Septal venous channel perforation during left bundle branch area pacing: a prospective study.

AIMS: To characterize the diagnosis, frequency, and procedural implications of septal venous channel perforation during left bundle branch area pacing (LBBAP). METHODS AND RESULTS: All consecutive patients undergoing LBBAP over an 8-month period were prospectively studied. During lead placement, obligatory septal contrast injection was performed twice, at initiation (implant entry zone) and at completion (fixation zone). An intuitive fluoroscopic schema using orthogonal views (left anterior oblique/right anterior oblique) and familiar landmarks is described. Using this, we resolved zonal distribution (I-VI) of lead position on the ventricular septum and its angulation (post-fixation angle θ). Subjects with and without septal venous channel perforation were compared. Sixty-one patients {male 57.3%, median age [interquartile range (IQR)] 69.5 [62.5-74.5] years} were enrolled. Septal venous channel perforation was observed in eight (13.1%) patients [male 28.5%, median age (IQR) 64 (50-75) years]. They had higher frequency of (i) right-sided implant (25% vs. 1.9%, P = 0.04), (ii) fixation in zone III at the mid-superior septum (75% vs. 28.3%, P = 0.04), (iii) steeper angle of fixation-median θ (IQR) [19 (10-30)° vs. 5 (4-19)°, P = 0.01], and (iv) longer median penetrated-lead length (IQR) [13 (10-14.8) vs. 10 (8.5-12.5) mm, P = 0.03]. Coronary sinus drainage of contrast was noted in five (62.5%) patients. Abnormal impedance drops during implantation (12.5% vs. 5.7%, P = NS) were not significantly different. CONCLUSION: When evaluated systematically, septal venous channel perforation may be encountered commonly after LBBAP. The fiducial reference framework described using fluoroscopic imaging identified salient associated findings. This may be addressed with lead repositioning to a more inferior location and is not associated with adverse consequence acutely or in early follow-up.

Open window mapping for redo accessory pathway ablation in Ebstein anomaly.

Accessory pathway ablation in Ebstein anomaly can be significantly more challenging than in structurally normal hearts. An alternative to the conventional approach to mapping APs is to detect points with a high-density mapping catheter based on an automated detection algorithm using open window mapping. It detects the sharpest signal at each point with high-density mapping rather than relying on the origin of the local electrogram to localize the pathway and determine a site for successful ablation. We herein report the first case in literature of a redo-accessory pathway ablation in Ebstein anomaly using this technique.

Right atrial appendage tachycardia: A rare cause of tachycardia induced cardiomyopathy in a 4-year-old child.

We present a rare case of tachycardiomyopathy in a 4-year-old girl. The child had incessant atrial tachycardia (AT) and refractory heart failure. Right atrial appendage (RAA) was localised as the source of the ectopic tachycardia. The child underwent successful radiofrequency ablation (RFA) using 3-D electroanatomical mapping. Fluoroscopy was used sparingly only to rule out underlying anomalies. The left ventricular functions returned to normal by one month after the procedure. RAA AT is rare in very young children and usually necessitates surgical appendectomies. RFA is a challenge in such age groups and there are very few published literature on RAA AT in very young children.

A case of exaggerated exuberance: Iatrogenic atrioventricular block/intra-Hisian Wenckebach during conduction system pacing.

Isolated sinus node dysfunction with its pursuant long-term risk for atrioventricular (AV) conduction disease poses a unique dilemma for proponents of CSP due to paucity of imprimatur guidelines. In such scenarios, the risk and prognosis of iatrogenic AV block is not well elucidated but is a valid concern. We report a case where CSP was complicated by iatrogenic AV block and peculiarly the rare phenomenon of intra-Hisian Wenckebach.

An unusual site of ablation for a ventricular tachycardia.

Scar-related ventricular tachycardia (VT) ablation involves localizing the critical isthmuses by overdrive pacing maneuvers and three-dimensional activation mapping. Implantable prosthetic devices have been known to complicate this by covering sites of potential isthmuses. We herein present a sentinel report of scar-VT ablation with a protected isthmus localized over an endothelialized post-myocardial infarction ventricular septal defect occluder device.

Clinical/electrophysiologic characteristics of infranodal Wenckebach in patients with indication for permanent ventricular pacing: A prospective study.

BACKGROUND: Infranodal Wenckebach is rare and not well characterized. OBJECTIVE: We prospectively studied clinical and electrophysiologic characteristics of patients with atrioventricular (AV) Wenckebach with an indication for permanent ventricular pacing. METHODS: During a 2-year period, all patients with an indication for permanent ventricular pacing underwent targeted preimplantation electrophysiologic study. Clinical and electrophysiologic characteristics at presentation and ventricular pacing percentage at 6-month follow-up were evaluated. RESULTS: A total of 163 patients (median age, 68 [interquartile range, 60-74] years; male, 59%; median QRS duration, 110 [90-130] ms; complete AV block in 123 [75.5%]) were included. AV Wenckebach was noted in 22 (13.4%) patients (median age, 70 [63-76.5] years; male, 54%; median QRS duration, 120 [110-140] ms) and classified as infranodal (12/163 [7.3%]) vs AV nodal (10/163 [6.1%]). Patients with infranodal Wenckebach (infrahisian in all), compared with AV nodal Wenckebach, demonstrated higher frequency with left ventricular ejection fraction ≤40% (41.7% vs 0%; P = .04), longer median HV interval (90 vs 49 ms; P = .005), lower frequency of isolated first-degree AV block (8.3% vs 60%; P = .02), higher frequency of right bundle branch block with left anterior fascicular block (75% vs 10%; P = .003), lesser PR increment at onset of AV Wenckebach (20.5 vs 80 ms; P = .002), and onset of 2:1 AV block at longer cycle lengths (91.7% vs 20%; P = .002). CONCLUSION: Of patients referred for pacemaker implantation, infranodal Wenckebach was present in 27.5% (11/40) without complete AV block. It was as frequent as AV nodal Wenckebach and associated with characteristic electrophysiologic findings.

Caveats related to conduction system pacing utilizing a proprietary deflectable mapping catheter with a stylet-driven lead.

BACKGROUND: Hitherto, lumen less leads (LLLs) were routinely utilized for conduction system pacing (CSP). We report the largest experience using stylet-driven leads (SDLs) with a deflectable mapping catheter for CSP. METHODS: Patients were prospectively and sequentially enrolled for CSP with SDL between June, 2021 and November, 2022 to (i) a novel deflectable mapping catheter (AgilisHisProTM, Abbott) (Group A) or (ii) a fixed curve sheath (Selectra3D, Biotronik) (Group B) in a 1:1 non-randomized fashion. The primary aim was to evaluate safety, feasibility, and efficacy of the CSP using SDL and deflectable mapping catheter (Group A) while reporting procedural success and intermediate-term follow-up. RESULTS: Seventy-nine patients (59.4%M, mean age 67.2+/-10.6 years) were allocated to either (i) Group A (n = 40) or (ii) Group B (n = 39). In Group A (n = 40, 50% M, mean age 67.2+/-9.5 years, follow-up 210.7 + 25.1days), His bundle pacing (HBP) was the default strategy with left bundle branch area pacing (LBBaP) for bailout. Procedural success with HBP was feasible in 17/40 (42.5%) patients with remaining 23/40 (57.5%) needing LBBaP bailout. After initial learning curve, a manual septal curve was introduced to successfully aid LBBaP in 6/23 (26.1%) cases. Procedural and follow-up parameters did not differ significantly in HBP vs. LBBaP. Head-to-head comparison was not performed between the groups owing to different default protocols (HBP-Group A, Discretionary-Group B). CONCLUSIONS: Use of SDL with single-curve deflectable mapping catheter was safe, feasible and yielded moderate procedural success with HBP and frequently needed a LBBaP bailout strategy. In approximately one-fourth of the latter, an out-of-plane manual septal curve was needed to optimize LBBaP.

Interventions in the diagnosis and adoption of pacemaker therapy in sinus node dysfunction patients: Results from the IMPROVE Brady study.

AIMS: IMPROVE Brady assessed whether a process improvement intervention could increase adoption of guideline-based therapy in sinus node dysfunction (SND) patients. METHODS: /Results: IMPROVE Brady was a sequential, prospective, quality improvement initiative conducted in India and Bangladesh. Patients with symptomatic bradycardia were enrolled. In Phase I, physicians assessed and treated patients per standard care. Phase II began after implementing educational materials for physicians and patients. Primary objectives were to evaluate the impact of the intervention on SND diagnosis and pacemaker (PPM) implant. SF-12 quality of life (QoL) and Zarit burden surveys were collected pre- and post-PPM implant. A total of 978 patients were enrolled (57.7 ± 14.8 years, 75% male), 508 in Phase I and 470 in Phase II. The diagnosis of SND and implantation of PPM increased significantly from Phase I to Phase II (72% vs. 87%, P < 0.001 and 17% vs. 32%, P < 0.001, respectively). Pacemaker implantation was not feasible in 41% of patients due to insurance/cost barriers which was unaltered by the intervention. Both patient QoL and caregiver burden improved at 6-months post-PPM implant (P < 0.001). CONCLUSIONS: A process improvement initiative conducted at centers across India and Bangladesh significantly increased the diagnosis of SND and subsequent treatment with PPM therapy despite the socio-economic constraints.

Myocarditis presenting as junctional ectopic tachycardia.

Junctional ectopic tachycardia (JET) is an unusual arrhythmia in children. It is usually described as a congenital tachycardia or as occurring in the postoperative setting. Here we report the case of an 8-year-old girl who presented with JET in the context of viral myocarditis and its later subsidence which could have been in response to Carvedilol therapy.

Brainstem infarct presenting as torsades de pointes.

Hypokalemia, as an adverse consequence of severe alkalosis, can prolong QT interval and cause torsades de pointes. This report describes a rare case of central neurogenic hyperventilation as a result of brainstem infarct, presenting primarily with refractory ventricular tachyarrhythmia due to secondary hypokalemia.

Influence of intrinsic myocardial conduction on paced QRS morphology during cardiac resynchronization therapy follow up.

We report two cases of patients of cardiac resynchronization therapy (CRT) whose ECGs, during follow up, showed different paced QRS morphology as compared to those of immediate post-device implantation. Parameters of leads, including sensitivity and capture thresholds, were unchanged. There was no lead dislodgement confirmed on fluoroscopy. The ECGs obtained in device off mode showed different intrinsic QRS morphology as compared to those of pre-implant morphology. These changes were attributable to electrolyte imbalance in one patient and progressive intraventricular conduction defect in the other. These cases demonstrate that intrinsic myocardial conduction pattern influences paced QRS morphology. Irreversible change in paced QRS morphology may indicate poor prognosis.