriate ICD therapy (HR = 1.07, 95% CI 0.78-1.47, p = 0.694) or inappropriate therapy (HR = 0.72, 95% CI 0.42-1.23, p = 0.232). However, DM was associated with a 31% increased risk for death or cardiac hospitalization (p = 0.005). Results were similar in subgroup analyses including ICD and defibrillators with cardiac resynchronization therapy function recipients, primary or secondary prevention indication for an ICD. CONCLUSIONS: Despite a significant excess of cardiac hospitalizations and mortality in the diabetic population, there was no difference in the rate of ICD treatments, suggesting that the outcome difference is not related to arrhythmias.

Outcome of contemporary acute coronary syndrome complicated by ventricular tachyarrhythmias.

AIM: To evaluate the incidence and prognostic implications of ventricular tachyarrhythmias (VTAs) complicating acute myocardial infarction (MI). METHODS AND RESULTS: We evaluated 7669 MI patients [ST elevation (n = 3573) and non-ST-elevation acute coronary syndrome (ACS) (n = 4096)] from the Acute Coronary Syndrome Israeli Survey for the incidence of VTA. Ventricular tachyarrhythmia occurred in 3.8% of patients [2.1% early (≤ 48 h) and 1.7% late (>48 h) VTA]. In-hospital mortality rates were higher for patients with VTA when compared with patients with no VTA (P < 0.001). Consistent with these findings, multivariable analysis demonstrated that early and late VTAs were associated with increased risk of in-hospital death [hazard ratio (HR) = 3.84; 95% confidence interval (CI) 1.77-6.78, P < 0.001, and HR = 8.23; 95% CI 4.84-13.98, P < 0.001, respectively]. In contrast, post-discharge outcomes demonstrated that only late VTA was independently associated with a significant increased risk of 30-day mortality (HR = 5.17; 95% CI 1.54-17.27, P = 0.007) with a trend towards an increased 1-year mortality risk (HR = 1.69; 95% CI 0.79-3.62, P = 0.17). The long-term risk associated with in-hospital VTA was driven by sustained ventricular tachycardia (VT) (HR = 3.28; 95% CI 1.92-5.60, P < 0.001) but not ventricular fibrillation (HR = 1.27; 95% CI 0.65-2.49, P = 0.47). CONCLUSIONS: Our findings suggest that in patients with ACS, both early and late VTAs are associated with an increased risk of in-hospital mortality. However, only late VTA, mostly sustained VT, is associated with long-term adverse outcome.

Type of Atrial Fibrillation and Clinical Outcomes in Patients Undergoing Transcatheter Aortic Valve Replacement.

BACKGROUND: There are limited data available regarding the relationship between atrial fibrillation (AF) clinical type, oral anticoagulation (OAC) treatment, and clinical outcome after transcatheter aortic valve replacement (TAVR). The study was designed to evaluate this relationship. METHODS: We analyzed data from the Rabin Medical Center TAVR registry, including 319 consecutive patients who underwent TAVR from 2008 to 2014. Patients were divided into three groups based on their history of AF: sinus rhythm (SR), paroxysmal AF (PAF), or nonparoxysmal AF (NPAF). RESULTS: There were 211 (66%), 56 (18%), and 52 (16%) patients in the SR, PAF, and NPAF groups, respectively. The cumulative risk for stroke or death at 2 years was highest among patients with NPAF (38%), but similarly low in PAF (15%) and SR patients (16%, P < 0.001). By multivariate analysis, patients with NPAF demonstrated a significantly higher risk of stroke or death (HR = 2.76, 95% CI 1.63-4.66, P < 0.001), as compared with SR. In contrast, patients with PAF had a similar risk of stroke or death compared with SR (HR = 0.80, P = 0.508). Patients with NPAF not treated with OAC demonstrated an 8.3-fold (P < 0.001) increased risk of stroke or death, whereas patients with PAF not treated with OAC had a similar risk of stroke or death compared with the SR group (HR = 1.25, P = 0.569). CONCLUSION: History of NPAF, but not PAF, is associated with a significant increased risk of stroke or death compared with sinus rhythm in patients undergoing TAVR.

Syncope in Primary Prevention Implantable Cardioverter Defibrillator Patients.

BACKGROUND: Syncope is a common clinical condition spanning from benign to life-threatening diseases. There is sparse information on the outcomes of syncopal patients who received an implantable cardiac defibrillator (lCD) for primary prevention of sudden cardiac death (SCD). OBJECTIVES: To assess the outcomes and prognosis of patients who underwent implantable cardiac defibrillator (ICD) implantation for primary prevention of SCD and compare them to patients who presented with or without prior syncope. METHODS: We compared the medical records of 75 patients who underwent ICD implantation for primary prevention of SCD and history of syncope to those of a similar group of 80 patients without prior syncope. We assessed the episodes of ventricular tachycardia (VT), ventricular fibrillation (VF), shock, anti-tachycardia pacing (ATP) and mortality in each group during follow-up. RESULTS: Mean follow-up was 893 days (810-976, 95% CI) (no difference between groups). There was no significant difference in gender or age. Patients with prior syncope had a higher ejection fraction rate (35.5 ? 12.6 vs. 31.4 8.76, P = 0.02), experienced more episodes of VT (21.3% vs. 3.8%, P = 0.001) and VF (8% vs. 0%, P = 0.01), and received more electric shocks (18.7% vs. 3.8%, P = 0.004) and ATP (17.3% vs. 6.2%, P = 0.031). There were no differences in inappropriate shocks (6.7% vs. 5%, P = 0.74), cardiovascular mortality (cumulative 5 year estimate 29.9% vs. 32.2%, P = 0.97) and any death (cumulative 5 year estimate 38.1% vs. 48.9%, P = 0.18). CONCLUSIONS: Patients presenting with syncope before ICD implantation seemed to have more episodes of VT/VF and shock or ATP. No differences in mortality were observed.

Association between Red Cell Distribution Width and Mortality after Cardiac Resynchronization Therapy.

BACKGROUND: Cardiac resynchronization therapy (CRT) is a non-pharmacological option for patients with heart failure and interventricular dyssynchrony. Elevated red cell distribution width (RDW) reflects higher size and heterogeneity of erythrocytes and is associated with poor outcome in patients with chronic heart failure. OBJECTIVES: To examine the association between RDW levels and outcomes after CRT implantation. METHODS: We conducted a cohort analysis of 156 patients (126 men, median age 69.0 years) who underwent CRT implantation in our institution during 2004-2008. RDW was measured at three time points before and after implantation. Primary outcome was defined as all-cause mortality, and secondary outcome as hospital re-admissions. We investigated the association between RDW levels and primary outcome during a median follow-up of 61 months. RESULTS: Ninety-five patients (60.9%) died during follow-up. Higher baseline RDW levels were associated with all-cause mortality (unadjusted HR 1.35, 95% CI 1.20-1.52, P < 0.001). On multivariate analysis adjusted for clinical, electrocardiographic and laboratory variables, baseline RDW levels were associated with mortality (HR 1.33, 95%CI 1.16-1.53). RDW levels 6 months and 12 months post-implantation were also associated with mortality (HR 1.22, 95%CI 1.08-1.38, P = 0.001; and HR 1.15, 95% CI 1.01-1.32, P = 0.02, respectively). Patients who were re-admitted to hospital during follow-up (n = 78) had higher baseline RDW levels as compared to those who were not (14.9%, IQR 14.0, 16.0% vs. 14.3%, IQR 13.7, 15.0%, respectively, P = 0.03). CONCLUSION: An elevated RDW level before and after CRT implantation is independently associated with all-cause mortality.

Renal dysfunction and clinical outcomes of patients undergoing ICD and CRTD implantation: data from the Israeli ICD registry.

BACKGROUND: Implantable cardioverter defibrillators (ICDs) and cardiac resynchronization therapy (CRT) reduce mortality in patients with heart failure (HF) and left ventricular dysfunction. However, their efficacy in patients with chronic kidney disease (CKD) is controversial. OBJECTIVE: We examined the association between renal dysfunction and clinical outcomes in patients undergoing ICD and CRT defibrillator (CRTD) implantation. METHODS: Data were collected from the Israeli ICD registry. Estimated glomerular filtration rate (eGFR) at implantation was assessed using the modification of diet in renal disease formula. Primary outcome was all-cause mortality. Secondary outcomes included the composite endpoints of death or HF and death or ventricular arrhythmias (ventricular tachycardia/ventricular fibrillation [VT/VF]); any hospitalizations; first appropriate and inappropriate ICD therapy. RESULTS: During the study period (July 2010-November 2012), 2,811 patients were implanted with ICD or CRTD. One-year follow-up data were available for 730 ICD patients and 453 CRTD patients. Patients with eGFR < 30 mL/minute/1.73 m(2) (n = 54, 4.6%) were older, had a higher prevalence of diabetes, hypertension, or ischemic heart disease. eGFR <30 mL/minute/1.73 m(2) was associated with increased mortality risk in ICD (HR 5.4; 95% CI 1.5-19.2), but not in CRTD patients (HR 0.9; 95% CI 0.1-7.5). Renal dysfunction was associated with the composite endpoints of death or HF and death or VT/VF in ICD, but not in CRTD patients. Mean eGFR during follow-up decreased by 8.0 ± 4.3 mL/minute/1.73 m(2) in ICD patients (P = 0.06) and by 1.8 ± 1.3 mL/minute/1.73 m(2) in patients with CRTD (P = 0.2). CONCLUSION: Based on this retrospective analysis, CKD is associated with adverse prognosis after ICD implantation, but not after CRTD implantation. GFR decreased in patients with ICD, but not in CRTD patients.

Prognostic value of left ventricular dyssynchrony by myocardial perfusion-gated SPECT in patients with normal and abnormal left ventricular functions.

BACKGROUND: Left ventricular (LV) dyssynchrony by phase analysis has been studied by myocardial perfusion imaging (MPI)-gated SPECT in patients with LV dysfunction in various clinical settings. We aimed to investigate the routine use of phase analysis with gated SPECT for predicting cardiac outcome. METHODS: Patients referred to a tertiary medical center in 2010-2011 prospectively underwent a gated SPECT and phase analysis, and follow-up for cardiac events. The values of clinical variables, MPI, LV function, and LV dyssynchrony in predicting cardiac events were tested by univariate and multivariate analyses. RESULTS: The study group included 787 patients (66.5 ± 11 years, 81% men) followed for a mean duration of 18.3 ± 6.2 months. There were 45 (6%) cardiac events defined as composite endpoint; cardiac death occurred in 26 patients, and the rest had new-onset or worsening heart failure and life-threatening arrhythmias. In multivariate analysis, it was shown that NYHA class, diabetes mellitus, and LVEF <50% were the independent predictors for composite endpoint. However, the independent predictors for cardiac mortality were NYHA class (for each increment in class) and phase standard deviation (SD) (for each 10° increment). CONCLUSION: Gated SPECT with phase analysis for the assessment of LV dyssynchrony can successfully predict cardiac death together with NYHA class, in patients with LV dysfunction.

Association of time of occurrence of electrical heart storms with environmental physical activity.

AIM: Many publications in recent decades have reported a temporal link between medical events and environmental physical activity. The aim of this study was to analyze the time of occurrence of electrical heart storms against levels of cosmological parameters. METHODS: The sample included 82 patients (71 male) with ischemic cardiomyopathy treated with an implantable cardioverter defibrillator at a tertiary medical center in 1999-2012 (5,114 days). The time of occurrence of all electrical heart storms, defined as three or more events of ventricular tachycardia or ventricular fibrillation daily, was recorded from the defibrillator devices. Findings were analyzed against data on solar, geomagnetic, and cosmic ray (neutron) activity for the same time period obtained from space institutions in the United States and Russia. RESULTS: Electrical storms occurred in all months of the year, with a slight decrease in July, August, and September. Most events took place on days with lower-than-average levels of solar and geomagnetic activity and higher-than-average levels of cosmic ray (neutron) activity. There was a significant difference in mean daily cosmic ray activity between the whole observation period and the days of electrical storm activity (P = 0.0001). CONCLUSION: These data extend earlier findings on the association of the timing of cardiac events and space weather parameters to the most dangerous form of cardiac arrhythmia-electric storms. Further studies are needed to delineate the pathogenetic mechanism underlying this association.

Cardiac resynchronization therapy in patients with atrial fibrillation: a 2-year follow-up study.

INTRODUCTION: Atrial fibrillation (AF) is the most common arrhythmia in patients with heart failure (HF) and represents an important comorbidity in these patients. Cardiac resynchronization therapy (CRT) has been shown to be beneficial in patients with HF. Whether patients with AF benefit similarly from CRT as their counterparts in sinus rhythm is controversial. METHODS AND RESULTS: We conducted a cohort analysis of 175 patients (138 men; age range 57-79 years) who underwent CRT implantation during 2004-2008 in our institution. AF was documented in 66 patients (37.7% of patients, 52 men). There were no differences in 1- or 2-year mortality between patients with and without AF (13.6% vs 11.79%, P = 0.7; 25.8% vs 16.9%, P = 0.2, respectively). There were no differences between the groups in the rate of complications after CRT implantation or in the rate of appropriate electrical shocks. In the subgroup of AF patients with cardiac resynchronization therapy defibrillator (CRT-D) (n = 32, 48.5%), the 1-year mortality was 3.1% as compared to 23.5% in AF patients with cardiac resynchronization therapy pacemaker (P = 0.03). This difference was no longer evident after 2 years (25.0% vs 26.5%, P = 0.8, respectively). Ten patients (15.2%) with AF underwent atrioventricular (AV) node ablation. The 2-year mortality of these patients was 10.0% as compared to 28.6% in AF patients who did not undergo AV-node ablation (P = 0.4). CONCLUSIONS: In this study, no difference in mortality appears to exist between patients with or without AF and who undergo CRT implantation. Our findings of the beneficial effects of AV-node ablation and CRT-D in AF patients deserve further investigation.

Electrocardiographic algorithm for the diagnosis of inadvertent implantation of permanent pacemaker lead in the left ventricular cavity.

Inadvertent placement of a pacemaker lead electrode in the left ventricle is an unusual complication and the electrocardiogram is a useful tool for the diagnoses. We present such a patient and review the electrocardiographic characteristics that should raise such a possibility.

Late potentials in the signal-averaged electrocardiogram in pre-pubertal children with ADHD, before and after methylphenidate treatment.

Reports on sudden cardiac death (SCD) of children and adolescents treated with stimulant agents have raised concerns regarding the need for cardiovascular monitoring and risk stratification schedules. Cardiac ventricular late potentials (LPs) represent delayed ventricular activation that might predispose to fatal ventricular arrhythmias and SCD in cardiac patients. LPs have not previously been measured in children with attention deficit/hyperactivity disorder (ADHD). LPs were measured in 18 physically healthy ADHD children (5 girls and 13 boys, age 11.9 ± 2.5 years, treatment duration 2.6 ± 1.9 years) before and 2 h after oral methylphenidate administration. No significant changes were detected and LPs were found to be within normal ranges. In conclusion, this preliminary small-scale study suggests that methylphenidate in physically healthy children with ADHD was not associated with cardiac ventricular LPs, suggesting the safety of the agent in this age group.

Implantable cardioverter defibrillator with and without defibrillation threshold testing.

BACKGROUND: Defibrillation threshold (DFT) testing at the time of implantable cardioverter defibrillator (ICD) insertion is performed routinely. This practice is being reconsidered due to doubts about its ability to improve ICD efficacy and evidence that survival may not be affected by the test. OBJECTIVES: To compare the outcome of ICD recipients who underwent DFT testing and those who did not. METHODS: A total of 213 eligible patients were implanted with an ICD between 2004 and 2009. DFT testing was performed in 80 of them. We compared total mortality, appropriate and inappropriate ICD shocks, and anti-tachycardia pacing (ATP) events between DFT and non-DFT patients during a follow-up of 2 years. RESULTS: On comparing the DFT and non-DFT groups, we found a 2 year mortality rate of 7.5% versus 8.3%, respectively (P = 0.8). Furthermore, 20.7% of patients in the DFT group and 12.4% in the non-DFT group had at least one episode of ICD shock (P = 0.15). With regard to ICD treatment (ICD shocks or ATP events), 57.7% in the DFT group and 64.2% in the non-DFT group received appropriate treatments (P = 0.78). CONCLUSIONS: No significant differences in the incidence of 2 year mortality or percentage of ICD treatment emerged between the DFT and non-DFT groups.

Clinical experience of two Israeli medical centers with the implantable loop recorder in patients with syncope: from diagnosis to treatment.

BACKGROUND: The implantable loop recorder (ILR) is an important tool for the evaluation of unexplained syncope, particularly in cases of rarely occurring arrhythmia. OBJECTIVES: To review the clinical experience of two Israeli medical centers with the ILR. METHODS: We reviewed the medical records of patients with unexplained syncope evaluated with the ILR at Rabin Medical Center (2006-2010) and Wolfson Medical Center (2000-2009). RESULTS: The study group included 75 patients (44 males) followed for 11.9 +/- 9.5 months after ILR implantation. Patients' mean age was 64 +/- 20 years. The ILR identified an arrhythmic mechanism of syncope in 20 patients (17 bradyarrhythmias, 3 tachyarrhythmias) and excluded arrhythmias in 12, for a diagnostic yield of 42.7%. It was not diagnostic in 17 patients (22.7%) at the time of explant; 26 patients (34.7%) were still in follow-up. In two patients ILR results that were initially negative were reversed by later ILR tracings. The patients with bradyarrhythmias included 9 of 16 (56.3%) with surface electrocardiogram conduction disturbances and 2 of 12 (16.7%) with negative findings on carotid sinus massage. All bradyarrhythmic patients received pacemakers; the seven patients for whom post-intervention data were available had no or mild symptoms. CONCLUSIONS: The ILR has a high diagnostic yield. Pre-ILR findings correlating with the ILR results are conduction disturbances (positive predictor of arrhythmia) and negative carotid sinus massage results (negative predictor of arrhythmia). Proper patient instruction is necessary to obtain accurate results. Caution is advised when excluding an arrhythmia on the basis of ILR tracings, and long-term follow-up is warranted.