Efficacy and safety of supraclavicular and pectoralis nerve blocks as primary peri-procedural analgesia for cardiac electronic device implantation: A pilot study.

BACKGROUND: Cardiac implantable electronic devices (CIEDs) are routinely implanted using intravenous drugs for sedation. However, some patients are poor candidates for intravenous sedation. OBJECTIVE: We present a case series demonstrating the safety and efficacy of a novel, ultrasound-guided nerve block technique that allows for pre-pectoral CIED implantation. The targets are the supraclavicular nerve (SCN) and pectoral nerve (PECS1). METHODS: We enrolled 20 patients who were planned for new CIED implantation. Following US-localization of the SCN and PECS1, local anesthetic (LA) was instilled at least 30-60 min pre-procedure. Successful nerve block was determined if < 5 mL of intraprocedural LA was used, along with lack of sensation with skin and deep tissue pinprick. Optional sedation was offered to patients' pre-procedure if discomfort was reported. RESULTS: Seventeen patients (85%) had a successful periprocedural nerve block, with only three patients exceeding 5 mL of LA. SCN and PECS1 success occurred in 19 (95%) and 18 (90%) patients, respectively. The overall success of nerve block by fulfilling all the criteria was demonstrated in 17 out of 20 patients (85%). Patients who reported no pain (VAS score = 0) were distributed as follows: 13 patients (65%) in the immediate post-procedure interval, 18 patients (90%) at the 1 h post-implant interval, and 14 patients (70%) at the 24 h post- implant interval. The median cumulative VAS score was 0 (IQR = 0 - 1). There were no reported significant adverse effects. CONCLUSION: SCN and PECS1 nerve blocks are safe and effective for patients undergoing CIED implantation to minimize or eliminate the use of intravenous sedation.

Wide QRS Complex Rhythm Requiring a Second Look.

This case report describes a patient in their 60s with atrial flutter ablation following admission to the hospital for heart failure exacerbation.

Loss-of-Function KCNE2 Variants: True Monogenic Culprits of Long-QT Syndrome or Proarrhythmic Variants Requiring Secondary Provocation?

BACKGROUND: Insight into type 6 long-QT syndrome (LQT6), stemming from mutations in the KCNE2-encoded voltage-gated channel ß-subunit, is limited. We sought to further characterize its clinical phenotype. METHODS AND RESULTS: Individuals with reported pathogenic KCNE2 mutations identified during arrhythmia evaluation were collected from inherited arrhythmia clinics and the Rochester long-QT syndrome (LQTS) registry. Previously reported LQT6 cases were identified through a search of the MEDLINE database. Clinical features were assessed, while reported KCNE2 mutations were evaluated for genotype-phenotype segregation and classified according to the contemporary American College of Medical Genetics guidelines. Twenty-seven probands possessed reported pathogenic KCNE2 mutations, while a MEDLINE search identified 17 additional LQT6 cases providing clinical and genetic data. Sixteen probands had normal resting QTc values and only developed QT prolongation and malignant arrhythmias after exposure to QT-prolonging stressors, 10 had other LQTS pathogenic mutations, and 10 did not have an LQTS phenotype. Although the remaining 8 subjects had an LQTS phenotype, evidence suggested that the KCNE2 variant was not the underlying culprit. The collective frequency of KCNE2 variants implicated in LQT6 in the Exome Aggregation Consortium database was 1.4%, in comparison with a 0.0005% estimated clinical prevalence for LQT6. CONCLUSIONS: On the basis of clinical phenotype, the high allelic frequencies of LQT6 mutations in the Exome Aggregation Consortium database, and absence of previous documentation of genotype-phenotype segregation, our findings suggest that many KCNE2 variants, and perhaps all, have been erroneously designated as LQTS-causative mutations. Instead, KCNE2 variants may confer proarrhythmic susceptibility when provoked by additional environmental/acquired or genetic factors, or both.

Atrial flutter and atrial fibrillation ablation - sequential or combined? A cost-benefit and risk analysis of primary prevention pulmonary vein ablation.

BACKGROUND: Recent studies have tested the hypothesis that preventive pulmonary vein isolation (PVI) at time of atrial flutter ablation in patients who have not had atrial fibrillation (AF) will reduce future incidence of AF. OBJECTIVE: To model relative procedural costs, risks, and benefits of sequential versus combined ablation strategies. METHODS: The decision model compares a sequential ablation strategy of atrial flutter ablation, followed by future PVI if necessary, with an initial combined flutter and preventive PVI ablation strategy. Assumptions are AF incidence 20% per year, PVI success rate 70%, PVI complication rate 4%, atrial flutter complication rate 1%, and costs $13,056 for PVI and $8,466 for atrial flutter ablation. RESULTS: The sequential ablation strategy is less expensive, at 1.4 vs 1.6 expected flutter ablation equivalents (FAE) ($11,852 vs $13,545) per patient, and entails less average risk, at 2% vs 4%. A combined ablation strategy is more expensive if the relative cost of PVI is more than 24.6% higher than atrial flutter ablation. A combined ablation strategy has higher total risk if PVI procedural risk is 24.6% more than atrial flutter ablation. CONCLUSIONS: Under base case assumptions of relative cost of PVI to flutter ablation 1.5 and relative risk 4, a sequential ablation approach has less total expected cost and less expected risk. There appears to be no compelling reason to adopt a combined ablation approach into standard practice. Nomograms are presented to allow the reader to assess which strategy is preferred according to local relative costs and risk.

Cryoablation versus RF ablation for AVNRT: A meta-analysis and systematic review.

INTRODUCTION: Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common supraventricular tachycardia referred for ablation. High success rates have been accompanied with a small risk of atrioventricular (AV) block. Cryoablation has been used as an alternative to radiofrequency (RF) ablation, but studies have been underpowered in comparing the 2 techniques. METHODS AND RESULTS: An electronic search and hand-search of reference lists for published and unpublished data was carried out. Comparative studies (cohort and randomized controlled trials) of RF versus cryoablation for AVNRT were identified independently by 2 reviewers. Searches were limited to English language human studies. The primary metameter was long-term AVNRT recurrence (>2 months postprocedure and ECG/electrophysiology study [EPS]-documented) and secondary metameters included acute procedural failure and AV block requiring pacing. A total of 5,617 patients in 14 trials were included in this systematic review. Acute procedural failure with cryoablation was slightly higher than with RF ablation, but the difference was not statistically significant (risk ratio [RR] 1.44 [95% confidence interval; CI 0.91-2.28], P = 0.12). Long-term recurrence was higher with cryoablation (RR 3.66 [95% CI 1.84-7.28], P = 0.0002) even after adjusting for larger (6 mm) cryocatheter tips, "insurance lesions" and longer (>6 months) follow-up duration. RF ablation for AVNRT was associated with permanent AV block in 0.75% of patients, but was not reported in any patients treated with cryoablation (n = 1066, P = 0.01). CONCLUSIONS: Cryoablation is a safe and effective treatment for AVNRT. Although late-recurrence is more common with cryoablation than with RF ablation, avoidance of permanent AVN block makes it an attractive option in patients where the avoidance of AV block assumes higher priority (such as children and young adults).

Early patient experience with an electro-anatomic navigation system dedicated to device lead implantation: feasibility and safety.

INTRODUCTION: Fluoroscopy-guided pacing lead placement has well-recognized limitations and risks. We studied the safety and feasibility of using a novel electromagnetic navigation system specifically designed to guide pacemaker and implantable cardioverter defibrillator lead placement. METHODS: Twenty-four patients (mean age of 54±34 years) underwent the study protocol; 16 before electrophysiology study and eight before device implantation. The navigational deflectable sheath assembly was introduced via the subclavian vein and advanced to seven prespecified targets within the right heart chambers. The time taken to reach each target site was measured. RESULTS: All seven prespecified targets were successfully reached by 21 of 24 patients (88%). The total time required to complete the study protocol ranged from 3.21 to 15.25 minutes (average 8.9 minutes), with an associated mean fluoroscopy time of 50±36 seconds. In three of the 24 patients, this navigation system was successfully used to guide right ventricular pacing lead placement. The average total procedure time for these devices was 97.8 minutes (excluding the study protocol), with an average associated fluoroscopy time of 6.93 minutes. These procedures were well tolerated and no periprocedural complications were noted. CONCLUSIONS: This study suggests that this novel electro-anatomic navigation system is a viable and safe alternative to traditional fluoroscopy-guided lead implantation. Further studies are required to determine the absolute reduction in radiation exposure and increased efficiency relative to current standard fluoroscopic techniques.