The efficacy of the LinoxSmart DX ICD lead from a single center experience.

PURPOSE: The Biotronik LinoxSmart DX implanted cardioverter defibrillator (ICD) lead is a novel VDD lead with the advantage of integrated atrial sensing dipole combined with a special augmentation and filtering mechanisms. We sought to determine the efficacy of the Biotronik LinoxSmart DX ICD lead. METHODS: Non-randomized consecutive patients implanted with Biotronik LinoxSmart DX lead at Sheba Medical Center were included in this study. Electrical parameters and arrhythmic events were recorded during follow up of one year. RESULTS: Seventy-three patients (69 males (94.5%), mean age 61 ± 12 years) were included. All patients were successfully implanted with a Biotronic VR-T DX device and LinoxSmart DX ICD lead (DX-17 in 37% and DX-15 in 63% patients). Mean P wave amplitude at time of implantation was 3.66 ± 2.9 mV and improved significantly throughout the follow-up (5.29 ± 4.39 mV, p = 0.009). Appropriate atrial sensing (defined as P wave amplitude of ≥0.8 mV) rate of 100% at implantation significantly decreased to 89% (p = 0.015) at 12 months. Three out of 67 (4.5%) patients without a known history of atrial fibrillation had documented new onset paroxysmal atrial fibrillation. Appropriate shocks occurred in 4 (5.5%) patients. One patient with atrial sensing less than 0.4 mV had inappropriate shock. CONCLUSIONS: Among patients implanted with the Biotronik LinoxSmart DX ICD lead in our single center, appropriate atrial sensing rate decreased over 12 months. Larger studies are needed to evaluate the reliability of long term appropriate atrial sensing.

Performance of the Linox implantable cardioverter defibrillator leads: A single-center experience.

BACKGROUND: An early failure of Biotronik Linox implantable cardioverter defibrillator (ICD) leads has been reported from several centers. AIM: To compare the performance of Linox ICD leads with different other ICD leads as a report of the Sheba Medical Center experience. METHODS: All patients who had implantation of Linox ICD leads between 2007 and 2016 were included in this study. ICD lead failure was defined as low- or high-voltage impedance; failure to capture, sense, or defibrillate; or the presence of nonphysiological signals not due to external interference. The survival probability of Linox leads was determined and compared to Medtronic Sprint Quattro ICD leads. RESULTS: A total of 340 patients (age 64.4 ± 1.8 years) were included in this analysis. They were followed up to 105 months (mean 45.7 ± 7, median 44 (Interquartile range (IQR) 26-63) months). Twelve patients (3.5%) met the criteria for lead failure within 61.2 ± 22.9 months (median 66.5 [IQR 48-85 months]) post implantation. Noise with inappropriate ventricular arrhythmias detection, with or without therapy, was seen in 10 patients (83%). High pacing thresholds and high impedances were detected in two patients (17%). The survival probability of Linox leads at 60 months (97.3%) was similar to the survival probability of Sprint Quattro leads (98.2%) (P = .58). Nevertheless, the survival probability at 105 months was much lower (81% vs 97%, Linox ICD lead and Sprint Quattro lead, respectively, P = .0039). CONCLUSION: Linox ICD leads have higher late failure rates compared to Sprint Quattro leads. These findings need to be confirmed in larger scale studies.

Effect of Left Atrial Enlargement on Success Rates of Catheter Ablation of Atrial Fibrillation in Women.

BACKGROUND: Catheter ablation (CA) is a well-established therapeutic option for patients with recurrent symptomatic atrial fibrillation (AF). Data on gender-related differences are limited with regard to baseline characteristics and long-term success rates of catheter ablation for AF. METHODS: We analyzed a cohort of 251 consecutive patients who underwent a first catheter ablation for AF in our institute during the period 2008 through 2015. All patients were followed by regular annual clinic visits, electrocardiograms, periodic 24-48 hour Holter monitoring, and loop recorders. The primary endpoint was first recurrence of AF during 1 year of follow-up. RESULTS: The cohort comprised 26% women (n=65), who were older (62.1 ± 9.6 vs. 54.4 ± 11.3 years, P < 0.01) and had a higher proportion of diabetes mellitus (23.1 vs. 5.4%, P < 0.001) than male patients. No other significant differences were evident. At 1 year follow-up, the cumulative survival free of AF was significantly higher in women compared with men (83% vs. 66%, respectively, log rank P value = 0.021). Subgroup analysis showed an interaction between female and small indexed left atrial diameter (LADi < 23 mm/m2). CONCLUSIONS: Our findings suggest that women experience a significantly lower rate of AF recurrence post-CA compared with men. This gender-related advantage appears to be restricted to women without significant left atrial enlargement. It further implies that left atrial enlargement has a stronger negative impact on post-CA AF recurrence in females than in males. Due to the relatively small sample number of females further research is warranted to validate our conclusions.

Cryoablation for Ventricular Tachycardia Originating from Anterior Papillary Muscle of Left Ventricle Guided by Intracardiac Echocardiography.

Papillary muscles (PMs) were reported to be origin of ventricular arrhythmia (VA). Radiofrequency (RF) ablation was reported to be acutely effective in eliminating VA. However, the recurrence rate is high. Recently, cryoablation guided by intracardiac echocardiography, 3-dimensional mapping system, and image integration was introduced as alternative strategy for this challenging ablation. We present a case of ventricular tachycardia originating from anterior PM of left ventricle treated by cryoablation guided only by intracardiac echocardiography.

Functional response to cardiac resynchronization therapy in patients with renal dysfunction and subsequent long-term mortality.

INTRODUCTION: Renal dysfunction is associated with increased morbi-mortality in heart failure patients. Data regarding functional and clinical efficacy of cardiac resynchronization therapy (CRT) in this population are limited. METHODS AND RESULTS: We aimed to evaluate the rate of functional response to CRT in patients with renal dysfunction and its association with long-term mortality. Our study included a total of 179 consecutive patients implanted between 2007 and 2010. The rate of functional response to CRT (defined by a composite score using New York Heart Association functional class, 6-minute walk test, and quality of life) was compared between patients with and without renal dysfunction (defined as eGFR < or ≥60 mL/min/1.73 m(2) ). Survival analysis estimates were constructed according to the Kaplan-Meier method, with results comparison using the log-rank test. During a median follow-up of 4.2 years, 73 patients (40%) died. Patients with low eGFR were older (72 ± 8 years vs. 64 ± 12 years; P < 0.001), and had higher prevalence of ischemic heart disease (75% vs. 53%; P = 0.003). Functional response rates did not differ significantly between patients with and without renal dysfunction (58% and 69%, respectively; P = 0.14). Despite overall higher mortality in patients with low eGFR (53.8% vs. 22.7%; P < 0.001), the presence of functional response at 1 year among patients with renal dysfunction was still independently associated with an improved long-term survival (HR = 0.49 [95%CI: 0.28-0.83]; P = 0.009). CONCLUSION: Functional response to CRT at 1 year does not differ significantly between patients with or without kidney disease, and is an independent predictor of improved long-term survival in patients with renal dysfunction.

Safety and efficacy of strategic implantable cardioverter-defibrillator programming to reduce the shock delivery burden in a primary prevention patient population.

AIMS: Strategically chosen ventricular tachycardia (VT)/ventricular fibrillation (VF) detection and therapy parameters aimed at reducing shock deliveries were proven effective in studies that utilized single manufacturer devices with a follow-up of up to 1 year. Whether these beneficiary effects can be generalized to additional manufacturers and be maintained for longer periods is to be determined. Our aim was to evaluate the durability and applicability of the programming of strategic implantable cardioverter-defibrillators (ICDs) of various manufacturers, which is aimed at reducing the shock delivery burden in primary prevention ICD recipients. METHODS AND RESULTS: A retrospective analysis of prospectively collected data of 300 ICD recipients of various manufacturers was conducted; 160 devices were strategically programmed to reduce shocks and 140 were not. The primary endpoint was the composite of death and appropriate shocks. Additional outcomes were inappropriate shocks, syncope events, and non-sustained VTs. At a median follow-up of 24 months, 19 patients died, 31 received appropriate shocks, and 41 received inappropriate shocks. Multivariate analysis showed that strategic programming dedicated to shock reduction was associated with a 64% risk reduction in the primary endpoint [hazard ratio (HR): 0.13-0.93; P = 0.03] and a 70% reduction in inappropriate shock deliveries (HR: 0.16-0.72; P = 0.01). Very few syncope events occurred (five patients, 1.6%), and there was no between-group difference in this outcome. CONCLUSION: Utilization of strategically chosen VT/VF detection and therapy parameters was found to be effective and safe in ICDs of various manufacturers at a median follow-up period of 2 years among primary prevention patients.

Beneficial effect of Bradycardia Tachycardia Response (BTR) algorithm on VT detection in the presence of rate smoothing.

INTRODUCTION: Rate smoothing algorithms, while known to help prevent ventricular tachyarrhythmias in some patients, have been shown to result in underdetection of ventricular tachycardia (VT) due to interaction between bradycardia pacing and tachycardia detection parameters. A new algorithm named Bradycardia Tachycardia Response (BTR) has been developed in order to prevent rate smoothing-induced underdetection. The efficacy of BTR is not known. The aim of this study was to assess the effectiveness of BTR in preventing VT underdetection due to rate smoothing. METHODS AND RESULTS: Two ICD models (TELIGEN and VITALITY AVT, Boston Scientific, St. Paul, MN, USA) bearing identical rate smoothing algorithms were connected to a VT simulator. Devices were programmed similarly except for the BTR feature that exists in TELIGEN only. The detection performance of both devices was tested using varying combinations of AV delay, rate smoothing down, and upper rate limit and compared between the two models. VT underdetection (delay or nondetection) occurred during pacing in 62% of the VT episodes with VITALITY AVT. In TELIGEN, all simulated VT episodes were detected appropriately as soon as their rates exceeded the programmed VT detection rate. Detection tended to be affected by higher upper rate, longer AV delays, and more aggressive rate smoothing. CONCLUSION: The BTR algorithm effectively counteracts VT detection delay caused by the interaction of rate smoothing with VT detection parameters, thus enabling safe use of the rate smoothing feature.

Left atrial contractile function following a successful modified Maze procedure at surgery and the risk for subsequent thromboembolic stroke.

OBJECTIVES: The aim of this study was to evaluate whether certain post-Maze left atrial (LA) contractile profiles may pose a risk for ischemic stroke. BACKGROUND: The mechanical contraction of the left atrium may be modified after the Maze procedure. Whether this imposes a risk for stroke, even in the presence of sinus rhythm and after removal of the LA appendage, is not known. METHODS: Clinical, surgery-related, and echocardiographic data from 150 patients who underwent radiofrequency and cryoablation Maze procedures without the use of atrial incisions between 2004 and 2009 and were in sustained sinus rhythm were collected and analyzed. The occurrence of stroke was evaluated by reviewing clinical records. All stroke events were adjudicated by a neurologist. RESULTS: At a mean follow-up time of 24.5 months, 15 patients (10%) had experienced ischemic strokes. Forty-seven patients (31%) had no evidence of LA mechanical contraction at 3 months after surgery (baseline assessment) and on follow-up echocardiography. Multivariate analysis showed that a lack of LA mechanical contraction at baseline was associated with a 5-fold increase in the risk for stroke (p = 0.02) during follow-up. Larger atria imposed a significant risk as well; LA volume index ≥33 ml/m(2) was associated with a 3-fold risk increase (p = 0.03). These effects were maintained regardless of the lack of mechanical valve implantation and anticoagulation treatment. CONCLUSIONS: Absence of LA contraction and LA volume index ≥33 ml/m(2) result in a significant increase in the risk for thromboembolic stroke after the Maze procedure for patients in sinus rhythm.

The effects of anodal stimulation on electrocardiogram, left ventricular dyssynchrony, and acute haemodynamics in patients with biventricular pacemakers.

AIMS: Anodal stimulation (ANS) is a recognized phenomenon among patients with cardiac resynchronization therapy (CRT); this is noted during left ventricular (LV) pacing by the LV tip to right ventricular (RV) ring configuration. Its incidence varies according to the implanted hardware. We aim at evaluating the incidence of ANS and its acute haemodynamic effects among CRT patients. METHODS AND RESULTS: We screened all our patients who previously had an implanted CRT-P/D devices for ANS. After excluding all non-eligible devices, the initial screening was done by evaluating the programmer electrocardiogram (ECG) during device interrogation while pacing LV only from LV tip to RV ring. Those with ANS underwent screening by 12-lead ECG during biventricular pacing with VV interval programmed to 0. Patients with electrocardiographic evidence of ANS underwent detailed echocardiography. We screened 224 patients, 187 patients were excluded due to various causes. Thirty-seven subjects were analysed for this study. Anodal stimulation was found in 29 patients (78.4%) by primary screening. Twelve patients (41.4%) showed electrocardiographic evidence of ANS by 12-lead ECG. The ANS threshold was significantly higher than true bipolar LV threshold (4.5±1.7 vs. 1.1±0.3 V, respectively, P=<0.0001). Ten patients, with ECG evidence of ANS, underwent detailed echocardiography during biventricular pacing with and without ANS. Overall, there were no significant differences in the haemodynamic, echocardiographic, or resynchronization effects with and without ANS, two patients showed significant reduction in LV function with ANS. CONCLUSION: Anodal stimulation is a common phenomenon among CRT patients. In many cases ANS is seen with LV pacing only, while these changes may not be seen by ECG during biventricular pacing. Echocardiography did not show any significant acute haemodynamic benefit during ANS, and some patients may even deteriorate.

The effect of electronic repositioning on left ventricular pacing and phrenic nerve stimulation.

AIMS: Cardiac resynchronization therapy (CRT) improves survival and reduces heart failure symptoms. However, phrenic nerve stimulation and high pacing thresholds are common problems that limit CRT effectiveness. Current technology allows reprogramming of left ventricular (LV) pacing vectors, permitting 'electronic repositioning' to overcome both phrenic nerve stimulation and high pacing output without the need for re-operation. METHODS AND RESULTS: Patients underwent prospective evaluation of a CRT system implantation with a bipolar LV. Optimal LV threshold and avoidance of phrenic nerve stimulation were determined at baseline and at 6 months. A subset of 48 patients underwent more detailed evaluation of pacing threshold and phrenic nerve stimulation at baseline and at 6 months. Between 2004 and 2007, 228 patients underwent CRT implantation (64 CRT pacemakers, 164 CRT defibrillators). At baseline, electronic reprogramming to determine an alternate configuration compared with standard LVtip to LVring found a ≥ 1.0 V reduction in pacing threshold in 80 patients (35%). Of the 17 patients who had an LVtip to LVring configuration and high pacing threshold (>5.0 V), 16 could be reduced by >1.0 V (94%) and 11 could be reduced by >2.0 V through electronic repositioning alone without repositioning the lead (65%). At implant, there were 48 patients with phrenic nerve stimulation at less than maximum pacing output (21%) using the standard LVtip to LVring configuration. In 37 cases (77%), there was at least one other configuration with no phrenic nerve stimulation, which prevented the need for lead revision. CONCLUSIONS: Electronic repositioning is an important tool in the management of CRT patients which may help to lower thresholds, avoid phrenic nerve stimulation, and prevent unnecessary re-operations for LV lead repositioning.

Is flecainide dangerous in long QT-3 patients?

Mutations of the cardiac sodium channel gene, SCN5A, are present in both long-QT and Brugada syndromes. Flecainide is used as a provocative test to unmask the electrocardiogram (ECG) phenotype of the Brugada syndrome, as well as long-term treatment for long QT-3 syndrome, since it shortens the QT interval. We report a case where oral flecainide induced syncope with a Brugada ECG pattern in a patient with known long QT-3 syndrome.

Qual a contribuição do tilt training (treinamento postural) na prevenção da síncope vasovagal ? / Tilt training: does it have a role in preventing vasovagal syncope? / ¿Cuál es el aporte del tilt training (entrenamiento postural) a la prevención del síncope vasovagal?

Histórico: A síncope vasovagal é um dos quadros clínicos mais comuns em adultos jovens. Estudos anteriores demonstram a eficácia do tilt training (treinamento postural) no tratamento desse transtorno clínico. Realizou-se um estudo prospectivo e randomizado com o objetivo de avaliar a contribuição do tilt training no tratamento de adultos jovens acometidos pela síncope vasovagal. Métodos: Quarenta e seis soldados , 25 dos quais do sexo masculino, média de idade de 19,4 mais ou menos 0,8 anos e diagnóstico clínico de síncope vasovagal pelo tilt teste, foram divididos aleatoriamente em dois grupos: um grupo controle e outro acometido de tilt training diariamente, por três meses. Nos dois grupos, os participantes foram instruídos a aumentar a ingestão de líquidos e sal e evitar situações indutoras de síncope, tais como permanecer em pé por períodos longos. Resultados: A adesão ao programa de treinamento, caracterizada pela realização de 50 por cento ou mais das sessões diárias de tilt training, foi de 91 por cento durante o primeiro mês, caindo para 58 por cento nos três meses. Os que realizaram o treinamento apresentaram uma média (distância interquartilica) e 5,0 episódios de síncope (0,5 a 16,0) durante um ano de acompanhamento, enquanto o grupo controle apresentou média de 2,0 episódios (0 a 6,0, P igual 0,737). Após a randomização não houve diferença significativa no tempo de ocorrência do primeiro episódio entre os dois grupos: média de 1,0 por mês (0,5 a 2,0) no grupo em tratamento...

Background: Vasovagal syncope is one of the most common medical conditions in young adults. Previous trials have shown effectiveness of tilt training in treating this condition. We conducted a prospective, randomized study in order to evaluate the role of tilt-training in young adults with vasovagal syncope. Methods: Forty-six soldiers (mean age 19.4 ± 0.8 years, 25 males), with a clinical diagnosis of vasovagal syncope supported by positive tilt test, were randomized to either three months of daily tilt training (treatment group), or no training (control group). Patients in both groups were instructed to increase fluid and salt intake, and to refrain from syncope-inducing situations, such as prolonged standing. Results: Compliance, defined as performing 50% or more of the tilt training daily sessions, was 91% during the first month, and declined to 58% during three months. Treatment group patients had a median (interquartile range) of 5.0 (0.5–16.0) syncope episodes during one-year follow up, compared to a median of 2.0 (0–6.0) episodes in the control group (P = 0.737). Also, there was no difference in time to first syncope after randomization between groups: a median of 1.0 (0.5–2.0) month in the treatment group, compared to 0.8 (0.5–2.0) month in the control group (P = 0.336). Conclusions: Adding daily three-month tilt training to modifications in lifestyle does not improve treatment results in youngadults with vasovagal syncope. Good compliance is difficult to achieve in a tilt training program.

Historial: El síncope vasovagal es uno de los cuadros clínicos más comunes en adultos jóvenes. Estudios anteriores han demostrado la eficiencia del tilt training (entrenamiento postural) en el tratamiento de ese trastorno clínico. Se llevó a cabo un estudio prospectivo y randomizado con el objetivo de evaluar el aporte del tilt training al tratamiento de adultos jóvenes acometidos por el síncope vasovagal. Métodos: Cuarenta y seis soldados, 25 de ellos del sexo masculino, promedio de edad de 19,4 ± 0,8 años y diagnóstico clínico de síncope vasovagal por el tilt test, fueron divididos aleatoriamente en dos grupos: un grupo control y otro sometido a tilt training diariamente, por tres meses. En ambos grupos, los participantes fueron instruidos a aumentar la ingesta de líquidos y sal y evitar situaciones inductoras del síncope, tales como permanecer en pie por largos períodos. Resultados: La adhesión al programa de entrenamiento, caracterizada por la realización del 50% o más de las sesiones diarias de tilt training, fue del 91% durante el primer mes, bajando al 58% a los tres meses. Quienes llevaron a cabo el entrenamiento presentaron un promedio (distancia intercuartílica) de 5,0 episodios de síncope (0,5 a 16,0) durante un año de acompañamiento, mientras el grupo control presentó un promedio de 2,0 episodios (0 a 6,0; P = 0,737). Tras la randomización, no hubo diferencia significativa en el tiempo de ocurrencia del primer episodio de síncope entre ambos grupos: promedio de 1,0 por mes (0,5 a 2,0) en el grupo en tratamiento y 0,8 (0,5 a 2,0) en el grupo control (P = 0,336). Conclusiones: La realización diaria del tilt training, aliada a los cambios de estilo de vida, no produjo mejora en el resultado del tratamiento de adultos jóvenes con síncope vasovagal. Se verificó asimismo la dificultad de obtener buena adhesión al programa de entrenamiento postural.

Comparison of results with different left ventricular pacing leads.

AIMS: To compare different coronary sinus (CS) leads and delivery systems (DSs) for left ventricular pacing. METHODS AND RESULTS: Delivery systems-related (including CS dissection and dislocations during sheath/stylet removal) and lead-related (including failure to accomplish implantations and long-term malfunctions resulting in abandonment or repositioning/replacing of the lead) complications between systems and leads were compared. We used Medtronic (MDT) attain DS (n = 123) with over-the-wire (OTW) (4193, 4194) and stylet-driven (2187) leads, and Guidant (GDT) DS (n = 126) with Easytrak OTW leads (4513, 4518, and 4525). Coronory sinus dissection occurred in 6/123 (5%) cases using the MDT DS vs. 7/126 (6%) with GDT DS (P= NS). Dislocations during sheath/stylet removal occurred in 8/123 cases (6%) with MDT DS, and in 8/126 (6%) with GDT DS (P= NS). Failure to achieve successful implantation occurred in 6/32 (19%) of the 2187 leads, in 11/87(13%) of the 4193/4194 leads, in 7/94(7%) of the 4513/4518 leads, and in 4/29 (14%) of the 4525 leads (P= NS). Long-term lead-related complications occurred in 5/32 (15%) of the 2187 leads, 19/80 (23%) of the 4193/4194 leads, 19/93 (20%) of the 4513/4518 leads, and 2/28 (7%) of the 4525 leads (P= NS). CONCLUSION: No significant differences in complication rates between systems and leads were observed.

Tilt training: does it have a role in preventing vasovagal syncope?

BACKGROUND: Vasovagal syncope is one of the most common medical conditions in young adults. Previous trials have shown effectiveness of tilt training in treating this condition. We conducted a prospective, randomized study in order to evaluate the role of tilt-training in young adults with vasovagal syncope. METHODS: Forty-six soldiers (mean age 19.4 +/- 0.8 years, 25 males), with a clinical diagnosis of vasovagal syncope supported by positive tilt test, were randomized to either three months of daily tilt training (treatment group), or no training (control group). Patients in both groups were instructed to increase fluid and salt intake, and to refrain from syncope-inducing situations, such as prolonged standing. RESULTS: Compliance, defined as performing 50% or more of the tilt training daily sessions, was 91% during the first month, and declined to 58% during three months. Treatment group patients had a median (interquartile range) of 5.0 (0.5-16.0) syncope episodes during one-year follow up, compared to a median of 2.0 (0-6.0) episodes in the control group (P = 0.737). Also, there was no difference in time to first syncope after randomization between groups: a median of 1.0 (0.5-2.0) month in the treatment group, compared to 0.8 (0.5-2.0) month in the control group (P = 0.336). CONCLUSIONS: Adding daily three-month tilt training to modifications in lifestyle does not improve treatment results in young adults with vasovagal syncope. Good compliance is difficult to achieve in a tilt training program.

Randomized comparison of J-shaped atrial leads with and without active fixation mechanism.

BACKGROUND: In this prospective, randomized, controlled study, we compared the performance of J-shaped active fixation (AF) atrial leads with J-shaped passive fixation (PF) leads, over a 1-year follow-up period. METHODS: A total of 200 consecutive patients were prospectively randomized for implantation with a Medtronic 5568 AF lead model (n = 103; Minneapolis, MN, USA) versus a Medtronic 5592 PF model (n = 97), and all lead-related measurements and complications were recorded over one year. RESULTS: All leads were successfully implanted with a nonsignificant difference in crossover rate to the alternative lead due to failed implantation (1 in the AF and 4 in the PF group, P = NS). Fluoroscopy time during implantation procedure was significantly shorter in the PF group (2.1 +/- 3.6 vs 3.3 +/- 4.5 minute, P < 0.05). Pacing thresholds during implantation were significantly lower in patients with PF leads (0.7 +/- 0.3 V vs 0.9 +/- 0.3 V, P < 0.001) and this difference persisted at 1-year follow-up (0.8 +/- 0.6 V vs 1.3 +/- 0.9 V in PF and AF leads respectively, P < 0.05). Lead-related complications occurred in PF and AF with similar frequency (4% and 9% respectively, P = 0.2). However, pericardial complications occurred only in the AF group (6 cases, P = 0.01). Lead dislodgement was observed in only two cases-both in the PF group (P = 0.3). CONCLUSION: Both types of J-shaped atrial leads had reasonable performance. PF leads required shorter fluoroscopy time for implantation, demonstrated a better pacing threshold over a 1-year follow-up period and had no pericardial complications, while AF lead implantation was complicated by pericardial irritation and/or effusion in 6% cases (P = 0.01).

Improvement of congestive heart failure by upgrading of conventional to resynchronization pacemakers.

AIMS: To compare the clinical response of patients with right ventricular apical pacing (RVAP) upgraded to cardiac resynchronization therapy (CRT) to that of previously nonpaced heart failure (HF) patients who had de novo CRT implantation. BACKGROUND: The role of CRT in patients with wide QRS and HF due to RVAP is less well established than in other CRT candidates. METHODS: Ninety-eight consecutive patients with CRT were studied (mean age 70, mean ejection fraction 0.23). Group A: patients having RVAP prior to CRT implantation (n = 25), group B: patients without prior RVAP (n = 73). Clinical and echocardiographic parameters were recorded prior to, and 3 months after, CRT implantation. RESULTS: Group A patients had a wider QRS at baseline compared to group B (203 +/- 32 ms vs 163 +/- 30 ms respectively, P < 0.001), and a shorter 6-minute walking distance (222 +/- 118 m vs 362 +/- 119 m, respectively, P < 0.005). Otherwise, clinical and echocardiographic parameters were not different. At follow up, group A patients had an average 0.7 +/- 0.5 decrease in their NYHA functional class, compared to 0.3 +/- 0.7 in group B patients (P < 0.05). Six-minute walking distance increased by 93 +/- 113 m in group A, versus 36 +/- 120 m in group B (P = 0.22). There was no difference in echocardiographic response to CRT between the groups. CONCLUSIONS: HF patients with prior RVAP demonstrate clinical improvement after upgrading to CRT that is comparable, and in some aspects, even better than that observed in HF patients with native conduction delay who undergo de novo CRT implantation.

The effect of patient sex on recurrence of atrial fibrillation following successful direct current cardioversion.

BACKGROUND: The effect of patient sex on recurrence of atrial fibrillation after a successful direct current cardioversion is unknown. METHODS: This prospective study included 773 patients (486 [63%] men and 287 [37%] women) undergoing successful direct current cardioversion of atrial fibrillation between May 2000 and July 2003. Patient characteristics at presentation were recorded. The primary end point was the time between cardioversion and the first documented recurrence of arrhythmia. RESULTS: At presentation, women were older and had a higher prevalence of hypertension and valvular disease compared with men. In addition, women had worse mechanical left atrial appendage function. Arrhythmia recurrence was more prevalent in women (50.0% at 1 year compared with 43.4% in men, and 75.8% at 2 years compared with 67.0% in men; P = .03). On the basis of multivariate analysis, patient sex was a significant predictor of arrhythmia recurrence. There was no significant difference in overall mortality between men and women. CONCLUSIONS: Women were more likely than men to have recurrence of atrial fibrillation after successful direct current cardioversion. Patient sex should be taken into account with other clinical factors when making the decision about cardioversion for atrial fibrillation.

Mechanism of diastolic mitral regurgitation in candidates for cardiac resynchronization therapy.

It was hypothesized that restricted diastolic leaflet motion is implicated not only in the mechanism of systolic mitral regurgitation (MR) but also in the mechanism of diastolic MR observed in patients with severe heart failure. Cardiac resynchronization therapy (CRT) can oppose increased mitral leaflet tethering by increasing transmitral pressure, thereby providing an opportunity to explore this hypothesis. A total of 26 consecutive candidates for CRT with diastolic MR were compared with 26 candidates without diastolic MR. Maximal diastolic mitral leaflet opening and inflow direction and measures of mitral valve apparatus (i.e., mitral annular diameters, calculated mitral annular area, and tethering distance) were assessed from the apical 4-chamber view before and during CRT. There were no significant differences in New York Heart Association functional class, ejection fraction, QRS duration, PR interval, systolic MR grade, or 2-dimensional geometry of the mitral valve apparatus between the groups. Patients with diastolic MR had more restricted maximal diastolic leaflet openings (54 degrees +/- 17 degrees vs 71 degrees +/- 11 degrees , p = 0.003) and substantially smaller inflow angles (66 degrees +/- 7 degrees vs 79 degrees +/- 9 degrees , p = 0.0003) compared with patients without diastolic MR. After the institution of CRT, diastolic MR was eliminated in all patients, although there were no significant changes in any of the parameters of mitral valve apparatus. In conclusion, abnormal mitral valve tethering is a constitutive element of the mechanism of diastolic MR in patients with left ventricular dysfunction. Its acute resolution after CRT does not seem to be caused by changes in mitral valve geometry but rather by an increase in transmitral closing forces.

Clinical surveillance of a tined, bipolar, silicone-insulated ventricular pacing lead.

AIMS: This study assesses short- and long-term performance of the S80TB ventricular lead manufactured by Sorin Biomedica, Italy. METHODS AND RESULTS: Three hundred and thirty leads were implanted and had complete follow-up with us for a minimum of 60 months or up to failure, removal, and/or patient death (mean 40 months, range: 1 day to 81 months). Thirty-two patients (9.6%) had spontaneous lead-related complications: 7 (2.1%) occurred during the first week; 25 (7.6%) had chronic complications, of which 20 (6.1%) necessitated re-operations; 3 (0.9%) were lead material failures. Of the 110 re-operations (90 pacemaker replacements and 20 operations due to complications), 7 additional cases (6.4%) were complicated by unique connector damage that occurred during disconnection of the lead from the connector block. The Kaplan-Meier estimated 5-year lead survival free of lead material failure and free of any significant lead complication were 97.9 and 87%, respectively. CONCLUSION: The S80TB lead demonstrates an acceptable rate of acute and chronic spontaneous complications and very few lead material failures over 5 years of follow-up. However, there seems to be a relatively high incidence of connector damage during disconnection from the connector block. Extra caution is required during those procedures in patients with this lead.

Long-term performance of screw-in atrial pacing leads: a randomized comparison of J-shaped and straight leads.

OBJECTIVE: In this prospective, randomized, control study we compared performance of J-shaped (JL) and straight atrial leads (SL) with active (screw-in) fixation mechanism, over a 5-year follow-up period. SUBJECTS AND METHODS: A total of 208 consecutive patients were randomized for implantation with a Medtronic 4568 JL model (n = 103) versus a Medtronic 4068 SL model (n = 105), and all lead-related measurements and complications were recorded. RESULTS: Lead-related complications occurred in JL and SL with similar frequency (6% and 9%, respectively, P = 0.45). Lead dislodgment occurred in 8 (7.8%) cases in SL versus none in JL (P = 0.004). Lead malfunction and excessive pacing thresholds without macrodislodgment occurred more frequently in JL (11; 10.7%) than in SL (4; 3.8%), P = 0.055. Lead material failure (insulation break) occurred only once in SL at the 5-year checkup. Most complications occurred during the first year after implantation. Other events occurred in both leads with similar frequency and included: death in 39 and 35, loss of follow-up in 8 and 6, and development of atrial fibrillation in 9 and 15 patients, respectively. Of those who completed follow-up, lead impedance and pacing threshold increased significantly in both groups. P wave decreased in SL but not in JL. CONCLUSION: More dislocations occurred in SL, but were counterbalanced by more lead malfunctions and excessive pacing thresholds in the JL group. Both leads demonstrated minor deterioration in electrical measurements during follow-up, with only 1 case of lead material failure in SL. Overall, both groups demonstrated favorable lead performance throughout follow-up.