Novel Epicardial Access Technique Facilitated by Carbon Dioxide Insufflation of the Pericardium for Ablation of Ventricular Arrhythmias: Lessons From the Early Experience From a Single Centre in Australia.

INTRODUCTION: Epicardial access for mapping and ablation of the epicardial substrate may be required in catheter ablation of ventricular tachycardias (VT). However, high complication rates are associated with the standard epicardial access approach. Recently, a novel method of intentional coronary vein (CV) exit with pericardial CO2 insufflation to facilitate epicardial access has been described. This study describes our initial experience with this technique. METHODS: Patients undergoing epicardial VT ablation between 1 February 2021 to 31 May 2022 at the Royal Prince Alfred Hospital, Sydney, NSW, were included in this study. Via femoral venous access, a branch of the coronary sinus was sub-selected and intentional CV exit was performed with a high tip load coronary angioplasty wire. A microcatheter was then advanced over the wire into the pericardial space, followed by pericardial CO2 insufflation, facilitating subxiphoid pericardial puncture. RESULTS: Five (5) patients underwent epicardial access for VT mapping and ablation. All patients had successful intentional CV exit and CO2 facilitated epicardial access. The mean time to successful epicardial access was 37.2±17.5 minutes. With increasing operator experience, there was improvement in epicardial access times, with the fifth case requiring only 13 minutes. There was one case of inadvertent right ventricular puncture (without haemodynamic or ventilatory compromise) due to inappropriate CO2 insufflation into the right ventricle. Epicardial access was successful on the second attempt. CONCLUSION: This is the first case series of epicardial access facilitated by CO2 insufflation in Australia. This technique enabled successful epicardial access in all patients in our early experience, with no adverse outcomes from epicardial access. With increasing operator experience, this technique may allow for more widespread adoption of up-front epicardial access for the treatment of VT.

Guideline-Directed Medical Therapy Before and After Primary Prevention Implantable Cardioverter Defibrillator Implantation in New Zealand (ANZACS-QI 66).

INTRODUCTION: Guidelines recommend angiotensin converting enzyme inhibitors (ACEi)/angiotensin receptor blockers (ARB)/angiotensin receptor neprilysin inhibitors (ARNI); beta blockers; and mineralocorticoid receptor antagonists (MRA) in patients with symptomatic heart failure and reduced left ventricular ejection fraction before consideration of primary prevention implantable cardioverter defibrillator (ICD). This study aims to investigate dispensing rates of guideline-directed medical therapy (GDMT) before and after primary prevention ICD implantation in New Zealand. METHODS: All patients receiving a primary prevention ICD between 2009 and 2018 were identified using nationally collected data on all public hospital admissions in New Zealand. This was anonymously linked to national pharmaceutical data to obtain medication dispensing. Medications were categorised as low dose (<50% of target dose), 50-99% of target dose or target dose based on international guidelines. RESULTS: Of the 1,698 patients identified, ACEi/ARB/ARNI, beta blockers and MRA were dispensed in 80.2%, 83.6% and 45.4%, respectively, prior to ICD implant. However, ≥50% target doses of each medication class were dispensed in only 51.8%, 51.8% and 34.5%, respectively. Only 15.8% of patients were receiving ≥50% target doses of all three classes of medications. In the 1,666 patients who survived 1 year after ICD implant, the proportions of patients dispensed each class of medications remained largely unchanged. CONCLUSION: Dispensing of GDMT was suboptimal in patients before and after primary prevention ICD implantation in New Zealand, and only a minority received ≥50% target doses of all classes of medication. Interventions are needed to optimise use of these standard evidence-based medications to improve clinical outcomes and avoid unnecessary device implantation.

Ten-year trends in cardiac implantable electronic devices in New Zealand: a national data linkage study (ANZACS-QI 51).

BACKGROUND: Implant rates for cardiac implantable electronic devices (CIED), including permanent pacemakers (PPM) and implantable cardioverter defibrillators (ICD), have increased globally in recent decades. AIMS: This is the first national study providing a contemporary analysis of national CIED implant trends by sex-specific age groups over an extended period. METHODS: Patient characteristics and device type were identified for 10 years (2009-2018) using procedure coding in the National Minimum Datasets, which collects all New Zealand (NZ) public hospital admissions. CIED implant rates represent implants/million population. RESULTS: New PPM implant rates increased by 4.6%/year (P < 0.001), increasing in all age groups except patients <40 years. Males received 60.1% of new PPM implants, with higher implant rates across all age groups compared with females. The annual increase in age-standardised implant rates was similar for males and females (3.4% vs 3.0%; P = 0.4). By 2018 the overall PPM implant rate was 538/million. New ICD implant rates increased by 4.2%/year (P < 0.001), increasing in all age groups except patients <40 and ≥ 80 years. Males received 78.1% of new ICD implants, with higher implant rates across all age groups compared to females. The annual increase in age-standardised implant rates was higher in males compared with females (3.5% vs 0.7%; P < 0.001). By 2018 the overall ICD implant rate was 144/million. CONCLUSION: CIED implant rates have increased steadily in NZ over the past decade but remain low compared with international benchmarks. Males had substantially higher CIED implant rates compared with females, with a growing gender disparity in ICD implant rates.

Regional variation in cardiac implantable electronic device implants trends in New Zealand over the past decade (ANZACS-QI 54).

BACKGROUND: Permanent pacemaker (PPM) and implantable cardioverter defibrillator (ICD) implant rates have increased in New Zealand over the past decade. AIMS: To provide a contemporary analysis of regional variation in implant rates. METHODS: New PPM and ICD implants in patients aged ≥15 years were identified for 10 years (2009-2018) using procedure coding in the National Minimum Datasets, which collects all New Zealand public hospital admissions. Age-standardised new implant rates per million adult population were calculated for each of the four regions (Northern, Midland, Central and Southern) and the 20 district health boards (DHB) across those regions. Trend analysis was performed using joinpoint regression. RESULTS: New PPM implant rates increased nationally by 3.4%/year (P < 0.001). The Northern region had the highest new PPM implant rate, increasing by 4.5%/year (P < 0.001). Excluding DHB with <50 000 people, the new PPM implant rate for 2017/2018 was highest in Counties Manukau DHB (854.3/million; 95% confidence interval (CI): 774.9-933.6/million) and lowest in Canterbury DHB (488.6/million; 95% CI: 438.1-539.0/million). New ICD implant rates increased nationally by 3.0%/year (P = 0.002). The Midland region had the highest new ICD implant rate, increasing by 3.8%/year (P = 0.013). Excluding DHB with <50 000 people, the new ICD implant rate for 2017-2018 was highest in the Bay of Plenty DHB (228.5/million; 95% CI: 180.4-276.6/million) and lowest in Canterbury DHB (90.2/million; 95% CI: 69.9-110.4/million). CONCLUSION: There was significant variation in PPM and ICD implant rates across regions and DHB, suggesting potential inequity in patient access across New Zealand.

Clinical utility of cardiac magnetic resonance imaging to assess the left atrium before catheter ablation for atrial fibrillation - A systematic review and meta-analysis.

AIMS: This systematic review and meta-analysis aims to clarify the role of pre-procedural cardiac magnetic resonance imaging (MRI) in identifying the association between left atrial (LA) characteristics and post-ablation atrial fibrillation (AF) recurrence. These characteristics include LA fibrosis, emptying function, sphericity, volume, volume index, peak strain and post-contrast T1 relaxation time. METHODS: PubMed, EMBASE, and Cochrane were searched up to July 2020 for English language articles reporting the use of cardiac MRI in catheter ablation for AF. Studies reporting the prognostic value of pre-ablation cardiac MRI were included. All references and citations were filtered for relevant manuscripts. RESULTS: Twenty-four publications were identified. Every 10% increase in LA fibrosis was associated with a 1.54-fold increase in post-ablation AF recurrence (95%CI: 1.39-1.70, I2 = 50.1%). Every 10 ml increase in LA volume resulted in a hazard ratio of 1.07 (95%CI:1.03-1.12; I2 = 41.4%) for post-ablation AF recurrence. For LA sphericity, there was no significant association with post-ablation AF recurrence (HR: 1.032 [95%CI: 0.962-1.103, I2 = 49.6%). Egger's test was non-significant for publication bias in all meta-analyses. LA volume index, emptying function, peak strain and post-contrast LA T1 relaxation time had insufficient compatible publications to conduct a meta-analysis. CONCLUSION: LA fibrosis quantified by cardiac MRI is associated with risk of AF recurrence after AF ablation, while increased LA volume is associated with AF recurrence to a lesser extent. There remains insufficient evidence to support the routine measurement of LA sphericity, LA volume index, LA emptying function, peak strain and LA T1 relaxation time to predict AF recurrence after AF ablation.

Ethnic variation in the trends of new implantable cardioverter defibrillator implants in New Zealand 2005-2019 (ANZACS-QI 63).

AIMS: Ethnic variation in implantable cardioverter defibrillator (ICD) implant rates have been reported internationally but have not previously been examined in New Zealand. This study examined trends in new ICD implants by ethnicity over an extended period. METHODS: All patients who received a new ICD implant between 2005 and 2019 were identified using the National Minimum Dataset, which collects information on all public hospital admissions in New Zealand. Ethnicity was classified using the following standard prioritisation: Maori, Pacific, Asian and European/Other. New ICD implant rates were analysed by ethnicity and age groups. RESULTS: A total of 5,514 new ICDs were implanted. New ICD implant rates increased from 41.4/million in 2005 to 98.2/million in 2019, an average increase of 5.4%/year (p<0.01). The highest age-standardised implant rates were among Maori, followed by Pacific, European/Other and Asian ethnicities. The largest increase was seen in Pacific people at 8.9%/year (p<0.01), followed by Maori and Asian people at 4.7%/year and 4.3%/year respectively (both p<0.01). In European/Other patients, ICD implant rates increased by 10.3%/year (p<0.01) between 2005 to 2012, then plateaued at -0.4%/year (p=0.71) between 2012 to 2019. By 2019, the age-standardised implant rates in Maori and Pacific people were two-fold higher than European/Others. CONCLUSION: There is marked ethnic variation in ICD implant rates in New Zealand. The higher implant rates in Maori and Pacific parallel known ethnic differences in rates of underlying cardiac disease. The more rapid increase in implant rates in these ethnic groups may represent more equitable treatment over time.

Unmasking latent preexcitation of a right-sided accessory pathway with intravenous adenosine after unexplained sudden cardiac arrest.

Intravenous adenosine is a simple test that can uncover latent preexcitation via an accessory pathway and is useful in the diagnostic workup of sudden cardiac arrest survivors without an identifiable cause. Latent preexcitation is usually associated with left free wall pathways but may also occur in right-sided accessory pathways with slow antegrade conduction. Although intermittent ECG evidence of preexcitation is generally considered a marker of low risk for sudden death, if this is due to an accessory pathway with long atrioventricular conduction time and short effective refractory period (rather than true intermittent conduction via the pathway), the risk for sudden death may be equal to those accessory pathways with manifest preexcitation.

Implantable cardioverter defibrillator and cardiac resynchronization therapy use in New Zealand (ANZACS-QI 33).

BACKGROUND: The ANZACS-QI Cardiac Implanted Device Registry (ANZACS-QI DEVICE) collects nationwide data on cardiac implantable electronic devices in New Zealand (NZ). We used the registry to describe contemporary NZ use of implantable cardioverter defibrillator (ICD) and cardiac resynchronization therapy (CRT). METHODS: All ICD and CRT Pacemaker implants recorded in ANZACS-QI DEVICE between 1 January 2014 and 31 December 2017 were analyzed. RESULTS: Of 1579 ICD implants, 1152 (73.0%) were new implants, including 49.0% for primary prevention and 51.0% for secondary prevention. In both groups, median age was 62 years and patients were predominantly male (81.4% and 79.2%, respectively). Most patients receiving a primary prevention ICD had a history of clinical heart failure (80.4%), NYHA class II-III symptoms (77.1%) and LVEF ≤35% (96.9%). In the secondary prevention ICD cohort, 88.4% were for sustained ventricular tachycardia or survived cardiac arrest from ventricular arrhythmia. Compared to primary prevention CRT Defibrillators (n = 155), those receiving CRT Pacemakers (n = 175) were older (median age 74 vs 66 years) and more likely to be female (38.3% vs 19.4%). Of the 427 (27.0%) ICD replacements (mean duration 6.3 years), 46.6% had received appropriate device therapy while 17.8% received inappropriate therapy. The ICD implant rate was 119 per million population with regional variation in implant rates, ratio of primary prevention ICD implants, and selection of CRT modality. CONCLUSION: In contemporary NZ practice three-quarters of ICD implants were new implants, of which half were for primary prevention. The majority met current guideline indications. Patients receiving CRT pacemaker were older and more likely to be female.

Recent trends in cardiac electrophysiology and catheter ablation in New Zealand.

BACKGROUND: Catheter ablation has rapidly become an integral part of the management of many arrhythmias. AIMS: To provide a history of clinical cardiac electrophysiology (EP) in New Zealand (NZ) and analysis of recent trends in EP procedures and catheter ablations across NZ, which has not previously been reported. METHODS: EP case type and volume were obtained from the EP databases from each of the four public and four private EP centres in NZ from 1 January 2014 to 31 December 2018. Procedure rates were expressed as per million population. RESULTS: A total of 7695 EP cases was performed, including 5929 (77%) in the public sector. Atrial fibrillation (AF) ablation was the most common procedure at 29%. EP procedure rates increased by 21% (to 353 per million in 2018), predominantly due to AF ablation rates increasing by 46%. Ventricular tachycardia ablation rates increased by 41% but only comprised 8% of procedures. There was a striking difference in the growth of EP procedure rates in the public compared to the private sector (4% vs 106%), as well as considerable differences in EP procedure and AF ablation rates across the public EP centres. NZ had lower ablation rates compared to countries with similar healthcare expenditure. CONCLUSION: There has been a substantial increase in EP procedure and AF ablation rates in NZ and international trends suggest this growth will continue. However, there is considerable variation in procedure rates and growth trends between EP centres, highlighting inequities in access within the country.

Completeness of ANZACS-QI Cardiac Implanted DEVICE Registry and agreement with national datasets: ANZACS-QI 30.

AIMS: The ANZACS-QI Cardiac Implanted Device Registry (ANZACS-QI DEVICE) collects data on cardiac implantable electronic devices inserted in New Zealand. We evaluated completeness of data capture and quality of ANZACS-QI DEVICE in 2016. METHODS: Complete datasets within ANZACS-QI DEVICE, comprising DEVICE-PPM (permanent pacemakers) and DEVICE-ICD (implantable cardioverter defibrillators), from 1 January 2016 to 31 December 2016 were linked with the National Hospitalisation dataset (all New Zealand public hospital admissions). The total number of implants included procedures captured in either dataset. Variables assessed included age, gender, ethnicity, procedure type, implanting centre, admission and procedure date. RESULTS: DEVICE-PPM captured 85.9% of all PPM procedures (n=2,512). This was similar regardless of age, sex and ethnicity. In the 84.4% of procedures captured in both datasets, agreement was >97% for all variables except admission date (90.1%). DEVICE-ICD captured 81.3% of all ICD procedures (n=690). Capture was similar across age, sex and ethnicity groups. In the 76.8% of procedures captured in both datasets, agreement was >96% for all variables except admission date (90.6%). CONCLUSION: The ANZACS-QI DEVICE registry had a good capture rate and excellent agreement with the national dataset. This high concordance supports the use of both datasets for future research.

Early direct current cardioversion or ablation for atrial fibrillation or atrial flutter and acute decompensated heart failure.

AIMS: Guidelines recommend initial rate control in haemodynamically stable patients with atrial fibrillation (AF) or atrial flutter (AFL) and acute decompensated heart failure (ADHF). There is limited data on early inpatient rhythm control. We investigated the outcomes of patients managed with early TOE-guided DC cardioversion (DCCV) or ablation. METHODS: We retrospectively analysed patients admitted to a single centre with AF or AFL and ADHF with LVEF≤40% that underwent inpatient TOE-guided DCCV or ablation. The primary endpoint was the one year composite outcome of mortality or rehospitalisation for heart failure. RESULTS: We identified 79 patients, including 33 with AF (32 DCCV, one ablation) and 46 with AFL (22 DCCV, 24 ablation). The primary endpoint occurred in 20%. One-year mortality was 2.5%. There were significantly fewer rehospitalisations for arrhythmia or heart failure with AFL-ablation compared to AFL-DCCV (21% vs 64%, p=<0.01). Clinical recurrence of AF or AFL was 43%. At follow-up LV assessment, LVEF>40% was found in 75% (p=<0.01), including 87% of patients without known cardiomyopathy and 82% of patients in sinus rhythm. CONCLUSION: Early inpatient DCCV or ablation for AF or AFL and ADHF had low mortality rates and rehospitalisation for heart failure with substantial improvement in LV function at follow-up.