A novel and practical technique to facilitate lead insertion at the His bundle region.

BACKGROUND: His bundle (HB) pacing techniques are challenging and time-consuming. This is primarily due to the limitations in locating the relatively small area of the HB body for pacing. METHODS: Permanent HB pacing was performed in 133 consecutive patients with symptomatic bradycardia. A right atrial septo-gram (RAS) was performed in all patients to locate the HB. Briefly, 8-10 cc of contrast was injected through the Medtronic C315HIS delivery sheath while fluoroscopy cine runs were obtained in the RAO 15-20° projection. The images obtained provided the visualization of an approximately 90° angle composed by the medial aspect of the tricuspid valve annulus (TVA) anteriorly and the superior aspect of the interatrial septum superiorly. The apex of this angle coincides with the tip of the triangle of Koch (TK), where the HB body is usually located. A Medtronic SelectSecure™ MRI SureScan™ Model 3830 lead was then advanced and directed towards this area. The HB was mapped using pace mapping and unipolar recordings from the lead tip. RESULTS: Localization of the apex of the TK/HB body with the RAS was successful in all patients. The overall acute success of inserting the lead at the HB was 95%. CONCLUSION: This study demonstrated that our method of utilizing a RAS to facilitate the localization the HB body proved to be safe and efficient in achieving permanent HB pacing with a success rate higher than previously reported.

Representation of the His Bundle Cloud on a Three-dimensional Electroanatomical Map and Its Implications for His Bundle Pacing.

His bundle pacing has been proposed as a more physiologic approach to chronic ventricular stimulation, yet the achievement of permanent His bundle pacing can be challenging.

A Novel and Practical Method of Performing Atrioventricular Nodal Ablation via a Superior Approach in Patients with Refractory Atrial Fibrillation Undergoing Cardiac Resynchronization Device Implantation.

Atrioventricular node (AVN) ablation is a strategy to manage patients with drug-refractory atrial fibrillation (AF) and heart failure in whom cardiac resynchronization therapy (CRT) device implantation has been prescribed. This study describes a practical method to perform these two procedures using the same surgical site. Twenty-seven patients were indicated for AVN ablation and concurrent CRT device implantation while presenting with AF and rapid ventricular response (RVR) refractory to medical therapy. After placement of the right and left ventricular leads, a third puncture was made in the axillary vein to obtain access to perform the ablation. After hand-injecting contrast media through a RAMP™ (Abbott Laboratories, Chicago, IL, USA) sheath positioned in the right atrial cavity, the anatomical area corresponding to the AVN was identified using fluoroscopy cine runs obtained in the right anterior oblique and left anterior oblique projections. The adequate site for ablation was confirmed by the bipolar recording of a His-bundle deflection at the tip of the ablation catheter. Radiofrequency energy was delivered to achieve complete heart block. Subsequently, device implant was completed. The method was successfully applied in 27 consecutive cases, achieving permanent complete heart block in all patients. The mean radiofrequency time to achieve heart block was 110 seconds ± 43 seconds. The average procedural time including AVN ablation and device implant was 87 minutes ± 21 minutes. The images obtained with the hand-injected contrast media provided adequate information to readily identify the anatomical area corresponding to the AVN with 100% accuracy. This study suggests that ablation of the AVN can be safely and effectively accomplished via a superior approach in patients undergoing a CRT device implant.

Antibacterial Envelope Is Associated With Low Infection Rates After Implantable Cardioverter-Defibrillator and Cardiac Resynchronization Therapy Device Replacement: Results of the Citadel and Centurion Studies.

OBJECTIVES: This study sought to determine whether the nonabsorbable TYRX Antibacterial Envelope (TYRX) reduces major cardiovascular implantable electronic device (CIED) infections 12 months after implant. BACKGROUND: TYRX is a monofilament polypropylene mesh impregnated with minocycline and rifampin specifically designed to hold a CIED in place and elute antimicrobials over time. There are limited data on its ability to reduce CIED infections. METHODS: We prospectively enrolled patients who underwent generator replacement with an implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy device (CRT), treated with TYRX. The primary endpoints were major CIED infection and CIED mechanical complications. Given the differences in infection rates among ICD and CRT patients, 3 different control populations were used: a published benchmark rate for ICD patients, and both site-matched and comorbidity-matched controls groups for CRT patients. RESULTS: Overall, a major CIED infection occurred in 5 of 1,129 patients treated with TYRX (0.4%; 95% confidence interval: 0.0% to 0.9%), significantly lower than the 12-month benchmark rate of 2.2% (p = 0.0023). Among the TYRX-treated CRT cohort, the major CIED infection rate was 0.7% compared with an infection rate of 1.0% and 1.3% (p = 0.38 and p = 0.02) in site-matched and comorbidity-matched control groups, respectively. Among the ICD group, the 12-month infection rate was 0.2% compared with the published benchmark of 2.2% (p = 0.0052). The most common CIED mechanical complication in study patients was pocket hematoma, which occurred in 18 of the 1,129 patients (1.6%; 95% confidence interval: 0.8 to 2.5), which is comparable with a published rate of 1.6%. CONCLUSIONS: Use of TYRX was associated with a lower major CIED infection rate. (TYRX™ Envelope for Prevention of Infection Following Replacement With a CRT or ICD; [Centurion]; NCT01043861/NCT01043705).

Atrial lead placement at the lower atrial septum: a potential strategy to reduce unnecessary right ventricular pacing.

AIMS: Right ventricular (RV) pacing has been shown to be potentially detrimental to left ventricular function. In conventional dual-chamber pacing the position of the atrial lead could influence duration of the atrio-ventricular (AV) intervals, which is one of the variables that could be associated with an increased percentage of RV pacing. We wanted to see if lead placement at selected atrial septal sites could reduce AV intervals in patients receiving a dual-chamber pacemaker or implantable cardioverter defibrillator. METHODS AND RESULTS: This was a prospective, acute, randomized single centre study that enrolled 57 patients. The atrial lead was placed in both the right atrial appendage (RAA) and the lower atrial septum (LAS) in each patient in random order. The P-wave durations, PR intervals, A sense-V sense (As-Vs), and A pace-V sense (Ap-Vs) intervals were measured at both atrial lead locations in each patient during device implant. The P-wave durations during sinus rhythm (SR), RAA pacing, and LAS pacing were 113 ± 19, 144 ± 27, and 84 ± 12 ms (RAA vs. LAS, P < 0.001), respectively. The PR intervals during SR, RAA pacing, and LAS pacing were 195 ± 47, 230 ± 61, and 167 ± 44 ms (RAA vs. LAS, P < 0.001), respectively. The As-Vs interval was 31% shorter in LAS pacing than in RAA pacing (134 ± 44 ms vs. 194 ± 52 ms, P < 0.001). The Ap-Vs interval was 24% shorter during LAS pacing than during RAA pacing (195 ± 45 ms vs. 257 ± 63 ms, P < 0.001). CONCLUSION: When compared with RAA pacing, LAS pacing was associated with a shorter P wave duration, PR interval, As-Vs, and Ap-Vs intervals. The potential long-term impact of the strategy of pacing from LAS in reducing unnecessary RV pacing needs to be explored in future studies.

Placement of a pacing lead at the inferior portion of the interatrial septum without special tools.

INTRODUCTION: Previous studies have suggested that, among septal sites, the inferior portion of the interatrial septum (IAS) is the most likely to prevent atrial fibrillation, though inserting an active fixation lead at this site can be tedious and time consuming. We describe a relatively straightforward technique to insert a lead at this site without special tools. METHOD: We studied 117 consecutive patients (mean age = 76 +/- 8 years, 69% men) with ACC/AHA class I and II pacing indications and histories of paroxysmal or permanent atrial fibrillation, undergoing implantation of a dual chamber pacing system. A technique using the "preshaped" stylet and fluoroscopic guidance is described. RESULTS: The insertion was successful in 111 patients (95%). Acute dislodgement occurred in six patients (5%). The intrinsic P-wave duration was 117 +/- 22 ms, and the paced P-wave duration was 90 +/- 20 ms (23% shortening, P < 0.001). The mean time required to insert the atrial lead was 12 +/- 8 minutes. No complications occurred. CONCLUSIONS: Insertion of an active fixation lead at the inferior portion of the interatrial septum was safe and highly successful in the majority of patients with this technique.

Dual-chamber versus single-chamber detection enhancements for implantable defibrillator rhythm diagnosis: the detect supraventricular tachycardia study.

BACKGROUND: Delivery of inappropriate shocks caused by misdetection of supraventricular tachycardia (SVT) remains a substantial complication of implanted cardioverter/defibrillator (ICD) therapy. Whether use of optimally programmed dual-chamber ICDs lowers this risk compared with that in single-chamber ICDs is not clear. METHODS AND RESULTS: Subjects with a clinical indication for ICD (n=400) at 27 participating centers received dual-chamber ICDs and were randomly assigned to strictly defined optimal single- or dual-chamber detection in a single-blind manner. Programming minimized ventricular pacing. The primary end point was the proportion of SVT episodes inappropriately detected from the time of programming until crossover or end of study. On a per-episode basis, 42% of the episodes in the single-chamber arm and 69% of the episodes in the dual-chamber arm were due to SVT. Mortality (3.5% in both groups) and early study withdrawal (14% single-chamber, 11% dual-chamber) were similar in both groups. The rate of inappropriate detection of SVT was 39.5% in the single-chamber detection arm compared with 30.9% in the dual-chamber arm. The odds of inappropriate detection were decreased by almost half with the use of the dual-chamber detection enhancements (odds ratio, 0.53; 95% confidence interval, 0.30 to 0.94; P=0.03). CONCLUSIONS: Dual-chamber ICDs, programmed to optimize detection enhancements and to minimize ventricular pacing, significantly decrease inappropriate detection.

Transvenous dual site left ventricular pacing plus biventricular pacing for the management of refractory ventricular tachycardia.

This is a case report of a male patient with nonischemic cardiomyopathy who had severely depressed left ventricular systolic function and functional class III congestive heart failure (CHF). He also had left bundle branch block (LBBB) and recurrent ventricular tachycardia (VT). Though the patient's CFH functional class improved after implantation of a transvenous biventricular ICD system, recurrent VT episodes required the initiation of amiodarone. After an improved condition for 28 months, recurrent VT episodes led to multiple consecutive ICD shocks, which constituted an electrical storm and a battery status of elective replacement indicator (ERI). The recurrent VT episodes were suppressed with intravenous amiodarone and lidocaine. As Radiofrequency ablation was declined by the patient, a new left ventricular (LV) lead was transvenously added, providing biventricular and dual site LV pacing. After this intervention the arrhythmia subsided and the intravenous antiarrhythmic medications were stopped. No episodes of sustained VT leading to ICD shocks were observed for the following 9 months. The events in this case suggest that dual site LV pacing with biventricular pacing could be an alternative strategy for the management of refractory VT.

AutoCapture with dual-coil leads of implantable cardioverter defibrillator.

AutoCapture (AC) can confirm ventricular capture with true bipolar single coil leads of implantable cardioverter defibrillators (ICD). The compatibility of AC with a new, true bipolar, dual-coil ICD lead needed to be evaluated. This multicenter study enrolled 46 patients (69 +/- 10 years, 37 men) undergoing ICD implantation. All patients received a true bipolar, dual-coil lead. Evoked response (ER) sensitivity and AC threshold tests were performed using a pulse generator with the AC algorithm. Mean capture threshold was 0.85 +/- 0.67 V, pacing impedance 612 +/- 225 Omega, R wave amplitude 13.85 +/- 6.17 mV, and defibrillation threshold 14.4 +/- 5.1 J. AC was recommended in 45 patients (97.8%) with ER and polarization values of 14.86 +/- 7.32 mV and 0.87 +/- 0.69 mV, respectively. The AC algorithm was highly compatible with true bipolar, dual-coil ICD leads. An AC algorithm specifically designed for an ICD may improve the generator longevity. Further examination of AC compatibility with other leads is warranted.

Analysis of troponin I levels after spontaneous implantable cardioverter defibrillator shocks.

INTRODUCTION: Serum cardiac troponin I (cTnI) is a sensitive and specific marker for myocardial injury. Myocardial ischemia and/or injury can be a trigger for ventricular arrhythmias. The aim of this study was to assess the frequency and significance of elevated serum cTnI levels after spontaneous implantable cardioverter defibrillator (ICD) shocks. METHODS AND RESULTS: Serial cTnI measurements and ECGs were performed in 35 patients with transvenous ICDs who were admitted after spontaneous ICD shocks. Elevated cTnI levels were found in 18 patients (51%). Acute coronary syndrome was diagnosed in 5 (22%) of 23 patients with known coronary artery disease. After excluding the patients with acute coronary syndrome, elevated cTnI levels were present in 13 (43%) of 30 patients: 18% of patients with < or =3 shocks and 58% of patients with >3 shocks. Patients with elevated cTnI levels received a higher number of shocks (16+/-18 vs 5+/-7; P < 0.05) and had higher total delivered energies (475+/-538 J vs 128+/-184 J; P < 0.05) compared with patients with normal cTnI. Patients with acute coronary syndrome had higher peak cTnI levels (18+/-16 ng/mL) compared with patients with elevated cTnI without acute coronary syndrome (3.8+/-4.3 ng/mL; P < 0.01). CONCLUSION: Serum cTnI rises occur in the majority of patients after multiple (>3) spontaneous ICD discharges but are due to acute coronary syndrome only 14% of the time (22% of the time in patients with known coronary artery disease).