Michael Cao

Postoperative Performance of the Quartet® Left Ventricular Heart Lead

Promote® Q CRT‐D and Quartet® LV Lead Study. Introduction: The Quartet® left ventricular (LV) lead is the first with 4 pacing electrodes (tip and 3 rings) that enables pacing from 10 different pacing vectors. Postoperative performance of this lead was evaluated in a prospective, nonrandomized, multicenter IDE study.

Impact of shock energy and ventricular rhythm on the success of first shock therapy: The ALTITUDE first shock study

BACKGROUND The efficacy of shock in converting different ventricular tachyarrhythmias has not been well characterized in a large natural-practice setting. OBJECTIVE To determine shock success rate by energy and ventricular rhythm in a large cohort of patients with implantable cardioverter-defibrillators. METHODS Two thousand patients with 5279 shock episodes were randomly sampled for analysis from the LATITUDE remote monitoring system. Within an episode, the rhythm preceding therapy (shock or antitachycardia pacing [ATP]) was adjudicated. Patients who died after unsuccessful implantable cardioverter-defibrillator shocks did not transmit final remote monitoring data and were not included in the study. RESULTS Of 3677 shock episodes for ventricular tachyarrhythmia, 2679 were treated with shock initially and were classified as monomorphic ventricular tachycardia ( n = 1544), polymorphic/monomorphic ventricular tachycardia (n = 371), or ventricular fibrillation (n = 764). The success rate after the first, second, and final shock averaged 90.3%, 96.4%, and 99.8%, respectively. After unsuccessful initial ATP (n = 998), the first, second, and final shock was successful in 84.8%, 92.9%, and 100% of the episodes. The success rate after the first or second shock was significantly lower after failed ATP compared to shock as first therapy (both P<.001). Among episodes treated initially with shock, the success rate for monomorphic ventricular tachycardia (89.2%) when treated with energy level ≤ 20 J was significantly higher than that for ventricular fibrillation (80.8%) (P = .04). The level of shock energy was a significant predictor of the success of the first shock (odds ratio 1.16; 95% confidence interval 1.03-1.30; P = .013). CONCLUSIONS The success rate of first shock as first therapy is approximately 90%, but was lower after failed ATP. Programming a higher level of energy after ATP is suggested.

Treatment of ventricular tachycardia in patients with heart failure.

Heart failure is a major public health concern that is frequently complicated by ventricular arrhythmias. Sustained ventricular tachycardia is associated with an increased risk for progressive heart failure and sudden death. We summarize the current management strategies for ventricular tachycardia in heart failure patients, including implantable cardioverter-defibrillator therapy, pharmacologic therapy, catheter ablation techniques, ventricular assist device therapy, and heart transplantation.

Unoperated Congenitally Corrected Transposition of the Great Arteries, Nonrestrictive Ventricular Septal Defect, and Pulmonary Stenosis in Middle Adulthood Do Multiple Wrongs Make a Right?

Submitted May 6, 2011; Accepted August 3, 2011. The survival into adulthood of patients with unoperated complex congenital heart disease with anomalies often considered life threatening in infancy and childhood requires a complex interplay of “balanced” defects allowing for cardiovascular physiology compatible with long-term survival. We report on a series of three cases from our advanced imaging database of middle-aged adults presenting with multiple similar defects providing a hemodynamically balanced circulation. The constellation of defects seen in each of these patients included congenitally corrected transposition of the great arteries, a large nonrestrictive ventricular septal defect, valvular pulmonary stenosis, and in two cases anomalous coronary arteries. Cardiovascular computed tomographic angiography (CCTA) and cardiovascular magnetic resonance imaging (CMR) were important to the characterization of the multiple defects and their three-dimensional relationships in these cases. Treatment decisions in patients with this constellation of findings are challenging, given the limited data due to the rarity of survival of patients with these defects into middle adulthood and the paucity of data related to decisions and approaches to medical management, surgical correction, or transplantation.

Spinal Cord Stimulation: A Triple Threat Therapy?

In the Journal, Liu et al. provide compelling evidence that acute spinal cord stimulation (SCS) improves myocardial energetics, ventricular function, and efficiency in a porcine model of postinfarct heart failure (HF).1 The presumptive mechanism for this improvement (not explored in this study) is attributed to both reduced sympathetic stimulation, and enhanced parasympathetic activity, which is thought to be vagally mediated.2,3 These salutary effects have been reported to occur even in the presence of neurohormonal blockade with beta-receptor blocker and angiotension inhibitor therapies.3 Compensatory changes in the autonomic nervous system activity are known to impact adversely the clinical course of HF and to cause a host of adverse structural changes that further worsen cardiac function. Advances in pharmacologic therapy for HF over the past 20 years have been achieved by attenuating these changes with drugs like betareceptor blockers, angiotensin converting enzyme inhibitors, angiotensin receptor blockers, and aldosterone antagonists. These therapies greatly improve functional status, cause neurohormonal and structural reverse remodeling, reduce hospitalization, and increase survival.4 There are compelling parallels between the pharmacologic neurohormonal agents and stimulatory neurohormonal therapy achieved with SCS.5 A confluence of animal and human data indicate that sympathetic activation can predispose to ventricular arrhythmias and that parasympathetic activation is protective.6,7 Similarly, particularly in HF, treatments that block excitatory neural traffic to the heart and achieve enhanced parasympathetic effects like beta-blocker receptor therapy and angiotension inhibitor therapy can increase the threshold to arrhythmia development and sudden death through direct and indirect effects.8-11 Issa et al. demonstrated in a canine model of postinfarction HF that SCS reduces the incidence of transient ischemia related ventricular arrhythmias while simultaneously decreasing sinus rate, increasing the PR interval, and reducing systolic blood pressure.12 Lopshire et al. evaluated the incidence of ventricular tachyarrhythmias with chronic SCS in canines after left anterior descending artery embolization and ICD implantation. The animals were assigned to control medical therapy (carvedilol), or SCS. After 10 weeks, the greatest recovery in

ATRIAL FIBRILLATION AND OUTCOMES IN A LARGE COHORT OF CRT RECIPIENTS: RESULTS FROM THE ALTITUDE STUDY

Abstract Category: 26. Clinical Electrophysiology—Supraventricular ArrhythmiasSession-Poster Board Number: 1161-402Authors: David A. Cesario, Brian Powell, Michael Cao, Leslie Saxon, John Day, Nicholas Wold, Keck School of Medicine at USC, Los Angeles, CABackground: Atrial ibrillation (AF) is a common co-morbidity in patients (pts) receiving Cardiac Resynchronization Therapy deibrillators (CRT-D). The effect of AF on pt outcomes in CRT-D remains incompletely understood. We sought to evaluate outcomes in CRT-D pts according to AF burden, using the Boston Scientiic LATITUDE remote monitoring system ALTITUDE database.Methods: The AF burden was determined in the irst year of implant using atrial tachycardia response (ATR) episode length and pacing mode. Pts were grouped as having Persistent AF (ATR > 7 days or programmed VVI/R, DDI/R mode), Paroxysmal AF 1-7 days (1 day < ATR < 7 days), Paroxysmal AF < 1 day (1 minute < ATR < 1 day), or no AF (all others). Survival after the irst year was evaluated between groups using Cox Proportional Hazard models adjusting for age, gender, percent CRT pacing and shock therapy in year 1.Results: The 23,743 pts studied consisted of pts with no AF (N=13,331, 56%), Persistent AF (N=4,711, 20%), Paroxysmal AF 1-7 days (N=896, 4%), and Paroxysmal AF < 1 day (N=4,805, 20%). Pts with AF were more likely to be male (78% vs 68%), older (72 11 vs 69 11), have lower CRT pacing (median 97% vs 99%) and more likely to have a shock episode within 1 year post implant (13% vs 6.4%), all p<.001. When compared to no AF, all 3 AF groups exhibited decreased survival (igure).Conclusion: In a large cohort of CRT recipients, AF was identiied as an independent marker for decreased survival. This observation was signiicant even for a very low burden of AF.

Impact of Relaxation Training on Patient-Perceived Measures of Anxiety, Pain, and Outcomes after Interventional Electrophysiology Procedures

Background: Electrophysiology procedures vary in invasiveness, duration, and anesthesia utilized. While complications are low and efficacy high, cases are elective and patient experiences related to anxiety, pain, and perceived outcomes are not well studied. We sought to determine if a 30‐minute audio compact disc (CD) that teaches relaxation techniques and wellness perception prior to an elective procedure impacts validated measures of anxiety, pain, and procedural outcomes.

Lead Extraction in Congenital Heart Disease Patients – Indications, Technique and Experience

Implantation of pacemakers and implantable cardioverter defibrillators (ICDs) are common procedures associated with very low complication rates(1-3). Device therapy is frequently used in the management of adult congenital heart disease (ACHD) patients given the high prevalence of arrhythmic complications encountered in this population. The ACHD population continues to grow at a rapid pace. It is estimated that that there are currently more surviving adults with severe congenital heart disease (CHD) than children(4). The prevalence of arrhythmias and conduction disorders in adults with surgically treated CHD as well as those with specific congenital defects associated with conduction system abnormalities has led to an increasing need for implantable devices (both pacemakers and ICDs) in these patients (5). Unfortunately, as the indications for device implantation in patients with CHD have increased, so have the rate of device related infections and other complications leading to a growth in referrals for lead extraction in this expanding patient population(6-8). A thorough understanding of the role that lead extraction plays in this growing subgroup of patients is therefore critical for any implanting and extracting practitioner.

Selection of Patients for CRT—Prevention or Reversal of Remodeling as a Therapeutic Endpoint for CRT

Currently approved FDA implantation criteria for patient selection for cardiac resynchronization therapy (CRT) include advanced functional class heart failure that is treated optimally on a standard medical regimen, QRS duration >120 msec, and left ventricular ejection fraction (LVEF) <35%.1 In this small nonrandomized study, Fung et al. investigate the effects of CRT in patients with relative preservation of LV function (mean LVEF 39%), mechanical dysynchrony, and class III symptoms.2 Unlike other ongoing large-scale randomized studies evaluating CRT in less symptomatic patients with LVEF <30%, this trial suggests that the reverse remodeling can be expected as early as 3 months after CRT in less compromised ventricles.3,4 The patients in this study2 had mild-to-moderate ventricular enlargement with a mean diastolic dimension of 5.1 cm and significant reductions to normal values were also observed (5.1 vs 4.6 cm, P < 0.001). Additional improvements in LVEF (39.1 vs 44.2, P < 0.05) and several other measures of systolic function were also seen. These benefits were similar in magnitude to those observed in a retrospectively identified group of registry patients undergoing CRT for conventional indications.