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Background: Phrenic nerve stimulation (PNS), occurring in 33%-37% of the patients with cardiac resynchronization therapy (CRT), is a limiting factor when implanting left ventricular (LV) leads from coronary veins.Objective: To test the hypothesis that PNS occurrence is related to bipolar electrode spacing.Methods: During standard CRT defibrillator implant procedures, a 5-F diagnostic electrophysiology catheter with 10 electrodes, spaced 2-5-2 mm, was positioned in a cardiac vein suitable for permanent LV lead placement. Pacing in the unipolar configuration identified the site with the lowest PNS threshold. PNS and left ventricular pacing (LVP) thresholds were then measured in different configurations at 0.5 ms: unipolar, each LV electrode served as the cathode in turn; and bipolar with different electrode spacing, cathode being the electrode with the lowest unipolar PNS threshold.Results: From February to September 2010, 40 patients undergoing CRT implantation were enrolled in 4 centers in Italy. It was possible to identify PNS and perform a complete set of measurements in 23 patients. A bipolar electrode spacing of 2 mm resulted in higher PNS thresholds in bipolar configurations han did a bipolar electrode spacing of ≥ 5 mm. However, no significant increase in the LVP threshold was observed (P = ns).Conclusions: This experience suggests that LVP with a bipolar electrode spacing of 2 mm significantly increases the PNS threshold without affecting the LVP threshold, thereby increasing the possibility of delivering CRT when the LV lead is placed in proximity to the phrenic nerve. [ABSTRACT FROM AUTHOR]

Background: Cardiac resynchronization therapy (CRT) is effective in patients with heart failure, but 30% to 50% of subjects are classified as nonresponders. Identifying responders remains a challenging task. Aims: The LODO-CRT trial investigated the association between left ventricular contractile reserve (LVCR) and clinical and echocardiographic long-term CRT response. Methods: This is a multicenter, prospective, observational study. Left ventricular contractile reserve was detected using a dobutamine stress echocardiography test, defined as an ejection fraction increase of >5 points. Clinical CRT response was defined as the absence of major cardiovascular events (ie, cardiovascular death or heart failure hospitalization). Echocardiographic response was defined as a left ventricle end-systolic volume reduction of >10%. Results: A total of 221 CRT-indicated patients were studied (80% presented LVCR). During a mean follow-up of 15 ± 5 months, 17 patients died and 16 were hospitalized due to heart failure. The proportion of clinical responders was 155 (88%) of 177 and 33 (75%) of 44 (P = .036) in the groups with and without LVCR, respectively. Kaplan-Meier analysis showed a significant difference in cardiac survival/hospitalization between patients with and without LVCR. The proportion of echocardiographic responders was 144 (87%) of 166 and 16 (42%) of 38 in the groups with and without LVCR (P < .001), respectively; LVCR showed 90% sensitivity and 87% positive predictive value to prefigure echocardiographic CRT responders. Multivariable analysis identified LVCR and interventricular dyssynchrony as independent predictors of CRT response. The concomitant presence of both factors showed 99% specificity and 83% sensitivity in detecting responders. Conclusion: The presence of LVCR helps in predicting a clinical and echocardiographic CRT response. Concomitant assessment of LVCR and interventricular dyssynchrony accurately stratifies responder and nonresponder patients. [ABSTRACT FROM AUTHOR]

Background: Cardiac resynchronization therapy (CRT) is effective in selected patients with heart failure (HF). Nevertheless, the nonresponder rate remains high. The low-dose dobutamine stress-echo (DSE) test detects the presence of left ventricular (LV) contractile reserve (LVCR) in HF patients of any etiology and may be useful in predicting response to resynchronization. Objective: The purpose of this study was to present the results of the LODO-CRT trial, which evaluated whether LVCR presence at baseline increases the chances of response to CRT. Methods: LODO-CRT is a multicenter prospective study that enrolled CRT candidates according to guidelines. LVCR presence was defined as an LV ejection fraction increase >5 units during DSE test. CRT response is assessed at 6-month follow-up as an LV end-systolic volume reduction ≥10%. Results: Two hundred seventy-one patients were enrolled. The DSE test was feasible without complications in 99% of patients. Nine patients died from noncardiac disease, and 31 presented inadequate data. Two hundred thirty-one patients were included in the analysis. Mean patient age was 67 ± 10 years; 95% were in New York Heart Association class III, and 42% had HF of ischemic etiology. Mean QRS and LV ejection fraction were 147 ± 25 ms and 27% ± 6%, respectively. LVCR presence was found in 185 subjects (80%). At follow-up, 170 (74%) patients responded to CRT, 145/185 in the group with LVCR (78%) and 25/46 (54%) in the group without LVCR. Difference in responder proportion to CRT was 24% (P <.001). Reported test sensitivity is 85%. Conclusion: The DSE test in CRT candidates is safe and feasible. LVCR presence at baseline increases the chances of response to CRT. [ABSTRACT FROM AUTHOR]

Failure modes and mechanisms of AlGaN/GaN high-electron-mobility transistors are reviewed. Data from three de-accelerated tests are presented, which demonstrate a close correlation between failure modes and bias point. Maximum degradation was found in "semi-on" conditions, close to the maximum of hot-electron generation which was detected with the aid of electroluminescence (EL) measurements. This suggests a contribution of hot-electron effects to device degradation, at least at moderate drain bias (VDS<30 V). A procedure for the characterization of hot carrier phenomena based on EL microscopy and spectroscopy is described. At high drain bias (VDS>30-50 V), new failure mechanisms are triggered, which induce an increase of gate leakage current. The latter is possibly related with the inverse piezoelectric effect leading to defect generation due to strain relaxation, and/or to localized permanent breakdown of the AlGaN barrier layer. Results are compared with literature data throughout the text. [ABSTRACT FROM PUBLISHER]

INTRODUCTION: Much clinical evidence has shown that right ventricular (RV) apical pacing is detrimental to left ventricular function. Preservation of the use of the His-Purkinje (H-P) system may be ideal in heart block that is restricted to the AV node, but may be of no benefit when H-P disease exists. AIM: To investigate the feasibility of direct His-bundle pacing (DHBP) using a new system consisting of a steerable catheter and a new 4.1 F screw-in lead. METHOD: Between May and December 2004, 26 patients (19 male, mean age: 77 +/- 5 years) with a standard pacemaker (PM) indication and preserved His-bundle conduction were enrolled and DHBP was attempted. RESULTS: DHBP was achieved in 24 patients (92%); two patients were paced in the His area, but the paced QRS morphology and duration were different from the native QRS. The mean time for lead positioning was 19 +/- 17 minutes, the mean fluoroscopy time was 11 +/- 8 minutes, and the total procedure time (skin-to-skin including positioning of a quadripolar diagnostic catheter for His recording) was 75 +/- 18 minutes. In DHBP pacing, the acute pacing threshold was 2.3 +/- 1.0 V at a pulse duration of 0.5 msec, and the sensed potentials were 2.9 +/- 2.0 mV. At a 3-month follow-up examination, the same QRS duration and morphology recorded on implantation were observed in all patients. The pacing threshold was 2.8 +/- 1.4 V, and sensed potentials were 2.5 +/- 1.8 mV; the sensing configuration was changed from bipolar to unipolar in 6 patients to resolve undersensing issues. No major complications were observed. CONCLUSIONS: This feasibility study shows that DHBP can be accomplished with a new system consisting of a steerable catheter and an active fixation lead in 92% of the patients in whom it was attempted. [ABSTRACT FROM AUTHOR]

Aims Evaluate the possible changes in myocardial metabolism and perfusion induced by biventricular pacing (BIVP) in patients affected by dilated cardiomyopathy (DC) and left bundle branch block (LBBB). Methods and results Eight male patients (aged 60–79 years, mean 69) affected by DC (NYHA functional class III and ejection fraction <40%) were submitted to cardiac PET in basal condition and 3 weeks after the implantation of a biventricular device. Metabolism was evaluated using F18-fluorodeoxyglucose (FDG), by the glucose load-insulin technique, and perfusion by N13-ammonia (NH3), injected at rest. Visual and a semi quantitative analyses were performed, calculating by ROIs the septum to lateral uptake ratio (SLR). The myocardial blood flow (MBF) was also calculated in ml/min/g using a dynamic acquisition and a modified Patlak method. Conclusions Our results suggest that, in patients affected by DC and LBBB, BIVP improves the septal glucose metabolism without significant changes in myocardial perfusion. [ABSTRACT FROM PUBLISHER]

The aim of the present study is to assess the incidence of underloverweight and obesity in a sample of children 6-11 years old in Turin province and to monitor the secular trend in weight. Our survey shows that about 2% of children are underweight, 17% overweight and 3% obese. Males show a prevalence of overweight and obesity, while females show also underweight problems. The comparison of current data with those collected in 1979 by Ente Italiano Moda (E.I.M.) [1] shows a significant increase of weight problems in both sexes: this, in childhood, is an emergent social problem that can produce adverse health effects in adulthood. It could be prevented encouraging correct eating behaviors and active lifestyle among children. [ABSTRACT FROM AUTHOR]

An abstract of the study "Cardiac resynchronization therapy in atrial fibrillation: an InSync Italian Registry long-term follow-up," by F. Oliva and colleagues, is presented.

Since 1999, 174 pts (135 male, mean age 71.1±8.6 y - range 36-92) underwent to CRT (64 with ICD back-up) for severe CHF: 56% had ischemic cardiomyopathy. At implant 31 pts were in AF, 47 were previously paced with right apical pacing. In 18 subjects CRT were a bridge to heart transplant. Clinical (NYHA class, Minnesota Quality Life Score-QLS) and echocardiographic evaluation (end systolic-diastolic [ESD]-[EDD] diameters, ejection fraction [EF] inter and intra-ventricular delay, % of mitral regurgitation area in left atrium [MR]) was scheduled every three month for the first year and then twice a year. The procedure success was 98,7%: coronary dissection and lead instability were the causes of failure. The mean follow-up was 25±16 months (range 1-66). After CRT, a significant reduction of the electric (QRS: 189±32 vs. 143±21ms, p<.001) and the mechanical (55±33 vs. 25±19ms, p<.001) delays was observed immediately after the procedure. The following parameters were significantly (p<.001) improved after CRT: Follow-up Implant 6 months 1 year 2 years 3 years 4 years n subjects 174 150 132 81 42 23 Mortality T. 1 (0,57%) 5 (3,34%) 8 (6,06%) 9 (11, 1%) 7 (16,7%) 5 (21,7%) NYHA 3,16±0.61 2,15±0.48 2,04±0.45 2,09±0.41 2,13±0.47 2,23±0,4 QLS 59±12 35±9 33±8 32±8 31±10 33±7 EF% 26,3±6,9 35,6±7,9 37,0±8,4 38,8±10 36,1±11 31,6±4,1 Moreover at 2 years (n=42) a significant reduction of ESD (63,1±10,6 vs. 55,2±9.8, p<.001), EDD (74,1±10,1 vs. 70,7±11,3, p<.001), MR% (21±18% vs. 12±12%, p<.001) has been observed. A marked decreased in hospitalization for CHF were observed during the first year follow-up (3.08±1.9 vs. 0.76±0.5, p<.001). Our real world experience confirms the benefit of CRT in a large unselected population in terms of clinical and echocardiographic improvements and reduction of both mortality and hospitalization rate. [ABSTRACT FROM PUBLISHER]

Cardiac resynchronization therapy (CRT) has become one of the main therapeutic alternatives for advanced congestive heart failure (CHF), but the effects on morbidity and mortality are still unclear.Aim of the Study was to analyze hospitalization rate and mortality - total mortality (TM) and cardiac mortality (CM) - in a wide patient population implanted in our institution in the last six years. Methods since 1999, 187 pts (158 male) underwent CRT for severe CHF (EF 26.3% ± 6.9). In 82 pts a backup ICD was associated. The mean age was 71.1 ± 8.8 years (range 36 to 92); 103 pts (53%) had ischemic heart disease (IHD) while 84 were non ischemic (NIHD); 36 pts were in atrial fibrillation at the time of implant; 46 were previously paced via the right ventricular apex; 16 were candidates for heart transplantation. All the pts were evaluated in our clinic and the follow-up was scheduled every three month for the first year and then twice a year. Results the implant success rate was 98.9%. The mean follow-up was 29±16 months (range 1 – 74 months). Compared to the year before CRT, a significant decrease in hospitalization rate was observed during the first year of follow-up (2.38±1.6 vs. 0.56±0.7, p<.001). TM was 10.7%, CM was 8.0 %. The ICD group shows a reduction of TM compared to the group without: 7.3% vs. 13.3%: - 46 %. Conclusions 1) the benefit of CRT is similar in IHD and NIHD; 2) IHD seems to have a worse prognosis than NIHD in term of TM and CM; 3) CRT decreases the hospitalization rate and increases survival; 4) the association with a back-up ICD strongly reduces the mortality in this population. [ABSTRACT FROM PUBLISHER]

Cardiac resynchronization therapy (CRT) by biventricular pacing is still challenging in terms of successful coronary sinus (CS) cannulation and left ventricular (LV) lead positioning. Thus, a system to facilitate the cannulation and the positioning may be preferable.Aim of the Study A new approach for coronary sinus cannulation and left ventricular lead positioning has been evaluated. This system consists of a guiding and an inner catheter as a telescopic way to cannulate the CS ostium and the target collateral vein (Dual-Catheter System-RAPIDO). Methods Forty-four consecutive patients with cardiomyopathy of any etiology (34 males, 72±9 yrs, QRS 169±23 ms, LV ejection fraction 27.6 ± 5.2%) underwent CRT (23 ICD) under standards indications. Results Successful cannulation was achieved in 100% of cases. The mean time from insertion of the telescopic system into the subclavian vein to cannulation of the CS was 1.3±2.5 min. The mean LV lead positioning time, measured from CS cannulation to lead positioning in the final LV lead location, was 6.3±7 min. The total fluoroscopy and total procedural time were 16±11 min and 87±35 min, respectively. No major complications were observed. Conclusion This approach using a dual telescopic catheter system leads to a high percentage of success procedure rates. It is safe and feasible with a reduction of fluoroscopy time, procedural time and contrast agent volume. In our experience this system is superior in terms of time consuming and success rate compared to the traditional approach. [ABSTRACT FROM PUBLISHER]

EPASS Pilot study compared right atrial appendage (RAA) and Interatrial Septum (IAS) pacing in patients (Pts) with SSS and atrial fibrillation (AF), in relation with the electrophysiologic study (EP) and pacing mode.Method 42 Pts (72±7 years old, 15M, 27F) were submitted to EP before randomization of pacing site and algorithms. The difference between basal and incremental conduction times (CT) was measured between the RAA and the coronary sinus os (csos) (delta-ctos). Pts with A2>100ms, ERP/A2<2,2, P wave duration >110ms and delta-ctos>60ms were group A. The remaining pts were group B. The number of AF episodes lasting more than 7 minutes (AF-Ep) was collected at 2 follow-ups of 3 months each by the pacemaker Selection 9000 (Vitatron). Results Group A (IAS) showed a reduction of AF-Ep/day with algorithms (p = 0,049) as to standard DDD. Group A (RAA) showed an increase of AF-Ep/day (p = 0,046) when continuously paced. Group B did not show statistically significant differences between DDD and DDD + Algorithms. Conclusion Pts with RA severe conduction delay may benefit of continuous pacing in the IAS, but not in the RAA. [ABSTRACT FROM PUBLISHER]

Purpose To verify the safety and efficacy of selective sites (SS) pacing using Medtronic Select Secure system. Methods In 25 Centers 72 pts were implanted in Right Atrium (RA) and/or Right Ventricle (RV) SS. 48 pts had atrial arrhythmias, 11 I AVB, 12 High degree AVB, 20 sick sinus syndrome. Results 40 pts were implanted in the RA: 6 in the Coronary Sinus Ostium, 4 in the Bachman Bundle, 35 in the Inter-Atrial Septum and 1 in Appendage. Conclusion Our data suggested that SS pacing is safe. Further data are needed to evaluate clinical data. [ABSTRACT FROM PUBLISHER]

Background a pacing system that could preserve His Bundle activation should be the ideal pacing approach. Aim to investigate whether the His bundle could be reached and effectively paced using the Select Secure (SS) system, composed by a steerable catheter and a 4Fr lead. Materials and Methods in 88 patients candidates to a standard PM implant, with narrow QRS (105ms±25), His bundle pacing was attempted using the SS. EP catheter was used to record His signals and to confirm final lead position. Results in 79/88 patients His or para-Hisian pacing site was achieved, in remaining ones: 7 in the septal Right Ventricular Outflow tract and 2 in the RV Apex .33 patients had a III Month Follow-up and the acute and III Month electrical performances are shown in the table below. Conclusion His/para-Hisian pacing site was safely and easily reached in 89.7% of implants. From these data His/para-Hisian pacing is feasible and safe, long-term data are necessary to validate this technique. [ABSTRACT FROM PUBLISHER]

Background Right ventricular apical pacing alters impulse conduction producing an intraventricular desynchronization that could be detrimental for LV function. Direct His bundle pacing (DHBP) represents a novel approach to cardiac pacing in pts with normal His-Purkinje activation because it maintains or restores the physiological activation of the ventricular muscle during cardiac pacing. Methods 13 pts (mean age 76±3 years; 2 females; QRS duration 118±24 ms; LV EF% 60±11; LV end-diastolic volume 61±22 ml/m2) have been investigated. At baseline and after DHBP Tissue Doppler Imaging was performed to evaluate the intraventricular dyssynchrony [defined as the interval between the earliest LV wall motion and the latest (intra LV delay) or as standard deviation (SD, modified Yu index) of all time intervals]. Tei index, E/A ratio, dP/dT, MR (mitral regurgitation-diameter of vena contracta) were also obtained. Baseline intra-LV desynchronization (intra-LV delay above 40 ms) was observed in 2 pts with normal QRS and in all 4 pts who had intraventricular conduction delay (QRS > 120 ms). Results in table are displayed the values at baseline and after DHBP: [ABSTRACT FROM PUBLISHER]