Result of the left bundle branch area pacing data collection registry, an international multicenter study of conduction system pacing with a Tendril STS 2088 stylet-driven lead

INTRODUCTION

Left bundle branch area (LBBA) pacing (LBBAP) has been proposed as an alternative therapy option in patients indicated for cardiac pacing to treat bradycardia or heart failure. The aim of the study was to evaluate the safety and effectiveness of LBBAP in patients implanted with a Tendril 2088 stylet-driven lead.

METHODS

The international retrospective data collection registry included 11 sites from 5 countries globally. Patients with attempted implants of the Tendril lead in the LBBA were followed for at least 6 months post the implant attempt. The primary safety and efficacy endpoints were freedom from LBBAP lead-related serious adverse events and the composite of LBBA capture threshold of ≤2.0 V and R-wave amplitudes ≥5 mV (or ≥value at implant), respectively.

RESULTS

Of 221 patients with attempted implants of the Tendril 2088 lead in the LBBA, 91.4% (202/221) had successful implants for LBBAP. Regardless of the LBBAP implant success, all patients were followed for at least 6 months (8.7 ± 7.3 months). Baseline characteristics: 44% female, 84% ≥65 years old, 34% coronary artery disease, and 86% of primary indications for pacemaker implant. Both primary safety and effectiveness endpoints were met (freedom from LBBAP lead-related serious adverse device effects of 99.5% and electrical performance composite success rate of 93%). The capture thresholds in LBBAP at implant and 6 months were 0.8 ± 0.3 V@0.4 ± 0.1 ms and 0.8 ± 0.3 V@0.4 ± 0.1 ms. The rate of patients with capture threshold rise ≥1 V was 1.5% through 6 months. The R-wave amplitudes in LBBAP at implant and 6 months were 9.3 ± 3.2 mV and 10.6 ± 3.0 mV.

CONCLUSIONS

This large multicenter study demonstrates that the stylet-driven Tendril™ STS 2088 lead is safe and effective for LBBAP with high success and low complication rates.

Physiological pacing: just a lot of buzz or the next paradigm shift in bradycardia pacing?

ABSTRACT

Cardiac pacing has been an established therapy for bradyarrhythmia due to sinus or atrioventricular nodal disease since the 1950s. However, contemporary studies have shown that conventional right ventricular pacing (RVP) causes electromechanical dyssynchrony, which can lead to atrial fibrillation, heart failure and even death. Recently, the push for a more physiological cardiac pacing has seen a revival in the utilisation and development of conduction system pacing (CSP). There has been a shift towards adopting His bundle pacing (HBP) or left bundle branch area pacing (LBBaP) in bradycardia patients worldwide and in Singapore. This review serves to outline the electrophysiological concepts behind CSP and illustrate the different paced electrocardiogram characteristics of HBP, LBBaP and RVP to aid understanding of this revolutionary pacing approach among medical practitioners in Singapore.

Contemporary wearable and handheld technology for the diagnosis of cardiac arrhythmias in Singapore

Twelve-lead electrocardiography (ECG) remains the gold standard for the diagnosis of cardiac arrhythmias. It provides a snapshot of the cardiac electrical activity while the leads are attached to the patient. As medical training is required to use the ECG machine, its use remains restricted to the clinic and hospital settings. These aspects limit the usefulness of 12-lead ECG in the diagnosis of cardiac arrhythmias, especially in individuals with short-lasting and infrequent paroxysmal symptoms. The introduction of ECG recording features in wearable and handheld smart devices has changed the paradigm of cardiac arrhythmia diagnosis, empowering patients to record their ECG as and when symptoms occur. This review describes contemporary ambulatory heart rhythm monitors commonly available in Singapore and their expanding role in the diagnosis of cardiac rhythm abnormalities.

Practical and systematic approach using the steerable catheter and stylet-driven lead to deliver safe and effective left bundle branch area pacing

INTRODUCTION

Current delivery tools were not designed for left bundle branch area pacing (LBBAP). Challenges using these tools include lack of reach into the right ventricle and poor support for the lead to penetrate the interventricular septum. Concerns using stylet-driven leads (SDL) for LBBAP have been previously highlighted. Knowledge and the technical know-how of using SDL for LBBAP need to be evaluated in a fair and consistent manner. A stepwise approach is devised for use of Agilis HisProTM steerable catheter with Tendril STS Model 2088TC lead for LBBAP and evaluated for safety and reproducibility.

METHODS

Consecutive patients undergoing LBBAP using the stepwise approach with Agilis HisProTM steerable catheter were analyzed. The safety, efficacy and reproducibility of the technique were evaluated. The lead parameters were analyzed in the immediate (1 day) and short-term period (3-6 months) post implantation.

RESULTS

LBBAP was attempted in 41 patients using the stepwise approach of which 37 (90.7%) were successful. The lead parameters were stable in the immediate and short-term post implantation in all our patients. There was no significant difference between the group of patients with multiple repositioning of the lead compared to those successful at the 1st attempt. There were no acute or short-term lead and procedural complications.

CONCLUSION

A stepwise and systematic approach using the Agilis HisProTM steerable catheter and proper handling of the Tendril STS Model 2088TC stylet-driven lead is an important part of the armamentarium to deliver LBBAP in a practical, effective and reproducible manner.

Trends and predictions of metabolic risk factors for acute myocardial infarction: findings from a multiethnic nationwide cohort

Background

Understanding the trajectories of metabolic risk factors for acute myocardial infarction (AMI) is necessary for healthcare policymaking. We estimated future projections of the incidence of metabolic diseases in a multi-ethnic population with AMI.

Methods

The incidence and mortality contributed by metabolic risk factors in the population with AMI (diabetes mellitus [T2DM], hypertension, hyperlipidemia, overweight/obesity, active/previous smokers) were projected up to year 2050, using linear and Poisson regression models based on the Singapore Myocardial Infarction Registry from 2007 to 2018. Forecast analysis was stratified based on age, sex and ethnicity.

Findings

From 2025 to 2050, the incidence of AMI is predicted to rise by 194.4% from 482 to 1418 per 100,000 population. The largest percentage increase in metabolic risk factors within the population with AMI is projected to be overweight/obesity (880.0% increase), followed by hypertension (248.7% increase), T2DM (215.7% increase), hyperlipidemia (205.0% increase), and active/previous smoking (164.8% increase). The number of AMI-related deaths is expected to increase by 294.7% in individuals with overweight/obesity, while mortality is predicted to decrease by 11.7% in hyperlipidemia, 29.9% in hypertension, 32.7% in T2DM and 49.6% in active/previous smokers, from 2025 to 2050. Compared with Chinese individuals, Indian and Malay individuals bear a disproportionate burden of overweight/obesity incidence and AMI-related mortality.

Interpretation

The incidence of AMI is projected to continue rising in the coming decades. Overweight/obesity will emerge as fastest-growing metabolic risk factor and the leading risk factor for AMI-related mortality.

Funding

This research was supported by the NUHS Seed Fund (NUHSRO/2022/058/RO5+6/Seed-Mar/03) and National Medical Research Council Research Training Fellowship (MOH-001131). The SMIR is a national, ministry-funded registry run by the National Registry of Diseases Office and funded by the Ministry of Health, Singapore.

Association of body mass index, metabolic health status and clinical outcomes in acute myocardial infarction patients: a national registry-based study

Introduction

Obesity is an important risk factor for acute myocardial infarction (AMI), but the interplay between metabolic health and obesity on AMI mortality has been controversial. In this study, we aimed to elucidate the risk of short- and long-term all-cause mortality by obesity and metabolic health in AMI patients using data from a multi-ethnic national AMI registry.

Methods

A total of 73,382 AMI patients from the national Singapore Myocardial Infarction Registry (SMIR) were included. These patients were classified into four groups based on the presence or absence of metabolic diseases, diabetes mellitus, hyperlipidaemia, and hypertension, and obesity: (1) metabolically-healthy-normal-weight (MHN); (2) metabolically-healthy-obese (MHO); (3) metabolically-unhealthy-normal-weight (MUN); and (4) metabolically-unhealthy-obese (MUO).

Results

MHO patients had reduced unadjusted risk of all-cause in-hospital, 30-day, 1-year, 2-year, and 5-year mortality following the initial MI event. However, after adjusting for potential confounders, the protective effect from MHO on post-AMI mortality was lost. Furthermore, there was no reduced risk of recurrent MI or stroke within 1-year from onset of AMI by the MHO status. However, the risk of 1-year mortality was higher in female and Malay AMI patients with MHO compared to MHN even after adjusting for confounders.

Conclusion

In AMI patients with or without metabolic diseases, the presence of obesity did not affect mortality. The exception to this finding were female and Malay MHO who had worse long-term AMI mortality outcomes when compared to MHN suggesting that the presence of obesity in female and Malay patients may confer worsened outcomes.

Comparison of the modified Singapore myocardial infarction registry risk score with GRACE 2.0 in predicting 1-year acute myocardial infarction outcomes

Risk stratification plays a key role in identifying acute myocardial infarction (AMI) patients at higher risk of mortality. However, current AMI risk scores such as the Global Registry of Acute Coronary Events (GRACE) score were derived from predominantly Caucasian populations and may not be applicable to Asian populations. We previously developed an AMI risk score from the national-level Singapore Myocardial Infarction Registry (SMIR) confined to ST-segment elevation myocardial infarction (STEMI) patients and did not include non-STEMI (NSTEMI) patients. Here, we derived a modified SMIR risk score for both STEMI and NSTEMI patients and compared its performance to the GRACE 2.0 score for predicting 1-year all-cause mortality in our multi-ethnic population. The most significant predictor of 1-year all-cause mortality in our population using the GRACE 2.0 score was cardiopulmonary resuscitation on admission (adjusted hazards ratio [HR] 6.50), while the most significant predictor using the SMIR score was age 80–89 years (adjusted HR 7.78). Although the variables used in the GRACE 2.0 score and SMIR score were not exactly the same, the c-statistics for 1-year all-cause mortality were similar between the two scores (GRACE 2.0 0.841 and SMIR 0.865). In conclusion, we have shown that in a multi-ethnic Asian AMI population undergoing PCI, the SMIR score performed as well as the GRACE 2.0 score.

The curious case of missing heartbeats

Paroxysmal atrioventricular block (AVB) is a poorly defined and easily missed bradyarrhythmia, which can potentially lead to sudden cardiac death. It is under-recognised due to its abrupt onset and unpredictability. We describe a case that had paroxysmal AVB post-coronary angioplasty and highlight the mechanism as well as the management of this rare condition.

Comparison of Mortality Outcomes in Acute Myocardial Infarction Patients With or Without Standard Modifiable Cardiovascular Risk Factors

Background

Acute myocardial infarction (AMI) cases have decreased in part due to the advent of targeted therapies for standard modifiable cardiovascular disease risk factors (SMuRF). Recent studies have reported that ST-elevation myocardial infarction (STEMI) patients without SMuRF (termed “SMuRF-less”) may be increasing in prevalence and have worse outcomes than “SMuRF-positive” patients. As these studies have been limited to STEMI and comprised mainly Caucasian cohorts, we investigated the changes in the prevalence and mortality of both SMuRF-less STEMI and non-STEMI (NSTEMI) patients in a multiethnic Asian population.

Methods

We evaluated 23,922 STEMI and 62,631 NSTEMI patients from a national multiethnic registry. Short-term cardiovascular and all-cause mortalities in SMuRF-less patients were compared to SMuRF-positive patients.

Results

The proportions of SMuRF-less STEMI but not of NSTEMI have increased over the years. In hospitals, all-cause and cardiovascular mortality and 1-year cardiovascular mortality were significantly higher in SMuRF-less STEMI after adjustment for age, creatinine, and hemoglobin. However, this difference did not remain after adjusting for anterior infarction, cardiopulmonary resuscitation (CPR), and Killip class. There were no differences in mortality in SMuRF-less NSTEMI. In contrast to Chinese and Malay patients, SMuRF-less patients of South Asian descent had a two-fold higher risk of in-hospital all-cause mortality even after adjusting for features of increased disease severity.

Conclusion

SMuRF-less patients had an increased risk of mortality with STEMI, suggesting that there may be unidentified nonstandard risk factors predisposing SMuRF-less patients to a worse prognosis. This group of patients may benefit from more intensive secondary prevention strategies to improve clinical outcomes.

Early Coronary Angiography Is Associated with Improved 30-Day Outcomes among Patients with Out-of-Hospital Cardiac Arrest

We evaluated the association between early coronary angiography (CAG) and outcomes in resuscitated out-of-hospital cardiac arrest (OHCA) patients, by linking data from the Singapore Pan-Asian Resuscitation Outcomes Study, with a national registry of cardiac procedures. The 30-day survival and neurological outcome were compared between patients undergoing early CAG (within 1-calender day), versus patients not undergoing early CAG. Inverse probability weighted estimates (IPWE) adjusted for non-randomized CAG. Of 976 resuscitated OHCA patients of cardiac etiology between 2011–2015 (mean(SD) age 64(13) years, 73.7% males), 337 (34.5%) underwent early CAG, of whom, 230 (68.2%) underwent PCI. Those who underwent early CAG were significantly younger (60(12) vs. 66(14) years old), healthier (42% vs. 59% with heart disease; 29% vs. 44% with diabetes), more likely males (86% vs. 67%), and presented with shockable rhythms (69% vs. 36%), compared with those who did not. Early CAG with PCI was associated with better survival and neurological outcome (adjusted odds ratio 1.91 and 1.82 respectively), findings robust to IPWE adjustment. The rates of bleeding and stroke were similar. CAG with PCI within 24 h was associated with improved clinical outcomes after OHCA, without increasing complications. Further studies are required to identify the characteristics of patients who would benefit most from this invasive strategy.

Optimal glucose, HbA1c, glucose-HbA1c ratio and stress-hyperglycaemia ratio cut-off values for predicting 1-year mortality in diabetic and non-diabetic acute myocardial infarction patients

Background

Stress-induced hyperglycaemia at time of hospital admission has been linked to worse prognosis following acute myocardial infarction (AMI). In addition to glucose, other glucose-related indices, such as HbA1c, glucose-HbA1c ratio (GHR), and stress-hyperglycaemia ratio (SHR) are potential predictors of clinical outcomes following AMI. However, the optimal blood glucose, HbA1c, GHR, and SHR cut-off values for predicting adverse outcomes post-AMI are unknown. As such, we determined the optimal blood glucose, HbA1c, GHR, and SHR cut-off values for predicting 1-year all cause mortality in diabetic and non-diabetic ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI) patients.

Methods

We undertook a national, registry-based study of patients with AMI from January 2008 to December 2015. We determined the optimal blood glucose, HbA1c, GHR, and SHR cut-off values using the Youden’s formula for 1-year all-cause mortality. We subsequently analyzed the sensitivity, specificity, positive and negative predictive values of the cut-off values in the diabetic and non-diabetic subgroups, stratified by the type of AMI.

Results

There were 5841 STEMI and 4105 NSTEMI in the study. In STEMI patients, glucose, GHR, and SHR were independent predictors of 1-year all-cause mortality [glucose: OR 2.19 (95% CI 1.74–2.76); GHR: OR 2.28 (95% CI 1.80–2.89); SHR: OR 2.20 (95% CI 1.73–2.79)]. However, in NSTEMI patients, glucose and HbA1c were independently associated with 1-year all-cause mortality [glucose: OR 1.38 (95% CI 1.01–1.90); HbA1c: OR 2.11 (95% CI 1.15–3.88)]. In diabetic STEMI patients, SHR performed the best in terms of area-under-the-curve (AUC) analysis (glucose: AUC 63.3%, 95% CI 59.5–67.2; GHR 68.8% 95% CI 64.8–72.8; SHR: AUC 69.3%, 95% CI 65.4–73.2). However, in non-diabetic STEMI patients, glucose, GHR, and SHR performed equally well (glucose: AUC 72.0%, 95% CI 67.7–76.3; GHR 71.9% 95% CI 67.7–76.2; SHR: AUC 71.7%, 95% CI 67.4–76.0). In NSTEMI patients, glucose performed better than HbA1c for both diabetic and non-diabetic patients in AUC analysis (For diabetic, glucose: AUC 52.8%, 95% CI 48.1–57.6; HbA1c: AUC 42.5%, 95% CI 37.6–47. For non-diabetic, glucose: AUC 62.0%, 95% CI 54.1–70.0; HbA1c: AUC 51.1%, 95% CI 43.3–58.9). The optimal cut-off values for glucose, GHR, and SHR in STEMI patients were 15.0 mmol/L, 2.11, and 1.68 for diabetic and 10.6 mmol/L, 1.72, and 1.51 for non-diabetic patients respectively. For NSTEMI patients, the optimal glucose values were 10.7 mmol/L for diabetic and 8.1 mmol/L for non-diabetic patients.

Conclusions

SHR was the most consistent independent predictor of 1-year all-cause mortality in both diabetic and non-diabetic STEMI, whereas glucose was the best predictor in NSTEMI patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-021-01395-3.

Implication of Current ASE/EACVI Left Ventricular Diastolic Function Classification in Predicting 2-Year MACE in Asymptomatic Patients with Diabetes and Hypertension

Background

Left ventricular diastolic dysfunction (LVDD) has been shown to be more prevalent in patients with diabetes, and once progress to overt heart failure, carry worse clinical outcomes. Substantial number of patients were classified as indeterminate DF based on the current ASE/EACVI guidelines. The implication of current DF classification in predicting MACE among diabetic patients is not well established.

Purpose

To assess prognostic impact of current guidelines-based DF classification, and determine predictors of 2-year MACE based on individual LVDD parameters.

Methods

A total of 111 patients with diabetes and hypertension who attended diabetic clinic follow-up at the primary healthcare settings were enrolled. All patients had no prior cardiovascular events, had preserved left ventricular (LV) ejection fraction on echocardiography and sinus rhythm on ECG at screening. Echocardiography was performed to obtain parameters of LV dimensions, LV volumes and LVDD. The 2016 ASE/EACVI guidelines were applied to classify DF. All patients were followed up until 2 years to assess MACE.

Results

There were 65 (58.6%) female patients. Mean age was 59.86 (7.45); mean duration of DM was 10.5 (5.41). 80 (72.1%) patients were classified as having normal DF (nDF); 24 (21.6%) patients were classified as indeterminate DF (iDF); 7 patients (6.3%) were classified as LVDD. Patients with LVDD had significantly higher LV mass index (LVMI) (mean 121.72±23.28g/m2 vs 116.62±24.66g/m2 in iDF vs 102.50±22.89g/m2 in nDF); higher left atrial volume index (LAVI) (mean 41.24±10.28ml/m2 vs 30.55±10.07ml/m2 in iDF vs 25.75±6.30ml/m2 in nDF); lower lateral e' velocity (mean 6.35±2.05cm/s vs 7.37±1.73cm/s in iDF vs 8.59±2.13cm/s in nDF); higher septal E/e' ratio (mean 14.89±3.29 vs 12.16±3.99 in iDF vs 9.99±2.35 in nDF); higher average septal-lateral E/e' ratio (mean 14.22±3.77 vs 11.34±3.74 in iDF vs 9.04±2.10 in nDF).

Among these 111 patients, 10 patients (9%) reported MACE at 2 years. The risk of 2-year MACE is elevated in both iDF [odds ratio (OR) 3.80, 95% CI 0.87–16.54, p=0.075] and LVDD [OR 7.60, 95% CI 1.11–52.02, p=0.039]. LVMI (OR 1.027, 95% CI 1.004– 1.051, p=0.023), LAVI (OR 1.092, 95% CI 1.017–1.172), and average septal-lateral E/e' ratio (OR 1.276, 95% CI 1.047–1.557, p=0.016) significantly correlated with 2-year MACE.

Conclusions

LVDD is correlated with increased MACE at 2 years. LVMI, LAVI and average septal-lateral E/e' ratio were predictors of increased risk of MACE at 2 years. Further investigation with larger sample size is warranted.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Health Malaysia

Association between smoking status and outcomes in myocardial infarction patients undergoing percutaneous coronary intervention

Smoking is one of the leading risk factors for cardiovascular diseases, including ischemic heart disease and hypertension. However, in acute myocardial infarction (AMI) patients, smoking has been associated with better clinical outcomes, a phenomenon termed the “smoker’s paradox.” Given the known detrimental effects of smoking on the cardiovascular system, it has been proposed that the beneficial effect of smoking on outcomes is due to age differences between smokers and non-smokers and is therefore a smoker’s pseudoparadox. The aim of this study was to evaluate the association between smoking status and clinical outcomes in ST-segment elevation (STEMI) and non-STEMI (NSTEMI) patients treated by percutaneous coronary intervention (PCI), using a national multi-ethnic Asian registry. In unadjusted analyses, current smokers had better clinical outcomes following STEMI and NSTEMI. However, after adjusting for age, the protective effect of smoking was lost, confirming a smoker’s pseudoparadox. Interestingly, although current smokers had increased risk for recurrent MI within 1 year after PCI in both STEMI and NSTEMI patients, there was no increase in mortality. In summary, we confirm the existence of a smoker’s pseudoparadox in a multi-ethnic Asian cohort of STEMI and NSTEMI patients and report increased risk of recurrent MI, but not mortality, in smokers.

Abstract P607: Interplay Between Post-Myocardial Infarction Left Ventricular Systolic Dysfunction and Atrial Fibrillation: Prognostic Implications for Post-Myocardial Infarction Acute Ischaemic Stroke

Introduction: Acute myocardial infarction (MI) and acute ischaemic stroke (AIS) are leading causes of morbidity and mortality. There is scarce data examining the interplay between post-MI left ventricular systolic dysfunction (LVSD), with or without atrial fibrillation (AF), and subsequent AIS, especially in patients with milder degrees of LVSD (ejection fraction 40-49%). Evidence of an association would be helpful in developing new strategies of reducing AIS after MI. As such, we sought to study this relationship in a real-world population-based registry.

Methods: This study involved linking national-level data from the Singapore Myocardial Infarction Registry with the Singapore Stroke Registry from 1st January 2007 to 31st December 2018. Both data sets have similar definitions for patient demographics. The ejection fraction (EF) and AF status were recorded during the MI episode. The outcome studied was the first instance of AIS that developed after the MI episode. We also studied the relationship between EF, AF and the severity of AIS as measured by the NIH Stroke Scale (NIHSS).

Results: There were 64,512 patients available for analysis. The median age was 65.7 (IQR 56.1-76.5) and 69.5% were male. The median duration post-MI to develop AIS was 16.9 (IQR 1.6-46.1) months. There was an independent association between LVSD and the outcome of AIS (adjusted HR 1.18, 95% CI 1.10-1.27); this was evident even in mild forms of LVSD (adjusted HR 1.16, 95% CI 1.06-1.27). AF was not a statistically significant predictor of AIS in post-MI patients with LVSD. Amongst patients without AF, post-MI LVSD was associated with a more severe stroke and higher NIHSS.

Conclusion: Post-MI LVSD is associated with the occurrence of subsequent AIS. Although this relationship was independent of AF status, patients with LVSD but no AF had suffered a more severe AIS. These findings support the need to develop effectives therapies to prevent AIS post-MI, especially among those with LVSD.

Impact of 2016 ASE/EACVI recommendations on evaluation of left ventricular diastolic function and clinical outcomes in patients with diabetes and hypertension without prior adverse cardiac events

Background

Left ventricular diastolic dysfunction (LVDD) has been shown to be more prevalent in patients with diabetes, and once progress to overt heart failure, carry worse clinical outcomes, compared to those without diabetes. The complexity of previous 2009 ASE/EACVI algorithms makes diastolic function (DF) assessment challenging. Hence, prognostic value of LVDD estimates in clinical setting is not well-established.

Objective

To evaluate the impact of 2016 recommendations in estimates of LVDD and predicting cardiovascular outcomes in patients with diabetes and hypertension.

Materials and methods

A total of 111 patients with diabetes and hypertension who attended diabetic clinic follow-up at the primary healthcare settings were enrolled. All patients were clinically NYHA Class I, had no prior adverse cardiac events, and had preserved left ventricular (LV) ejection fraction on echocardiography at screening. Echocardiography was performed to obtain parameters of LV dimensions, LV volumes and LVDD. Both 2009 and 2016 algorithms were applied in DF assessment. All patients follow-up at 1 year to assess clinical outcomes.

Results

There were 65 (58.6%) female patients. Mean age was 59.86 (7.45); mean duration of diabetes was 10.5 (5.41). 55 (50.5%) patients had LV hypertrophy on echocardiography.

Prevalence of LVDD (14.4% vs 55.0%) and elevated LV filling pressure (9.0% vs 26.1%) were lower with 2016 compared with 2009 recommendations. Prevalence of indeterminate DF was 18.0% and 12.6% according to 2016 and 2009 recommendations respectively. Concordance between 2016 and 2009 recommendations was fair (k=0.29, p<0.001), with a reclassification rate of 45.9%.

None out of 45 patients who were diagnosed with indeterminate and normal DF according to 2016 and LVDD with 2009 algorithms developed MACE at 1 year. Out of 12 patients diagnosed with LVDD based on both 2016 and 2009 recommendations, 4 patients developed MACE at 1 year. 2016 recommendations showed better accuracy (sensitivity=80.0%; specificity=88.68%) than 2009 recommendations (sensitivity=80.0%; specificity= 45.28%) in predicting MACE at 1 year.

Conclusions

The application of 2016 recommendations results in lower prevalence of LVDD. The 2016 criteria detect more advanced cases and predict 1 year cardiovascular outcomes better. Further studies are warranted to investigate the prognostic impact of this criteria.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): National Institute of Health (NIH), Ministry of Health Malaysia

Safety of electronic massagers in patients with cardiac implantable electronic devices

BACKGROUND

Current recommendations by cardiac implantable electronic devices (CIEDs) manufacturers on electromagnetic interference (EMI) are based on extrapolations of studies exposing CIEDs to electromagnetic fields produced by Helmholtz coils and industrial equipment. There are currently little data whether commercially available electronic massagers can cause EMI in CIEDs in vivo. This is of interest as the use of electronic massagers is common in Asia.

METHODS

The study evaluated CIED patients before, during and after a 10-minute exposure to a commercially available electronic backrest upper body massager. Post-exposure sensing, pacing threshold, and lead impedance were compared to baseline values. The presence of artefacts, EMI, and adverse clinical events during exposure was recorded.

RESULTS

Eighty-six patients (59 pacemakers and 27 implantable cardioverter-defibrillators) with a total of 151 leads (60 atrial, 86 right ventricular, and 5 left ventricular) were evaluated. There was no incidence of EMI causing inappropriate inhibition of pacing or inappropriate defibrillation. There was no significant difference in the pacing threshold, sensing, and lead impedance post-exposure compared to baseline values.

CONCLUSION

Our study, though limited by small numbers and exposure to only 1 type of electronic massager, shows that it is potentially safe for patients with CIEDs to use commercially available electronic massagers with similar characteristics as the one tested in this study.

Rhythm blues in the time of coronavirus disease 2019 (COVID-19): how the cardiac electrophysiologist adapts to a viral pandemic in Singapore

Coronavirus disease 2019 (COVID-19) is a major healthcare disaster in the modern times. Healthcare services must adapt to effectively juggle between pandemic management and maintenance of business-as-usual services so that both COVID-19 and non-COVID-19 patients receive appropriate clinical care. We share our experience of significant cardiac rhythm abnormalities seen in COVID-19 patients in Singapore, how the viral pandemic has affected the cardiac electrophysiology and pacing service in a large acute care general hospital and the steps taken to alleviate the negative impact.

The Lipid Paradox is present in ST-elevation but not in non-ST-elevation myocardial infarction patients: Insights from the Singapore Myocardial Infarction Registry

Lowering low-density lipoprotein (LDL-C) and triglyceride (TG) levels form the cornerstone approach of cardiovascular risk reduction, and a higher high-density lipoprotein (HDL-C) is thought to be protective. However, in acute myocardial infarction (AMI) patients, higher admission LDL-C and TG levels have been shown to be associated with better clinical outcomes - termed the ‘lipid paradox’. We studied the relationship between lipid profile obtained within 72 hours of presentation, and all-cause mortality (during hospitalization, at 30-days and 12-months), and rehospitalization for heart failure and non-fatal AMI at 12-months in ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI) patients treated by percutaneous coronary intervention (PCI). We included 11543 STEMI and 8470 NSTEMI patients who underwent PCI in the Singapore Myocardial Infarction Registry between 2008–2015. NSTEMI patients were older (60.3 years vs 57.7 years, p < 0.001) and more likely to be female (22.4% vs 15.0%, p < 0.001). In NSTEMI, a lower LDL-C was paradoxically associated with worse outcomes for death during hospitalization, within 30-days and within 12-months (all p < 0.001), but adjustment eliminated this paradox. In contrast, the paradox for LDL-C persisted for all primary outcomes after adjustment in STEMI. For NSTEMI patients, a lower HDL-C was associated with a higher risk of death during hospitalization but in STEMI patients a lower HDL-C was paradoxically associated with a lower risk of death during hospitalization. For this endpoint, the interaction term for HDL-C and type of MI was significant even after adjustment. An elevated TG level was not protective after adjustment. These observations may be due to differing characteristics and underlying pathophysiological mechanisms in NSTEMI and STEMI.

Elderly Asian Patients Have Lower Revascularisation Rates and Poorer Outcomes for ST-Elevation Myocardial Infarction Compared to Younger Patients

INTRODUCTION

There is limited information on elderly patients presenting with ST- elevation myocardial infarction (STEMI). This study aimed to study the outcomes of elderly Asian patients with STEMI compared to younger patients.

MATERIALS AND METHODS

The study utilised data from 2007 to 2012 from the Singapore Myocardial Infarction Registry, a mandatory national population-based registry. Elderly patients were defined as ≥80 years of age, middle-aged to old (MAO) patients were defined as 45-80 years of age and young patients were defined as ≤45 years of age. The primary outcome of the study was 1-year mortality and secondary outcomes included in-hospital complications and mortality.

RESULTS

There were 12,409 STEMI patients with 1207 (9.7%) elderly patients, 10,093 (81.3%) MAO patients and 1109 (8.9%) young patients. Elderly patients had more cardiovascular risk factors and lower rates of total percutaneous coronary intervention (26.0% vs 72.4% vs 85.5%, respectively; P <0.0001) compared to MAO and young patients. They had higher 1-year mortality (60.6% vs 18.3% vs 4.1%, respectively; P <0.0001) when compared to MAO and young patients.

CONCLUSION

Elderly patients with STEMI have poorer outcomes than MAO and young patients. This is potentially attributable to a myriad of factors including age, higher burden of comorbidities and a lesser likelihood of receiving revascularisation and guideline-recommended medical therapy.

Clinical characteristics and outcomes of South-East Asian patients with Takotsubo (stress-induced) cardiomyopathy

Background

There is limited data on the natural history of Takotsubo (stress-induced) cardiomyopathy in South-East Asian patients. We aim to evaluate the clinical characteristics, predisposing factors and outcomes of patients diagnosed with Takotsubo cardiomyopathy in our region.

Methods

From January 2010 to March 2017, 98 patients were diagnosed with Takotsubo cardiomyopathy in our institution. Data were collected retrospectively on baseline clinical characteristics, presenting symptoms, precipitating factors, clinical investigations and in-hospital clinical outcomes.

Results

82% of the patients were female. An antecedent physical stressor was more common than emotional trigger with 35% of patients having no identifiable stressor. The most common presenting symptoms were chest pain (53.1%), dyspnea (45%) and diaphoresis (18.5%).

The apical variant (89%) was the most common form of Takotsubo cardiomyopathy followed by the mid-ventricular type (5.1%). The mean left ventricular ejection fraction was 35 ± 11%.

In-hospital mortality due to cardiovascular causes was 4.1%. 38% of patients developed in-hospital complications. By multi-variable analysis, lower left ventricular function was an independent predictor of in-hospital complication.

Conclusion

South-East Asian patients with Takotsubo cardiomyopathy are characterised by female predominance, higher incidence of physical triggers and low cardiovascular mortality. Lower left ventricular function was an independent predictor of adverse outcomes.

Spatially and angularly resolved spectroscopy for in-situ estimation of concentration and particle size in colloidal suspensions

Successful implementation of process analytical technology (PAT) hinges on the ability to make continuous or frequent measurements in-line or at-line of critical product attributes such as composition and particle size, the latter being an important parameter for particulate processes such as suspensions and emulsions. A novel probe-based spatially and angularly-resolved diffuse reflectance measurement (SAR-DRM) system is proposed. This instrument, along with appropriate calibration models, is designed for online monitoring of concentration of chemical species and particle size of the particulate species in process systems involving colloidal suspensions. This measurement system was investigated using polystyrene suspensions of various particle radius and concentration to evaluate its performance in terms of the information obtained from the novel configuration which allows the measurement of a combination of incident light at different angles and collection fibres at different distances from the source fibres. Different strategies of processing and combining the SAR-DRM measurements were considered in terms of the impact on partial least squares (PLS) model performance. The results were compared with those obtained using a bench-top instrument which was used as the reference (off-line) instrument for comparison purposes. The SAR-DRM system showed similar performance to the bench top reference instrument for estimation of particle radius, and outperforms the reference instrument in estimating particle concentration. The investigation shows that the improvement in PLS regression model performance using the SAR-DRM system is related to the extra information captured by the SAR-DRM configuration. The differences in SAR-DRM spectra collected by the different collection fibres from different angular source fibres are the dominant reason for the significant improvement in the model performance. The promising results from this study suggest the potential of the SAR-DRM system as an online monitoring tool for processes involving suspensions. Graphical abstract A probe designed to acquire diffuse reflectance measurements at different source-detector distances for three incidence angles 0°, 30° and 45° was used to estimate particle size and concentration of polystyrene beads in aqueous suspension using partial least squares calibration models.

Clinical characteristics, risk factors and outcomes of South-East Asian patients with acute pulmonary embolism

BACKGROUND

The clinical features of acute PE have not been well studied in South-East Asia. We therefore sought to evaluate the clinical characteristics, risk factors and outcomes of patients diagnosed with acute pulmonary embolism (PE) in our region.

METHODS

From January 2008 to March 2013, 343 patients were admitted to our tertiary institution with acute PE. Data were collected retrospectively on baseline clinical characteristics, presenting signs and symptoms, results of electrocardiographic and imaging studies, therapeutic modality and hospital course.

RESULTS

91% of the patients presented with submassive PE. 6.1% of patients had saddle PE. The most common presenting symptom was dyspnea (72.3%) followed by chest pain (12.8%), hemoptysis (2.6%), syncope (2.6%) and cardiovascular collapse (1.2%). Risk factors for PE were idiopathic cause (33.5%), immobilization (21%), malignancy (6.1%) and hypercoagulable state (2.9%). The overall in-hospital mortality was 5%. Factors associated with mortality were massive PE, tachycardia at presentation, right ventricular dysfunction and cardiogenic shock. Bleeding complications occurred in 10.2% of patients (major bleeding in 3.5%).

CONCLUSION

Acute PE in the South-East Asian patients is associated with an overall mortality rate of 5%. The bleeding complications from treatment are also high.

Overview of implantable cardioverter defibrillator and cardiac resynchronisation therapy in heart failure management

Clinical trials have established the benefits of implantable cardioverter defibrillators (ICDs) and cardiac resynchronisation therapy (CRT) in the treatment of heart failure patients. As adjuncts to guideline-directed medical therapy, ICDs confer mortality benefits from sudden cardiac arrest, while CRT reduces mortality, hospitalisation rates and improves functional capacity. This review discusses the use of ICDs and CRT devices in heart failure management, outlining the evidence supporting their use, indications and contraindications.

Impact of pharmacist-involved collaborative care on the clinical, humanistic and cost outcomes of high-risk patients with type 2 diabetes (IMPACT): a randomized controlled trial

WHAT IS KNOWN AND OBJECTIVE

With the increasing prevalence of diabetes, the physician-centred model is challenged to deliver holistic care in Asia. Diabetes may be managed effectively within a multidisciplinary collaborative care model; however, evidence on its effectiveness in Asian patients is lacking. Therefore, the primary objective was to evaluate the clinical outcomes of multidisciplinary collaborative care vs physician-centred care in diabetes. The secondary objectives were to evaluate humanistic and economic outcomes among the two types of care.

METHODS

This 6-month prospective, open-label, parallel-arm, randomized, controlled study was conducted at four outpatient healthcare institutions. High-risk patients aged ≥21 years with uncontrolled type 2 diabetes, polypharmacy and comorbidities were included. Patients with type 1 diabetes or those who were unable to communicate independently were excluded. The control arm received usual care with referrals to nurses and dietitians as needed. The intervention arm (multidisciplinary collaborative care) was followed up with pharmacists regularly, in addition to receiving the usual care. The primary outcomes included HbA1c, systolic blood pressure, low-density lipoprotein and triglycerides. The secondary outcomes included scores from the Problem Areas in Diabetes (PAID) and the Diabetes Treatment Satisfaction Questionnaires (DTSQ), and diabetes-related health service utilization rates and costs.

RESULTS AND DISCUSSION

Of 411 eligible patients, 214 and 197 patients were randomized into the intervention and control arms, respectively. At 6 months, 141 patients in the intervention arm (65.9%) and 189 patients in the control arm (95.9%) completed the study. Mean HbA1c reduced from 8.6%±1.5% at baseline to 8.1%±1.3% at 6 months in the intervention arm (P=.04), with up to mean HbA1c improvement of 0.8% in patients with greater levels of uncontrolled glycemia. Whereas the mean HbA1c in the control arm remained unchanged (8.5%±1.4%) throughout the 6-month period. Improvements in PAID and DTSQ scores, reduction in physician workload and an average cost savings of US$91.01 per patient were observed in the intervention arm over 6 months.

WHAT IS NEW AND CONCLUSIONS

The positive clinical, humanistic and economic outcomes highlighted the value of multidisciplinary collaborative care for Asian diabetic patients, thereby supporting the effectiveness of this approach in managing chronic diseases.

A practical approach to perioperative management of cardiac implantable electronic devices

With the increased use of cardiac implantable electronic devices (CIEDs), it is increasingly important to recognise the unique challenges involved in the management of patients with CIEDs who are undergoing surgery. Practice advisories and consensus statements have been issued by the American Society of Anesthesiologists and the Heart Rhythm Society, advocating a multidisciplinary approach. This review discusses and presents a practical approach to perioperative CIED management in the Singapore context.

Influence of Ethnicity, Age, and Time on Sex Disparities in Long-Term Cause-Specific Mortality After Acute Myocardial Infarction

Background

We examined the influence of sex, ethnicity, and time on competing cardiovascular and noncardiovascular causes of death following acute myocardial infarction in a multiethnic Asian cohort.

Methods and Results

For 12 years, we followed a prospective nationwide cohort of 15 151 patients (aged 22–101 years, median age 63 years; 72.3% male; 66.7% Chinese, 19.8% Malay, 13.5% Indian) who were hospitalized for acute myocardial infarction between 2000 and 2005. There were 6463 deaths (4534 cardiovascular, 1929 noncardiovascular). Compared with men, women had a higher risk of cardiovascular death (age‐adjusted hazard ratio [HR] 1.3, 95% CI 1.2–1.4) but a similar risk of noncardiovascular death (HR 0.9, 95% CI 0.8–1.0). Sex differences in cardiovascular death varied by ethnicity, age, and time. Compared with Chinese women, Malay women had the greatest increased hazard of cardiovascular death (HR 1.4, 95% CI 1.2–1.6) and a marked imbalance in death due to heart failure or cardiomyopathy (HR 3.4 [95% CI 1.9–6.0] versus HR 1.5 [95% CI 0.6–3.6] for Indian women). Compared with same‐age Malay men, Malay women aged 22 to 49 years had a 2.5‐fold (95% CI 1.6–3.8) increased hazard of cardiovascular death. Sex disparities in cardiovascular death tapered over time, least among Chinese patients and most among Indian patients; the HR comparing cardiovascular death of Indian women and men decreased from 1.9 (95% CI 1.5–2.4) at 30 days to 0.9 (95% CI 0.5–1.6) at 10 years.

Conclusion

Age, ethnicity, and time strongly influence the association between sex and specific cardiovascular causes of mortality, suggesting that health care policy to reduce sex disparities in acute myocardial infarction outcomes must consider the complex interplay of these 3 major modifying factors.

Anticoagulation use and predictors of stroke, bleeding and mortality in multi-ethnic Asian patients with atrial fibrillation: A single centre experience

INTRODUCTION

Atrial fibrillation (AF) is the most common cardiac arrhythmia in singapore. We describe a cohort of multi-ethnic Asian patients with AF, with the aim to evaluate anticoagulation use and to identify factors predictive of stroke, bleeding and all-cause mortality.

MATERIALS AND METHODS

this was a single centre, retrospective cohort study. All patients with an admission diagnosis of AF between 1 January 2000 and 31 December 2010 were identified. Of these patients, those who had follow-up data up to 31 December 2012 were included in the study.

RESULTS

there were 1095 eligible patients. the mean age was 67±14 years, mean cHADs2 score was 2±1 and mean HAs-bLED score 2±1. Of the 1095 patients, 657 (62.0%) had a cHADs2 score ≥ 2 but only 215 (32.7%) were eventually prescribed warfarin. Patients not on warfarin were older (p<0.0001) and were more likely females (p<0.0001). Among patients not on warfarin, 52% had HAs-bLED score ≤3. Multivariate analysis revealed that warfarin use and high HAs-bLED score were associated with increased bleeding risk. Age, Indian ethnicity and cHADs2 score were predictive of ischemic stroke. All-cause mortality was significantly related to age, presence of heart failure and HAs-bLED score.

CONCLUSIONS

Anticoagulation management of AF patients remains inadequate. Objective assessment of bleeding risks should be performed before withholding anticoagulation.

Clinical and Safety Outcomes of Oral Antithrombotics for Stroke Prevention in Atrial Fibrillation: A Systematic Review and Network Meta-analysis

INTRODUCTION

Novel oral anticoagulants (NOACs) expanded the options for stroke prevention in atrial fibrillation (AF). Earlier studies comparing their relative effectiveness and safety typically do not incorporate age-related differences or postmarketing studies. This study aimed to summarize and compare clinical and safety outcomes of oral antithrombotics for stroke prevention in AF in younger (65-74 years) and older (≥75 years) elderly.

METHODS

We searched PubMed, Embase, and The Cochrane Library from inception through May 1, 2015, for randomized and nonrandomized studies comparing NOACs, warfarin, and aspirin in elderly with AF. Stroke and systemic embolism (SSE) and major bleeding (MB) are the main outcomes. We also studied secondary outcomes of ischemic stroke, all-cause mortality, intracranial bleeding, and gastrointestinal bleeding.

RESULTS

Of 5255 publications identified, 25 randomized controlled trials and 24 nonrandomized studies of 897,748 patients were included. NOACs reduced the risk of SSE compared with warfarin (rate ratios [RRs] range from 0.78-0.82). Relative to SSE, NOACs demonstrated a smaller benefit for ischemic stroke (dabigatran 110 mg, RR 1.08; edoxaban, 1.00; apixaban, 0.99). On the contrary, aspirin was associated with a significantly higher risk of SSE, ischemic stroke, and mortality than warfarin or NOACs (RR > 1), particularly in older elderly. Regarding safety, medium-dose aspirin (100-300 mg daily) and aspirin/clopidogrel combination showed an increased risk of MB compared with warfarin (RR 1.17 and 1.15, respectively), as per dabigatran 150 mg and rivaroxaban in older elderly (RR 1.17 and 1.12, respectively). Among the NOACs, dabigatran 150 mg conferred greater gastrointestinal bleeding risk compared with warfarin (RR 1.51), whereas rivaroxaban (RR 0.73) demonstrated less benefit of reduced intracranial bleeding than other NOACs (RRs range 0.39-0.46).

CONCLUSIONS

Lower rates of SSE and intracranial bleeding were observed with the NOACs compared with warfarin. Dabigatran 150 mg and rivaroxaban were associated with higher rates of MB in older elderly.

Long-term prognosis and risk heterogeneity of heart failure complicating acute myocardial infarction

The Killip classification of acute heart failure was developed decades ago to predict short-term mortality in patients with acute myocardial infarction (AMI). The aim of this study was to determine the long-term prognosis of acute heart failure graded according to the Killip classification in 15,235 unselected patients hospitalized for AMI from 2000 to 2005. Vital status for each patient was ascertained, through to March 1, 2012, from linkage with national death records. A stepwise gradient in the adjusted hazard ratio (HR) for 12-year mortality was observed with increasing Killip class: class I (n = 10,123), HR 1.00 (reference group); class II (n = 2,913), HR 1.13 (95% confidence interval [CI] 1.06 to 1.21); class III (n = 1,217) HR 1.49 (95% CI 1.37 to 1.62); and class IV (n = 898), HR 2.80 (95% CI 2.53 to 3.10). Unexpectedly, in a landmark analysis excluding deaths <30 days after admission, patients in Killip class IV had lower adjusted long-term mortality than those in class III. The adjusted HR for 12-year mortality comparing Killip class IV with Killip class III in patients <60 years of age was 1.71 (95% CI 1.33 to 2.19, p <0.001) and in patients >60 years of age was 2.30 (95% CI 2.07 to 2.56, p <0.001). In conclusion, on the basis of simple clinical features, the Killip classification robustly predicted 12-year mortality after AMI. The heterogeneity in early versus late risk in patients with Killip class IV heart failure underscores the importance of appropriate early treatment in cardiogenic shock.

Impact of the joint association between sex, age and diabetes on long-term mortality after acute myocardial infarction

BACKGROUND

The role of sex, and its joint effect with age and diabetes mellitus, on mortality subsequent to surviving an acute myocardial infarction (AMI) beyond 30 days are unclear. The high prevalence of diabetes mellitus in an ethnically diverse Asian population motivates this study.

METHODS

The study population comprised of a nationwide cohort of Asian patients with AMI, hospitalized between 2000 to 2005, who survived the first 30 days post-admission and were followed prospectively until death or 12 years.

RESULTS

Among the 13,389 survivors, there were fewer women (25.5%) who were older than men (median 70 vs. 58 years) and a larger proportion had diabetes mellitus at admission (51.4% vs. 31.4%). During follow-up 4,707 deaths (women 13.2%; men 22.0%) occurred, with women experiencing higher mortality than men with an averaged hazard ratio (HR): 2.08; 95% confidence interval : 1.96-2.20. However the actual adverse outcome, although always greater, reduced over time with an estimated HR: 2.23 (2.04-2.45) at 30 days to HR: 1.75; (1.47-2.09) 12 years later. The difference in mortality also declined with increasing age: HR 1.80 (1.52-2.13) for those aged 22-59, 1.26 (1.11-1.42) for 60-69, 1.06 (0.96-1.17) and 0.96 (0.85-1.09) for those 70-79 and 80-101 years. Significant two-factor interactions were observed between sex, age and diabetes (P < 0.001). Diabetic women <60 years of age had greater mortality than diabetic men of the same age (adjusted HR: 1.44; 1.14-1.84; P = 0.003), while diabetic women and men ≥60 years of age had a less pronounced mortality difference (adjusted HR: 1.12; 0.99-1.26).

CONCLUSIONS

One in two women hospitalized for AMI in this Asian cohort had diabetes and the sex disparity in post-MI mortality was most pronounced among these who were <60 years of age. This underscores the need for better secondary prevention in this high-risk group.

Interventional strategies associated with improvements in survival for out-of-hospital cardiac arrests in Singapore over 10 years

AIM

We aim to study if there has been an improvement in survival for Out-of-Hospital Cardiac Arrest (OHCA) in Singapore, the effects of various interventional strategies over the past 10 years, and identify strategies that contributed to improved survival.

METHODS

Rates of OHCA survival were compared between 2001-2004 and 2010-2012, using nationwide data for all OHCA presenting to EMS and public hospitals. A multivariate logistic regression model for survival to discharge was constructed to identify strategies with significant impact.

RESULTS

A total of 5453 cases were included, 2428 cases from 2001 to 2004 and 3025 cases from 2010 to 2012. There was significant improvement in Utstein (witnessed, shockable) survival to discharge from 2001-2004 (2.5%) to 2010-2012 (11.0%), adjusted odds ratio (OR) 9.6 [95% CI: 2.2-41.9]). Overall survival to discharge increased from 1.6% to 3.2% (adjusted OR 2.2 [1.5-3.3]). Bystander CPR rates increased from 19.7% to 22.4% (p=0.02). The multivariate regression model (adjusted for important non-modifiable risk factors) showed that response time <8min (OR 1.5 [1.0-2.3]), bystander AED (OR 5.8 [2.0-16.2]), and post-resuscitation hypothermia (OR 30.0 [11.5-78.0]) were significantly associated with survival to hospital discharge. Conversely, pre-hospital epinephrine (OR 0.6 [0.4-0.9]) was associated negatively with survival.

CONCLUSIONS

OHCA survival has improved in Singapore over the past 10 years. Improvement in response time, public AEDs and post-resuscitation hypothermia appear to have contributed to the increase in survival. Singapore's experience might suggest that developing EMS systems should focus on reducing times to basic life support, including bystander defibrillation and post-resuscitation care.

Implications for public access defibrillation placement by non-traumatic out-of-hospital cardiac arrest occurrence in Singapore

INTRODUCTION

The American Heart Association recommends automated external defibrillator placement in public areas with a high probability (>1) of out-of-hospital cardiac arrest (OHCA) occurring in 5 years. We aimed to determine the incidence rate of OHCA for different location categories in Singapore.

METHODS

Cardiac arrest incidence was obtained from a national registry. Denominators for the actual number of sites per location category were obtained from public accessible sources, government officers and purchased statistics. Analysis was performed and expressed in terms of the corresponding 95% confidence interval (CI).

RESULTS

From 1 October 2001 to 14 October 2004, 2254 non-trauma OHCA cases were included. Mean age for arrests was 62.2 years, with 67.5% men. The location category with the highest incidence of cardiac arrests per site per 5 years was Port/Airport/Immigration Checkpoints (5.24 CI [3.66-7.20]). Top individual site with high average incidence of cardiac arrests per 5 years was Changi Airport (25.0 CI [16.18-36.90]). Seventy-one per cent of arrests occurred in residential areas. The postal sector with the highest average incidence per 100 000 population was Bedok Reservoir (54.89), whereas that with the highest population density was Bukit Merah/Alexandra with 348.14 population per 100 km(2) .

CONCLUSION

In this study, we found the categories and individual sites that clearly fulfilled the American Heart Association criteria of at least 1 OHCA per site per 5 years. This study provides a model of how cardiac arrest registry data can be used to guide local health policy on automated external defibrillator deployment.