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Boaz Avitall

Publications and source records attributed to Boaz Avitall.

10 recordsLinked to original sources
PubMed2005

Ablation of atrial-ventricular junction tissues via the coronary sinus using cryo balloon technology.

INTRODUCTION: The coronary sinus (CS) can provide access to targets across and within the atrioventricular (AV) junction. METHODS: In 12 dogs (32 +/- 3 Kg), cryo balloons (10-19 mm) were applied to regions of the AV junction for 3 minutes at a temperature of -75.9( composite function) +/- 9(composite function)C (ranging -57 to -83). Electrical activity and pacing within the CS were assessed pre and post ablation and at least 3 months later in 9 dogs. In the 3 other dogs, hearts were examined immediately after cryo ablation. CS and circumflex angiography was performed pre and post ablation. The hearts, CS, and Cx were then examined for structural injury. The AV junction was sectioned and the hearts were immersed in Tetrazolium, and the lesions were inspected for transmurality across the AV groove. RESULTS: In 3/12 dogs the distal CS cryo lesions resulted in inferior ST segment depression that resolved within 5 minutes. There was no arrhythmia or hemodynamic changes. No CS electrical activity was noted post ablation. The pacing threshold increased from 2 +/- 2.3 mA to 7.4 +/- 3.6 mA (p < 0.001). Pathological examination of 3 acute hearts revealed hematomas. There was no pericardial effusion. No evidence of stenosis or thrombosis was seen within the CS and the circumflex artery. After 3 months of recovery, transmural lesions across the AV groove were present in all of the targeted AV regions. CONCLUSION: Intra-CS cryo balloon ablation is safe and can potentially replace endocardial RF ablation targeting the AV junction and the CS muscular sleeve.

Analysis of Variance↗
PubMed2004

The safety and efficacy of multiple consecutive cryo lesions in canine pulmonary veins-left atrial junction.

OBJECTIVE: The purpose of the study is to evaluate the safety and efficacy of multiple cryo lesions in canine pulmonary veins-left atrial junction. BACKGROUND: The use of radiofrequency to achieve electrical isolation of the pulmonary veins (PVs) has been associated with PV stenosis. No information is currently available concerning the safety and the electrophysiological effects of multiple and consecutive cryo applications at the PV-left atrial junction. METHODS: Liquid N(2)O was delivered into semi-compliant 15 to 22-mm-diameter balloons. In 13 dogs weighing 34 +/- 2 kg, one to four consecutive cryo lesions were randomly applied to each PV for 3 minutes in 6-minute intervals. The pre- and post-PV sizes were recorded by angiography. Electrogram activity and pacing thresholds were recorded before and after cryo. PV patency and the PV-atrial tissue characteristics were evaluated grossly and histologically. RESULTS: Pacing capture was not possible with 10 mA postablation in 26/46 (57%) electrodes, and in 20 (43%) electrodes pacing threshold increased from 1.6 +/- 1.7 mA to 7.8 +/- 3.2 mA. The total elimination of recorded electrograms was noted in 22%, 29%, and 18% following 1, 2, and 3 cryo lesions respectively. After 4 lesions this value increased to 53%. No significant changes in PV diameter were recorded in any of the veins pre vs the terminal study. The PVs and PV-atrial interface tissue were soft, compliant, and without collagen or cartilaginous tissue. There was no hemoptysis in any of the dogs. CONCLUSION: In this study, cryo balloon technology is effective and safe regardless of the number of lesions applied and the freezing temperatures achieved. Four consecutive cryo applications result in a significant increase in pacing threshold and a decrease in activity of local atrial electrograms.

Analysis of Variance↗
PubMed2003

Outcomes of chronic heart failure.

BACKGROUND: Outcomes related to chronic heart failure (HF) remain relatively poor, despite advances in pharmacological therapy and medical and nursing care. Experts agree that outpatient care may be among the factors that affect HF outcomes. We hypothesized that the method by which outpatient care is delivered may affect outcomes in this patient population. METHODS: A prospective, randomized design was used to compare HF outcomes from 216 patients randomized to 1 of 2 home health care delivery methods for 3 months after discharge. Care was delivered by the home nurse visit (HNV) or the nurse telemanagement (NTM) method. In the latter, patients used transtelephonic home monitoring devices to measure their weight, blood pressure, heart rate, and oxygen saturation. These data were transmitted daily to a secure Internet site. An advanced-practice nurse worked collaboratively with a cardiologist and subsequently treated patients via the telephone. Both delivery methods used the same HF-specific clinical guidelines to direct care. Outcomes include HF readmissions and length of stay, anxiety, depression, self-efficacy, and quality of life. Data were primarily tested using a 2-group analysis of variance (ANOVA). We used a repeated-measures ANOVA to conduct preintervention-postintervention analyses. RESULTS: After 3 months, patients in the NTM group (n = 108; mean +/- SD age, 62.9 +/- 13.2 years; 83% African American; 64% female) had fewer HF readmissions (13 vs 24; P</=.001) with shorter lengths of stay (49.5 vs 105.0 days; P</=.001) compared with the HNV group (n = 108; mean +/- SD age, 63.2 +/- 12.6 years; 89% African American; 62% female). Hospitalization charges at 3 months were less in the NTM group compared with the HNV group ($65 023 vs $177 365; P</=.02). At 6 and 12 months, cumulative readmission charges in the NTM group were also less ($223 638 vs $500 343 [P<.03] and $541 378 vs $677 710 [P</=.16], respectively) compared with the HNV group. Quality of life was significantly improved for both groups when we compared postintervention and preintervention scores. CONCLUSION: The adaptation of state-of-the-art computerized technology to closely monitor patients with HF with advanced-practice nurse care under the guidance of a cardiologist significantly improves HF management while reducing the cost of care.

Adult↗
PubMed2003

Body surface Laplacian electrocardiogram of ventricular depolarization in normal human subjects.

INTRODUCTION: The body surface Laplacian electrocardiogram (ECG) mapping provides a noninvasive means for spatiotemporal mapping of cardiac electrical events. The aim of the present study was to explore the relationship between the Laplacian ECG and the underlying cardiac activities during ventricular depolarization in healthy human subjects. METHODS AND RESULTS: A 95-channel body surface potential ECG was recorded over the anterolateral chest from 11 healthy male subjects. The surface Laplacian (SL) ECG was estimated from the recorded potentials during QRS complex by means of a novel spline SL estimator, as well as by the conventional 5-point SL estimator for comparison purpose. A simulation study was also conducted using a realistic geometry heart-torso model in an attempt to qualitatively interpret the experimental results. For all subjects, more spatial details were observed in the SL ECG maps compared with the potential ECG maps, with spline SL more robust against noise than the 5-point SL. In total, three positive activities (denoted as P1, P2, P3) and four negative activities (denoted as N1, N2, N3, N4) in the spline SL ECG maps were observed during ventricular depolarization. Initial localized P1 and N1 activities were observed in 11 and 8 subjects, respectively. Then, the initial P1 was divided into three positive activities (P1, P2, P3) in 9 subjects. After the appearance of multiple positive activities, three negative activities (N2, N3, N4) appeared in 11, 8, and 9 subjects, respectively. Similar findings were obtained in the computer simulation study. CONCLUSION: The present study demonstrates that the SL ECG provides more spatial details than the potential ECG, and multiple simultaneously active ventricular activities could be revealed in the SL ECG maps. The results suggest that the SL ECG may provide an alternative for noninvasive mapping of cardiac electrical activity.

Adult↗
PubMed2003

New cryotechnology for electrical isolation of the pulmonary veins.

INTRODUCTION: Creation of radiofrequency lesions to isolate the pulmonary veins (PV) and ablate atrial fibrillation (AF) has been complicated by stenosis of the PVs. We tested a cryoballoon technology that can create electrical isolation of the PVs, with the hypothesis that cryoenergy will not result in PV stenosis. METHODS AND RESULTS: Lesions were created in 9 dogs (weight 31-37 kg). Cryoenergy was applied to the PV-left atrial (LA) interface. Data collected before and after ablation included PV orifice size, arrhythmia inducibility, electrogram activity, and pacing threshold in the PVs. Tissue examination was performed immediately after ablation in 3 dogs and after 3 months (4.8 +/- 1.0) in 6 dogs. After ablation there was no localized P wave activity in the ablation zone and no LA-PV conduction. Before ablation, the pacing threshold was 1.9 +/- 1.1 mA in each PV. After ablation, the pacing threshold increased significantly to 7.2 +/- 1.8 mA, or capture was not possible. Burst pacing did not induce any sustained arrhythmias. Most dogs had hemoptysis during the first 24 to 48 hours. Acute tissue examination revealed hemorrhagic injury of the atrial-PV junction that extended into the lung parenchyma. After recovery, the lesions were circumferential and soft with no PV stenosis. Histologic examination revealed fibrous tissue with no PV-LA interface thickening. CONCLUSION: This new cryoballoon technology effectively isolates the PVs from LA tissue. No PV stenosis was noted. Acute tissue hemorrhage and hemoptysis are short-term complications of this procedure. After 3 months of recovery, cryoablated tissue exhibits no collagen or cartilage formation.

Animals↗
PubMed2002

Estimation of noise level and signal to noise ratio of laplacian electrocardiogram during ventricular depolarization and repolarization.

Body surface Laplacian ECG (LECG) has demonstrated its enhanced capability to localize cardiac electrical sources closest to the recording site. The aim of the present study was to evaluate the noise level and signal to noise ratio (SNR) in the LECG as compared to the potential ECG (PECG). Such evaluation is important to determine the applicability of the LECG to localizing and imaging of cardiac electrical activity in an experimental setting. Experimental studies were conducted in six healthy men. A 150-channel PECG was recorded from the anterolateral chest and the LECG was estimated using the finite difference algorithm. The noise level in the PECG and LECG was evaluated using multiple estimation protocols. The signal level during ventricular depolarization and repolarization was also estimated, and the corresponding SNR was calculated. Different filtering techniques were examined to evaluate their effects on the noise level and SNR of the LECG and PECG. The experimental results indicate that with basic signal processing techniques (baseline adjustment, three-point moving average filter, and Wiener spatial filter), the SNR of the LECG is about 30-40% of that of the PECG. Furthermore, the SNR estimated during ventricular depolarization is about three times that obtained during ventricular repolarization for the PECG and LECG. The present study indicates that the LECG derived from the PECG using a local finite difference estimation procedure has satisfactory SNR during the periods of ventricular depolarization and repolarization, and suggests the feasibility of estimating the LECG from the recorded PECG in human subjects in an experimental setting.

Body Surface Potential Mapping↗
PubMed2002

Linear lesions provide protection from atrial fibrillation induction with rapid atrial pacing.

INTRODUCTION: In the animal model, segmentation of the atria with radiofrequency-generated linear lesions (LL) using the loop catheter has been shown to be highly effective in terminating chronic atrial fibrillation (AF). This study addresses the question whether the same lesion set also would prevent reinduction and sustainability of AF. METHODS AND RESULTS: We studied two groups of dogs. The AF group included eight dogs in which the atria were paced until chronic AF was present. After 6 months of sustained AF, the dogs were converted to normal sinus rhythm (NSR) by the creation of LL in both atria. Rapid atrial pacing was restarted 6 months later and continued for 4 weeks. In the NSR group, there were nine dogs in NSR without inducible AF at baseline. LL were created, and after 6 months rapid atrial pacing was applied for 4 weeks. Rhythm status was monitored weekly. Transthoracic echocardiography was performed at baseline, before linear lesion placement, and before pacing/repacing. At the conclusion of the study, the hearts were excised and examined. The lesions were stained, and their quality was assessed. AF was induced in a much shorter interval in the dogs in which AF had previously been present than in NSR dogs (8 +/- 5 days vs 25 +/- 13 days; P < 0.05). LL prevented sustainability of AF induced via rapid pacing once the pacing stimulus was stopped. Incomplete lesions were associated with increased inducibility of atrial tachycardia and AF. CONCLUSION: In this animal model of AF, LL are not only capable of terminating chronic AF, but also lead to self-termination of AF once the rapid pacing is stopped. Self-termination of AF after induction with rapid pacing was not observed in this AF model in the absence of LL. In the dogs with 6 months of AF, the presence of AF led to increased atrial susceptibility to AF induction by rapid pacing, even with LL and after 6 months of recovery. Incomplete LL allows induction of atrial tachycardia and AF.

Analysis of Variance↗
PubMed2001

Atrial Fibrillation.

The conversion of atrial fibrillation (AF) to normal sinus rhythm should be attempted in patients who present with this condition, as long as the cure is not worse than the disease itself. In young patients with normal hearts, AF has a small impact on morbidity and mortality. The primary indication for conversion in this population is often symptoms. In contrast, in patients with diseased hearts or who are older than 65 years, maintaining sinus rhythm may have a favorable impact on stroke risk, ventricular function, and symptoms. In the absence of normal sinus rhythm, these patients should receive anticoagulants. Rate control is the preferred first-line strategy for asymptomatic patients and patients presenting with a history of long-standing, persistent AF, making conversion and maintenance of sinus rhythm unlikely. Rate control may be used in patients who develop AF during an acute systemic illness, which will likely terminate with time or therapy. Conversion to sinus rhythm should be considered in patients with a first episode of AF, as unconverted AF tends to perpetuate itself. Conversion can be attempted if the duration of AF is less than 48 hours or if the patient has received anticoagulants when the duration is not known. Other indications for cardioversion are prolonged episodes in patients with otherwise infrequent episodes of paroxysmal AF, and in patients who refuse to take anticoagulants or in whom anticoagulation is contraindicated. After the patient is converted to sinus rhythm, the decision to initiate chronic drug therapy should be based on the presence of other cardiac and medical diseases that increase the risk of recurrence and serious symptoms in case of recurrence (such as hypertrophic cardiomyopathy or mitral stenosis). It is acceptable to manage patients with new-onset AF and normal cardiac function with cardioversion alone and not initiate chronic antiarrhythmic therapy afterwards. However, in patients with abnormal hearts (coronary artery disease, hypertensive or mitral valvular heart disease, and cardiomyopathy) AF is likely to recur, and such patients should be placed on antiarrhythmic medication.

Journal Article↗
PubMedDate not supplied

Integrating telehealth as a strategy for patient management after discharge for cardiac surgery: results of a pilot study.

Advances in telecommunication technologies have improved access and availability of telehealth for use in healthcare. In cardiac care, telehealth has predominantly been used to manage patients with heart failure. The use of telehealth as a strategy for patient management after discharge for cardiac surgery can be beneficial in monitoring postoperative status and in the early detection of complications. This article provides an overview of the use of telehealth and telemanagement in cardiac patients and discusses the results of a pilot study as an example of an application of the use of telehealth for elderly cardiac surgery patients at high risk of postoperative complications.

Aged↗