Prevalence and Impact of Poorly Controlled Modifiable Risk Factors Among Patients Who Underwent Atrial Fibrillation Ablation.

Managing atrial fibrillation (AF) risk factors (RFs) improves ablation outcomes in obese patients. However, real-world data, including nonobese patients, are limited. This study examined the modifiable RFs of consecutive patients who underwent AF ablation at a tertiary care hospital from 2012 to 2019. The prespecified RFs included body mass index (BMI) ≥30 kg/m2, >5% fluctuation in BMI, obstructive sleep apnea with continuous positive airway pressure noncompliance, uncontrolled hypertension, uncontrolled diabetes, uncontrolled hyperlipidemia, tobacco use, alcohol use higher than the standard recommendation, and a diagnosis-to-ablation time (DAT) >1.5 years. The primary outcome was a composite of arrhythmia recurrence, cardiovascular admissions, and cardiovascular death. In this study, a high prevalence of preablation modifiable RFs was observed. More than 50% of the 724 study patients had uncontrolled hyperlipidemia, a BMI ≥30 mg/m2, a fluctuating BMI >5%, or a delayed DAT. During a median follow-up of 2.6 (interquartile range 1.4 to 4.6) years, 467 patients (64.5%) met the primary outcome. Independent RFs were a fluctuation in BMI >5% (hazard ratio [HR] 1.31, p = 0.008), diabetes with A1c ≥6.5% (HR 1.50, p = 0.014), and uncontrolled hyperlipidemia (HR 1.30, p = 0.005). A total of 264 patients (36.46%) had at least 2 of these predictive RFs, which was associated with a higher incidence of the primary outcome. Delayed DAT over 1.5 years did not alter the ablation outcome. In conclusion, substantial portions of patients who underwent AF ablation have potentially modifiable RFs that were not well controlled. Fluctuating BMI, diabetes with hemoglobin A1c ≥6.5%, and uncontrolled hyperlipidemia portend an increased risk of recurrent arrhythmia, cardiovascular hospitalizations, and mortality after ablation.

Stellate ganglia stimulation counteracts vagal stimulation by significantly increasing heart rate and blood pressure.

BACKGROUND: Vasovagal syncope (VVS) is the leading cause of syncope. The most frequent mechanism is that of a cardioinhibitory response, vasodepressor response, or mixture of both. Neural stimulation that negates or overcomes the effects of vagal tone may be used as a treatment strategy for VVS. METHODS: Six male canines were studied. Stimulation (10-Hz, 2 ms pulse duration, 2 min duration) of the cervical vagus (CV), thoracic vagus (TV), and stellate ganglia (SG) was performed using needle electrodes at 3 V, 5 V, and 10 V output. SG stimulation at an output of 10 V overlaying TV stimulation at the same output was performed. Heart rate (HR), blood pressure (BP), and cardiac output (CO) were measured before, during, and after stimulation. RESULTS: Right cervical vagal stimulation was associated with significant hemodynamic changes. HR, SBP, and DBP were reduced (107 ± 16 vs. 78 ± 15 bpm [P < 0.0001], 116 ± 24 vs. 107 ± 28 mmHg [P = 0.002] and 71 ± 18 vs. 58 ± 20 mmHg [P < 0.0001]), respectively, while left cervical vagal stimulation had minimal changes. CV stimulation was associated with greater hemodynamic changes than TV stimulation. Left and right SG stimulation significantly increased systolic blood pressure (SBP), diastolic blood pressure (DBP), and HR at 5 V and 10 V, which could be observed within 30 s after stimulation. An output-dependent increase in hemodynamic parameters was seen with both left and right SG stimulation. No difference between left and right SG stimulation was seen. SG stimulation overlay significantly increased HR, BP, and CO from baseline vagal stimulation bilaterally. CONCLUSIONS: Stellate ganglia stimulation leads to increased HR and BP despite significant vagal stimulation. This may be exploited therapeutically in the management of vasovagal syncope.

Predictive value of interatrial block on electrocardiogram among obese patients undergoing atrial fibrillation ablation.

BACKGROUND: Determine a predictive value of interatrial block (IAB) on atrial fibrillation (AF) ablation outcomes in obese patients. METHODS: Medical records were retrospectively reviewed for 205 consecutive patients with body mass indices (BMI) ≥ 30 kg/m2 who underwent initial AF ablation. Evidence of partial IAB defined as P-wave duration (PWD) ≥ 120 ms and advanced IAB with PWD ≥ 120 ms and biphasic or negative P-wave in inferior leads was examined from sinus electrocardiograms (ECGs) within 1-year pre-ablation. The primary outcome was recurrent atrial arrhythmia after 3-month blanking period post-ablation. RESULTS: The mean BMI was 36.9 ± 5.7 kg/m2. Partial IAB and advanced IAB were observed in 155 (75.61%) and 42 (20.49%) patients, respectively. During the median follow-up of 1.35 (interquartile range 0.74, 2.74) years, 115 (56.1%) patients had recurrent atrial arrhythmias. In multivariable analysis adjusting for age, gender, persistent AF, use of antiarrhythmic drugs (AADs), left atrial volume index (LAVI), partial IAB, and advanced IAB were independent predictors of recurrent arrhythmia with hazard ratio (HR) of 2.80 (95% confidence interval [CI] 1.47-6.05; p = 0.001) and HR 1.79 (95% CI 1.11-2.82; p = 0.017), respectively. The results were similar in a subgroup analysis of patients who had no severe left atrial enlargement and a subgroup analysis of patients who were not on AADs. CONCLUSIONS: IAB is highly prevalent in patients with obesity and AF. Partial IAB, defined as PWD ≥ 120 ms, and advanced IAB with evidence of biphasic P-wave in inferior leads were independently associated with increased risk of recurrent arrhythmia after AF ablation. Its predictive value is independent of other traditional risk factors, LAVI, or use of AADs.

Perioperative changes in left ventricular systolic function following surgical revascularization.

BACKGROUND: Nearly 1/3rd of patients undergoing coronary artery bypass graft surgery (CABG) have left ventricular systolic dysfunction. However, the extent, direction and implications of perioperative changes in left ventricular ejection fraction (LVEF) have not been well characterized in these patients. METHODS: We studied the changes in LVEF among 549 patients with left ventricular systolic dysfunction (LVEF <50%) who underwent CABG as part of the Surgical Treatment for Ischemic Heart Failure (STICH) trial. Patients had pre- and post-CABG (4 month) LVEF assessments using identical cardiac imaging modality, interpreted at a core laboratory. An absolute change of >10% in LVEF was considered clinically significant. RESULTS: Of the 549 patients (mean age 61.4±9.55 years, and 72 [13.1%] women), 145 (26.4%) had a >10% improvement in LVEF, 369 (67.2%) had no change and 35 (6.4%) had >10% worsening of LVEF following CABG. Patients with lower preoperative LVEF were more likely to experience an improvement after CABG (odds ratio 1.36; 95% CI 1.21-1.53; per 5% lower preoperative LVEF; p <0.001). Notably, incidence of postoperative improvement in LVEF was not influenced by presence, nor absence, of myocardial viability (25.5% vs. 28.3% respectively, p = 0.67). After adjusting for age, sex, baseline LVEF, and NYHA Class, a >10% improvement in LVEF after CABG was associated with a 57% lower risk of all-cause mortality (HR: 0.43, 95% CI: 0.26-0.71). CONCLUSIONS: Among patients with ischemic cardiomyopathy undergoing CABG, 26.4% had >10% improvement in LVEF. An improvement in LVEF was more likely in patients with lower preoperative LVEF and was associated with improved long-term survival.

Improvement of left ventricular function with surgical revascularization in patients eligible for implantable cardioverter-defibrillator.

INTRODUCTION: Left ventricular ejection fraction (EF) ≤ 35% is the cornerstone criterion for implantable cardioverter-defibrillator (ICD) eligibility. Improvement in EF may occur in ICD-eligible patients after coronary artery bypass graft surgery (CABG). However, the incidence, predictors, and outcomes of this process are unclear. METHODS AND RESULTS: We studied 427 patients with EF ≤ 35% who underwent CABG in the Surgical Treatment for Ischemic Heart Failure (STICH) trial and had a systematic pre- and postoperative (4 months) EF assessment using the identical cardiac imaging modality. All imaging studies were interpreted at a core laboratory. Improvement in EF was defined as postoperative EF > 35% and >5% absolute improvement from baseline. Of the 427 patients (mean age 61.8 ± 9.5 and 50 women), 125 (29.2%) had EF improvement. Their mean EF increased from 26.8% (±5.8%) to 43.3% (±6.5%) (p < .0001). EF improvement occurred in only 20% of patients with a preoperative EF < 25%. The odds of EF improvement were 1.96 times higher (95% confidence interval [CI]: 0.91-4.23, p = .09) in patients with myocardial viability. In adjusted analyses, EF improvement was associated with a significantly lower risk of all-cause mortality (hazard ratio [HR]: 0.58, 95% CI: 0.35-0.96; p = .03) and heart failure mortality (HR: 0.31, 95% CI: 0.11-0.87; p = .027). CONCLUSION: Nearly 1/3rd of ICD-eligible patients undergoing CABG had significant improvement in EF, obviating the need for primary prevention ICD implantation. These results provide patients and clinicians data on the likelihood of ICD eligibility after CABG and support the practice of reassessment of EF after revascularization.

Incremental benefit of a novel signal recording system during mapping and ablation.

AIMS: Current electrophysiology signal recording and mapping systems have limited dynamic range (DR) and bandwidth, which causes loss of valuable information during acquisition of cardiac signals. We evaluated a novel advanced signal processing platform with the objective to obtain and assess additional information of clinical importance. METHODS AND RESULTS: Over 10 canines, we compared intracardiac recordings within all cardiac chambers, in various rhythms, in pacing and during radiofrequency (RF) ablation across two platforms; a conventional system and the PURE EP™ [(PEP); Bio Sig Technologies, Inc., Los Angeles, CA, USA]. Recording cardiac signals with varying amplitudes were consistently and reproducibly observed, without loss of detail or introduction of artefact. Further the amplitude of current of injury (COI) on the unipolar signals correlated with the instantaneous contact force (CF) recorded on the sensing catheter in all the animals (r2 = 0.94 in ventricle). The maximum change in the unipolar COI correlated with the change in local electrogram amplitude during non-irrigated RF ablation (r2 = 0.61 in atrium). Reduction in artefact attributable to pacing (20 sites) and noise during ablation (48 sites) was present on the PEP system. Within the PEP system, simultaneous display of identical signals, filtered differently, aided the visualization of discrete conduction tissue signals. CONCLUSION: Compared to current system, the PEP system provided incremental information including identifying conduction tissue signals, estimates of CF and a surrogate for lesion formation. This novel signal processing platform with increased DR and minimal front-end filtering may be useful in clinical practice.

Catheter ablation of premature ventricular contractions originating from periprosthetic aortic valve regions.

BACKGROUND: Little is known about the ablation outcomes of premature ventricular contractions (PVCs) that originate from the periprosthetic aortic valve (PPAV) regions of patients with aortic valve replacement (AVR). METHODS AND RESULTS: Our study had 11 patients who underwent catheter ablation for PVCs arising from the PPAV regions (bioprosthetic aortic valve, n = 5; mechanical aortic valve, n = 6). The PVC characteristics, procedure characteristics, and efficacy of ablation were compared with the control group (n = 33). At baseline, the PPAV group had a lower left ventricular ejection fraction (mean [SD], 41% [12%] vs. 51% [8%]; p = .002). The rate of acute ablation success was 90.9% in the PPAV group. Ablation sites were identified above the left coronary cusp (LCC) and right coronary cusp commissure (LRCC) in one PVC, below the prosthetic valve in eight PVCs (four below LCC and four below LRCC), and within the distal coronary sinus in two PVCs. The mean procedure time, fluoroscopy time, and radiation in the PPAV group were all significantly greater than those in the control group (all p < .05). However, the number of radiofrequency ablation energy deliveries was not different. The PPAV group had a long-term success rate compared with the control group (72.7% vs. 87.9%, p = .48) and an increase of left ventricular ejection fraction from 43% to 49% after successful PVC ablation at follow-up (p < .001). Echocardiography showed no significant change in valve regurgitation after ablation. No new atrioventricular block occurred. CONCLUSION: PVCs arising from PPAV regions can be successfully ablated in patients with prior AVR, without damaging the prosthetic aortic valve and atrioventricular conduction.

Cardiac safety of off-label COVID-19 drug therapy: a review and proposed monitoring protocol.

More than 2,000,000 individuals worldwide have had coronavirus 2019 disease infection (COVID-19), yet there is no effective medical therapy. Multiple off-label and investigational drugs, such as chloroquine and hydroxychloroquine, have gained broad interest due to positive pre-clinical data and are currently used for treatment of COVID-19. However, some of these medications have potential cardiac adverse effects. This is important because up to one-third of patients with COVID-19 have cardiac injury, which can further increase the risk of cardiomyopathy and arrhythmias. Adverse effects of chloroquine and hydroxychloroquine on cardiac function and conduction are broad and can be fatal. Both drugs have an anti-arrhythmic property and are proarrhythmic. The American Heart Association has listed chloroquine and hydroxychloroquine as agents which can cause direct myocardial toxicity. Similarly, other investigational drugs such as favipiravir and lopinavir/ritonavir can prolong QT interval and cause Torsade de Pointes. Many antibiotics commonly used for the treatment of patients with COVID-19, for instance azithromycin, can also prolong QT interval. This review summarizes evidenced-based data regarding potential cardiac adverse effects due to off-label and investigational drugs including chloroquine and hydroxychloroquine, antiviral therapy, monoclonal antibodies, as well as common antibiotics used for the treatment of COVID-19. The article focuses on practical points and offers a point-of-care protocol for providers who are taking care of patients with COVID-19 in an inpatient and outpatient setting. The proposed protocol is taking into consideration that resources during the pandemic are limited.

Long-Term Outcomes After Transcatheter and Surgical Aortic Valve Replacement in Patients With Cirrhosis: A Guide for the Hepatologist.

BACKGROUND AND AIMS: Hepatologists often determine whether transcatheter aortic valve replacement (TAVR) or surgical aortic valve replacement (SAVR) is preferred for patients with cirrhosis and severe aortic stenosis. The goal of this cohort study is to compare outcomes following TAVR and SAVR in patients with cirrhosis to inform the preferred intervention. APPROACH AND RESULTS: Prospectively collected data on 105 consecutive patients with cirrhosis and aortic stenosis who underwent TAVR (n = 55) or SAVR (n = 50) between 2008 and 2016 were reviewed retrospectively. Two control groups were included: 2,680 patients without cirrhosis undergoing TAVR and SAVR and 17 patients with cirrhosis who received medical therapy alone. Among the 105 patients with cirrhosis, the median Society of Thoracic Surgeons score was 3.8% (1.5, 6.9), and the median Model for End-Stage Liver Disease (MELD) score was 11.6 (9.4, 14.0). The TAVR group had similar in-hospital (1.8% vs. 2.0%) and 30-day mortality (3.6% vs. 4.2%) as the SAVR group. During the median follow-up of 3.8 years (95% confidence interval, 3.0-6.9), there were 63 (60%) deaths. MELD score (adjusted hazard ratio, 1.13; 95% confidence interval, 1.05-1.21; P = 0.002) was an independent predictor of long-term survival. In the subgroup of patients with MELD score <12, the TAVR group had reduced survival compared with the SAVR group (median survival of 2.8 vs. 4.4 years; P = 0.047). However, in those with MELD score ≥12, survival after TAVR, SAVR, and medical therapy was similar (1.3 vs. 2.1 vs. 1.6 years, respectively; P = 0.53). CONCLUSION: In select patients with cirrhosis, both TAVR and SAVR have acceptable and comparable short-term outcomes. MELD score, but not Society of Thoracic Surgeons score, independently predicts long-term survival after TAVR and SAVR. For patients with MELD score <12, SAVR is a preferred procedure; however, neither procedure appears superior to medical therapy in patients with MELD score ≥12.

A novel percutaneous stabilizing sheath for minimal invasive epicardial echocardiography and ablation.

PURPOSE: Epicardial ablation and mapping are critical adjuncts to the electrophysiologist's approach to arrhythmias; however, ablation within the epicardial space requires the avoidance of coronary arteries (CA). We aimed to evaluate the feasibility and performance of a novel-stabilizing ablation sheath housing an intracardiac echocardiography (ICE) catheter to (1) obtain Epicardial Echocardiography (EE) images, (2) visualize CAs, and (3) enable targeted delivery of radiofrequency energy away from visualized CAs. METHODS: We designed a sheath that could enclose a regular ICE catheter. This sheath has flanges and a balloon, with three interspersed windows surrounded by an electrode. In an acute canine model (N = 6), the sheath was manipulated within the pericardial space to visualize cardiac structures and CAs. Visualization of CAs was confirmed with angiography. Ablation was then performed through the window either proximal or distal to the CA. RESULTS: The novel sheath was successfully deployed in six canines, with no acute procedural complications. Images with an excellent spatial resolution of cardiac structures were obtained including the right ventricular outflow tract; aortic, pulmonary, and mitral valves; and left atrial appendage. CAs were successfully visualized, and ablation from a sheath window either proximal or distal to the CA did not produce angiographic or histopathological evidence of CA damage despite evidence of acute injury to the adjacent ablated myocardium. CONCLUSIONS: This novel percutaneous stabilizing sheath was able to successfully obtain high-quality EE images as well as provide a non-fluoroscopic intra-procedural means to visualize CAs. Use of this sheath enabled successful delivery of energy to avoided CA damage.

Comparing the incidence of ventricular arrhythmias during epicardial ablation in swine versus canine models.

BACKGROUND: Choosing the appropriate animal model for development of novel technologies requires an understanding of anatomy and physiology of these different models. There are little data about the characteristics of different animal models for the study of technologies used for epicardial ablation. We aimed to compare the incidence of ventricular arrhythmias during epicardial radiofrequency ablation between swine and canine models using novel epicardial ablation catheters. METHODS: We conducted a retrospective study using data obtained from epicardial ablation experiments performed on swine (Sus Scrofa) and canine (Canis familiaris) models. We compared the incidence of ventricular arrhythmias during ablation between swine and canine using multivariate regression analysis. Six swine and six canine animals underwent successful epicardial radiofrequency ablation. A total of 103 ablation applications were recorded. RESULTS: Ventricular arrhythmias requiring cardioversion occurred in 13.11% of radiofrequency ablation applications in swine and 9.75% in canine (relative risk: 117.6%, 95% confidence interval [CI]: 83.97-164.69, animal-based odds ratio [OR]: .55, 95% CI: .23-61.33; P = .184). When adjusting for application position, duration of ablation and power, the odds of developing potentially lethal ventricular arrhythmia in swine increased significantly compared to canine (OR: 3.60, 95% CI: 1.35-9.55; P = .010). CONCLUSIONS: The swine myocardium is more susceptible to developing ventricular arrhythmias compared to canine model during epicardial ablation. This issue should be carefully considered in future studies.

Electroporation of epicardial autonomic ganglia: Safety and efficacy in medium-term canine models.

BACKGROUND: Endocardial radiofrequency ablation of epicardial ganglionic plexus (GP) for atrial fibrillation (AF) is complicated by myocardial damage. OBJECTIVES: We hypothesized that an epicardial approach with a novel nitinol catheter system capable of causing irreversible electroporation (IRE) with direct current (DC) could selectively and permanently destroy GP without collateral myocardial injury. METHODS: Acute studies and medium-term terminal studies (mean survival, 1137 days) were performed with seven dogs. In the acute studies, DC was used to target epicardial GP within the transverse sinus, oblique sinus, vein of Marshall, and right periaortic space. Successful electroporation was defined as the presence of ablative lesions in the GP without collateral myocardial damage. A four-point integer system was used to classify histologic changes in tissue harvested from the ablation sites. Atrial effective refractory period (AERP) was measured during the acute and medium-term studies. RESULTS: For six dogs in the medium-term studies, the postablation period was uneventful without complications. Lesions were successfully created at 20 of 21 sites (95.2%) with more than minimal myocardial damage in one dog. An increase in AERP occurred in both atria during the acute studies but was maintained only in the right atrium at medium-term follow-up (5032 milliseconds). No dog had damage to the esophagus, adjacent great arteries, or pulmonary veins. CONCLUSIONS: This proof-of-concept study suggests that safe, effective, and selective epicardial ablation of GP can be performed with DC by IRE with minimal collateral myocardial damage.

Correction to: Iatrogenic atrial septal defect: reassurance or inquisitiveness.

The original version of this article unfortunately contained a mistake. The presentation of reference 1 was incorrect. The correct information is given below.

Potentially modifiable factors of dofetilide-associated risk of torsades de pointes among hospitalized patients with atrial fibrillation.

PURPOSE: There is a significant variation in the clinical approach of initiation and dose adjustment of dofetilide in atrial fibrillation (AF). Excessive QT prolongation could predispose patients to torsades de pointes (TdP), which can be fatal. METHODS: We performed a retrospective case-control study at Mayo Clinic Rochester (January 1, 2003 to December 31, 2016). "TdP risk" cases were defined as patients on dofetilide therapy for AF with subsequent TdP or excessive QTc prolongation requiring dose reduction or discontinuation (N = 31). A control group was matched 1:1 with cases by age, gender, year of admission, and dofetilide dose (N = 31). RESULTS: Using multivariate regression analysis, independent predictors of TdP risk included baseline QTc exceeding recommendations (adjusted odd ratio [AOR] 4.57; P = 0.023); underlying AF with rapid ventricular rate (AOR 16.95; P = 0.004); and diuretic therapy for acute heart failure (AOR 8.42; P = 0.007). Poor inter-observer agreement was identified among QT interval measurement in patients with AF and rapid ventricular rate compared to those in rate controlled AF or sinus rhythm. TdP risk cases receiving diuretics for acute heart failure had a significant decline in creatinine clearance than controls, although serum electrolytes and replacement did not differ among the two groups. CONCLUSIONS: Excessive QTc prolongation and AF with rapid ventricular rate at time of dofetilide initiation (likely due to difficulty in measuring QT intervals), and diuretic therapy for acute heart failure were independent factors for dofetilide-related TdP risk. Based on these data, possible preventive strategies could be adapted for safety protocols among hospitalized patients.

Supraventricular Arrhythmias: Clinical Framework and Common Scenarios for the Internist.

Supraventricular arrhythmias can cause uncomfortable symptoms for patients. Often, the first point of contact is in the primary care setting, and thus, it is imperative for the general internist to have a clinical framework in place to recognize this cluster of cardiac arrhythmias, be familiar with immediate and long-term management of supraventricular tachycardias, and understand when cardiac electrophysiologic consultation is necessary. The electrocardiographic characteristics can have subtle but important clues to the diagnosis and initial management. An understanding of the mechanisms of these arrhythmias is essential to provide proper therapy to the patient. In addition, there are common practice strategies that should be emphasized to avoid common misperceptions that could pose risk to the patient. In this review, we provide a framework to more easily recognize and classify these arrhythmias. We also illustrate the mechanism for these arrhythmias to provide an understanding of the interventions generally used.