Ablation catheter orientation: In vitro effects on lesion size and in vivo analysis during PVI for atrial fibrillation.

BACKGROUND: Catheter-delivered radiofrequency (RF) lesion formation is a complex phenomenon, and few studies have explored the effect of catheter orientation on lesion size and catheter orientation behavior during pulmonary vein isolation (PVI) procedures. We evaluated the influence of catheter orientation on lesion dimensions in an in vitro experimental setting and investigated the catheter orientation behavior during PVI. METHODS AND RESULTS: 72 lesions were created in vitro on a porcine heart using a contact force catheter in a parallel, oblique, and perpendicular tip to tissue orientation. The superficial lesion length (SLL) increased shifting the catheter from perpendicular to parallel orientation. The intratissue absolute maximal lesion length (AML) was greater with an oblique catheter orientation. The lesion depth (LD) and the superficial lesion width (SLW) resulted similar with any orientation. Data from 21 PVI procedures in patients with paroxysmal atrial fibrillation using the "wide antral circumferential RF ablation" (WACA) technique were retrospectively analyzed. The mean contact angle among 1130 RF lesions was 28 ± 20°. A prevalent parallel orientation was noted in the anterior WACA segments, whereas it resulted more perpendicular in the posterior segments. Significant differences in catheter orientation between the three operators were found only in few WACA segments. CONCLUSIONS: In an in vitro setting, catheter orientation affects SLL and AML, but not LD and SLW. During PVI procedures, catheter orientation resulted mostly parallel to the endocardium. Catheter orientation varied among different WACA segments, but only small differences were found between three operators when considering similar WACA segments.

Multicentre experience with the second-generation subcutaneous implantable cardioverter defibrillator and the intermuscular two-incision implantation technique.

INTRODUCTION: The recently developed second-generation subcutaneous implantable cardioverter defibrillator (S-ICD) and the intermuscular two-incision implantation technique demonstrate potential favorable features that reduce inappropriate shocks and complications. However, data concerning large patient populations are lacking. The aim of this multicentre prospective study was to evaluate the safety and outcome of second-generation S-ICD using the intermuscular two-incision technique in a large population study. METHODS AND RESULTS: The study population included 101 consecutive patients (75% male; mean age, 45 ± 13 years) who received second-generation S-ICD (EMBLEM; Boston Scientific, Marlborough, MA) implantation using the intermuscular two-incision technique as an alternative to the standard implantation technique. Twenty nine (29%) patients were implanted for secondary prevention. Twenty four (24%) patients had a previously implanted transvenous ICD. All patients were implanted without any procedure-related complications. Defibrillation testing was performed in 80 (79%) patients, and ventricular tachycardia was successfully converted at less than or equal to 65 J in 98.75% (79/80) of patients without pulse generator adjustments. During a median follow-up of 21 ± 10 months, no complications requiring surgical revision or local or systemic device-related infections were observed. Ten patients (9.9%) received appropriate and successful shocks for ventricular arrhythmias. Three (2.9%) patients experienced inappropriate shocks due to oversensing the cardiac signal (n = 1), noncardiac signal (n = 1), and a combination of both cardiac and noncardiac signals (n = 1), with one patient requiring device explantation. No patients required device explantation due to antitachycardia pacing indications. CONCLUSIONS: According to our multicentre study, second-generation S-ICD implanted with the intermuscular two-incision technique is an available safe combination and appears to be associated with a low risk of complications, such as inappropriate shocks.

Prospective Evaluation of Lesion Index-Guided Pulmonary Vein Isolation Technique in Patients with Paroxysmal Atrial Fibrillation: 1-year Follow-Up.

INTRODUCTION: Pulmonary vein isolation (PVI) using contact force (CF) sensing ablation catheters currently relies on CF and force-time integral (FTI) guidelines. Such measurement of lesion effectiveness still lacks information on current delivery to the tissue, influenced by system impedance and power. Lesion Index (LSI) is a multi-parametric index incorporating CF and radiofrequency current data across time. We aimed to prospectively assess the efficacy of an LSI-guided approach to PVI in patients with paroxysmal atrial fibrillation (PAF). METHODS AND RESULTS: The study prospectively enrolled 28 consecutive patients with PAF undergoing PVI with a CF sensing catheter (TactiCathTM, Abbott). LSI-guided ablation target was adapted according to the mean regional thickness of pulmonary vein antra (PVA): LSI range 5.5-6 was pursued in the anterior and septal portions of PVA, 5-5.5 elsewhere. Data from 32 consecutive PAF patients who underwent PVI ablation with a non-CF guided approach (NCF-group) were retrospectively collected for comparison of procedural and clinical outcome.AF-free survival rate at follow-up (17±6 months) was higher for LSI-guided group than NCF-group (89.3% vs 65.6%, p=0.037), with no increase in periprocedural complication rate (no tamponades or other major adverse events reported). Among 1126 lesions with LSI within target range (5-6), average CF was >10g and <30g for 976 lesions (86.7%). Moreover, 1015 lesions (90.1%) had FTI>400gs, but with wide distribution: 30.2% within 400-500gs, 30.0% within 501-600gs, 29.9% over 600gs. CONCLUSION: In this first prospective study, LSI-guided PVI improved clinical outcome without any increase in complication rate when compared with standard, non-LSI-guided approach.

Safety and efficacy of the new bidirectional rotational Evolution® mechanical lead extraction sheath: results from a multicentre Italian registry.

Aims: The aim of this prospective multicentre study is to evaluate safety and efficacy of the new bidirectional rotational mechanical lead extraction (LE) sheath (Evolution RL, Cook Medical, USA) in chronically implanted leads (>1-year-old leads). Methods and results: Between September 2013 and June 2016, a total of 238 leads in 124 consecutive patients were removed by using the new Evolution RL rotational mechanical sheath. Indications for LE were cardiac device infection in 63 (50.8%) cases, lead malfunction in 41 (33.1%), upgrade in 1 (0.8%) case and for other reasons in the remaining 19 cases (15.3%). Ninety-one leads (38.2%) were implantable cardioverter defibrillator leads (81 dual coil vs. 10 single coil), 38 (16%) right ventricular leads, 86 (36.1%) right atrial leads, and 23 (9.7%) coronary sinus leads. The mean implant duration was 92.2 ± 52.9 months (range 12-336). 91.6% of the leads (218/238) were extracted completely with the Evolution RL alone, with the complete success rate rising to 98.7% (235/238 leads) with combined use of a snare. Overall clinical success rate was 100%. No Evolution sheath-related complications were noted. There were no deaths or major complications. Five minor complications (4%) were encountered. In cases of companion leads no wrapping or lead damage were observed. Conclusion: On the basis of our prospective multicentre study, the new hand-powered bidirectional rotational mechanical LE sheath is an effective and safe tool for the extraction of chronically implanted leads without major complications and lead wrapping or lead damage.

In Vitro Validation of the Lesion Size Index to Predict Lesion Width and Depth After Irrigated Radiofrequency Ablation in a Porcine Model.

OBJECTIVES: In an in vitro model, the authors tested the hypotheses that: 1) lesion dimensions correlate with lesion size index (LSI); and 2) LSI could predict lesion dimensions better than power, contact force (CF), and force-time integral (FTI). BACKGROUND: When performing radiofrequency (RF) catheter ablation for cardiac arrhythmias, reliable predictors of lesion quality are lacking. The LSI is a multiparametric index incorporating time, power, CF, and impedance recorded during ablation. METHODS: RF lesions were created on porcine myocardial slabs by using an open-tip irrigated catheter capable of real-time monitoring of catheter-tissue CF. Initially, 3 power settings of 20, 25, and 30 W were used with a fixed CF of 10 g. A fixed power of 20 W was then set with a CF of 20 and 30 g, thereby yielding a total of 5 ablation groups. In each group, LSI values of 5, 6, 7, and 8 were targeted. Sixty RF lesions were created by using 20 ablation protocols (3 lesions for each protocol). RESULTS: Lesion width and depth were not correlated with power or CF, but the results significantly correlated with FTI (p < 0.01) and LSI (p < 0.0001). Four steam pops occurred with power set at 30 W; no pops were noted with 20 or 25 W even when high LSI values were targeted. CONCLUSIONS: In this in vitro model, FTI and LSI predicted RF lesion dimensions, whereas power and CF did not. The LSI predictive value was higher than that of FTI. Steam pops occurred only using high ablation power levels, regardless of the targeted LSI.

The economic impact of battery longevity in implantable cardioverter-defibrillators for cardiac resynchronization therapy: the hospital and healthcare system perspectives.

AIMS: Patients receiving cardiac resynchronization therapy defibrillators (CRT-Ds) are likely to undergo one or more device replacements, mainly for battery depletion. We assessed the economic impact of battery depletion on the overall cost of CRT-D treatment from the perspectives of the healthcare system and the hospital. We also compared devices of different generations and from different manufacturers in terms of therapy cost. METHODS AND RESULTS: We analysed data on 1792 CRT-Ds implanted in 1399 patients in 9 Italian centres. We calculated the replacement probability and the total therapy cost over 6 years, stratified by device generation and manufacturer. Public tariffs from diagnosis-related groups were used together with device prices and hospitalization costs. Generators were from 3 manufacturers: Boston Scientific (667, 37%), Medtronic (973, 54%), and St Jude Medical (152, 9%). The replacement probability at 6 years was 83 and 68% for earlier- and recent-generation devices, respectively. The need for replacement increased total therapy costs by more than 50% over the initial implantation cost for hospitals and by more than 30% for healthcare system. The improved longevity of recent-generation CRT-Ds reduced the therapy cost by ∼6% in both perspectives. Among recent-generation CRT-Ds, the replacement probability of devices from different manufacturers ranged from 12 to 70%. Consequently, the maximum difference in therapy cost between manufacturers was 40% for hospitals and 19% for the healthcare system. CONCLUSIONS: Differences in CRT-D longevity strongly affect the overall therapy cost. While the use of recent-generation devices has reduced the cost, significant differences exist among currently available systems.

A Nonfluoroscopic Technique for Coronary Arteries Three-Dimensional Mapping during Epicardial Ventricular Tachycardia Ablation.

When performing epicardial ablation of ventricular tachycardia (VT), caution must be taken not to damage the coronary arteries. We report a case in which a new, nonfluoroscopic technique for incorporating an accurate, real-time reconstruction of the main coronary vessels into a three-dimensional electroanatomic map was used for epicardial VT ablation.

Intermuscular Two-Incision Technique for Subcutaneous Implantable Cardioverter Defibrillator Implantation: Results from a Multicenter Registry.

BACKGROUND: The traditional technique for subcutaneous implantable cardioverter defibrillator (S-ICD) implantation, which involves three incisions and a subcutaneous pocket, is associated with possible complications, including inappropriate interventions. The aim of this prospective multicenter study was to evaluate the efficacy and safety of an alternative intermuscular two-incision technique for S-ICD implantation. METHODS: The study population included 36 consecutive patients (75% male, mean age 44 ± 12 years [range 20-69]) who underwent S-ICD implantation using the intermuscular two-incision technique. This technique avoids the superior parasternal incision for the lead placement and consists of creating an intermuscular pocket between the anterior surface of the serratus anterior and the posterior surface of the latissimus dorsi muscles instead of a subcutaneous pocket. RESULTS: All patients were successfully implanted in the absence of any procedure-related complications with a successful 65-J standard polarity defibrillation threshold testing, except in one, who received a second successful shock after pocket revision. During a mean follow-up of 10 months (range 3-30), no complications requiring surgical revision were observed. At device interrogation, stable sensing without interferences was observed in all patients. Two patients (5.5%) experienced appropriate and successful shock on ventricular fibrillation and in four patients (11%), a total of seven nonsustained self-terminated ventricular tachycardias were correctly detected. No inappropriate interventions were observed. CONCLUSIONS: Our experience suggests that the two-incision intermuscular technique is a safe and efficacious alternative to the current technique for S-ICD implantation that may help reducing complications including inappropriate interventions and offer a better cosmetic outcome, especially in thin individuals.

Longevity of implantable cardioverter-defibrillators for cardiac resynchronization therapy in current clinical practice: an analysis according to influencing factors, device generation, and manufacturer.

AIMS: Device replacement at the time of battery depletion of implantable cardioverter-defibrillators (ICDs) may carry a considerable risk of complications and engenders costs for healthcare systems. Therefore, ICD device longevity is extremely important both from a clinical and economic standpoint. Cardiac resynchronization therapy defibrillators (CRT-D) battery longevity is shorter than ICDs. We determined the rate of replacements for battery depletion and we identified possible determinants of early depletion in a series of patients who had undergone implantation of CRT-D devices. METHODS AND RESULTS: We retrieved data on 1726 consecutive CRT-D systems implanted from January 2008 to March 2010 in nine centres. Five years after a successful CRT-D implantation procedure, 46% of devices were replaced due to battery depletion. The time to device replacement for battery depletion differed considerably among currently available CRT-D systems from different manufacturers, with rates of batteries still in service at 5 years ranging from 52 to 88% (log-rank test, P < 0.001). Left ventricular lead output and unipolar pacing configuration were independent determinants of early depletion [hazard ratio (HR): 1.96; 95% 95% confidence interval (CI): 1.57-2.46; P < 0.001 and HR: 1.58, 95% CI: 1.25-2.01; P < 0.001, respectively]. The implantation of a recent-generation device (HR: 0.57; 95% CI: 0.45-0.72; P < 0.001), the battery chemistry and the CRT-D manufacturer (HR: 0.64; 95% CI: 0.47-0.89; P = 0.008) were additional factors associated with replacement for battery depletion. CONCLUSION: The device longevity at 5 years was 54%. High left ventricular lead output and unipolar pacing configuration were associated with early battery depletion, while recent-generation CRT-Ds displayed better longevity. Significant differences emerged among currently available CRT-D systems from different manufacturers.

Implanting cardiac rhythm devices during uninterrupted warfarin therapy: a prospective, single center experience.

AIM: The aim of the present study was to assess the safety of cardiac rhythm device implantation during uninterrupted oral anticoagulant therapy. METHODS: Patients at high thromboembolic risk (venous thromboembolism <3 months, nonvalvular atrial fibrillation with CHADS2 score >2, valvular atrial fibrillation, prosthetic heart valves) underwent procedures during uninterrupted warfarin (on warfarin group) and were compared to low-risk patients who underwent procedures after warfarin withdrawal (off warfarin group). Primary endpoint was a composite of hematoma requiring warfarin interruption, reoperation, or blood transfusion; death; hemothorax; and tamponade. Secondary endpoints were nonsignificant hematoma and clinical arterial thromboembolism assessed at discharge and at a 2 month follow-up. RESULTS: One hundred and ninety-one patients were enrolled, 102 in the 'on warfarin group' and 89 in the 'off warfarin group'. The majority of procedures were first implants (73% in the 'on warfarin group' vs. 87% in the 'off warfarin group', P= 0.01). Pacemakers, implantable cardioverter defibrillators, and biventricular devices were included. International normalized ratio at implant was 2 ±â€Š0.28 (range 1.6-3.2) in the 'on warfarin group' and 1.3 ±â€Š0.19 (range 1-1.6) in the 'off warfarin group' (P= 0.0001). Incidence of hemathoma was five of 102 in the 'on warfarin group' vs. three of 89 in the 'off warfarin group' (5 vs. 3%, P = not significant) and all hemathomas resolved spontaneously. There were no significant hemathomas in either group. There was no death, hemothorax, or tamponade. There were no thromboembolic events at 2 months. CONCLUSION: Cardiac rhythm device implantation during uninterrupted warfarin was not associated with increased bleeding compared with warfarin interruption.

Catheter ablation of atrioventricular nodal reentrant tachycardia in patients with a prolonged PR interval at sinus rhythm.

Radiofrequency transcatheter ablation is an effective and safe treatment for atrioventricular node reentry tachycardia. Slow pathway ablation is considered the ablative technique of choice, but when atrioventricular nodal reentrant tachycardia is associated with a prolonged PR interval at sinus rhythm, a higher risk of delayed atrioventricular (AV) block has been reported. Studies on the subject are few, enrolling low numbers of patients with variable selection criteria and producing different results. Hence, optimal ablation strategy remains controversial. The aim of this study is to review the available knowledge on the topic. Experience from our centers is also briefly reported.

Radiofrequency ablation of drug-refractory atrial fibrillation: an observational study comparing 'ablate and pace' with pulmonary vein isolation.

AIMS: To compare clinical characteristics, procedure complexity, acute and long-term outcome of 'ablate and pace' (A&P) with pulmonary vein isolation (PVI) in patients with drug-refractory atrial fibrillation (AF). So far, only few small studies have compared the two procedures. METHODS AND RESULTS: We analysed retrospectively a cohort of symptomatic consecutive patients with drug-refractory AF. Group 1 included 100 patients treated with A&P and Group 2 included 144 patients treated with PVI. Group 1 patients were older (74 +/- 8 vs. 56 +/- 9 years; P < 0.0001), had lower left ventricular ejection fraction (50 +/- 13% vs. 59 +/- 7%; P < 0.05), and a lower prevalence of paroxysmal AF (46% vs. 65%; P < 0.05). Acute success was not statistically different (98% vs. 92.3%, P = ns). Group 1 patients had shorter procedure time and lower radiation exposure with respect to Group 2 patients (70 +/- 15 vs. 204 +/- 58 min, and 8 +/- 4 vs. 57 +/- 22 min; P < 0.0001, respectively). After a median follow-up of 29 months (I, III quartile; 15, 40 months) vs. 25 months (I, III quartile; 8, 36 months) (P = ns), all the patients in Group 1 were free of symptomatic AF, while 113 patients (79%) of Group 2 were in stable sinus rhythm (P < 0.0001). Persistent or permanent AF has been documented in 58 patients (58%) of Group 1 vs. 11 (8%) of Group 2 (P < 0.0001). CONCLUSION: In this series (i) patients treated with A&P and PVI for drug-refractory AF showed significant differences in clinical profile; (ii) A&P is a shorter and less complex procedure, but is associated with a higher rate of persistent AF; (iii) symptomatic recurrences of paroxysmal AF were more frequent in PVI group. Randomized studies appear necessary to identify the best strategy in selected cases.

Association of deranged adrenal steroid metabolism with anemia in chronic heart failure.

The relation between adrenal steroid hormone imbalance, as quantified by the cortisol/dehydroepiandrosterone (DHEA) ratio, and hemoglobin concentrations was appraised in 92 men with stable chronic heart failure (CHF). The cortisol/DHEA ratio was independently and inversely associated with hemoglobin concentrations, suggesting that alterations of the steroid milieu may play a role in the pathogenesis of anemia in CHF.

Comparison between anatomical and integrated approaches to atrial fibrillation ablation: adjunctive role of electrical pulmonary vein disconnection.

INTRODUCTION: The aim of this study was to compare the outcome of anatomical pulmonary vein (PV) radiofrequency (RF) ablation with that of an integrated approach (anatomical with electrophysiological confirmation of PV disconnection). METHODS: Sixty consecutive patients affected by drug-refractory paroxysmal (39), persistent (13), and permanent (8) atrial fibrillation (AF) were assigned to an anatomical (group A: 30 patients; 25 male, 5 female, mean age: 55 +/- 7 years) or integrated approach (group B: 30 patients; 26 male, 4 female, mean age: 52 +/- 9 years). In all cases, RF ablation was performed by means of the Carto system in order to anatomically create circumferential lines around PVs. In group B, the persistence of PV potentials was then assessed with a multipolar circular catheter. If PV potentials persisted, RF pulses targeting the electrophysiological breakthroughs were delivered to disconnect PVs. RESULTS: Total procedure duration, fluoroscopy time, and RF delivery time were similar in both groups: 227 +/- 43, 50 +/- 23, and 43 +/- 16 minutes (group A); 232 +/- 32, 55 +/- 15, and 42 +/- 10 minutes (group B), respectively (ns). One asymptomatic PV stenosis and one pericardial effusion occurred in group A and B, respectively. After 15.4 +/- 7.4 months, 17 (57%) group A patients and 25 (83%) group B patients were in stable sinus rhythm (P = 0.02) (RR 1.78; 95% CI: 1.7-2.9). CONCLUSIONS: PV ablation by means of an integrated anatomical and electrophysiological approach seems more effective than a purely anatomical RF ablation approach. Electrophysiological confirmation of PV disconnection could be a useful marker of successful RF treatment of AF.

Overexpression of tumor necrosis factor (TNF)alpha and TNFalpha receptor I in human viral myocarditis: clinicopathologic correlations.

Proinflammatory cytokines, including tumor necrosis factor (TNF)alpha, have been recognized as important physiopathogenetic factors in the initiation and continuation of inflammatory cardiomyopathies. Experimental and preliminary human studies have demonstrated that TNFalpha plays a crucial role in enteroviral-induced myocarditis. In this study, we investigated the expression of TNFalpha and both its receptors (TNFRI and TNFRII) in both viral and nonviral myocarditis. Myocardial expression of TNFalpha was then correlated with different clinical and pathologic findings. TNFalpha expression was investigated in endomyocardial biopsies obtained from 38 patients with myocarditis and from eight control subjects by using reverse transcriptase-polymerase chain reaction (PCR) and immunohistochemistry. Viral etiology was diagnosed by PCR in 20 cases: enterovirus in seven, Epstein-Barr virus in four, hepatitis C virus in three, adenovirus in two, influenza virus in two, cytomegalovirus in one, and double infection adenovirus and enterovirus in one. Immunohistochemistry was also used to analyze both TNFalpha receptors (RI and RII). A semiquantitative analysis was employed (score 0-3) for necrosis, inflammation, fibrosis and immunohistochemical findings. TNFalpha mRNA and TNFalpha protein were significantly more present in viral myocarditis than in nonviral myocarditis (16/20 vs 3/18, P=0.001). Remarkable immunostaining was observed for both receptors, particularly TNFRI. Histological analysis revealed that myocardial necrosis (mean score 1.89 vs 1.15, P=0.01) and cellular infiltration (mean score 2.26 vs 1.78, P=0.05) were more prominent in TNFalpha-positive cases. Among TNFalpha-positive cases, the greater TNFalpha mRNAs, the more impaired was cardiac function. Our findings suggest that the expression of TNFalpha may play an important role in the pathogenesis of viral myocarditis of any etiology and may influence the severity of cardiac dysfunction. Cytokine effects are more strictly linked to overexpression of TNFRI.