Detection of atrial fibrillation in real world setting in patients with cryptogenic stroke and an implantable loop recorder.

INTRODUCTION: Implantable loop recorders (ILR) are used to screen for atrial fibrillation (AF) in patients with cryptogenic stroke (CS). However, there is limited real-world data regarding the long-term rate of AF detection using ILR and management consequences in patients with CS. The objective is to assess the rate of AF detection in patients with CS in a real-world study over 36 months of follow-up and its consequences on stroke prevention. METHODS: This retrospective study included patients with an ILR placed for CS at Baylor College of Medicine and Baylor St. Luke's Medical Center between January 2014 and July 2021. The primary outcome was AF detection in patients with ILR. The secondary outcome was the rate of subsequent strokes after ILR placement in patients with or without diagnosed AF. The AF detection rate in our cohort was compared to the rate in CRYSTAL-AF Trial at 36-month follow-up. The impact of AF detection on clinical management was examined. RESULTS: We identified 225 patients. 51.1% were women and 38.2% African American. Among 85 patients with ILR labeled AF, 43 patients had true AF, and 42 had incorrectly labeled AF (48.3% false positive). The estimated AF detection rate at 36 months follow-up was 28.6% (95% CI, 26.6%-30.6%). 58.1% of patients with AF were initiated on oral anticoagulation, 80.0% of whom were started on a direct oral anticoagulant. 13.8% of patients had recurrent strokes after ILR implantation; 4 of whom were diagnosed with AF. CONCLUSION: Compared to CRYSTAL-AF, the AF detection rate in our cohort is similar, but this cohort includes a higher proportion of female and African American patients. Most patients with recurrent strokes after ILR implant did not have AF during 36 months of monitoring.

Reconstituting electrical conduction in soft tissue: the path to replace the ablationist.

Cardiac arrhythmias are a leading cause of morbidity and mortality in the developed world. A common mechanism underlying many of these arrhythmias is re-entry, which may occur when native conduction pathways are disrupted, often by myocardial infarction. Presently, re-entrant arrhythmias are most commonly treated with antiarrhythmic drugs and myocardial ablation, although both treatment methods are associated with adverse side effects and limited efficacy. In recent years, significant advancements in the field of biomaterials science have spurred increased interest in the development of novel therapies that enable restoration of native conduction in damaged or diseased myocardium. In this review, we assess the current landscape of materials-based approaches to eliminating re-entrant arrhythmias. These approaches potentially pave the way for the eventual replacement of myocardial ablation as a preferred therapy for such pathologies.

High prevalence of cholesterol-rich atherosclerotic lesions in ancient mummies: A near-infrared spectroscopy study.

Computed tomography has been used previously in mummies to detect arterial calcification, which is a marker of later-stage atherosclerosis. Here, using the novel approach of near-infrared spectroscopy, we detected cholesterol-rich atherosclerotic plaques in arterial samples from ancient mummies. In this proof-of-concept study, we are the first to noninvasively detect these earlier-stage lesions in mummies from different geographical areas, suggesting that atherosclerosis has been present in humans since ancient times.

Accuracy of Voltage Signal Measurement During Radiofrequency Delivery Through the SMARTTOUCH Catheter.

INTRODUCTION: Current methods for measuring voltage during radiofrequency (RF) ablation (RFA) necessitate turning off the ablation catheter. If voltage could be accurately read without signal attenuation during RFA, turning off the catheter would be unnecessary, allowing continuous ablation. We evaluated the accuracy of the Thermocool SMARTTOUCH catheter for measuring voltage while RF traverses the catheter. METHODS AND RESULTS: We studied 26 patients undergoing RFA for arrhythmias. A 7.5F SMARTTOUCH catheter was used for sensing voltage and performing RFA. Data were collected from the Carto-3 3-dimensional mapping system. Voltages were measured during ablation (RF-ON) and immediately before or after ablation (RF-OFF). In evaluating the accuracy of RF-ON measurements, we utilized the RF-OFF measure as the gold standard. We measured 465 voltage signals. The median values were 0.2900 and 0.3100 for RF-ON and RF-OFF, respectively. Wilcoxon signed rank testing showed no significant difference in these values (P = 0.608). The intraclass correlation coefficient (ICC) was 0.96, indicating that voltage measurements were similarly accurate during RF-OFF versus RF-ON. Five patients had baseline atrial fibrillation (AF), for whom 82 ablation points were measured; 383 additional ablation points were measured for the remaining patients. The voltages measured during RF-ON versus RF-OFF were similar in the presence of AF (P = 0.800) versus non-AF rhythm (P = 0.456) (ICC, 0.96 for both). CONCLUSION: Voltage signal measurement was similarly accurate during RF-ON versus RF-OFF independent of baseline rhythm. Physicians should consider not turning off the SMARTTOUCH ablation catheter when measuring voltage during RFA.

Cryoballoon pressure waveform change during balloon inflation is not a reliable predictor of adequate pulmonary vein occlusion.

BACKGROUND: Cryoballoon ablation of pulmonary veins (PVs) is widely used to treat atrial fibrillation (AF). Successful ablation requires occluding the PVs by cryoballoon. Angiography is a standard method of assessing PV occlusion. To decrease contrast doses and overcome potential contraindications (e.g., allergy to contrast, renal disease), alternative methods have been tested, including intracardiac echocardiography, transesophageal echocardiography-color flow Doppler, and distal cryoballoon pressure monitoring. OBJECTIVE: We evaluated pressure monitoring's accuracy in detecting PV occlusion during cryoballoon ablation. METHODS: We studied 72 PVs in 18 nonconsecutive patients (mean age 68 ± 8 years; 13 male) who underwent cryoballoon ablation for paroxysmal AF. In 67 PVs, we documented the point at which the recorded pressure waveform at the distal tip of the inflated cryoballoon transformed from a left atrial into a pulmonary arterial pressure waveform. PV occlusion was confirmed by concurrent PV angiography through the distal balloon channel. Occlusion was rated on a I­IV scale in which I indicated poor occlusion with major leakage and IV indicated complete occlusion without leakage. RESULTS: In 43 of 67 PVs (64%), the change in the pressure waveform from left atrial to pulmonary arterial was associated with complete PV occlusion (grade IV), confirmed by angiography. In the other 24 PVs, complete occlusion was achieved by further movement of the cryoballoon under intracardiac echocardiographic guidance and angiographic confirmation. All 67 PVs were electrically isolated with cryoballoon. CONCLUSIONS: The change in pressure waveforms at the distal tip of inflated cryoballoon is not a reliable predictor of complete PV occlusion during cryoballoon ablation.

Implantable Cardioverter-Defibrillator Shocks During COVID-19 Outbreak.

Background COVID-19 was temporally associated with an increase in out-of-hospital cardiac arrests, but the underlying mechanisms are unclear. We sought to determine if patients with implantable defibrillators residing in areas with high COVID-19 activity experienced an increase in defibrillator shocks during the COVID-19 outbreak. Methods and Results Using the Medtronic (Mounds View, MN) Carelink database from 2019 and 2020, we retrospectively determined the incidence of implantable defibrillator shock episodes among patients residing in New York City, New Orleans, LA, and Boston, MA. A total of 14 665 patients with a Medtronic implantable defibrillator (age, 66±13 years; and 72% men) were included in the analysis. Comparing analysis time periods coinciding with the COVID-19 outbreak in 2020 with the same periods in 2019, we observed a larger mean rate of defibrillator shock episodes per 1000 patients in New York City (17.8 versus 11.7, respectively), New Orleans (26.4 versus 13.5, respectively), and Boston (30.9 versus 20.6, respectively) during the COVID-19 surge. Age- and sex-adjusted hurdle model showed that the Poisson distribution rate of defibrillator shocks for patients with ≥1 shock was 3.11 times larger (95% CI, 1.08-8.99; P=0.036) in New York City, 3.74 times larger (95% CI, 0.88-15.89; P=0.074) in New Orleans, and 1.97 times larger (95% CI, 0.69-5.61; P=0.202) in Boston in 2020 versus 2019. However, the binomial odds of any given patient having a shock episode was not different in 2020 versus 2019. Conclusions Defibrillator shock episodes increased during the higher COVID-19 activity in New York City, New Orleans, and Boston. These observations may provide insights into COVID-19-related increase in cardiac arrests.

Contact-force recovery predicts the absence of cardiac perforation during steam pops.

PURPOSE: Cardiac perforation (CP) is an uncommon but clinically important complication of radiofrequency ablation (RFA). We previously showed that contact-force recovery after a steam pop predicts the absence of CP in an open-chest animal model after pericardial dissection. We attempted to determine whether this also applies when pericardium is present. METHODS: In 5 open-chest sheep, left atrial RFA was performed under direct observation with a 7.5F ThermoCool SmartTouch force-sensing catheter (Biosense Webster Inc., Irvine, CA, USA). The catheter's contact force was measured every 50 ms during RFA. After each steam pop, the presence (+) or absence (-) of CP was noted, as well as whether pericardium was present over the ablation site. Contact-force signals were analyzed to detect contact-force recovery. Perforation rates were compared between sites with or without pericardium. RESULTS: Ninety-six steam pops occurred: 77 with pericardium and 19 without. For the pericardial steam pops, contact-force recovery occurred in 31/60 CP- events (52%) and 1/17 CP+ events (6%; P = 0.0006). For nonpericardial steam pops, contact-force recovery occurred in 4/9 CP- events (44%) and 1/10 CP+ events (P = 0.14). The rate of CP was 22% with pericardium and 52% without (P = 0.02). Pericardial tissue charred extensively during steam pop induction, even in the absence of CP. CONCLUSIONS: Contact-force recovery predicts the absence of CP during RFA independently of whether the pericardium is present. The presence of the pericardium may decrease the likelihood of perforation, perhaps by acting as a thermal sink. Additional studies are needed to correlate these results with clinical experience.

Thromboembolism in Atrial Fibrillation: Role of the Left Atrial Appendage.

Atrial fibrillation (AF) is the most common arrhythmia. Patients with AF have a higher risk for thromboembolism than individuals without AF. The left atrial appendage (LAA) is the main source of thromboembolism because of its anatomic, mechanical, and electrophysiologic properties, and accounts for more than 90% of thrombus formation in patients with AF. Advancement in imaging expands knowledge about anatomic and physiologic characteristics of LAA. The risk of thromboembolism events in patients with AF depends on clinical comorbidities and structural and physiologic parameters of atria, especially LAA. This article discusses AF-related thromboembolic events and the role of the LAA.

Potential Effects of Coronaviruses on the Cardiovascular System: A Review.

Importance: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19) has reached a pandemic level. Coronaviruses are known to affect the cardiovascular system. We review the basics of coronaviruses, with a focus on COVID-19, along with their effects on the cardiovascular system. Observations: Coronavirus disease 2019 can cause a viral pneumonia with additional extrapulmonary manifestations and complications. A large proportion of patients have underlying cardiovascular disease and/or cardiac risk factors. Factors associated with mortality include male sex, advanced age, and presence of comorbidities including hypertension, diabetes mellitus, cardiovascular diseases, and cerebrovascular diseases. Acute cardiac injury determined by elevated high-sensitivity troponin levels is commonly observed in severe cases and is strongly associated with mortality. Acute respiratory distress syndrome is also strongly associated with mortality. Conclusions and Relevance: Coronavirus disease 2019 is associated with a high inflammatory burden that can induce vascular inflammation, myocarditis, and cardiac arrhythmias. Extensive efforts are underway to find specific vaccines and antivirals against SARS-CoV-2. Meanwhile, cardiovascular risk factors and conditions should be judiciously controlled per evidence-based guidelines.

Effect of High Influenza Activity on Risk of Ventricular Arrhythmias Requiring Therapy in Patients With Implantable Cardiac Defibrillators and Cardiac Resynchronization Therapy Defibrillators.

Influenza is associated with an increased risk of cardiovascular events. Influenza's association with ventricular arrhythmias (VAs) has not been adequately studied. We investigated the relation of seasonal influenza activity with the incidence of VAs requiring therapy in patients with an implantable cardiac defibrillator or cardiac resynchronization therapy defibrillator. We retrospectively studied 163,831 patients with an implantable cardiac defibrillator or cardiac resynchronization therapy defibrillator who were enrolled in the Abbott Medical Merlin.net remote-monitoring network between January 2009 and December 2015. We used cross-correlation to assess the temporal relationship between influenza activity and the incidence of VAs requiring shock or antitachycardia pacing (ATP). We used a generalized linear model to test the possible effect of seasonal influenza activity on the occurrence of VAs requiring shock or ATP treatment, after adjustment for within-patient effects, age, gender, device type, and calendar year. We found a significant correlation between influenza activity and the incidence of VAs requiring shock or ATP treatment. The multivariate generalized linear model showed that during high influenza activity, patients were more likely to have a VA treated with shock (odds ratio = 1.06, p < 0.001) or ATP (odds ratio = 1.06, p < 0.0001). The impact of high influenza activity was most prominent during the years 2014 and 2015. We conclude that high influenza activity is associated with increased risk of VAs requiring therapy.

Anesthetic Management of Laser Lead Extraction for Cardiovascular Implantable Electronic Devices.

Cardiovascular implantable electronic devices (CIEDs) play a significant role in the modern management of cardiovascular disease. CIEDs include implantable pacemakers (PMs), implantable cardioverter-defibrillators (ICDs), and cardiac resynchronization therapy (CRT) devices. These devices improve the quality of life of their recipients and help reduce the incidence of sudden cardiac death. Traditionally, CIEDs have been reliant on the use of transvenous endocardial leads to directly connect with the heart. Over time, these endovascular leads may become endothelialized rendering removal extremely difficult. As the indications for CIEDs expands and with the continuing evolution of these devices, the number of patients requiring explantation for device recall, malfunction, and infection continues to increase. In this manuscript, we review the most common CIEDs, the indications and process of lead removal/device explantation, potential complications associated with the procedure and the anesthetic management of these patients.

Anesthetic Management of Patients Undergoing Percutaneous Endocardial and Epicardial Left Atrial Appendage Occlusion.

Atrial fibrillation is the most common cardiac arrhythmia in adults affecting almost 6 million adults in the United States. The 2 most common comorbidities associated with atrial fibrillation are heart failure and thromboembolic events. Heart failure symptoms may be treated with rate control, antiarrhythmic medications or by catheter ablation. Unfortunately, despite optimal medical management, thromboembolic events still occur. Recently, there has been a great deal of interest and innovation in finding an alternative to chronic anticoagulation. Several percutaneous left atrial appendage occlusion devices have been developed over recent years, some of which have proven to be noninferior to anticoagulation in preventing strokes in atrial fibrillation patients. The 2 most widely used left atrial appendage occlusion devices are the WATCHMAN (Atritech Inc, Plymouth, MN, USA) and the LARIAT (SentreHEART, Palo Alto, CA, USA) devices. After a detailed description of the procedures, the anesthetic considerations of each procedure and management of specific adverse events are discussed within this review.

Fluoroscopy-free Atrial Transseptal Puncture.

INTRODUCTION: Fluoroscopy is traditionally used in atrial transseptal puncture (TSP); however fluoroscopy exposes patient and physician to excess radiation. Here, we describe a feasibility study of a zero-fluoroscopy transseptal puncture (ZFTSP) technique utilising electroanatomical mapping (EAM) and intracardiac echo (ICE) in a small case series of patients undergoing ablation for atrial fibrillation (AF). We then compare this technique to other established ZFTSP techniques for paroxysmal AF ablation. METHODS: Seven patients received ZFTSP. An Acunav™ ICE catheter (Biosense Webster Inc., California, US) was placed in the right atrium, then an Agilis™ sheath (St. Jude Medical, Saint Paul, Minnesota, US) was established into the inferior vena cava. A ThermoCool® SmartTouch™ catheter (Biosense Webster Inc., California, US) was inserted through the Agilis to map the fossa ovalis. Mapping catheter exchange for dilator and needle allowed for facile ZFTSP. AF outcome, fluoroscopy times, and procedure times were compared with eight age-matched control patients. RESULTS: There were no significant differences in age, body mass index (BMI) or AF duration between the two groups and no immediate complications. ZFTSP procedure time was 183.9±33.7 minutes versus 293.13±129.9 minutes for TSP-only controls (p=0.05). Fluoroscopy time was 17.5±14.1 minutes in ZFTSP patients versus 73.4±50.3 minutes in controls (p=0.01). AF recurrence in ZFTSP patients was 14% versus 25% in controls. CONCLUSION: ZFTSP utilising ICE and EAM is safe, effective, and time-efficient. There is a small but significant reduction in radiation exposure to patient and physician by the use of this technique.

A Review of the LARIAT Suture Delivery Device for Left Atrial Appendage Closure.

The prevalence of atrial fibrillation (AF) is 1-2 % in the general population, and the risk of embolic stroke in AF patients is 4-5 times higher than that in the general population. AF-related strokes are often severe, and the rate of permanent disability is much higher among individuals who have AF-related strokes than in those who have strokes unrelated to AF. In patients with AF, more than 90 % of thrombi originate from the left atrial appendage (LAA). The purpose of this paper is to review the efficacy and safety of performing the LAA closure with the LARIAT Suture Delivery Device to prevent AF-related stroke in patients with contraindications to oral anticoagulant therapy.

Left Atrial Appendage Ligation in Nonvalvular Atrial Fibrillation Patients at High Risk for Embolic Events With Ineligibility for Oral Anticoagulation: Initial Report of Clinical Outcomes.

OBJECTIVES: This study sought to assess long-term clinical outcomes in adults with nonvalvular atrial fibrillation (AF) who are ineligible for oral anticoagulation therapy and underwent left atrial appendage (LAA) ligation with the Lariat device. BACKGROUND: LAA exclusion has been used to prevent thrombus formation within the LAA in AF patients and is believed to decrease the risk of cardioembolic events. METHODS: LAA ligation with the Lariat device was performed in 139 patients with nonvalvular AF. LAA closure was verified during the procedure by LA angiography and transesophageal echocardiography. A follow-up transesophageal echocardiography was performed at 30 to 45 days post-procedure. After the procedure, patients received aspirin only, clopidogrel only, aspirin plus clopidogrel, or no antithrombotic drugs. Patients did not receive transition oral anticoagulation therapy post-LAA ligation. Patients were followed for LAA closure and adverse events, including stroke, systemic events, and death. RESULTS: Acute closure was accomplished in 138 of 139 treated patients (99%). In 1 patient, a posterior lobe was partially closed. At the day-30 to day-45 transesophageal echocardiography (n = 127), 114 (90%) had complete LAA closure, and 13 (10%) had a 2- to 4-mm leak. There were no leaks ≥5 mm. The periprocedural adverse event rate was 11.5%, including 2 cardiac perforations and 1 death due to pulmonary embolus. Over a mean follow-up of 2.9 ± 1.1 years, the event rate for the composite endpoint of stroke and systemic embolism was 1.0% per year (n = 4). The combined stroke, embolism, and death of any cause event rate was 2.8% (n = 11) per year. CONCLUSIONS: The findings from this analysis of post-procedure event rates suggest that LAA ligation with the Lariat device effectively closes the LAA and may be a beneficial approach to reduce the risk of embolic events in AF patients ineligible to oral anticoagulation therapy. However, future randomized clinical trials are needed to verify these results and to determine device and procedural safety.