Public attitudes towards automated external defibrillators: results of a survey in the Australian general population

BackgroundSwift defibrillation by lay responders using automated external defibrillators (AEDs) increases survival in out-of-hospital cardiac arrest (OHCA). This study evaluated newly designed yellow–red vs. commonly used green–white signage for AEDs and cabinets and assessed public attitudes to using AEDs during OHCA.MethodsNew yellow–red signage was designed to enable easy identification of AEDs and cabinets. A prospective, cross-sectional study of the Australian public was conducted using an electronic, anonymised questionnaire between November 2021 and June 2022. The validated net promoter score investigated public engagement with the signage. Likert scales and binary comparisons evaluated preference, comfort and likelihood of using AEDs for OHCA.ResultsThe yellow–red signage for AED and cabinet was preferred by 73.0% and 88%, respectively, over the green–white counterparts. Only 32% were uncomfortable with using AEDs, and only 19% indicated a low likelihood of using AEDs in OHCA.ConclusionThe majority of the Australian public surveyed preferred yellow–red over green–white signage for AED and cabinet and indicated comfort and likelihood of using AEDs in OHCA. Steps are necessary to standardise yellow–red signage of AED and cabinet and enable widespread availability of AEDs for public access defibrillation

Comparison of new-generation renal artery denervation systems: assessing lesion size and thermodynamics using a thermochromic liquid crystal phantom model

Aims: The aim of this study was to evaluate and compare lesion dimensions and thermodynamics of the new-generation multi-electrode Symplicity Spyral and the new-generation multi-electrode EnligHTN renal artery denervation systems, using a thermochromic liquid crystal phantom model. Methods and results: A previously described renal artery phantom model was used as a platform for radiofrequency ablation. A total of 32 radiofrequency ablations were performed using the multi-electrode Symplicity Spyral (n=16) and the new-generation EnligHTN systems (n=16). Both systems were used as clinically recommended by their respective manufacturer. Lesion borders were defined by the 51°C isotherm. Lesion size (depth and width) was measured and compared between the two systems. Mean lesion depth was 2.15±0.02 mm for the Symplicity Spyral and 2.32±0.02 mm for the new-generation EnligHTN (p-value <0.001). Mean lesion width was 3.64±0.08 mm and 3.59±0.05 mm (p-value=0.61) for the Symplicity Spyral and the new-generation EnligHTN, respectively. Conclusions: The new-generation EnligHTN system produced lesions of greater depth compared to the Symplicity Spyral under the same experimental conditions. Lesion width was similar between both systems. Achieving greater lesion depth by use of the new-generation EnligHTN may result in better efficacy of renal artery denervation

The compression type of coronary artery motion in patients with ST-segment elevation acute myocardial infarction and normal controls: a case-control study

<p>Abstract</p> <p>Background</p> <p>Prediction of the location of culprit lesions responsible for ST-segment elevation myocardial infarctions may allow for prevention of these events. A retrospective analysis of coronary artery motion (CAM) was performed on coronary angiograms of 20 patients who subsequently had ST-segment elevation myocardial infarction treated by primary or rescue angioplasty and an equal number of age and sex matched controls with normal angiograms.</p> <p>Findings</p> <p>There was no statistically significant difference between the frequency of CAM types of the ST-segment elevation acute myocardial infarction and control patients (p = 0.97). The compression type of CAM is more frequent in the proximal and mid segments of all three coronary arteries. No statistically significant difference was found when the frequency of the compression type of CAM was compared between the ST-segment elevation acute myocardial infarction and control patients for the individual coronary artery segments (p = 0.59).</p> <p>Conclusion</p> <p>The proportion of the compression type of coronary artery motion for individual artery segments is not different between patients who have subsequent ST-segment elevation myocardial infarctions and normal controls.</p

Transcatheter non-contact microwave ablation may enable circumferential renal artery denervation while sparing the vessel intima and media

Aims: Trials of transcatheter renal artery denervation (RDN) have failed to show consistent antihypertensive efficacy. Procedural factors and limitations of radiofrequency ablation can lead to incomplete denervation. The aim of the study was to show that non-contact microwave catheter ablation could produce deep circumferential perivascular heating while avoiding injury to the renal artery intima and media. Methods and results: A novel microwave catheter was designed and tested in a renal artery model consisting of layers of phantom materials embedded with a thermochromic liquid crystal sheet, colour range 50-78°C. Ablations were performed at 140 W for 180 sec and 120 W for 210 sec, delivering 25,200 J with renal arterial flow at 0.5 L/min and 0.1 L/min. Transcatheter microwave ablations 100-160 W for 180 sec were then performed in the renal arteries of five sheep. In vitro, ablations at 140 W and 0.5 L/min flow produced circumferential lesions 5.9±0.2 mm deep and 19.2±1.5 mm long with subendothelial sparing depth of 1.0±0.1 mm. In vivo, transcatheter microwave ablation was feasible with no collateral visceral thermal injury. There was histological evidence of preferential outer media and adventitial ablation. Conclusions: Transcatheter microwave ablation for RDN appears feasible and provides a heating pattern that may enable more complete denervation while sparing the renal arterial intima and media

Early and long-term outcomes after manual and remote magnetic navigation guided catheter ablation for ventricular tachycardia

Aims Remote magnetic navigation (RMN) is a safe and effective means of performing ventricular tachycardia (VT) ablation. It may have advantages over manual catheter ablation due to ease of manoeuvrability and catheter stability. We sought to compare the safety and efficacy of RMN vs. manual VT ablation. Methods and results Retrospective study of procedural outcomes of 139 consecutive VT ablation procedures (69 RMN, 70 manual ablation) in 113 patients between 2009 and 2015 was performed. Remote magnetic navigation was associated with overall higher acute procedural success (80% vs. 60%, P = 0.01), with a trend to fewer major complications (3% vs. 9% P = 0.09). Seventy-nine patients were followed up for a median of 17.0 [interquartile range (IQR) 3.0–41.0] months for the RMN group and 15.5 (IQR 6.5–30.0) months for manual ablation group. In the ischaemic cardiomyopathy subgroup, RMN was associated with longer survival from the composite endpoint of VT recurrence leading to defibrillator shock, re-hospitalization or repeat catheter ablation and all-cause mortality; single-procedure adjusted hazard ratio (HR) 0.240 (95% CI 0.070–0.821) P = 0.023, multi-procedure HR 0.170 (95% CI 0.046–0.632) P = 0.002. In patients with implanted defibrillators, multi-procedure VT-free survival was superior with RMN, HR 0.199 (95% CI 0.060–0.657) P = 0.003. Conclusion Remote magnetic navigation may improve clinical outcomes after catheter ablation of VT in patients with ischaemic cardiomyopathy. Further prospective clinical studies are required to confirm these findings

Sudden Death Risk-Stratification in 2018–2019: The Old and the New

Sudden Cardiac Death (SCD) is a major public health issue, accounting for half of all cardiovascular deaths world-wide. The implantable cardioverter-defibrillator (ICD) has been solidified as the cornerstone therapy in primary prevention of SCD in ischaemic and non-ischaemic cardiomyopathy. However, what has become increasingly clear is that the left ventricular ejection fraction (LVEF) is an inadequate tool to select patients for a prophylactic ICD, despite its widespread use for this purpose. Use of LVEF alone has poor specificity for arrhythmic versus non-arrhythmic death. In addition, the vast majority of sudden deaths occur in patients with more preserved cardiac function. Alternate predictors of sudden death include electrophysiology study, non-invasive markers of electrical instability, myocardial fibrosis, genetic and bio-markers. The challenge for the future is finding a risk stratification test, or combination of tests, that adequately select patients at high risk of SCD with low competing risk of non-sudden death

Sudden Death Risk-Stratification in 2018–2019:The Old and the New

Sudden Cardiac Death (SCD) is a major public health issue, accounting for half of all cardiovascular deaths world-wide. The implantable cardioverter-defibrillator (ICD) has been solidified as the cornerstone therapy in primary prevention of SCD in ischaemic and non-ischaemic cardiomyopathy. However, what has become increasingly clear is that the left ventricular ejection fraction (LVEF) is an inadequate tool to select patients for a prophylactic ICD, despite its widespread use for this purpose. Use of LVEF alone has poor specificity for arrhythmic versus non-arrhythmic death. In addition, the vast majority of sudden deaths occur in patients with more preserved cardiac function. Alternate predictors of sudden death include electrophysiology study, non-invasive markers of electrical instability, myocardial fibrosis, genetic and bio-markers. The challenge for the future is finding a risk stratification test, or combination of tests, that adequately select patients at high risk of SCD with low competing risk of non-sudden death

A review of the safety aspects of radio frequency ablation

In light of recent reports showing high incidence of silent cerebral infarcts and organized atrial arrhythmias following radiofrequency (RF) atrial fibrillation (AF) ablation, a review of its safety aspects is timely. Serious complications do occur during supraventricular tachycardia (SVT) ablations and knowledge of their incidence is important when deciding whether to proceed with ablation. Evidence is emerging for the probable role of prophylactic ischemic scar ablation to prevent VT. This might increase the number of procedures performed. Here we look at the various complications of RF ablation and also the methods to minimize them. Electronic database was searched for relevant articles from 1990 to 2015. With better awareness and technological advancements in RF ablation the incidence of complications has improved considerably. In AF ablation it has decreased from 6% to less than 4% comprising of vascular complications, cardiac tamponade, stroke, phrenic nerve injury, pulmonary vein stenosis, atrio-esophageal fistula (AEF) and death. Safety of SVT ablation has also improved with less than 1% incidence of AV node injury in AVNRT ablation. In VT ablation the incidence of major complications was 5–11%, up to 3.4%, up to 1.8% and 4.1–8.8% in patients with structural heart disease, without structural heart disease, prophylactic ablations and epicardial ablations respectively. Vascular and pericardial complications dominated endocardial and epicardial VT ablations respectively. Up to 3% mortality and similar rates of tamponade were reported in endocardial VT ablation. Recent reports about the high incidence of asymptomatic cerebral embolism during AF ablation are concerning, warranting more research into its etiology and prevention

Long-term survival in patients presenting with STEMI complicated by out of hospital cardiac arrest

Background: There is limited data regarding long-term survival in patients who present with STEMI and out of hospital cardiac arrest (OHCA). Methods: We prospectively analysed outcomes in 3521 consecutive patients who were diagnosed with STEMI and underwent primary percutaneous coronary intervention (PPCI) or coronary artery bypass surgery from 2004 to 2017. They were divided into two groups according to the presence of cardiac arrest (group I, patients with cardiac arrest; n = 156 group II, patients without cardiac arrest; n = 3365). Results: Patients with OHCA had higher in hospital mortality (27.7% vs 2.9%, p < 0.01), sustained VT or VF (44.6% vs 4.3%, p < 0.01) and cardiogenic shock (22.9% vs 6.8%, p < 0.01). 30-day mortality (excluding death within first 24 h) was also higher in the OHCA group (24.6% vs 3.3%, p < 0.01). There was no significant difference in recurrent AMI, TVR, stroke, major bleeds or new onset heart failure. After a mean follow-up of 18.6 months, mortality was higher in patients with OHCA (7.9% vs 3.8%, p 0.04). This was driven mainly by an increase in cardiac mortality (5% vs 1.1%, p < 0.01). OHCA was a significant predictor of mortality beyond 30 days (HR – 2.5, 95% CI 0.99–6.3). Kaplan–Meier curves and the log-rank test revealed that patients with OHCA had significantly lower survival (p < 0.01). Conclusions: Patients with STEMI complicated by OHCA remain a high-risk group associated with high in hospital mortality. Beyond 30 days the occurrence of cardiac arrest was a significant predictor of all-cause and cardiac mortality

Gender differences in the severity and extent of coronary artery disease

To investigate whether women presenting with suspected angina would show less severe coronary artery disease in than men as determined by the extent score. We examined 994 participants of the Australian Heart Eye Study presenting for coronary angiography in the investigation of chest pain from June 2009 to February 2012. People were excluded if there was a history of coronary artery bypass surgery, previous stenting procedure or incomplete angiogram scoring. An extent and vessel score was calculated using invasive coronary angiography. Normal coronary arteries were defined as having no luminal irregularity (Extent score = 0). Obstructive coronary artery disease was defined as a luminal narrowing of greater than 50%. Women compared to men without infarction had a lower burden of CAD with up to 50% having normal coronary arteries in the 30–44 year group and 40% in the 45–59 year group. Compared to men, women with chest pain had lower mean extent scores (19.6 vs 36.8, P < 0.0001) and lower vessel scores (0.7 v 1.3, P < 0.0001). Although the mean extent score was lower in women than men with myocardial infarction, this was not statistically significant (34.8 vs 41.6 respectively, P = 0.18). There is a marked difference in coronary artery disease severity and burden between females and males presenting for the investigation of suspected angina. Women are more likely to have normal coronary arteries or less severe disease than age-matched men, particularly if they do not present with myocardial infarction