Pacemaker-induced ventricular fibrillation during radiofrequency catheter ablation for ventricular tachycardia.

Prior to ventricular tachycardia ablation, this patient's cardiac implantable electronic device (CIED) was temporarily programmed to backup pacing mode with tachycardia therapies disabled. During radiofrequency energy delivery, the patient developed ventricular fibrillation requiring emergent cardioversion. Electrogram interrogation showed that the CIED switched to noise reversion mode during ablation. The consequent asynchronous pacing resulted in a paced QRS landing on an intrinsic T wave, inducing ventricular fibrillation. This serves as an important reminder that asynchronous pacing consequent to CIED oversensing could occur in any procedure that could cause electromagnetic interference such as radiofrequency cathteter ablation.

British Heart Rhythm Society Clinical Practice Guidelines on the Management of Patients Developing QT Prolongation on Antipsychotic Medication.

The British Heart Rhythm Society's Clinical Practice Guidelines on the Management of Patients Developing QT Prolongation on Antipsychotic Medication are written for heart rhythm consultants, primary care physicians, specialist registrars, nurses and physiologists who may be requested to review ECGs or advise on cases where antipsychotic-induced QT prolongation is suspected or proven. The guidance is adapted from the latest Maudsley Prescribing Guidelines in Psychiatry, published in 2018.

Cost-effectiveness of colchicine treatment on post-operative atrial fibrillation events in patients of major cardiac surgery.

Aims: Post-operative atrial fibrillation (POAF) occurs in 20-50% of patients amid post-operative stay after Cardiac Surgery. We intend to determine whether colchicine therapy in patients undergoing cardiac surgery is a cost-effective strategy for prevention of POAF. To undertake cost utility analysis and calculate incremental cost utility ratio (ICUR) for colchicine therapy in these subgroup of patients. Methods and results Design: Decision tree model to calculate the ICUR comparing two treatment strategies in patients undergoing cardiac surgery. One wherein patients received colchicine along with usual care and second where they received placebo or just usual care. Cost utility analysis was undertaken using relevant data from the systematic review and meta-analysis of the available randomized controlled trials till June 2016 and mean cost calculations from validated available sources across various jurisdictions. Results: Colchicine treatment based on mean costs for life expectancy calculated at 10 years' post-surgery using recommended discounting rates of 3.5% was € 17544.80 cheaper per quality-adjusted life-year (QALY) gained. The incremental cost is negative and the incremental effect (QALY) is positive (South East quadrant), Hence the intervention of colchicine treatment is unequivocally cost-effective, meaning it is dominant and achieves better outcomes at a lower cost. Conclusion: Our findings provide a benchmark for current and future analyses relating to effectiveness of colchicine on POAF events after cardiac surgery. Currently, there are few reports that provide cutting edge estimates of the higher expenses associated with POAF. Future analyses should likewise explore the impact of added costs from using pharmacologic efforts to prevent and treat POAF after cardiac surgery.

Colchicine for primary prevention of atrial fibrillation after open-heart surgery: Systematic review and meta-analysis.

BACKGROUND: Atrial fibrillation occurs frequently after open-heart surgery. It is associated with increased morbidity and mortality, longer hospital stays, and increased healthcare costs. Prophylactic administration of colchicine may mitigate post-operative atrial fibrillation (POAF). METHODS: We searched PubMed, ClinicalTrials.gov and CENTRAL databases to identify randomized controlled trials (RCTs) that; (1) compared prophylactic use of colchicine to placebo, or usual care, in patients with sinus rhythm who underwent elective open-heart surgery and (2) reported POAF-incidence. We excluded trials focused on incidence of atrial fibrillation after percutaneous interventions or colchicine treatment of diagnosed pericarditis or post-pericardiotomy-syndrome. A random-effects model was used to pool data for POAF-incidence as the primary outcome and for drug-related adverse effects, major adverse events (death and stroke), and hospital length-of-stay as secondary outcomes. RESULTS: We included five RCTs (1412 patients). Colchicine treatment reduced POAF-events by 30% versus placebo or usual care (18% vs. 27%, risk ratio (RR) 0.69, 95% confidence interval (CI) 0.57 to 0.84, p=0.0002). Adverse drug-related effects, especially gastrointestinal intolerance, increased with colchicine; (21% vs. 8.2%, RR 2.52, 95% CI 1.62 to 3.93, p<0.0001). However, major adverse events were unchanged (3.2% vs. 3.2%, RR 0.96, 95% CI 0.48 to 1.95, p=0.92). Length-of-stay decreased by 1.2days with colchicine (95% CI -1.89 to -0.44, p=0.002). CONCLUSION: Colchicine demonstrated superior efficacy versus usual care for prevention of atrial fibrillation after cardiac surgery. Moreover, colchicine treatment was associated with shorter hospital stays. These benefits outweigh increased risk of adverse drug-related effects; although further work is needed to minimize gastrointestinal effects.

Ripple mapping: Initial multicenter experience of an intuitive approach to overcoming the limitations of 3D activation mapping.

BACKGROUND: Ripple mapping (RM) displays electrograms as moving bars over a three-dimensional surface displaying bipolar voltage, and has shown in a single-center series to be effective for atrial tachycardia (AT) mapping without annotation of local activation time or window-of-interest assignment. We tested the reproducibility of these findings in operators naïve to RM, using it for the first time in postablation AT. METHODS: Maps were collected with multielectrode catheters and CARTO ConfiDENSE. A diagnosis of the tachycardia mechanism was made using RM and an assessment of operator confidence was made according to a three-grade scale (1 highest-3 lowest). RESULTS: The first 20 patients (64 ± 9 years, median two previous ablations) undergoing RM-guided AT ablation across five sites were studied. High-density maps (2,935 ± 1,328 points) in AT (CL = 296 ± 95 milliseconds) were collected. Macroreentrant ATs bordered by scar or anatomical obstacles were identified in n = 12 (60%), small reentrant ATs around scar in n = 3 (15%), and focal ATs from scar in n = 5 (25%). Diagnostic confidence with RM was grade 1 in n = 13 (65%), where operators felt confident to proceed to ablation without entrainment. Ablation offered the correct diagnosis n = 18 (90%). Retrospective review of the accompanying LAT maps demonstrated potential sources for error related to the window of interest selection, interpolation, and differentiating regions of scar during tachycardia on the voltage map. CONCLUSION: RM was easy to adopt by operators using it for the first time, and identified the correct target for ablation with high diagnostic confidence in most cases of complex AT.

Extended bipolar left ventricular pacing as a possible therapy for late electrical storm induced by cardiac resynchronization therapy.

Although cardiac resynchronization therapy (CRT) has become a well-established treatment option for patients with drug-refractory severe systolic heart failure, there has been some evidence of adverse proarrhythmic events. We report a case of a patient with ischemic cardiomyopathy who underwent CRT with a defibrillator for primary prevention of sudden cardiac death. Two years after the implantation, the patient presented with electrical storm, which was completely terminated by modifying the left ventricular (LV) pacing configuration from true to extended bipolar LV pacing. We discuss the possible pathophysiologic mechanisms of this phenomenon through a brief review of the literature on CRT-induced proarrhythmia.

Is cardiac resynchronisation therapy feasible, safe and beneficial in the very elderly?

OBJECTIVE: To evaluate whether cardiac resynchronisation therapy (CRT) implantation was feasible and safe in octogenarians and the association with symptoms. METHODS: Consecutive patients undergoing CRT implantation were recruited from two UK centers. Patients grouped according to age: < 80 & ≥ 80 years. Baseline demographics, complications and outcomes were compared between those groups. RESULTS: A total of 439 patients were included in this study, of whom 26% were aged ≥ 80 years. Octogenarians more often received cardiac resynchronization therapy pacemaker in comparison to cardiac resynchronisation therapy-defibrillator. Upgrade from pacemaker was common in both groups (16% < 80 years vs. 22% ≥ 80 years, P = NS). Co-morbidities were similarly common in both groups (overall diabetes: 25%, atrial fibrillation: 23%, hypertension: 45%). More patient age ≥ 80 years had significant chronic kidney disease (CKD, estimated glomerular filtration rate < 45 mL/min per 1.73 m(2), 44% vs. 22%, P < 0.01). Overall complication rates (any) were similar in both groups (16% vs. 17%, P = NS). Both groups demonstrated symptomatic benefit. One-year mortality rates were almost four fold greater in octogenarians as compared with the younger cohort (13.9% vs. 3.7%, P < 0.01). CONCLUSIONS: CRT appears to be safe in the very elderly despite extensive co-morbidity, and in particular frequent severe CKD. Symptomatic improvement appears to be meaningful. Strategies to increase the appropriate identification of elderly patients with CHF who are potential candidates for CRT are required.

No Benefit of Complex Fractionated Atrial Electrogram Ablation in Addition to Circumferential Pulmonary Vein Ablation and Linear Ablation: Benefit of Complex Ablation Study.

BACKGROUND: The optimal ablation strategy for persistent atrial fibrillation (AF) remains unclear. METHODS AND RESULTS: This multicentre randomized study compared circumferential pulmonary vein ablation+linear ablation (control arm) versus circumferential pulmonary vein ablation+linear ablation+complex fractionated atrial electrogram (CFAE) ablation (CFAE arm) in patients with persistent AF. Circumferential pulmonary vein ablation was performed followed by roof and mitral isthmus ablation, before CFAE ablation in the CFAE arm. Ablation strategy was maintained at the first redo procedure. Sixty-five patients were recruited in each arm. The mean age was 61±10 years, 75% were men, median AF duration was 2 years, 42% had long-lasting persistent AF, 68% had associated cardiovascular disease, mean left atrial dimension was 46±6 mm, and median CHA2DS2-VASc score was 2. Ablation and procedure times were significantly longer in the CFAE arm (70±20 versus 55±17; 201±35 versus 152±45 minutes; P<0.005). After a mean follow-up of 35±5 months, single-procedural success off antiarrhythmic drugs at 12 months (CFAE: 30/65 [46%] versus control: 37/65 [57%]; P=0.29) and multiprocedural success (CFAE: 51/65 [78%] versus control: 52/65 [80%]; P=1.0) were not significantly different. At the first redo procedure, patients in the CFAE arm had a higher incidence of organized atrial tachycardia/flutter (24/33 [73%] versus 11/31 [35%]; P=0.005) and gap-related macro-re-entrant flutter (8/33[24%] versus 1/31[3%]; P=0.03). Early recurrence of atrial arrhythmia was an independent predictor of late recurrence. CONCLUSIONS: CFAE ablation did not confer incremental benefit when performed in addition to circumferential pulmonary vein ablation and linear ablation. It was associated with a higher incidence of gap-related flutter. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01711047.