Faculty Bibliography

PURPOSE/OBJECTIVE:Catheter ablation procedures for atrial fibrillation (AF) were significantly curtailed during the peak of coronavirus disease 2019 (COVID-19) pandemic to conserve healthcare resources and limit exposure. There is little data regarding peri-procedural outcomes of medical procedures during the COVID-19 pandemic. We enacted protocols to safely reboot AF ablation while limiting healthcare resource utilization. We aimed to evaluate acute and subacute outcomes of protocols instituted for reboot of AF ablation during the COVID-19 pandemic. METHODS:Perioperative healthcare utilization and acute procedural outcomes were analyzed for consecutive patients undergoing AF ablation under COVID-19 protocols (2020 cohort; n=111) and compared to those of patients who underwent AF ablation during the same time period in 2019 (2019 cohort; n=200). Newly implemented practices included preoperative COVID-19 testing, selective transesophageal echocardiography (TEE), utilization of venous closure, and same-day discharge when clinically appropriate. RESULTS:Pre-ablation COVID-19 testing was positive in 1 of 111 patients. There were 0 cases ablation-related COVID-19 transmission and 0 major complications in either cohort. Pre-procedure TEE was performed in significantly fewer 2020 cohort patients compared to the 2019 cohort patients (68.4% vs. 97.5%, p <0.001, respectively) despite greater prevalence of persistent arrhythmia in the 2020 cohort. Same-day discharge was achieved in 68% of patients in the 2020 cohort, compared to 0% of patients in the 2019 cohort. CONCLUSIONS:Our findings demonstrate the feasibility of safe resumption of complex electrophysiology procedures during the COVID-19 pandemic, reducing healthcare utilization and maintaining quality of care. Protocols instituted may be generalizable to other types of procedures and settings.

Background/UNASSIGNED:There is limited information on the long-term outcomes of ICDs in patients with inherited arrhythmia syndromes. Methods/UNASSIGNED:Prospective registry study of inherited arrhythmia patients with an ICD. Incidence of therapies and complications were measured as 5-year cumulative incidence proportions and analyzed with the Kaplan-Meier method. Incidence was compared by device indication, diagnosis type and device type. Cox-regression analysis was used to identify predictors of appropriate shock and device complication. Results/UNASSIGNED:123 patients with a mean follow up of 6.4 ± 4.8 years were included. The incidence of first appropriate shock was 56.52% vs 24.44%, p < 0.05 for cardiomyopathy and channelopathy patients, despite similar ejection fraction (61% vs 60%, p = 0.6). The incidence of first inappropriate shock was 13.46% vs 56.25%, p < 0.01 for single vs. multi-lead devices. The incidence of first lead complication was higher for multi-lead vs. single lead devices, 43.75% vs. 17.31%, p = 0.04. Patients with an ICD for secondary prevention were more likely to receive an appropriate shock than those with primary prevention indication (HR 2.21, CI 1.07-4.56, p = 0.03). Multi-lead devices were associated with higher risk of inappropriate shock (HR 3.99, CI 1.27-12.52, p = 0.02), with similar appropriate shock risk compared to single lead devices. In 26.5% of patients with dual chamber devices, atrial sensing or pacing was not utilized. Conclusion/UNASSIGNED:The rate of appropriate therapies and ICD complications in patients with inherited arrhythmia is high, particularly in cardiomyopathies with multi-lead devices. Risk-benefit ratio should be carefully considered when assessing the indication and type of device in this population.

BACKGROUND:More than 3 million cardiovascular implantable electronic devices (CIEDs) are implanted annually. There are minimal data regarding the timing of diagnosis of acute complications after implantation. It remains unclear whether patients can be safely discharged less than 24 hours postimplantation. OBJECTIVE:The purpose of this study was to determine the precise timing of acute complication diagnosis after CIED implantation and optimal timing for same-day discharge. METHODS:A retrospective cohort analysis of adults 18 years or older who underwent CIED implantation at a large urban quaternary care medical center between June 1, 2015, and March 30, 2020, was performed. Standard of care included overnight observation and chest radiography 6 and 24 hours postprocedure. Medical records were reviewed for the timing of diagnosis of acute complications. Acute complications included pneumothorax, hemothorax, pericardial effusion, lead dislodgment, and implant site hematoma requiring surgical intervention. RESULTS:A total of 2421 patients underwent implantation. Pericardial effusion or cardiac tamponade was diagnosed in 13 patients (0.53%), pneumothorax or hemothorax in 19 patients (0.78%), lead dislodgment in 11 patients (0.45%), and hematomas requiring surgical intervention in 5 patients (0.2%). Of the 48 acute complications, 43 (90%) occurred either within 6 hours or more than 24 hours after the procedure. Only 3 acute complications identified between 6 and 24 hours required intervention during the index hospitalization (0.12% of all cases). CONCLUSION/CONCLUSIONS:Most acute complications are diagnosed either within the first 6 hours or more than 24 hours after implantation. With rare exception, patients can be considered for discharge after 6 hours of appropriate monitoring.

This article reviews and compares the rationale and evidence supporting high-power, short-duration radiofrequency (RF) ablation with those of conventional-power, conventional-duration RF ablation for atrial fibrillation (AF). The pros and cons of each approach, biophysics of ablation, pre-clinical studies informing clinical utilization, and the accumulated clinical evidence are presented. Both conventional-power, conventional-duration RF ablation and high-power, short-duration ablation are similarly safe, and effective approaches for AF ablation. Theoretical advantages of high-power, short-duration ablation, including greater procedure efficiency and limited conductive heating of collateral structures, must be weighed against the narrower safety margin related to rapid energy delivery during high power ablation.

OBJECTIVES/OBJECTIVE:This study sought to analyze high-frequency catheter excursion in relation to lesion quality markers in 20 consecutive patients undergoing first-time radiofrequency (RF) ablation for paroxysmal atrial fibrillation (AF). BACKGROUND:Ablation therapy for AF requires the delivery of durable lesions. The extent to which lesion sequence, catheter spatial stability, and anatomic location influence lesion formation during RF ablation of AF is not well understood. METHODS:Three-dimensional spatial excursion of the ablation catheter sampled at 60 Hz during pre-specified pairs of RF lesions was extracted from the CARTO3 System (Biosense Webster Inc., Irvine, California) and analyzed by using custom-developed MATLAB software (MathWorks, Natick, Massachusetts) to define precise catheter spatial stability during RF ablation. Ablation parameters including bipolar electrogram amplitude reduction, impedance decline and transmurality-associated unipolar electrogram (TUE) as evidence of lesion transmurality during lesion placement were recorded and analyzed. RESULTS:We collected 437,760 position data points during lesion placement. Ablation catheter spatial stability and lesion formation parameters varied considerably by anatomic location. Lesions placed immediately had similar bipolar electrogram amplitude reduction, smaller impedance decline, but higher likelihood of achieving TUE compared to delayed lesions. Greater catheter spatial stability correlated with lesser impedance decline. CONCLUSIONS:Lesion sequence, ablation catheter spatial stability, and anatomic location are important modifiers of RF lesion formation. Lesions placed immediately are more likely to exhibit TUE. Greater ablation catheter stability is associated with lesser impedance decline but greater likelihood of TUE.

BACKGROUND:The prolongation in QT interval typically observed following cardiac arrest is considered to be multifactorial and induced by external triggers such as hypothermia therapy and exposure to antiarrhythmic medications. OBJECTIVE:To evaluate the corrected QT interval (QTc) dynamics in the first 10 days following cardiac arrest with respect to the etiology of arrest, hypothermia and QT prolonging medications. METHODS:We enrolled 104 adult survivors of cardiac arrest, where daily ECG was available for at least 3 days. We followed their QT and QRS intervals for the first 10 days of hospitalization. We used both Bazett and Fridericia formulas to correct for heart rate. For patients with QRS < 120 we analyzed the QTc interval (n = 90) and for patients with QRS > 120 ms we analyzed the JTc (n = 104) vs. including only the narrow QRS samples (n = 89). We stratified patients by 3 groups: (1) presence of ischemic heart disease (IHD) (2) treatment with hypothermia protocol, and (3) treatment with QTc prolonging medications. Additionally, genetic information obtained during hospitalization was analyzed. RESULTS:QTc and JTc intervals were significantly prolonged in the first 6 days. Maximal QTc/JTc prolongation was observed in day 2 (QTcB = 497 ± 55). There were no differences in daily QTc/JTc and QRS intervals in the first 2 days post arrest between patients with or without hypothermia induction but such difference. All subgroups demonstrated significantly prolonged QTc/JTc interval regardless of the presence of IHD, hypothermia protocol or QTc prolonging medication exposure. Our results were consistent for both Bazetts' and Frediricia correction and for any QRS duration. Prolongation of the JTcB beyond 382 ms after day 3 predicted sustained QTc/JTc prolongation beyond day 6 with an ROC of 0.78. CONCLUSIONS:QTc/JTc interval is significantly and independently prolonged post SCA, regardless of known QT prolonging triggers. Normalization of the QTc post cardiac arrest should be expected only after day 6 of hospitalization. Assessment of the QTc for adjudication of the etiology of arrest or for monitoring the effect of QT prolonging medications may be unreliable.