Thoracoscopic infrared ablation to create a box lesion as a treatment for atrial fibrillation

Background Creating a box lesion in the posterior wall of the left atrium from the epicardial side of the beating heart remains a challenge. Although a transmural lesion can be created by applying radiofrequency (RF) energy at clampable sites, it is still difficult to create a transmural lesion at unclampable sites because the inner blood flow in the unclampable free wall weakens the thermal effect on the outside. Our aim was to apply the newly developed infrared coagulator to create linear transmural lesions on the beating heart thoracoscopically to treat atrial fibrillation (AF). Case presentation A 71-year-old male was referred to our hospital with a diagnosis of hypertrophic cardiomyopathy and permanent atrial fibrillation. The patient was first diagnosed with atrial fibrillation 20 years before. Direct current cardioversion had been performed every few years a total of four times, but sinus rhythm restoration had always been temporary. On February 27, 2020, thoracoscopic PV isolation together with infrared roof- and bottom-line ablation to create a box lesion and left atrial appendage amputation (LAAA) were performed. The coagulator could be applied to clinical thoracoscopic surgery to successfully create a box lesion without any complication. The patient restored a regular sinus rhythm, it has been maintained for eleven months, and there have been no adverse events. Conclusions The infrared coagulator might have enough potential to create transmural lesions on the beating heart in thoracoscopic AF surgery.

A Higher Polygenic Risk Score Is Associated with a Higher Recurrence Rate of Atrial Fibrillation in Direct Current Cardioversion-Treated Patients

Background and Objectives: Recurrence of atrial fibrillation (AF) within six months after sinus rhythm restoration with direct current cardioversion (DCC) is a significant treatment challenge. Currently, the factors influencing outcome are mostly unknown. Studies have found a link between genetics and the risk of AF and efficacy of rhythm control. The aim of this study was to examine the association between eight single-nucleotide variants (SNVs) and the risk of AF development and recurrence after DCC. Materials and Methods: Regarding the occurrence of AF, 259 AF cases and 108 controls were studied. Genotypes for the eight SNVs located in the genes CAV1, MYH7, SOX5, KCNN3, ZFHX3, KCNJ5 and PITX2 were determined using high-resolution melting analysis and confirmed with Sanger sequencing. Six months after DCC, a telephone interview was conducted to determine whether AF had recurred. A polygenic risk score (PRS) was calculated as the unweighted sum of risk alleles. Multivariate regression analyses were performed to assess SNV and PRS association with AF occurrence and recurrence after DCC. Results: The risk allele of rs2200733 (PITX2) was significantly associated with the development of AF (p = 0.012, OR = 2.31, 95% CI = 1.206–4.423). AF recurred in 60% of patients and the allele generally associated with a decreased risk of AF of rs11047543 (SOX5) was associated with a greater risk of AF recurrence (p = 0.014, OR = 0.223, 95% CI = 0.067–0.738). A PRS of greater than 7 was significantly associated (p = 0.008) with a higher likelihood of developing AF after DCC (OR = 4.174, 95% CI = 1.454–11.980). Conclusions: A higher PRS is associated with increased odds of AF recurrence after treatment with DCC. PITX2 (rs2200733) is significantly associated with an increased risk of AF. The protective allele of rs11047543 (SOX5) is associated with a greater risk of AF recurrence. Further studies are needed to predict the success of rhythm control and guide patient selection towards the most efficacious treatment.

Cardioversion in patients with newly diagnosed non-valvular atrial fibrillation: observational study using prospectively collected registry data

Objective To investigate the clinical outcomes of patients who underwent cardioversion compared with those who did not have cardioverson in a large dataset of patients with recent onset non-valvular atrial fibrillation. Design Observational study using prospectively collected registry data (Global Anticoagulant Registry in the FIELD-AF—GARFIELD-AF). Setting 1317 participating sites in 35 countries. Participants 52 057 patients aged 18 years and older with newly diagnosed atrial fibrillation (up to six weeks’ duration) and at least one investigator determined stroke risk factor. Main outcome measures Comparisons were made between patients who received cardioversion and those who had no cardioversion at baseline, and between patients who received direct current cardioversion and those who had pharmacological cardioversion. Overlap propensity weighting with Cox proportional hazards models was used to evaluate the effect of cardioversion on clinical endpoints (all cause mortality, non-haemorrhagic stroke or systemic embolism, and major bleeding), adjusting for baseline risk and patient selection. Results 44 201 patients were included in the analysis comparing cardioversion and no cardioversion, and of these, 6595 (14.9%) underwent cardioversion at baseline. The propensity score weighted hazard ratio for all cause mortality in the cardioversion group was 0.74 (95% confidence interval 0.63 to 0.86) from baseline to one year follow-up and 0.77 (0.64 to 0.93) from one year to two year follow-up. Of the 6595 patients who had cardioversion at baseline, 299 had a follow-up cardioversion more than 48 days after enrolment. 7175 patients were assessed in the analysis comparing type of cardioversion: 2427 (33.8%) received pharmacological cardioversion and 4748 (66.2%) had direct current cardioversion. During one year follow-up, event rates (per 100 patient years) for all cause mortality in patients who received direct current and pharmacological cardioversion were 1.36 (1.13 to 1.64) and 1.70 (1.35 to 2.14), respectively. Conclusion In this large dataset of patients with recent onset non-valvular atrial fibrillation, a small proportion were treated with cardioversion. Direct current cardioversion was performed twice as often as pharmacological cardioversion, and there appeared to be no major difference in outcome events for these two cardioversion modalities. For the overall cardioversion group, after adjustments for confounders, a significantly lower risk of mortality was found in patients who received early cardioversion compared with those who did not receive early cardioversion. Study registration ClinicalTrials.gov NCT01090362 .

AED applied, not recommending defibrillation - A validation study of the new variable “AED” in the Danish Cardiac Arrest Registry

Background: to design and implement a new variable, in accordance with the Utstein style – namely the variable “AED” - considering the challenges of reporting cases in which the AED did not recommend an electrical shock after analyzing cardiac arrhythmias, for use in the Danish Cardiac Arrest Registry.Participants: Patients with out-of-hospital cardiac arrest for which resuscitation was attempted between 2016 and 2019, identified in the nationwide Danish Cardiac Arrest Registry. Their medical records were reviewed to establish a positive variable in “AED”.Methods: Data from the national Danish Cardiac Arrest Registry were used to identify core features of out-of-hospital cardiac arrests medical recording in Denmark and its possible improvement. Results: Among n= 1080 cases, summary statistics on core recording variables of interest were collected. We found statistically significant differences in the two cohorts of cardiac arrests where an AED was present on the scene and recorded in the Danish Cardiac Arrest Registry, regarding age, location, emeregency medical service response time, witnesses, bystander cardiopulmonary resuscitation, first monitored rhythm, direct current cardioversion shock delivered by the medical staff and survival outcomes such as return of spontaneous circulation at any time, status at arrival at hospital and 30-day survival. Conclusions: This validation study showed an improved completeness of registration of out-of-hospital cardiac arrests when implementing the new AED-variable, in accordance with the Utstein style. Thus, the new AED-variable is a valid and substantial resource for future epidemiological studies. However, a future effort to improve registration completeness along with continuous improvement of the Danish Cardiac Arrest Registry is needed.

Investigating the efficacy of chest pressure for direct current cardioversion in atrial fibrillation: a randomised control trial protocol (Pressure-AF)

IntroductionAtrial fibrillation (AF) is the most common sustained arrhythmia worldwide. Direct current cardioversion is commonly used to restore sinus rhythm in patients with AF. Chest pressure may improve cardioversion success through decreasing transthoracic impedance and increasing cardiac energy delivery. We aim to assess the efficacy and safety of routine chest pressure with direct current cardioversion for AF.Methods and analysisMulticentre, double blind (patient and outcome assessment), randomised clinical trial based in New South Wales, Australia. Patients will be randomised 1:1 to control and interventional arms. The control group will receive four sequential biphasic shocks of 150 J, 200 J, 360 J and 360 J with chest pressure on the last shock, until cardioversion success. The intervention group will receive the same shocks with chest pressure from the first defibrillation. Pads will be placed in an anteroposterior position. Success of cardioversion will be defined as sinus rhythm at 1 min after shock. The primary outcome will be total energy provided. Secondary outcomes will be success of first shock to achieve cardioversion, transthoracic impedance and sinus rhythm at post cardioversion ECG.Ethics and disseminationEthics approval has been confirmed at all participating sites via the Research Ethics Governance Information System. The trial has been registered on the Australia New Zealand Clinical Trials Registry (ACTRN12620001028998). De-identified patient level data will be available to reputable researchers who provide sound analysis proposals.

The efficacy and safety of a nurse-led electrical cardioversion service for atrial fibrillation over a two-year time period

Funding Acknowledgements Type of funding sources: None. Background & Purpose Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia worldwide, with a significant impact on morbidity, mortality and utilisation of healthcare resources. Electrical direct-current cardioversion (DCCV) is offered to patients with ongoing symptoms despite medical management. In this study we aim to evaluate the safety and efficacy of a specialised nurse-led DCCV cardioversion service. Methods This was a retrospective cohort study analysing the outcome of patients presenting with atrial fibrillation or flutter, who were subsequently referred for a nurse-led DCCV procedure between August 2017 and December 2019. Results Analysis included a total of 341 patients (mean age = 68.37; STDV = 10.96) who presented with either atrial fibrillation (N = 267; 78.30%) or atrial flutter (N = 74; 21.70%). Approximately 30% of patients were female (N = 101); and 70% were male (N = 240). Of the 341 patients who underwent DCCV, 299 were successfully cardioverted (87.68%), whilst 42 patients remained in AF (12.32%). Of those patients successfully cardioverted, 167 remained in sinus rhythm after 6 weeks (55.85%); 93 patients reverted back to AF (31.10%). 38 patients were lost to follow up (12.71%). Of all 341 patients who underwent DCCV, only 24 patients were admitted to hospital during the subsequent 3 month period (7.04%). Of these admissions, 11 were due to persistent AF (45.83%), and 13 were due to other non-related reasons (54.17%). Importantly, no patients were admitted as a direct complication of the DCCV procedure. Using a Chi-squared analysis, we found a significant difference in cardioversion success rates between patients presenting with atrial flutter (97% success rate) versus those in atrial fibrillation (85% success rate) (χ2 = 8.089; p = 0.004; α<0.05). We did not find a significant difference in cardioversion success rates between males and females (χ2 = 1.651; p = 0.199; α<0.05); nor did we witness a significant impact from the presence of ischaemic heart disease (χ2 = 1.545; p = 0.214; α<0.05) or hypertension (χ2 = 2.075; p = 0.150; α<0.05). Similarly, we found negligible impact of LV ejection fraction (χ2 = 1.494; p = 0.684; α<0.05) or LA size (χ2 = 1.310; p = 0.727; α<0.05) upon cardioversion success rates. We witnessed a dramatic improvement in DC cardioversion success rates in patients taking antiarrhythmic medication in preference to a rate control strategy alone (χ2 = 11.825; p = 0.008; α<0.05). Conclusion Overall, data gathered from this study provides positive evidence to support the use of a nurse-led DCCV service. In addition to obtaining very successful cardioversion rates, we found low remission rates, with a very low hospital readmission rate for AF related issues after successful DCCV.

COVID-19 induced ventricular tachycardia storm unmasking a clinically silent cardiomyopathy: a case report

Background Coronavirus disease (COVID-19) is a systemic illness characterized by raging impact of cytokine storm on multiple organs. This may trigger malignant ventricular arrhythmias and unmask a clinically silent cardiomyopathy. Case summary A 57-year-old gentleman, known case of hyperthyroidism and diabetes, was referred to our emergency department with history of two ventricular tachycardia (VT) episodes requiring direct current cardioversion in last 3 h followed by another episode in our emergency department that was cardioverted. There was no past history of cardiac illness. His 12-lead electrocardiogram (during sinus rhythm) along with screening echocardiography suggested Arrhythmogenic right ventricular cardiomyopathy (ARVC). He was coincidentally found to be COVID-19 positive by reverse transcription-polymerase chain reaction (RT-PCR) as part of our routine screening. However, he had no fever or respiratory complaints. We noted raised systemic inflammatory markers and cardiac troponin T which progressively increased over the next 4 weeks paralleled by an increase in ventricular premature contraction burden and thereafter started decreasing and returned to baseline by 6th week when the patient became COVID-19 negative by RT-PCR. Subsequently, a single-chamber automated implantable cardioverter-defibrillator implantation was done following which there was a transient increase in these biomarkers that subsided spontaneously. The patient is asymptomatic during 6 weeks of follow-up. Discussion COVID-19-associated cytokine surge triggering VT storm and unmasking a clinically silent ARVC has not yet been reported. The case highlights a life-threatening presentation of COVID-19 and indicates a probable link between inflammation and arrhythmogenicity.

The Impact of Personal Thoracic Impedance on Electrical Cardioversion in Patients with Atrial Arrhythmias

Background and Objectives—Direct current cardioversion (DCCV) is a safe and useful treatment for atrial tachyarrhythmias. In the past, the energy delivered in DCCV was decided upon empirically, based only on the type of tachyarrhythmia. This conventional method does not consider individual factors and may lead to unnecessary electrical damage. Materials and Methods—We performed DCCV in patients with atrial tachyarrhythmias. The impedance and electrical current at the moment of shock were measured. The human thoracic impedance between both defibrillator patches and the electric current that was used were measured. Results—A total of 683 DCCVs were performed on 466 atrial tachyarrhythmia patients. The average impedance was 64 ± 11 Ω and the average successful current was 23 ± 6 mA. The magnitude of the electrical current that was successful depended upon the human impedance (linear regression, B = −0.266, p < 0.001) and the left atrial diameter (B = 0.092, p < 0.001). Impedance was directly proportional to body mass index (BMI) (B = 1.598, p < 0.001) and was higher in females than in males (77 ± 15 Ω vs. 63 ± 11 Ω, p < 0.001). Notably, the high-impedance (>70 Ω) group had a higher BMI (27 ± 4 kg/m2 vs. 25 ± 3 kg/m2, p < 0.001) and a higher proportion of females (37% vs. 9%, p < 0.001) than the low-impedance group (<70 Ω). However, thoracic impedance was not an independent predictor for successful DCCV. Conclusions—Human thoracic impedance was one of the factors that impacted the level of electrical current required for successful DCCV in patients with atrial arrhythmias. In the future, it will be helpful to consider individual predictors, such as BMI and gender, to minimize electrical damage during DCCV.