2023 Cardiac Society of Australia and New Zealand Expert Position Statement on Catheter and Surgical Ablation for Atrial Fibrillation.

Catheter ablation for atrial fibrillation (AF) has increased exponentially in many developed countries, including Australia and New Zealand. This Expert Position Statement on Catheter and Surgical Ablation for Atrial Fibrillation from the Cardiac Society of Australia and New Zealand (CSANZ) recognises healthcare factors, expertise and expenditure relevant to the Australian and New Zealand healthcare environments including considerations of potential implications for First Nations Peoples. The statement is cognisant of international advice but tailored to local conditions and populations, and is intended to be used by electrophysiologists, cardiologists and general physicians across all disciplines caring for patients with AF. They are also intended to provide guidance to healthcare facilities seeking to establish or maintain catheter ablation for AF.

Out of hospital cardiac arrest in Western Sydney-an analysis of outcomes and estimation of future eCPR eligibility.

BACKGROUND: Refractory out of hospital cardiac arrest (OHCA) is associated with extremely poor outcomes. However, in selected patients extracorporeal cardiopulmonary resuscitation (eCPR) may be an effective rescue therapy, allowing time treat reversible causes. The primary goal was to estimate the potential future caseload of eCPR at historically 'low-volume' extracorporeal membrane oxygenation (ECMO) centres. METHODS: A 3-year observational study of OHCA presenting to the Emergency Department (ED of an urban referral centre without historical protocolised use of eCPR. Demographics and standard Utstein outcomes are reported. Further, an a priori analysis of each case for potential eCPR eligibility was conducted. A current eCPR selection criteria (from the 2-CHEER study) was used to determine eligibly. RESULTS: In the study window 248 eligible cardiac arrest cases were included in the OHCA registry. 30-day survival was 23.4% (n = 58). The mean age of survivors was 55.4 years. 17 (6.8%) cases were deemed true refractory arrests and fulfilled the 2-CHEER eligibility criteria. The majority of these cases presented within "office hours" and no case obtained a return of spontaneous circulation standard advanced life support. CONCLUSIONS: In this contemporary OHCA registry a significant number of refractory cases were deemed potential eCPR candidates reflecting a need for future interdisciplinary work to support delivery of this therapy.

Ventricular Tachycardia in a Patient With Dilated Cardiomyopathy Caused by a Novel Mutation of Lamin A/C Gene: Insights From Features on Electroanatomic Mapping, Catheter Ablation and Tissue Pathology.

Lamin A/C (LMNA) cardiomyopathy forms an important and increasingly recognised group within the broad spectrum of non-ischaemic cardiomyopathies. LMNA cardiomyopathy typically presents with atrioventricular block followed by recurrent ventricular arrhythmias with a high tendency to progression to end stage heart failure. We present a case of recurrent ventricular tachycardia in a patient with dilated cardiomyopathy caused by a novel mutation of LMNA gene. Through electroanatomic mapping, catheter ablation and tissue pathology we provide detailed insights into this highly pathogenic inherited cardiomyopathy.

Ventricular Tachycardia Storm Ablation With Pre-Emptive Circulatory Support by Extracorporeal Membrane Oxygenation: Australian Experience.

BACKGROUND: Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) can provide circulatory support in high-risk patients undergoing drug refractory ventricular tachycardia (VT) ablation procedures. We report experience using VA-ECMO in a pre-emptive approach for high-risk patients with VT storm and previously ineffective ablation procedures. METHODS AND RESULTS: Four (4) patients with drug refractory ventricular tachycardia (mean age 61±3 years; left ventricular ejection fraction 21±5%) presenting for VT ablation had pre-emptive VA-ECMO. All patients during current admission had VT storm. Pre-ablation, 22 total monomorphic VTs (cycle length 402±69 ms) were induced or spontaneously observed (median of 4, IQR25-75% 1-6). At the end of the procedure, 86% of all inducible VTs were rendered non-inducible. Median hospitalisation following VA-ECMO supported ablation was 5 days (IQR25-75% 3-12). During follow-up (median 138 days [IQR25-75% 57-277]), VT recurred in one patient as an isolated episode reverted by anti-tachycardia pacing. There was a 99% reduction in VT burden post ablation. One (1) patient died of cardiogenic shock within 24 hours whilst still on VA-ECMO, all other patients were successfully weaned off support and discharged. Two (2) patients underwent cardiac transplantation at 199 and 512 days post ablation following implantation of ventricular assist devices for worsening heart failure. CONCLUSIONS: The pre-emptive use of VA-ECMO for high-risk patients undergoing catheter ablation for VT storm was found to be effective in maintaining haemodynamic status, and allowing successful mapping and catheter ablation for VT.

Mechanical Circulatory Support During Catheter Ablation of Ventricular Tachycardia: Indications and Options.

Mapping of scar-related ventricular tachycardia (VT) in structural heart disease is fundamentally driven by identifying the critical isthmus of conduction that supports re-entry in and around myocardial scar. Mapping can be performed using activation and entrainment techniques during VT, or by substrate mapping performed in stable sinus or paced rhythm. Activation and entrainment mapping requires the patient to be in continuous VT, which may not be haemodynamically tolerated, or, if tolerated, may lead to adverse sequelae related to impaired end organ perfusion. Mechanical circulatory support (MCS) devices may facilitate haemodynamic stability and preserve end organ perfusion during sustained VT to permit mapping for long periods. Available options for haemodynamic support include an intra-aortic balloon pump (IABP), TandemHeart left atrial to femoral artery bypass system (CardiacAssist Inc., Pittsburgh, PA, USA), Impella left ventricle (LV) to aorta flow-assist system (Abiomed, Danvers, MA, USA), and extracorporeal membrane oxygenation (ECMO); the bypass and assist devices provide far better augmentation of cardiac output than IABP. MCS has potential key advantages including maintenance of vital organ perfusion, reduction of intra-cardiac filling pressures, reduction of LV volumes, wall stress, and myocardial consumption of oxygen, and improvement of coronary perfusion during prolonged periods of VT induction and/or mapping. Observational studies show MCS allows for longer duration of mapping, and increased likelihood of VT termination, without an increased risk of peri-procedural mortality or VT recurrence in follow-up, despite being used in a significantly sicker cohort of patients. However, MCS has increased risk of complications related to vascular access, bleeding, thromboembolic risk, mapping system interference, increase procedural complexity and increased cost. Acute haemodynamic decompensation occurs in ∼11% of patients undergoing VT ablation, and is associated with increased mortality. Prospectively identifying patients at risk of acute haemodynamic decompensation in the peri-procedural period may allow prophylactic MCS. Although observational studies of MCS in patients at high risk of haemodynamic decompensation are encouraging, its benefit needs to be proven in randomised trials. This review will summarise the indication for MCS, forms of MCS, procedural outcomes, complications and utility of MCS during VT ablation.

Early Catheter Ablation Versus Initial Medical Therapy for Ventricular Tachycardia Storm.

BACKGROUND: Ventricular tachycardia (VT) storm is associated with significantly increased morbidity, mortality, and exponential healthcare utilization. Although catheter ablation (CA) may be curative, there are limited data directly comparing outcomes of early CA with initial medical therapy. METHODS: We compared outcomes of patients presenting with VT storm treated with initial CA versus those treated with initial medical therapy during their first storm presentation in an observational study. Retrospective data from the host institution from January 2014 to April 2020 of 129 patients with their first VT storm presentation were analyzed (58 underwent initial CA, 71 underwent treatment with initial medical therapy). Outcomes were compared in follow-up. RESULTS: Median time to initial CA was 6 days. Over a median follow-up of 702 days, patients who underwent initial CA compared with those treated with initial medical therapy had significantly less: (i) VA recurrence (43% versus 92%; P=0.002); (ii) VT storm recurrence (28% versus 73%; P<0.001); (iii) composite end point of death, heart transplant, VT storm recurrence, and VT-related hospitalization (47% versus 89%; P=0.002); (iv) iatrogenic complications (at 12 months: 17% versus 45%; P<0.001); (v) cardiovascular-related hospitalizations (50% versus 89%; P=0.01); (vi) total number of hospitalizations (median 1 versus 4; P<0.001); and (vi) cumulative days in hospital (median 0.5 versus 18; P<0.001). There were no intraprocedural deaths in patients treated with early CA. CONCLUSION: In an observational setting in which patients presenting with storm, early CA appears superior to initial medical therapy in terms of VT recurrence, storm recurrence, iatrogenic complications, cardiovascular hospitalizations, and cumulative days in hospital in follow-up.

The Prolonged Use of VV ECMO Support in COVID-19: A Case Report.

COVID-19 has resulted in unprecedented global health and economic challenges. The reported mortality in patients with COVID-19 requiring mechanical ventilation is high. VV ECMO may serve as a lifesaving rescue therapy for a minority of patients with COVID-19; however, its impact on overall survival of these patients is unknown. To date, few reports describe successful discharge from ECMO in COVID-19 after a prolonged ECMO run. The only Australian case of a COVID-19 patient, supported by prolonged VV ECMO in conjunction with prone ventilation, complicated by significant airway bleeding, and successfully decannulated after forty-two days, is described. VV ECMO is a resource-intense form of respiratory support. Providing complex therapies such as VV ECMO during a pandemic has its unique challenges. This case report provides a unique insight into the potential clinical sequelae of COVID-19, supported in an intensive care environment which was not resource-limited at the time, and adds to the evolving experience of prolonged VV ECMO support for ARDS with a goal to lung recovery.

An isocratic fluorescence HPLC assay for the monitoring of l-asparaginase activity and l-asparagine depletion in children receiving E. colil-asparaginase for the treatment of acute lymphoblastic leukaemia.

A novel assay for the determination of l-asparaginase activity in human plasma is described that is based on the HPLC quantitation of l-aspartic acid produced during enzyme incubation. Methods for monitoring l-asparagine depletion are also described. Chromatography of l-aspartic acid, l-asparagine and l-homoserine (the internal standard) involved derivatization with o-pthaldialdehyde, then separation from other amino acids on a Phenomenex Luna C(18) column using a 1 mL/min flow rate and a mobile phase consisting of di-potassium hydrogen orthophosphate propionate buffer, pH 6, with 10% methanol and 10% acetonitrile. Fluoresence detection was at excitation/emission wavelengths of 357/455 nm. Under these conditions l-aspartic acid, l-asparagine and l-homoserine had retention times of 3.5, 9.8 and 17.7 min, respectively. The l-asparaginase assay was linear from 0.1 to 10 U/mL activity and interday precision and accuracy were less than 13%. The limit of quantitation was approximately 0.03 U/mL. The assay utility was established in 12 children who received E. coli l-asparaginase as treatment for acute lymphoblastic leukaemia.