Selective-site pacing in paediatric patients: a new application of the Select Secure system.

AIMS: The aim of this study was to evaluate the feasibility and reliability of selective-site pacing by means of a new lead system in a paediatric population. This lead system is composed of a 4.1 Fr, active-fixation lead and a steerable catheter that allows easy positioning in selective sites. METHODS AND RESULTS: Thirty young patients (mean age 9.0 +/- 4.5 years, range 2-16 years) received a single- (10) or dual- (20) chamber pacemaker. The 3830 lead was implanted successfully in the targeted chambers in all patients. The selective RV sites of pacing in 26 of the patients were: 18 mid-septum, 5 outflow tract, 1 low-septum, and 2 LEVO-RV-Apex. In all patients, an intracardiac loop was left in order to avoid stretching of the lead with growth. Mean follow-up duration was 11 +/- 10 months. Atrial sensing and pacing thresholds were 3.2 +/- 1.7 mV and 0.8 +/- 0.6 V at 0.5 ms at implantation and 3.4 +/- 2.1 mV and 0.6 +/- 0.3 V at 0.5 ms at follow-up. Ventricular sensing and pacing thresholds were 12.1 +/- 4.9 and 0.7 +/- 0.4 V at 0.5 ms on implantation and 12.7 +/- 6.1 mV and 0.8 +/- 0.5 V at 0.5 ms at follow-up (P = NS). No adverse events were reported. CONCLUSION: Select Secure is a promising system for selective-site pacing in children.

The Drug And Pace Health cliNical Evaluation (DAPHNE) study: a randomized trial comparing sotalol versus beta-blockers to treat symptomatic atrial fibrillation in patients with brady-tachycardia syndrome implanted with an antitachycardia pacemaker.

BACKGROUND: Atrial tachyarrhythmias (ATAs) are mainly treated by pharmacologic therapy for rate control or rhythm control. The aim of our study was to compare sotalol (S) versus beta-blocking agents (BB) in terms of prevention of ATA, cardioversions (CVs), and cardiovascular hospitalizations (H) in patients paced for bradycardia-tachycardia form of sinus node disease (BT-SND). METHODS: One hundred thirty-five patients (67 males, aged 73 +/- 7 years) were enrolled in a prospective, parallel, randomized, single-blind, multicenter study. All patients received a dual chamber rate adaptive pacemaker; after 1 month, 66 patients were randomly assigned to BB (62 +/- 26 and 104 +/- 47 mg/d for atenolol and metoprolol, respectively) and 69 patients to S (167 +/- 66 mg/d). RESULTS: After an observation period of 12 months, the percentage of patients free from ATA recurrences was 29% in both BB and S group. Cardioversion and H were significantly (P < .01) fewer in the 12 months after implantation than in the 12 months before both in patients treated with S (CV 69.4% vs 22.2%, H 91.7% vs 33.3%) and in patients treated with BB (CV 58.5% vs 17.1%, H 82.9% vs 26.8%). Kaplan-Meier survival analysis showed a nonsignificant trend toward a lower incidence of the composite end point (CV + H) among BB patients. CONCLUSIONS: In the complex context of "hybrid therapy" in patients with BT-SND implanted with a modern dual chamber rate adaptive pacemaker device delivering atrial antitachycardia pacing, no differences were found between the use of beta-blocker and the use of S, at the relatively low dose achieved after clinical titration, in terms of prevention of cardiovascular H or need for atrial CV.

Direct His bundle pacing preserves coronary perfusion compared with right ventricular apical pacing: a prospective, cross-over mid-term study.

AIMS: The His bundle is regarded as the most physiological site for ventricular pacing, in that it avoids the adverse effects of right ventricular apical pacing (RVAP). However, very few studies have compared the effects of direct His bundle pacing (DHBP) and RVAP. The aim of our study was the intra-patient comparison of myocardial perfusion corresponding to these two different pacing techniques, as perfusion expresses local workload and is related to long-term outcome. METHODS AND RESULTS: Twelve consecutive patients with standard pacemaker indication (9 male, 74 +/- 9 years) entered the study. Pacing leads were implanted in the right ventricular apex and directly in the His bundle, and were connected to different ports of the pacemaker. All patients first underwent 3 months of DHBP, followed by 3 months of RVAP. At the end of each 3-month period, myocardial perfusion was measured at rest using scintigraphy with Tc99m-SestaMIBI. The average values of perfusion were evaluated on a 20-segment basis. All patients also underwent clinical evaluation, echocardiography, and tissue Doppler imaging (TDI), to measure dyssynchrony, and a blood sample was taken for brain natriuretic peptide (BNP) assay. The perfusion score during DHBP pacing was significantly better than during RVAP (0.44 +/- 0.5 vs. 0.71 +/- 0.53, respectively; P = 0.011). None of the patients showed lower perfusion during DHBP than during RVAP. We found no significant difference in NYHA class, ventricular volumes, ejection fraction, or plasmatic BNP between DHBP and RVAP. However, mitral regurgitation (0.26 +/- 0.21 vs. 0.37 +/- 0.25; P < 0.001) and dyssynchrony (13.75 +/- 4.28 vs. 22.02 +/- 8.44; P = 0.008) were significantly less during DHBP than during RVAP. CONCLUSION: Direct His bundle pacing is superior to RVAP in preserving the physiologic distribution of myocardial blood flow and reducing mitral regurgitation and left ventricular dyssynchrony.

Effect of atrial pacing on ventricular rate during atrial fibrillation. A human study.

OBJECTIVE: This research study tests the hypothesis that atrial pacing near the atrioventricular node during atrial fibrillation can affect ventricular rate. METHODS: In 13 patients, two monophasic action potential catheters were advanced into the low anterior septum (ANT) and the low posterior septum (POST) near the atrioventricular node. After induction of atrial fibrillation, measurement of the excitable gap was attempted at the ANT and POST regions. During atrial pacing, ventricular cycle length (CL) at the longest excitable gap was compared to ventricular CL at the shortest excitable gap by pairwise analysis. RESULTS: Transient capture of ANT tissue during ANT pacing was observed in six patients, whereas transient capture of POST tissue during POST pacing was observed in four patients. The ventricular response to ANT and POST pacing at multiple rates was recorded in six and seven patients, respectively. An increase in POST pacing CL by 40 +/- 24 ms prolonged (P < 0.05) ventricular CL by 45 +/- 56 ms. Conversely, an increase in ANT pacing CL by 48 +/- 42 ms shortened (P < 0.05) ventricular CL by 45 +/- 40 ms. CONCLUSIONS: ANT and POST pacing CL affected ventricular CL during atrial fibrillation, even though capture was transient. The opposite direction of the effects of ANT and POST pacing CL on ventricular CL may indicate that the atrial impulses from the POST region are more likely to conduct to the ventricle than impulses from the ANT region as the CL of activation is decreased.

Permanent direct his bundle pacing does not induce ventricular dyssynchrony unlike conventional right ventricular apical pacing. An intrapatient acute comparison study.

BACKGROUND: Benefits of A-V synchrony during right ventricular apical pacing are neutralized by induction of ventricular dyssynchrony. Only a few data are reported about direct His bundle pacing influence on ventricular synchronism. AIM: Was to assess the capability of direct His bundle pacing to prevent pacing-induced ventricular dyssynchrony comparing DDD- (or VVI- in case of Atrial Fibrillation) right ventricular apical pacing with DDD- (or VVI-) direct His bundle pacing in the same patients cohort. METHODS: 23 of 24 patients (mean age 75.1 +/- 6.4 years) with narrow QRS (HV < 65 ms) underwent permanent direct His bundle pacing for "brady-tachy syndrome" (11) or supra-Hisian II/III-degree AV Block (permanent atrial fibrillation 7, AV Node ablation 1). A 4.1 F screw-in lead was fixed in His position, guided by endocardial pacemapping and unipolar recordings. Additional permanent (13 patients) or temporary right ventricular apical pacing leads were also positioned. Inter- and left intra-ventricular dyssynchrony, mitral regurgitation and left systolic ventricular function Tei index were assessed during either direct His bundle pacing or right ventricular apical pacing. RESULTS: Permanent direct His bundle pacing was obtained in 23 of 24 patients. Indexes of ventricular dyssynchrony were drastically reduced, mitral regurgitation decreased and left systolic ventricular function Tei index improved during direct His bundle pacing (or His bundle and septum pacing) in comparison to apical pacing (p < 0.05). No statistically significant differences were observed between direct His bundle pacing and combined His bundle and septum pacing. CONCLUSION: Direct His bundle pacing (also fused with adjacent septum capture) prevents pacing-induced ventricular dyssynchrony.

A feasible approach for direct his-bundle pacing using a new steerable catheter to facilitate precise lead placement.

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.