Posttransplant atrial fibrillation: Evidence of early posttransplant recipient-to-donor atrioatrial connections

INTRODUCTION

Atrial fibrillation and atrial flutter originating from the donor s heart is a commonly reported complication post heart transplant. Atrial tachyarrhythmia originating from the recipient s heart, propagated through recipient-to-donor connections, is rare with only few cases reported in the literature; most reported cases from our review occur years post-transplant.

CASE

A 47-year-old male presented with atrial tachycardia 6 months post heart transplant. Electrophysiologic study demonstrated atrial fibrillation originating from native heart and propagated through atrio-atrial connections to the donor heart. This arrhythmia was successfully terminated with radiofrequency ablation.

CONCLUSION

Atrio-atrial connection between recipient and donor can form as early as a few months post heart transplant. Radiofrequency ablation appears to be an effective treatment for atrial fibrillation propagated through donor-to-recipient connections.

Predictors of Atrial Fibrillation in Patients With Stroke Attributed to Large- or Small-Vessel Disease: A Prespecified Secondary Analysis of the STROKE AF Randomized Clinical Trial

Importance

The Stroke of Known Cause and Underlying Atrial Fibrillation (STROKE AF) trial found that approximately 1 in 8 patients with recent ischemic stroke attributed to large- or small-vessel disease had poststroke atrial fibrillation (AF) detected by an insertable cardiac monitor (ICM) at 12 months. Identifying predictors of AF could be useful when considering an ICM in routine poststroke clinical care.

Objective

To determine the association between commonly assessed risk factors and poststroke detection of new AF in the STROKE AF cohort monitored by ICM.

Design, Setting, and Participants

This was a prespecified analysis of a randomized (1:1) clinical trial that enrolled patients between April 1, 2016, and July 12, 2019, with primary follow-up through 2020 and mean (SD) duration of 11.0 (3.0) months. Eligible patients were selected from 33 clinical research sites in the US. Patients had an index stroke attributed to large- or small-vessel disease and were 60 years or older or aged 50 to 59 years with at least 1 additional stroke risk factor. A total of 496 patients were enrolled, and 492 were randomly assigned to study groups (3 did not meet inclusion criteria, and 1 withdrew consent). Patients in the ICM group had the index stroke within 10 days before insertion. Data were analyzed from October 8, 2021, to January 28, 2022.

Interventions

ICM monitoring vs site-specific usual care (short-duration external cardiac monitoring).

Main Outcomes and Measures

The ICM device automatically detects AF episodes 2 or more minutes in length; episodes were adjudicated by an expert committee. Cox regression multivariable modeling included all parameters identified in the univariate analysis having P values <.10. AF detection rates were calculated using Kaplan-Meier survival estimates.

Results

The analysis included the 242 participants randomly assigned to the ICM group in the STROKE AF study. Among 242 patients monitored with ICM, 27 developed AF (mean [SD] age, 66.6 [9.3] years; 144 men [60.0%]; 96 [40.0%] women). Two patients had missing baseline data and exited the study early. Univariate predictors of AF detection included age (per 1-year increments: hazard ratio [HR], 1.05; 95% CI, 1.01-1.09; P = .02), CHA2DS2-VASc score (per point: HR, 1.54; 95% CI, 1.15-2.06; P = .004), chronic obstructive pulmonary disease (HR, 2.49; 95% CI, 0.86-7.20; P = .09), congestive heart failure (CHF; with preserved or reduced ejection fraction: HR, 6.64; 95% CI, 2.29-19.24; P < .001), left atrial enlargement (LAE; HR, 3.63; 95% CI, 1.55-8.47; P = .003), QRS duration (HR, 1.02; 95% CI, 1.00-1.04; P = .04), and kidney dysfunction (HR, 3.58; 95% CI, 1.35-9.46; P = .01). In multivariable modeling (n = 197), only CHF (HR, 5.06; 95% CI, 1.45-17.64; P = .05) and LAE (HR, 3.32; 1.34-8.19; P = .009) remained significant predictors of AF. At 12 months, patients with CHF and/or LAE (40 of 142 patients) had an AF detection rate of 23.4% vs 5.0% for patients with neither (HR, 5.1; 95% CI, 2.0-12.8; P < .001).

Conclusions and Relevance

Among patients with ischemic stroke attributed to large- or small-vessel disease, CHF and LAE were associated with a significantly increased risk of poststroke AF detection. These patients may benefit most from the use of ICMs as part of a secondary stroke prevention strategy. However, the study was not powered for clinical predictors of AF, and therefore, other clinical characteristics may not have reached statistical significance.

Trial Registration

ClinicalTrials.gov Identifier: NCT02700945.

Watchman outcomes comparing post-implantation anticoagulation with warfarin versus direct oral anticoagulants

PURPOSE

As left atrial appendage occlusion devices (LAAO) implantation rates grow, continued evaluation on best patient practices is important. We report pooled Watchman outcomes at a multicenter Texas healthcare system with an emphasis on clinical outcomes and post-implantation anticoagulation with direct oral anticoagulants (DOACs) versus warfarin.

METHODS

Data for 163 patients with atrial fibrillation (AF) undergoing Watchman implantation was collected via retrospective chart review between June 2016 and June 2018. A Fisher's exact test was utilized to evaluate associations in bivariate comparisons of categorical data. Tests of non-inferiority, applied between DOACs and warfarin, utilized a ratio of 2.

RESULTS

Outcomes were significant for similar rates of stroke, disabling stroke, major bleeds, and all-cause mortality when compared to published clinical trials. Most patients with cerebrovascular events were found to have >5 mm peri-device leaks (PDLs), were on warfarin at the time of the event (75%), and all occurred within the first 6 months post implant. A significant number of patients were discharged on DOACs (42%). DOACs were shown to be non-inferior to warfarin with respect to stroke (p = 0.0048), disabling stroke (p = 0.0383), gastrointestinal bleeding (p = 0.0287), mortality (p = 0.0165), and combined adverse outcomes (p = 0.0040). DOACs were associated with less combined adverse outcomes (p = 0.021).

CONCLUSION

Our findings suggest that additional imaging or aggressive management of PDLs in Watchman recipients within the initial 6-month follow-up may aid in reducing stroke rates. Additionally, anticoagulation with DOACs' post Watchman implantation was found non-inferior to warfarin, with some evidence of lower risk for adverse outcomes favoring DOACs.

The prognostic significance of left ventricular ejection fraction in patients with advanced cancer treated in phase I clinical trials

BACKGROUND

New targeted agents may cause acute cardiac events. The purpose of our study was to investigate the incidence and the prognostic significance of left ventricular ejection fraction (LVEF) in phase I trials.

PATIENTS AND METHODS

Between October 2008 and September 2011, the records of 1166 consecutive patients with advanced cancer treated in the Phase I Clinic who underwent echocardiography were retrospectively reviewed.

RESULTS

Most of the patients were White (78%), and the most common tumor types were colorectal cancer and melanoma. Of 1166 patients, 177 (15.2%) patients had an LVEF of <50%. No difference in overall survival (OS) between patients with LVEF ≥ 50% and patients with LVEF < 50% was seen (median OS 7.4 versus 7.0 months, P = 0.84). Patients with LVEF ≤ 35% had shorter survival compared with those with LVEF between 35% and 50% (median 4.2 versus 8.0 months; P = 0.005). In multivariate analysis of patients with LVEF < 50%, independent factors predicting longer survival were LVEF > 35%, ≤2 prior systemic therapies, ≤2 metastatic sites, and normal lactate dehydrogenase and albumin levels.

CONCLUSION

Echocardiography would improve patient selection for enrollment in phase I clinical trials. These data suggest that it is safe to treat patients with LVEF between 35% and 50%.

Chemotherapy-induced cardiovascular toxicity: beyond anthracyclines

It is not uncommon for anesthesiologists to encounter cancer patients who have received chemotherapy agents known to cause cardiovascular toxicities such as heart failure, systemic hypertension and thromboembolic events. Anthracyclines have been for several decades the most studied agents because of their known cardiovascular effects and relatively high incidence of heart failure. However, cancer patients are currently treated with newer chemotherapeutics such as imatinib, sunitinib, trastuzumab and bevacizumab that are also responsible of causing cardiovascular toxicities. The type of cardiotoxicity associated with these newer agents (type II cardiotoxicity) appears to be different in terms of pathogenesis to that caused by anthracyclines (type I cardiotoxicity). Thus, anesthesiologist needs to be aware of the clinical features of each type of cardiac toxicity. This review will summarize the current clinical evidence on cardiovascular toxicity induced by chemotherapeutic agents and will try to shed light on the current information regarding the perioperative management of patients with chemotherapy-induced cardiovascular toxicity.

Dronedarone for the treatment of atrial fibrillation and atrial flutter: approval and efficacy

Dronedarone, a new Class III antiarrhythmic agent, has now been approved by the US Food and Drug Administration for use in patients with atrial fibrillation or atrial flutter. Approval came in March 2009 due to the positive results of the ATHENA trial showing significant reductions in all-cause mortality and cardiovascular hospitalization with dronedarone use. A post hoc analysis of the ATHENA data also suggested a decrease in stroke risk with this agent. However, due to safety concerns in the heart failure population in the earlier ANDROMEDA trial, dronedarone is not recommended for patients with an ejection fraction <35% and recent decompensated heart failure. Dronedarone is an amiodarone analog with multichannel blocking electrophysiologic properties similar to those of amiodarone, but several structural differences. Dronedarone’s lack of the iodine moiety reduces its potential for thyroid and pulmonary toxicity. Preliminary data from the DIONYSOS trial, and an indirect meta-analysis comparing amiodarone with dronedarone, showed amiodarone to be more effective in maintaining sinus rhythm, while dronedarone was associated with fewer adverse effects resulting in early termination of the drug. Dronedarone is the first antiarrhythmic drug for the treatment of atrial fibrillation and atrial flutter shown to reduce cardiovascular hospitalizations. In patients with structural heart disease who have an ejection fraction >35% and no recent decompensated heart failure, dronedarone should be considered earlier than amiodarone in the treatment algorithm.

Breathing patterns during cardiac arrest

The absence of respiratory movements is a major criterion recommended for use by bystanders for recognizing an out-of-hospital cardiac arrest (CA), as the persistence of eupneic breathing is considered to be incompatible with CA. The basis for CA-related apnea is, however, uncertain, since brain stem Po2 is not expected to drop immediately to the critical level where anoxic apnea occurs. It is therefore essential on both clinical and physiological grounds to determine whether and when breathing stops after the onset of CA. In eight patients, we measured the ventilatory response at the onset of ventricular fibrillation (VF) for 12–15 s during the placement of an implantable cardioverter-defibrillator device. We found that regular eupneic breathing was maintained unchanged despite the cessation of systemic and pulmonary blood flow generated by the heart. We extended these findings in adult sheep and found that, as in humans, the normal ventilatory pattern persists unchanged for the first 15 s despite the drop in blood pressure, followed by a progressive increase in minute ventilation, which was sustained for up to 164 s. The ensuing apnea was disrupted by typical gasps occurring at a very slow frequency. These observations suggest a complete “decoupling” between the return of CO2 to the pulmonary circulation and continued effective respiratory activity, contrary to what we predicted. This delayed cessation of eupneic breathing during the absence of cardiac pump function is likely related to the time needed for brain stem anoxia to develop. These findings challenge the notions that 1) ventilation stops as pulmonary blood flow/cardiac output ceases and 2) the presence of eupneic breathing is a reliable sign of effective cardiac pumping activity.

Value of quantitative analysis of mitral regurgitation jet eccentricity by color flow Doppler for identification of flail leaflet

Early surgical intervention improves the outcome of patients with mitral regurgitation (MR) secondary to flail leaflet. Current criteria for the diagnosis of flail leaflet require a detailed definition of mitral valve anatomy, which is often challenging by transthoracic echocardiography (TTE) and, occasionally, even by transesophageal echocardiography (TEE). We studied 57 patients (mean age 63 +/- 15 years) with anatomically confirmed flail mitral leaflet and a control group of 57 patients (mean age 68 +/-14 years) with at least moderate MR but no flail leaflet. In patients with flail mitral leaflet, the mean angle formed by the axis of the MR jet and the plane of the mitral annulus was 33 +/- 11 degrees and 29 +/- 16 degrees when measured with TTE and TEE, respectively. In controls the mean angle was 66 +/- 16 degrees and 66 +/- 17 degrees by TTE and TEE, respectively (p <0.0001). Based on receiver- operating characteristic analysis, the optimal cutoff jet angle value for diagnosing flail mitral leaflet was 45 degrees with TTE (sensitivity 88%, specificity 88%), and 47 degrees by TEE (sensitivity 88%, specificity 88%). MR jet angles < or =45 degrees were also correctly identified by visual assessment of TTE images in >90% of cases, with good interobserver agreement (k = 0.76). Thus, quantitative analysis of MR jet eccentricity by color flow Doppler is highly sensitive and specific for diagnosing flail mitral leaflet.