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Background: The use of a Left Ventricular Assist Device (LVAD) in patients with advanced heart failure refractory to optimal medical management has progressed steadily over the past two decades. Data have demonstrated reduced LVAD efficacy, worse clinical outcome, and higher mortality for patients who experience significant ventricular tachyarrhythmia (VTA). We hypothesize that a novel prophylactic intra‐operative VTA ablation protocol at the time of LVAD implantation may reduce the recurrent VTA and adverse events postimplant. Methods: We designed a prospective, multicenter, open‐label, randomized‐controlled clinical trial enrolling 100 patients who are LVAD candidates with a history of VTA in the previous 5 years. Enrolled patients will be randomized in a 1:1 fashion to intra‐operative VTA ablation (n = 50) versus conventional medical management (n = 50) with LVAD implant. Arrhythmia outcomes data will be captured by an implantable cardioverter defibrillator (ICD) to monitor VTA events, with a uniform ICD programming protocol. Patients will be followed prospectively over a mean of 18 months (with a minimum of 9 months) after LVAD implantation to evaluate recurrent VTA, adverse events, and procedural outcomes. Secondary endpoints include right heart function/hemodynamics, healthcare utilization, and quality of life. Conclusion: The primary aim of this first‐ever randomized trial is to assess the efficacy of intra‐operative ablation during LVAD surgery in reducing VTA recurrence and improving clinical outcomes for patients with a history of VTA. [ABSTRACT FROM AUTHOR]

Background: Percutaneous catheter ablation (CA) to achieve pulmonary vein isolation is an effective treatment for drug‐refractory paroxysmal and persistent atrial fibrillation (AF). However, recurrence rates after a single AF ablation procedure remain elevated. Conventional management after CA ablation has mostly been based on clinical AF recurrence. However, continuous recordings with insertable cardiac monitors (ICMs) and patient‐triggered mobile app transmissions post‐CA can now be used to detect early recurrences of subclinical AF (SCAF). We hypothesize that early intervention following CA based on personalized ICM data can prevent the substrate progression that promotes the onset and maintenance of atrial arrhythmias. Methods: This is a randomized, double‐blind (to SCAF data), single‐tertiary center clinical trial in which 120 patients with drug‐refractory paroxysmal or persistent AF are planned to undergo CA with an ICM. Randomization will be to an intervention arm (n = 60) consisting of ICM‐guided early intervention based on SCAF and patient‐triggered mobile app transmissions versus a control arm (n = 60) consisting of a standard intervention protocol based on clinical AF recurrence validated by the ICM. Primary endpoint is AF burden, which will be assessed from ICMs at 15 months post‐AF ablation. Secondary endpoints include healthcare utilization, functional capacity, and quality of life. Conclusion: We believe that ICM‐guided early intervention will provide a novel, personalized approach to post‐AF ablation management that will result in a significant reduction in AF burden, healthcare utilization, and improvements in functional capacity and quality of life. [ABSTRACT FROM AUTHOR]

Introduction: Rapid, continuous implementation of credible scientific findings and regulatory approvals is often slow in large, diverse health systems. The coronavirus disease 2019 (COVID‐19) pandemic created a new threat to this common "slow to learn and adapt" model in healthcare. We describe how the University of Pittsburgh Medical Center (UPMC) committed to a rapid learning health system (LHS) model to respond to the COVID‐19 pandemic. Methods: A treatment cohort study was conducted among 11 429 hospitalized patients (pediatric/adult) from 22 hospitals (PA, NY) with a primary diagnosis of COVID‐19 infection (March 19, 2020 ‐ June 6, 2021). Sociodemographic and clinical data were captured from UPMC electronic medical record (EMR) systems. Patients were grouped into four time‐defined patient "waves" based on nadir of daily hospital admissions, with wave 3 (September 20, 2020 ‐ March 10, 2021) split at its zenith due to high volume with steep acceleration and deceleration. Outcomes included changes in clinical practice (eg, use of corticosteroids, antivirals, and other therapies) in relation to timing of internal system analyses, scientific publications, and regulatory approvals, along with 30‐day rate of mortality over time. Results: The mean (SD) daily number of admissions across hospitals was 26 (29) with a maximum 7‐day moving average of 107 patients. System‐wide implementation of the use of dexamethasone, remdesivir, and tocilizumab occurred within days of release of corresponding seminal publications and regulatory actions. After adjustment for differences in patient clinical profiles over time, each month of hospital admission was associated with an estimated 5% lower odds of 30‐day mortality (adjusted odds ratio [OR] = 0.95, 95% confidence interval: 0.93‐0.97, P <.001). Conclusions: In our large LHS, near real‐time changes in clinical management of COVID‐19 patients happened promptly as scientific publications and regulatory approvals occurred throughout the pandemic. Alongside these changes, patients with COVID‐19 experienced lower adjusted 30‐day mortality following hospital admission over time. [ABSTRACT FROM AUTHOR]

Introduction Methods Results Conclusions The implantable cardioverter defibrillator reduces mortality among patients with heart failure (HF) due to ischemic heart disease. Clinical trial data have called into question the benefit of an ICD in patients with HF due to nonischemic cardiomyopathy (NICM). We developed a risk stratification score for ventricular tachyarrhythmia (VTA) among patients with NICM receiving a primary prevention ICD.The study population comprised 1515 patients with NICM who were enrolled in the landmark MADIT trials. Fine and Gray analysis was used to develop a model to predict the occurrence of VTAs and ICD therapies while accounting for the competing risk of non‐arrhythmic mortality. External validation was carried out in the RAID Trial population.Four risk factors associated with increased risk for VTA were identified: male sex, left ventricular ejection fraction ≤25%, no indication for cardiac resynchronization therapy with a defibrillator (CRT‐D), and Black race. A score was generated based on this model, and patients were stratified into low (N = 390), intermediate (N = 728), and high‐risk (N = 387) groups. The 5‐year cumulative incidences of VTA were 15%, 24%, and 42%, respectively. Application of score groups for the secondary endpoints of Fast VT or VF and Appropriate ICD Shock revealed similar findings. Recurrent event analysis yielded consistent results. The AUC in the validation cohort for the endpoint of Appropriate ICD Shock was 69.3.Our study shows that patients with NICM can be risk stratified using demographic and clinical variables and may be used when evaluating such patients for a primary prevention ICD. [ABSTRACT FROM AUTHOR]

Background: Sepsis is characterized by life-threatening organ dysfunction caused by a dysregulated host response to infection and affects over 1 million Americans annually. Loss of glycemic control in sepsis is associated with increased morbidity and mortality, and novel approaches are needed to promote euglycemia and improve outcomes in sepsis. Recent studies from our laboratory demonstrate that early low-level enteral dextrose infusion in septic mice attenuates the systemic inflammatory response and improves glycemic control by inducing intestine-derived incretin hormone secretion.Aim: The aim of the Study of Early Enteral Dextrose in Sepsis (SEEDS) is to test the effect of a 24-hour enteral dextrose infusion in critically ill septic patients as a therapeutic agent to decrease systemic inflammation and promote euglycemia.Methods: SEEDS is a single-center, double-blind, randomized, controlled trial that will enroll 60 septic patients admitted to the intensive care units at the University of Pittsburgh Medical Center Health System in Pittsburgh. Participants will be randomized 1:1 to receive enteral dextrose (n = 30) or water (placebo, n = 30) infusion for 24 hours. The primary outcome is the circulating interleukin-6 level measured after the 24-hour infusion compared between dextrose and placebo groups. Secondary outcomes include postinfusion circulating insulin, incretin, and other proinflammatory cytokine levels, as well as incidence of hyperglycemia and hypoglycemia during the infusion period.Discussion: This trial will characterize the effects of early enteral dextrose on endogenous endocrine pathways and the systemic inflammatory response in sepsis. The results of this trial will inform future larger interventional studies of early enteral nutrients in critically ill patients with sepsis. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to compare national estimates of self-reported and measured height and weight, BMI, and obesity prevalence among adults from US surveys.Methods: Self-reported height and weight data came from the National Health and Nutrition Examination Survey (NHANES), the National Health Interview Survey, and the Behavioral Risk Factor Surveillance System for the years 1999 to 2016. Measured height and weight data were available from NHANES. BMI was calculated from height and weight; obesity was defined as BMI ≥ 30.Results: In all three surveys, mean self-reported height was higher than mean measured height in NHANES for both men and women. Mean BMI from self-reported data was lower than mean BMI from measured data across all surveys. For women, mean self-reported weight, BMI, and obesity prevalence in the National Health Interview Survey and Behavioral Risk Factor Surveillance System were lower than self-report in NHANES. The distribution of BMI was narrower for self-reported than for measured data, leading to lower estimates of obesity prevalence.Conclusions: Self-reported height, weight, BMI, and obesity prevalence were not identical across the three surveys, particularly for women. Patterns of misreporting of height and weight and their effects on BMI and obesity prevalence are complex. [ABSTRACT FROM AUTHOR]

Introduction: Targeting repeating‐pattern atrial fibrillation (AF) sources (reentry or focal drivers) can help in patient‐specific ablation therapy for AF; however, the development of reliable and accurate tools for locating such sources remains a major challenge. We describe iterative catheter navigation (ICAN) algorithm to locate AF drivers using a conventional circular Lasso catheter. Methods and Results: At each step, the algorithm analyzes 10 bipolar electrograms recoded at a given catheter location and the history of previous catheter movements to determine if the source is inside the catheter loop. If not, it calculates new coordinates and selects a new position for the catheter. The process continues until a source is located. The algorithm was evaluated in a computer model of atrial tissue with various degrees of fibrosis under a broad range of arrhythmia scenarios. The latter included slow and fast reentry, macroreentry, figure‐of‐eight reentry, and fibrillatory conduction. Depending on the initial distance of the catheter from the source and scenario, it took about 3 to 16 steps to localize an AF source. In 94% of cases, the identified location was within 4 mm from the source, independently of the initial position of the catheter. The algorithm worked equally well in the presence of patchy fibrosis, low‐voltage areas, fragmented electrograms, and dominant‐frequency gradients. Conclusions: AF repeating‐pattern sources can be localized using circular catheters without the need to map the entire tissue. The proposed algorithm has the potential to become a useful tool for patient‐specific ablation of AF sources located outside the pulmonary veins. [ABSTRACT FROM AUTHOR]

Cardiac Resynchronization Therapy and QRS Axis. Background: Mildly symptomatic heart failure (HF) patients derive substantial clinical benefit from cardiac resynchronization therapy with defibrillator (CRT-D) as shown in MADIT-CRT. The presence of QRS axis deviation may influence response to CRT-D. The objective of this study was to determine whether QRS axis deviation will be associated with differential benefit from CRT-D. Methods : Baseline electrocardiograms of 1,820 patients from MADIT-CRT were evaluated for left axis deviation (LAD: quantitative QRS axis -30 to -90) or right axis deviation (RAD: QRS axis 90-180) in left bundle branch block (LBBB), right bundle branch block (RBBB), and nonspecific interventricular conduction delay QRS morphologies. The primary endpoints were the first occurrence of a HF event or death and the separate occurrence of all-cause mortality as in MADIT-CRT. Results: Among LBBB patients, those with LAD had a higher risk of primary events at 2 years than non-LAD patients (20% vs 16%; P = 0.024). The same was observed among RBBB patients (20% vs 10%; P = 0.05) but not in IVCD patients (22% vs 23%; P = NS). RAD did not convey any increased risk of the primary combined endpoint in any QRS morphology subgroup. When analyzing the benefit of CRT-D in the non-LBBB subgroups, there was no significant difference in hazard ratios for CRT-D versus ICD for either LAD or RAD. However, LBBB patients without LAD showed a trend toward greater benefit from CRT therapy than LBBB patients with LAD (HR for no LAD: 0.37, 95% CI: 0.26-0.53 and with LAD: 0.54, 95% CI: 0.36-0.79; P value for interaction = 0.18). Conclusions: LAD in non-LBBB patients (RBBB or IVCD) is not associated with an increased benefit from CRT. In LBBB patients, those without LAD seem to benefit more from CRT-D than those with LAD. (J Cardiovasc Electrophysiol, Vol. 24, pp. 442-448, April 2013) [ABSTRACT FROM AUTHOR]

We describe a unique presentation of arrhythmogenic right ventricular dysplasia (ARVD) in a 14-year-old Caucasian male who was additionally diagnosed with long QT syndrome (LQTS). Genetic testing eventually confirmed the diagnosis of both ARVD and LQTS, which combined, to our knowledge, has not been reported in the literature. [ABSTRACT FROM AUTHOR]

QRS Fragmentation and the Risk of Sudden Cardiac Death in MADIT II. Background: QRS fragmentation (fQRS) has been reported as a useful ECG parameter in predicting mortality in high-risk postinfarction patients. Its prognostic value for sudden cardiac death (SCD) and ventricular arrhythmias in ischemic cardiomyopathy (ICM) remains unknown. Methods: MADIT II enrollment 12-lead ECGs were analyzed for fQRS defined as RSR' patterns (≥1 R' or notching of S or R wave) in patients with a normal QRS duration and >2 notches on the R or S wave in patients with abnormal QRS duration, present in 2 contiguous leads. Exclusion criteria included a paced rhythm and an uninterpretable or incomplete ECG. Study endpoints included SCD, SCD or appropriate implantable cardioverter defibrillator (ICD) shock, and total mortality (TM). Results: Of the 1,232 ECGs reviewed, 1,040 were of suitable quality for fQRS analysis. QRS fragmentation was found in 33% of patients in any leads, in 10% of patients in anterior leads, in 8% of patients in lateral leads and in 21% of patients in inferior leads. Anterior and lateral location of QRS fragmentation was not associated with follow-up events. Inferior location of fQRS was found to be predictive of SCD/ICD shock (hazard ratio [HR] 1.46, P = 0.032), SCD (HR 2.05, P = 0.007), and TM (HR 1.44, P = 0.036). This association was driven primarily by the increase in events found in LBBB patients: SCD/ICD shock (HR 2.05, P = 0.046), SCD (HR 4.24, P = 0.002), and TM (HR 2.82, P = 0.001). Conclusions: Fragmented QRS, especially identified in inferior leads, is predictive of SCD, SCD or appropriate ICD shock, and all-cause mortality in patients with ICM. Identifying inferior fQRS in patients with LBBB is of particular prognostic significance and should reinforce the use of ICD therapy in this high-risk group. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1343-1348, December 2012) [ABSTRACT FROM AUTHOR]

Risk of Mortality for Ventricular Arrhythmia. Background: There are limited data regarding the incidence and prognostic significance of ventricular arrhythmias (VA) in ambulatory continuous flow left ventricular assist device (LVAD) patients. Methods: Sixty-one consecutive patients from November 1, 2006 through December 31, 2010 with an LVAD and implantable cardioverter defibrillator that survived to discharge from the LVAD implantation admission were studied. Follow-up began from date of discharge with both devices in situ and ended with death, transplant, on June 1, 2011. Pre-LVAD VA history was related to the primary endpoints of post-LVAD VA, mortality, and the combined endpoint of post-LVAD VA/mortality. Results: During a mean follow-up of 622 days 19 patients (31%) experienced VA (14 episodes of VT, 5 episodes of VF). Pre-LVAD VA was predictive of post-LVAD VA (hazard ratio [HR] 2.91, P = 0.026) and the combined post-LVAD VA/mortality endpoint (HR 2.70, P = 0.021) but only displayed a nonsignificant association with mortality (HR 2.30, P = 0.11). In multivariate analysis, pre-LVAD VA remained a significant predictor of post-LVAD VA (HR 2.84, P = 0.03) and the combined post-LVAD VA/mortality endpoint (HR 2.65, P = 0.025). Post-LVAD VA was the strongest univariate predictor of mortality (HR 13.92, P < 0.001) and remained so after multivariate adjustment (HR 9.69, P = 0.001). Post-LVAD VA occurred at a mean of 1 year from mortality events with 45% within 1 month. Conclusions: Pre-LVAD VA is a significant predictor of post-LVAD VA but not of mortality. VA in the continuous flow LVAD population carries a significant risk of mortality often within the first month. (J Cardiovasc Electrophysiol, Vol. 23, pp. 515-520, May 2012) [ABSTRACT FROM AUTHOR]

Coronary Revascularization and Long-Term Mortality in MADIT-II. Introduction: Coronary revascularization (CR) may reduce arrhythmia risk and improve long-term outcome in patients with left ventricular dysfunction. This study was designed to evaluate the effect of elapsed time from CR on long-term mortality and arrhythmic risk among patients who receive an implantable cardioverter defibrillator (ICD). Methods and Results: We evaluated the risk of 8-year mortality by elapsed time from CR to ICD implantation (categorized as: no CR; recent CR [<2 years]; or nonrecent CR [≥2 years], and assessed as a continuous measure) among 720 ICD recipients enrolled in the Multicenter Automatic Defibrillator Trial-II. At 8years of follow-up, patients who did not undergo CR and those who underwent nonrecent CR had significantly higher mortality rates than patients who underwent recent CR (54%, 54%, and 36%, respectively; P < 0.001). Multivariate analysis demonstrated that no- and nonrecent CR were associated with respective 48% (P = 0.022) and 67% (P < 0.001) increases in mortality risk compared with recent CR. Assessment of time from CR as a continuous measure showed that every year elapsed from CR was associated with an adjusted 6% increase in 8-year mortality (P < 0.001), and in respective 6% (P < 0.001) and 6% (P = 0.003) increased risk for in-trial appropriate ICD therapy of ventricular tachyarrhythmias and appropriate ICD shocks. Conclusions: We observed a direct relationship between elapsed time from CR and long-term mortality following ICD implantation. The favorable long-term effect on outcome of recent CR may be related to a time-dependent effect of CR on ventricular arrhythmic burden and the need for appropriate ICD shocks. (J Cardiovasc Electrophysiol, Vol. pp. 1-6) [ABSTRACT FROM AUTHOR]

Ann Noninvasive Electrocardiol 2011;16(4):403-406 [ABSTRACT FROM AUTHOR]

Preventive Cardiac Resynchronization in the Elderly. Background: Elderly patients comprise a large portion of patients with heart failure (HF). Limited data exist on the effectiveness of cardiac resynchronization therapy with defibrillator (CRT-D) in patients with mild HF symptoms in this population. Methods and Results: The benefit of CRT-D compared with ICD-only therapy in reducing HF or death was assessed by age categories (prespecified as <60 [n = 548], 60-74 [n = 941], and ≥75 [n = 331] years) among 1,820 patients in MADIT-CRT. In patients with ICD-only, there was a graded age-related increase in the Kaplan-Meier cumulative probability of HF or death at 3-year follow-up (19%, 33%, and 36%, in patients aged <60, 60-74, and ≥75 years, respectively, P = 0.003). Multivariate analysis demonstrated that CRT-D therapy was associated with a significant reduction in the risks of HF or death in patients aged 60-74, and ≥75 years (HR = 0.57, P = <0.001 and HR = 0.59, P = 0.017, respectively), and no significant benefit in patients aged <60 years (HR = 0.81, P = 0.3; P-value for all treatment-by-age interactions >0.10). There was no significant difference in the rate of device-related adverse events within 90 days following CRT-D implantation among age-subgroups (16.7%, 15.7%, and 11.7%, in patients <60, 60-74, and ≥75 years, respectively, P = 0.42). Conclusion: CRT-D was associated with a significant clinical benefit in older patients (≥60 years) during an average 2.4-year follow-up. These effects were preserved for the elderly patients ≥75 years of age but attenuated in patients <60 years. Elderly patients had no increase in device-related adverse events compared with younger patients. (J Cardiovasc Electrophysiol, Vol. 22, pp. 892-897, August 2011) [ABSTRACT FROM AUTHOR]

Objectives: Critical care medicine (CCM) is of growing interest among emergency physicians (EPs), but the number of CCM-trained EPs and their postfellowship practice is unknown. This study’s purpose was to conduct a descriptive census survey of EPs who have completed or are currently in a CCM fellowship. Methods: The authors created a Web-based survey, and requests to participate were sent to EPs who have completed or are currently in a CCM fellowship. Responses were collected over a 12-month period. Physicians were located via multiple whom electronic mailing lists, including the Emergency Medicine Section of the Society of Critical Care Medicine, Critical Care Section of the American College of Emergency Physicians, and the Emergency Medicine Residents’ Association. The authors also contacted CCM fellowship coordinators and used informal networking. Data were collected on emergency medicine (EM) and other residency training; discipline, duration, and year of CCM fellowship; current practice setting; and board certification status, including the European Diploma in Intensive Care (EDIC). Results: A total of 104 physicians completed the survey (97% response rate), of whom 73 had completed fellowship at the time of participation, and 31 of whom were in fellowship training. Of those who completed fellowship, 36/73 (49%) practice both EM and CCM, and 45/73 (62%) practice in academic institutions. Multiple disciplines of fellowship were represented: multidisciplinary (39), surgical (28), internal medicine (16), anesthesia (14), and other (4). Together, the CCM fellowships at the University of Maryland R Adams Cowley Shock Trauma Center and the University of Pittsburgh have trained 42% of all EM-CCM physicians, with 38 other institutions training from one to four fellows each. The number of EPs completing CCM fellowships has risen: from 1974 to 1989, 12 EPs; from 1990 to 1999, 15 EPs; and from 2000 to 2007, 43 EPs. Conclusions: Emergency physicians are entering CCM fellowships in increasing numbers. Almost half of these EPs practice both EM and CCM. ACADAEMIC EMERGENCY MEDICINE 2010; 17:325–329 © 2010 by the Society for Academic Emergency Medicine [ABSTRACT FROM AUTHOR]

Introduction: Implantable cardioverter-defibrillator (ICD) therapy is well established in preventing sudden cardiac death in patients with left ventricular dysfunction. The influence of right ventricular (RV) function on ICD therapy for sudden cardiac death (SCD) is not known. Methods: We retrospectively studied 222 patients receiving an ICD for primary prevention of SCD. Baseline clinical and echocardiographic data were gathered. RV systolic function was qualitatively assessed as normal or abnormal (described as mildly, moderately, or severely reduced). Primary endpoint was combined ICD therapy or death and secondary endpoint was ICD therapy alone. Results: The mean follow-up was 940 ± 522 days. The mean left ventricular ejection fraction was 0.23 ± 0.07. By Kaplan-Meier analysis, RV dysfunction was predictive of combined ICD therapy or death when comparing between normal and abnormal RV function (P = 0.008) and among qualitative ranges of RV function (P = 0.012). RV dysfunction was not predictive of ICD therapy alone with either type of classification. After adjusting for clinical covariates, severe RV dysfunction was predictive of the combined endpoint of ICD therapy or death (HR 2.02, 95% CI 1.04–3.92, P = 0.037). Conclusion: Severe RV dysfunction appears to be an independent predictor of the combined endpoint of ICD therapy or death. RV dysfunction does not reliably predict the incidence of ICD therapy alone. [ABSTRACT FROM AUTHOR]

Atrioventricular nodal (AVN) ablation with concomitant pacemaker implantation is one of the strategies that reduce symptoms in patients with atrial fibrillation (AF). However, the long-term adverse effects of right ventricular (RV) apical pacing have led to the search for alternating sites of pacing. Biventricular pacing produces a significant improvement in functional capacity over RV pacing in patients undergoing AVN ablation. Another alternative site for pacing is direct His bundle to reduce the adverse outcome of RV pacing. Here, we present a case of direct His bundle pacing using steerable lead delivery system in a patient with symptomatic paroxysmal AF with concurrent AVN ablation. [ABSTRACT FROM AUTHOR]

The author reflects on a study on implantable cardioverter defibrillator (ICD) for patients with ischemic cardiomyopathy. The author claim that only a minority of patients received appropriate therapies for the first year of implant. They further emphasize the study's progress in identifying better ICD candidates, addressing the sudden death problem in patients, and reducing morbidity of ICD systems.

Background: The availability of stored intracardiac electrograms from implantable defibrillators (ICDs) has facilitated the study of the mechanisms of ventricular tachyarrhythmia onset. This study aimed to determine the patterns of initiation of ventricular fibrillation (VF) in Multicenter Automatic Defibrillator Implantation Trial (MADIT) II patients along with associated electrocardiogram (ECG) parameters and clinical characteristics. Methods: Examination of stored electrograms enabled us to evaluate the rhythm preceding each episode of VF and to calculate (intracardiac) ECG parameters including QT, QT peak (QTp), coupling interval, and prematurity index. Results: Sixty episodes of VF among 29 patients (mean age 64.4 ± 2.5 years) were identified. A single ventricular premature complex (VPC) initiated 46 (77%) episodes whereas a short-long-short (SLS) sequence accounted for 14 (23%) episodes. Of the 29 patients studied, 23 patients had VF episodes preceded by a VPC only, two patients with SLS only, and four patients with both VPC and SLS-initiated episodes. There were no significant differences between initiation patterns in regards to the measured ECG parameters; a faster heart rate with SLS initiation (mean RR prior to VF of 655 ± 104 ms for SLS and 744 ± 222 ms for VPC) approached significance (P = 0.06). The two patients with SLS only were not on β-blockers compared to 83% of the VPC patients. Conclusion: Ventricular fibrillation is more commonly initiated by a VPC than by a SLS sequence among the MADIT II population. Current pacing modes designed to prevent bradycardia and pause-dependent arrhythmias are unlikely to decrease the incidence of VPC-initiated episodes of VF. [ABSTRACT FROM AUTHOR]

Introduction: We aim to evaluate the mortality benefit from defibrillator therapy in eligible elderly patients. Effective primary prevention of sudden cardiac death with implantable cardioverter defibrillators is well demonstrated in patients with coronary disease and depressed ventricular function. Methods and Results: Among 1,232 patients enrolled with prior infarct and left ventricular ejection fraction ≤0.30, 204 were ≥75 years old. Of these 204 patients, 121 underwent defibrillator implant. Relative to the younger patients, those ≥75 years had a higher incidence of atrial fibrillation, elevated blood urea nitrogen (BUN), widened QRS, and lower use of beta-blockers and HMG-CoA reductase inhibitors. Relevant clinical covariates were similar in elderly patients randomized to conventional and defibrillator therapy. The hazard ratio for the mortality risk in patients ≥75 years assigned to defibrillator implant compared with those in conventional therapy was 0.56 (95 confidence interval 0.29–1.08; P = 0.08) after a mean follow-up of 17.2 months. Comparatively, the hazard ratio in patients <75 years assigned to defibrillator implant was 0.63 (0.45–0.88; P = 0.01) after 20.8 months. Elderly patients had similar reductions in quality of life (QoL) regardless of treatment randomization. Scores through Health Utilities Index Mark III (HUI) Questionnaire changes from baseline to 1 year were −0.22 for patients with conventional therapy versus −0.20 for patients with ICD, and −0.36 versus −0.27 at 2 years, respectively (P = NS). Conclusion: The implantable defibrillator is associated with an equivalent reduction of mortality in elderly and younger patients, with no compromise in the QoL in the older age subjects. [ABSTRACT FROM AUTHOR]

The incidence of sudden cardiac death increases with age and the proportion of the US population in progressively more advanced age strata is dramatically increasing. While several randomized controlled trials support the use of implantable cardioverter-defibrillators (ICDs) to reduce sudden cardiac death, no randomized trials have been done to evaluate whether there is a mortality benefit of ICDs in an elderly population. In the current review, the authors examined six of the major primary prophylaxis ICD trials for evidence pertaining to the elderly. A majority of these trials suggest a mortality benefit in the elderly patients who have met the stringent inclusion and exclusion criteria to be eligible for enrollment. Subset analysis seems to support ICD implantation in a highly select elderly subgroup, but a prospective randomized trial may be warranted. [ABSTRACT FROM AUTHOR]

Focuses on performing a noninvasive assessment of the biventricular (BiV) pacing system using the 12-lead electrocardiogram and intracardiac electrograms. Heart failure in which BiV pacing system is used; Difference of the pacing system from the conventional permanent pacemaker; Factors that can influence the accurate assessment of BiV pacer function.

Hybrid Therapy for Atrial Fibrillalion. Introduction: Maintenance of sinus rhythm in patients with recurrent atrial fibrillation is often difficult to achieve with pharmacologic therapy. Complex catheter ablative procedures are being developed, but efficacy and safely issues remain In be clarified. We hypothesized that combined pharmacologic and simple ablative therapies in a targeted subset of patients will improve success in flit treatment of atrial fibrillation. Methods and Results: We identified 13 patients (mean age 61.5 ± 16.2 years) with atrial fibrillation who converted to electrocardiographic atrial flutter during antiarrhythmic drug treatment. Surface ECG suggested “typical” atrial flutter in 11 patients and “atypical” atrial flutter in 2. Intracardiac mapping and entrainment studies revealed 9 patients had counterclockwise isthmus-dependent atrial flutter, and the remaining 4 had complex activation patterns, suggesting the presence of multiple wavefronts. All 9 patients with typical atrial flutter underwent successful ablation. None of the 4 patients with complex activation patterns had successful ablation. Patients were followed for recurrences of atrial arrhythmias via clinic visits, record review, and interviews. In patients who underwent successful ablation and continued (in antiarrhythmic drugs, 88.9% remain in sinus rhythm after a mean follow-up of 14.3 ± 6.9 months (range 1 to 28). Conclusion: In patients who experience conversion of atrial fibrillation to atrial flutter during antiarrhythmic drug treatment, ablation and continuation of pharmacolagic therapy is a safe and effective means of achieving and maintaining sinus rhythm. [ABSTRACT FROM AUTHOR]

Introduction: Substantial progress has been made in our understanding of transmural activation across ventricular muscle through studies of excitation patterns and potential distributions. In contrast, repolarization sequences are poorly understood because of experimental difficulties in mapping action potential durations (APDs) using extracellular electrodes. Methods and Results: Langendorff-perfused guinea pig hearts and isolated coronary-perfused left ventricular sheet preparations were stained with the voltage-sensitive dye RH-421 and optical APs were recorded with a photodiode array. Epicardial maps were constructed using a triangulation method applied to matrices of activation and repolarization times determined from (dF/dt)max and (d²F/dt²)max respectively. Numerical simulations were carried out based on: (1) modified Luo-Rudy model; (2) the three-dimensional architecture of ventricular fibers; and (3) the intrinsic spatial distribution of APDs. In ventricular sheets, epicardial stimulation elicited elliptical activation patterns with the major axis aligned with the longitudinal axis of epicardial fibers. When the pacing electrode was progressively inserted from epicardium to endocardium, the major axes rotated gradually, clockwise by 45°, and the eccentricity decreased from 2 to 1.14. Repolarization showed a relatively uniform pattern, independent of pacing site, beginning at the apex and spreading to the base. Conclusion: In experiments and simulations, the helical rotation of epicardial excitation isochrones caused by pacing at increasing depth in the myocardium correlated with the helical three-dimensional architecture of ventricular fibers. In contrast, repolarization was independent of the activation sequence and was mainly guided by spatial differences in APDs between apex and base. [ABSTRACT FROM AUTHOR]

A brother and sister, presented to our Arrhythmia Clinic for evaluation of possible long QT syndrome (LQTS). They are 18 and 15 years of age, respectively. Their mother has been diagnosed with LQTS and the family history is remarkable for a number of sudden deaths. The electrocardiogram (ECG) of the sister is presented in Figure 1. The siblings had been followed by pediatric cardiology since infancy and now they are referred for further evaluation. They are both asymptomatic and very active teenagers, and are not on any medications. Echocardiograms were normal. Holter monitoring also did not show any rhythm abnormalities in either sibling.The mother had been evaluated as a teenager when she had a presyncopal episode while running track in high school. Her QT interval on one 12-lead tracing showed borderline prolonged QT. She had originally been started on beta-blockers, but she had taken herself off of these over the years. The family history is significant for sudden deaths in several distant relatives. In addition, the mother's aunt had an abnormal ECG in the setting of multiple syncopal episodes. In the interim, she had been treated with beta-blockers. [ABSTRACT FROM AUTHOR]

Ann Noninvasive Electrocardiol 2010;15(4):384-386 [ABSTRACT FROM AUTHOR]

A 78-year-old man with an implantable cardioverter-defibrillator (ICD) for ischemic cardiomyopathy and prior ventricular tachycardia (VT) ablation presented with abdominal pain and was found to have a small bowel obstruction requiring immediate surgery. His postoperative course was complicated by incessant VT leading to multiple ICD shocks. He was referred to our hospital for repeat VT ablation. TEE revealed a wire coiled in the right pulmonary artery. This is the first reported identification of an embolized wire by transesophageal three-dimensional echocardiography. [ABSTRACT FROM AUTHOR]