Asirvatham, Samuel J

Pulsed electrical field (PEF) energy is a promising technique for catheter ablation of cardiac arrhythmias. In this article, the key aspects that need to be considered for safe and effective PEF delivery are reviewed, and their impact on clinical feasibility is discussed. The most important benefit of PEF appears to be the ability to kill cells through mechanisms that do not alter stromal proteins, sparing sensitive structures to improve safety, without sacrificing cardiomyocyte ablation efficacy. Many parameters affect PEF treatment outcomes, including pulse intensity, waveform shape, and number of pulses, as well as electrode configuration and geometry. These physical and electrical characteristics must be titrated carefully to balance target tissue effects with collateral implications (muscle contraction, temperature rise, risk of electrical arcing events). It is important to note that any combination of parameters affecting PEF needs to be tested for clinical efficacy and safety. Applying PEF clinically requires knowledge of the fundamentals of this technology to exploit its opportunities and generate viable, durable health improvements for patients.

AbstractObjectiveEndomyocardial biopsy (EMB) is a useful diagnostic tool though the yield may be limited in many myocardial diseases. Data on the diagnostic yield and prognostic significance of EMB guided by abnormal electrograms (EGM‐Bx) in suspected cardiac sarcoidosis (CS) are scarce.MethodsSeventy‐nine patients (mean age: 56 ± 12 years; 61% men) with suspected CS based on clinical and imaging features underwent right or left ventricular EGM‐Bx guided by electroanatomic mapping. Tissue samples were obtained from sites with abnormal EGMs and/or abnormal cardiac imaging. The diagnostic yield of EGM‐Bx was evaluated in reference to histopathologic analysis. Left ventricular assist device (LVAD) and transplantation‐free survival were compared between patients with positive and negative EGM‐Bx for CS.ResultsA total of 254 samples were obtained from abnormal EGM sites, and 126 samples from normal EGM sites guided by pre‐procedure imaging findings. Abnormal histopathology was noted in 65 (26%) and 10 (8%) samples from abnormal and normal EGM sites, respectively. Histopathology confirmed CS in 16 (20%) patients, while an alternative tissue diagnosis emerged in 10 (13%) patients. Abnormal EGMs at the biopsy site had sensitivity 89% and specificity 33% for a histopathologic diagnosis of CS. LVAD and transplantation‐free survival were not significantly associated with the EGM‐Bx result (log‐rank p = .91).ConclusionIn patients with suspected CS, abnormal EGM‐Bx has high sensitivity and low specificity for establishing a definite CS diagnosis. Consideration of substrate abnormalities apparent on preprocedural imaging as an adjunct for selection of biopsy sites may further improve EGM‐Bx yield.

Abstract Purpose: To evaluate the effect of single-dose intravenous dexamethasone on AF recurrence following radiofrequency catheter ablation. Methods: A cohort of 94 adult patients (>18 years) underwent catheter ablation at Mayo Clinic Rochester from January to March 2019. Only first-time ablation patients were included, with all re-do ablations excluded to minimize heterogeneity. Administration of intraoperative dexamethasone 4 mg or 8 mg was determined by chart review from the procedure. At our institution, intraoperative intravenous steroids are administered for postoperative nausea and vomiting (PONV) prophylaxis at the discretion of the anesthesiologist. AF recurrence was determined by ECG or cardiac monitoring at less than 3 months or between 3 months and 1 year with an in-person follow-up visit. Results: A total of 36.2% of patients received intravenous dexamethasone compared to 63.8% who did not (providing a 2:1 comparison group). The incidence of documented AF or flutter lasting greater than 30 seconds was 20.6% in the dexamethasone group versus 21.7% in the non-dexamethasone group, p value 1.00. AF or atrial flutter recurrence from 3 months to 1 year was 20.6% in the dexamethasone group compared to 21.7% in the non-dexamethasone group, p value 1.00. Conclusion: These data suggest that intraoperative intravenous dexamethasone administered during AF ablation for postoperative nausea and vomiting prophylaxis does not have a significant effect on AF recurrence rates.

AbstractBackgroundPulmonary vein isolation (PVI) with autonomic modulation may be more successful than PVI alone for atrial fibrillation (AF) ablation and may be signaled by changes in sinus rhythm heart rate (HR) post ablation. We sought to determine if a change in sinus rhythm HR predicted AF recurrence post PVI.MethodsPatients who underwent AF ablation from 2000 to 2011 were included if sinus rhythm was noted on ECG within 90 days pre and 7 days post ablation. Basic ECG interval and HR changes were analyzed and outcomes determined.ResultsA total of 1152 patients were identified (74.3% male, mean age 57 ± 11 years). Mean AF duration was 5.2 ± 5.3 years. Paroxysmal AF was noted in 712 (61.8%) of the patients. Mean EF was 61% ± 6%. Sinus rhythm HR was 61 ± 11 pre‐ablation and 76 ± 13 bpm post‐ablation (27% ± 24% increase, p < .001). The ability of relative HR change post‐ablation to predict AF recurrence was borderline (hazard ratio 0.65 [0.41–1.01], p = .067). With patients separated into quartiles based on the relative HR change, the upper quartile with the largest relative increase in HR had a significantly lower rate of AF recurrence compared to the lowest quartile following multi variable modeling (p = .038). There were significant changes in PR (171 ± 28 to 167 ± 30 ms) and QTc (424 ± 25 to 434 ± 29 ms) intervals (both p < .001) but these were not predictive of outcome.ConclusionRelative changes in HR post AF ablation correlates with AF recurrence. Further prospective studies are needed to confirm this relationship.

AbstractBackgroundSeveral chemotherapy agents are associated with the development of non‐ischemic cardiomyopathy (NIC). When chemotherapy‐induced cardiomyopathy (CHIC) is associated with left bundle branch block (LBBB) and a left ventricular ejection fraction (LVEF) 35% or lower, cardiac resynchronization therapy (CRT) is often utilized to improve cardiac function and relieve symptoms.ObjectiveTo determine the echocardiographic and clinical outcomes of CRT in patients with CHIC.MethodsThe study included 29 patients with CHIC (CHIC group) and 58 patients with other types of NIC (control group) who underwent CRT implantation between 2004 and 2017. The primary endpoints were changes in LVEF, left ventricular end‐systolic diameter (LVESD), and left ventricular end‐diastolic diameter (LVEDD) at 6–18 months after CRT. The secondary outcomes included changes in left ventricular global longitudinal strain (GLS), systolic strain rate (SRS), early diastolic strain rate (SRE), and overall survival.ResultsOut of 29 patients with CHIC, 62.1% received chemotherapy for lymphoma, 13.7% for breast cancer, and 24.1% for sarcoma. The agent implicated in 93.1% of the patients was an anthracycline. Half of the patients had LBBB. The mean baseline LVEF was 28% ± 8%. The mean baseline QRS duration was 146 ± 26 ms. Twenty‐eight patients had post‐CRT follow‐up data. CRT was associated with improvement in echocardiographic outcomes in the CHIC group and the control group. There was no difference in overall survival between the two groups (log‐rank p = .148).ConclusionCRT improves left ventricular function and reverses remodeling in patients with CHIC.

AbstractBackgroundEffective therapy for inappropriate sinus tachycardia (IST) remains challenging with high rates of treatment failure and symptom recurrence. It is uncertain how effective pharmacotherapy and procedural therapy are long‐term, with poor response to medical therapy in general.MethodsWe retrospectively reviewed all patients with the diagnosis of IST at a tertiary academic medical center from 1998 to 2018. We extracted data related to prescribing patterns and symptom response to medical therapy and sinus node modification (SNM), assessing efficacy and periprocedural complication rates.ResultsA total of 305 patients with a formal diagnosis of IST were identified, with 259 (84.9%) receiving at least one prescription medication related to the condition. Beta‐blockers were the most commonly used medication (n = 245), with a majority of patients reporting no change or worsening of symptoms, and poor response was seen to other medication classes. Improvement was seen significantly more often with ivabradine than beta blockers, though the sample size was limited (p = .003). Fifty‐five patients (18.0% of all IST patients), mean age 32.0 ± 9.1 years, underwent a SNM procedure, with an average of 1.8 ± 0.9 procedures per patient. Acute symptomatic improvement (<6 months) was seen in 58.2% of patients. Long‐term complete resolution of symptoms was seen in 5.5% of patients, modest improvement in 29.1%, and no long‐term benefit was seen in 65.5% of patients.ConclusionsAmong all medical therapies, there were high rates of treatment failure or symptom worsening in over three‐quarters of patients in our study. Ivabradine was most beneficial, though the sample size was small. While most patients receiving SNM ablation for IST perceive an acute symptomatic improvement, almost two‐thirds of patients have no long‐term improvement, and resolution of symptoms is quite rare. AV node ablation with pacemaker implantation following lack of response to SNM offered increased success, though the sample size was limited.

AbstractBackgroundThe subcutaneous implantable cardioverter‐defibrillator (S‐ICD) has a larger generator and its implantation involves more dissection and tunneling compared to traditional transvenous defibrillator system. Liposomal bupivacaine, an extended‐release bupivacaine with 72 h of duration has been used for postoperative pain management in patients undergoing S‐ICD implantation. Our aim was to compare postoperative pain and opioid prescription patterns among patients undergoing S‐ICD implantation who received intraprocedural liposomal bupivacaine and those who did not.MethodsWe performed a retrospective analysis of all patients who underwent subcutaneous ICD implantation from January 1, 2013 to March 30, 2018 at the Mayo Clinic in Rochester, Minnesota. Patients were categorized into those who received liposomal bupivacaine and those who did not. Data on inpatient pain score, outpatient opioid prescription rates at discharge, and doses based on oral morphine equivalents (OME) were collected.ResultsA total of 104 patients underwent S‐ICD implantation. Intraprocedural liposomal bupivacaine was used in 69% of patients. Patients who received intraprocedural liposomal bupivacaine had similar mean inpatient pain scores (2.9 vs. 2.9, p = .786). There was also no difference in the rate of inpatient opioid administration (79.2% vs. 87.5%, p = .4139), outpatient opioid prescription (23.6% vs. 12.5%, p = .29), or mean OME (41.7‐mg vs. 16.6‐mg, p = .188) when comparing patients those who received intraprocedural liposomal bupivacaine and those who did not.ConclusionIntraprocedural liposomal bupivacaine administration was not associated with any significant impact on postoperative pain scores, inpatient opioid administration, and outpatient opioid prescription rates or OME amounts at discharge.