Outcomes of combined left bundle branch area pacing with atrioventricular nodal ablation in patients with atrial fibrillation and pulmonary disease.

INTRODUCTION: Concomitant left bundle branch area pacing (LBBAP) with atrioventricular (AV) nodal ablation is emerging as a viable management option in atrial fibrillation refractory to medical management. Its viability in patients with pulmonary disease and atrial fibrillation is unknown. METHODS AND RESULTS: This is a retrospective, observational cohort study in consecutive patients who underwent concomitant LBBAP with AV nodal ablation with advanced pulmonary disease at the Cleveland Clinic Fairview Hospital between January 2019 and January 2023. Patient characteristics, comorbidities, and medication use were extracted via chart review. Rates of hospitalizations, medication use, and structural disease seen on echocardiography were compared before and after the procedure. There were 27 patients with group 3 pulmonary hypertension who underwent the procedure. In the 24 months preprocedure, there were 114 admissions for heart failure or atrial fibrillation compared to 9 admissions postprocedure (p < .001). Mean follow up was 17.3 ± 12.1 months. There were no significant complications or lead dislodgements. Echocardiographic characteristics were similar prior to and after pacemaker implantation. Use of medications for rate and rhythm control was common preprocedure, and was reduced dramatically postprocedure. CONCLUSION: This small, retrospective cohort study suggests concomitant LBBAP with AV nodal ablation may be safe and efficacious for management of atrial fibrillation in patients with advanced pulmonary disease.

Contact force catheter ablation for the treatment of persistent atrial fibrillation: Results from the PERSIST-END study.

INTRODUCTION: Use of a novel magnetic sensor enabled optical contact force ablation catheter has been established to be safe and effective for treatment of symptomatic drug-refractory paroxysmal atrial fibrillation (AF) but has yet to be demonstrated in the persistent AF (PersAF) population. METHODS: PERSIST-END was a multicenter, prospective, nonrandomized, investigational study designed to demonstrate the safety and effectiveness of TactiCath™ Ablation Catheter, Sensor Enabled™(SE) (TactiCath SE) for use in the treatment of subjects with documented PersAF refractory or intolerant to at least one Class I/III AAD. The ablation strategy included pulmonary vein isolation and additional targets at physician discretion. Follow-up through 15-months, including a 3-month blanking period and 3-month therapy consolidation period, was performed with cardiac event and Holter monitoring. Primary safety, primary effectiveness, clinical success, and quality of life (QOL) endpoints were analyzed. RESULTS: Of 224 subjects enrolled at 21 investigational sites in the United States and Australia, 223 underwent ablation with the investigational catheter. The primary safety event rate was 3.1% (seven events in seven subjects). The Kaplan-Meier estimate of freedom from AF/atrial flutter/atrial tachycardia recurrence at 15-months was 61.6% and clinical success at 15 months was 89.8%. Subject QOL significantly improved following ablation as assessed via AFEQT (31.6 point increase, p < .0001) and EQ-5D-5L (10.7 point increase, p < .0001) and was met with a 53% reduction in all cause cardiovascular healthcare utilization. CONCLUSION: The sensor-enabled force-sensing catheter is safe and effective for the treatment of drug refractory recurrent symptomatic PersAF, reducing arrhythmia recurrence while improving QOL and healthcare utilization.

Validating and implementing cardiac telemetry for continuous QTc monitoring: A novel approach to increase healthcare personnel safety during the COVID-19 pandemic.

BACKGROUND: Minimizing direct patient contact among healthcare personnel is crucial for mitigating infectious risk during the coronavirus disease 2019 (COVID-19) pandemic. The use of remote cardiac telemetry as an alternative to 12­lead electrocardiography (ECG) for continuous QTc monitoring may facilitate this strategy, but its application has not yet been validated or implemented. METHODS: In the validation component of this two-part prospective cohort study, a total of 65 hospitalized patients with simultaneous ECG and telemetry were identified. QTc obtained via remote telemetry as measured by 3 independent, blinded operators were compared with ECG as assessed by 2 board-certified electrophysiologists as the gold-standard. Pearson correlation coefficients were calculated to measure the strength of linear correlation between the two methods. In a separate cohort comprised of 68 COVID-19 patients treated with combined hydroxychloroquine and azithromycin, telemetry-based QTc values were compared at serial time points after medication administration using Friedman rank-sum test of repeated measures. RESULTS: Telemetry-based QTc measurements highly correlated with QTc values derived from ECG, with correlation coefficients of 0.74, 0.79, 0.85 (individual operators), and 0.84 (mean of all operators). Among the COVID-19 cohort, treatment led to a median QTc increase of 15 milliseconds between baseline and following the 9th dose (p = 0.002), with 8 (12%) patients exhibiting an increase in QTc ≥ 60 milliseconds and 4 (6%) developing QTc ≥ 500 milliseconds. CONCLUSIONS: Cardiac telemetry is a validated clinical tool for QTc monitoring that may serve an expanding role during the COVID-19 pandemic strengthened by its remote and continuous monitoring capability and ubiquitous presence throughout hospitals.

Use of the Leadless Pacemaker to Provide Empiric Pacing Support for a Young Patient with Prior Ablation of a Mid-septal Accessory Pathway Resulting in Damage to the Compact AV Node.

The leadless cardiac pacemaker was selected to provide empiric pacing support in this patient with a manifest mid-septal accessory pathway who had undergone a previous ablation resulting in injury to the compact atrioventricular node. Although this patient's accessory pathway currently demonstrates stable antegrade conduction properties, diminished and complete resolution of manifest pre-excitation has been well described in patients with Wolff-Parkinson-White syndrome. Because of the patient's young age, an increased risk is present for long-term complications inherent with traditional transvenous pacing. The Nanostim leadless pacemaker (St. Jude Medical, St. Paul, MN, USA) was implanted into the right ventricular myocardium without complication. Pacing performance has remained stable, and the patient has been free of device-related adverse events at 19 months after implant.

Safety of oral dofetilide for rhythm control of atrial fibrillation and atrial flutter.

BACKGROUND: Although dofetilide is widely used in the United States for rhythm control of atrial fibrillation, there is limited postapproval safety data in the atrial fibrillation population despite its known risk of Torsade de pointes (TdP). METHODS AND RESULTS: We conducted a retrospective chart review of a cohort of 1404 patients initially loaded on dofetilide for atrial fibrillation suppression at the Cleveland Clinic from 2008 to 2012 to evaluate the incidence and risk factors for in-hospital adverse events and the long-term safety of continued use. Of the 17 patients with TdP during loading (1.2%), 10 had a cardiac arrest requiring resuscitation (1 death), 5 had syncope/presyncope, and 2 were asymptomatic. Dofetilide loading was stopped for 105 patients (7.5%) because of QTc prolongation or TdP. Variables correlated with TdP were (1) female sex, 2) 500-µg dose, (3) reduced ejection fraction, and (4) increase in QTc from baseline. One-year all-cause mortality was higher in patients who continued dofetilide compared with those who discontinued use (hazard ratio, 2.48; 95% confidence interval, 1.08-5.71; P=0.03). Those patients who had a TdP event had higher one-year all-cause mortality than those who did not (17.6% versus 3% at 1 year; P<0.001). CONCLUSIONS: Dofetilide loading has a low but finite risk of TdP and other adverse events that warrant the current Food and Drug Administration-mandated practice of inpatient monitoring during drug loading. In this cohort, all-cause mortality was higher at 1 year in those patients continued on dofetilide and in those patients who experienced TdP while loading.

Selecting antithrombotic therapy for patients with atrial fibrillation.

When considering anticoagulant therapy for patients with atrial fibrillation, one must balance the reduction in risk of thromboembolism that this therapy offers against the risk of bleeding that it poses. The American Heart Association, American College of Cardiology, and Heart Rhythm Society updated their atrial fibrillation guidelines in 2014. This review outlines a rationale for clinical decision-making based on the new guidelines and summarizes the currently approved drugs.

Real-time ultrasound guidance reduces total and major vascular complications in patients undergoing pulmonary vein antral isolation on therapeutic warfarin.

BACKGROUND: Vascular complications are a known risk of catheter-based pulmonary vein antral isolation (PVAI). Procedure-related thromboembolic events necessitate full-dose anticoagulation, which worsens outcomes in the event of vascular access injury. OBJECTIVE: Real-time ultrasound allows direct visualization of vascular structures. We hypothesized that ultrasound use with venipuncture reduces vascular complications associated with PVAI. METHODS: Retrospective analysis of all adverse events occurring with PVAI was performed during two periods: 2005-2006 when ultrasound was not used and 2008-2010 when ultrasound was routinely employed. All patients received full-dose IV heparin during PVAI. In the no ultrasound cohort, only 14 % underwent PVAI without stopping warfarin, while 91 % of patients in the ultrasound cohort were on continued warfarin. Only patients deemed at high risk for thromboembolism with a periprocedural international normalized ratio (INR) less than 2 were bridged with subcutaneous low-molecular-weight heparin. RESULTS: Ultrasound reduced total vascular complications (1.7 vs. 0.5 %, p < 0.01) and decreased the incidence of major vascular complications by sevenfold. Warfarin with INR ≥ 1.2 on the day of PVAI was associated with more vascular complications (4.3 vs. 1.2 %, p < 0.01). Ultrasound guidance overcame the risk associated with warfarin therapy. Vascular complications in anticoagulated patients with INR ≥ 1.2 using ultrasound guidance were two- and ninefold lower than those in patients not using ultrasound with an INR < 1.2 (0.5 vs. 1.2 %, p < 0.05) and INR ≥ 1.2 (0.5 vs. 4.3 %, p < 0.01), respectively. CONCLUSION: Ultrasound-guided venipuncture improves the safety profile of PVAI, reducing vascular complications in patients on warfarin to levels below those with no ultrasound and off warfarin.

Blockade of electron transport before ischemia protects mitochondria and decreases myocardial injury during reperfusion in aged rat hearts.

Myocardial injury is increased in the aged heart following ischemia and reperfusion (I-R) in both humans and experimental models. Hearts from aged 24-month-old Fischer 344 rats sustain greater cell death and decreased contractile recovery after I-R compared with 6-month-old adult controls. Cardiac mitochondria incur damage during I-R contributing to cell death. Aged rats have a defect in complex III of the mitochondrial electron transport chain (ETC) localized to the interfibrillar population of cardiac mitochondria (IFM), situated in the interior of the cardiomyocyte among the myofibrils. The defect involves the quinol oxidation site (Qo) and increases the production of reactive oxygen species (ROS) in the baseline state. Ischemia further decreases complex III activity via functional inactivation of the iron-sulfur subunit. We studied the contribution of ischemia-induced defects in complex III with the increased cardiac injury in the aged heart. The reversible blockade of the ETC proximal to complex III during ischemia using amobarbital protects mitochondria against ischemic damage, removing the ischemia component of mitochondrial dysfunction. Reperfusion of the aged heart in the absence of ischemic mitochondrial damage decreases net ROS production from mitochondria and reduces cell death. Thus, even despite the persistence of the age-related defects in electron transport, protection against ischemic damage to mitochondria can reduce injury in the aged heart. The direct therapeutic targeting of mitochondria protects against ischemic damage and decreases cardiac injury during reperfusion in the high risk elderly heart.

Percutaneous extraction of stented device leads.

BACKGROUND: There are limited published data regarding the percutaneous extraction of device leads jailed by a venous stent. OBJECTIVE: In this study we assessed the feasibility and safety of percutaneous extraction of stented device leads. METHODS: We reviewed our experience percutaneously extracting 7 chronically implanted device leads jailed to the wall of the left innominate and/or subclavian veins by a previously placed stent. RESULTS: All leads were successfully extracted by using a percutaneous approach. Both pacing leads and defibrillator leads were extracted. The oldest pacing lead extracted was 14 years old. The oldest defibrillator lead extracted was 6 years old. Three of the leads were extracted with simple manual traction alone. The 4 remaining leads required a more complex, femoral extraction approach for successful removal. CONCLUSION: In our experience extracting 7 stented device leads, complete percutaneous removal was feasible 100% of the time using a combination of simple manual traction and a femoral approach. No major complications were associated with the extraction procedures.

Ischemic preconditioning does not protect via blockade of electron transport.

Ischemic preconditioning (IPC) before sustained ischemia decreases myocardial infarct size mediated in part via protection of cardiac mitochondria. Reversible blockade of electron transport at complex I immediately before sustained ischemia also preserves mitochondrial respiration and decreases infarct size. We proposed that IPC would attenuate electron transport from complex I as a potential effector mechanism of cardioprotection. Isolated, Langendorff-perfused rat hearts underwent IPC (3 cycles of 5-min 37 degrees C global ischemia and 5-min reperfusion) or were perfused for 40 min without ischemia as controls. Subsarcolemmal (SSM) and interfibrillar (IFM) populations of mitochondria were isolated. IPC did not decrease ADP-stimulated respiration measured in intact mitochondria using substrates that donate reducing equivalents to complex I. Maximally expressed complex I activity measured as rotenone-sensitive NADH:ubiquinone oxidoreductase in detergent-solubilized mitochondria was also unaffected by IPC. Thus the protection of IPC does not occur as a consequence of a partial decrease in complex I activity leading to a decrease in integrated respiration through complex I. IPC and blockade of electron transport both converge on mitochondria as effectors of cardioprotection; however, each modulates mitochondrial metabolism during ischemia by different mechanisms to achieve cardioprotection.