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.

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.

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.

Outcomes of supraventricular tachycardia ablation: Results from the Singapore ablation and cardiac devices registry.

BACKGROUND: The Singapore Cardiac Databank was designed to monitor the performance and outcomes of catheter ablation. We investigated the outcomes of paroxysmal supraventricular tachycardia (PSVT)-ablation in a prospective, nationwide, cohort study. METHODS: Atrioventricular nodal re-entrant tachycardia (AVNRT), atrioventricular re-entry tachycardia (AVRT), or atrial tachycardia (AT)-ablations in Singapore from 2010 to 2018 were studied. Outcomes include acute success, periprocedural-complications, postoperative pacing requirement, arrhythmic recurrence and 1-year all-cause mortality. RESULTS: Among 2260 patients (mean age 45 ± 18 years, 50% female, 57% AVNRT, 37% AVRT, 6% AT), overall acute success rates of PSVT-ablation was 98.4% and increased in order of AT, AVRT, and AVNRT (p < .001). Periprocedural cardiac tamponade occurred in two AVRT patients. A total of 15 pacemakers (6 within first 30-days, 9 after 30-days) were implanted (seven AV block, eight sinus node dysfunction [SND]), with the highest incidence of pacemaker implantation after AT-ablation (5% vs. 0.6% AVNRT vs. 0.1% AVRT, p < .001). Repeat ablations (0.9% AVNRT, 7% AVRT, 4% AT, p < .001) were performed in 78 (3.5%) patients and 13 (0.6%) patients died within a year of ablation. Among outcomes considered adjusting for age, sex, PSVT-type and procedure-time, AT was independently associated with 6-fold increased odds of total (adjusted odds ratio [AOR] 6.32, 95% confidence interval [CI] 1.95-20.53) and late (AOR 6.38, 95% CI 1.39-29.29) pacemaker implantation, while AVRT was associated with higher arrhythmic recurrence with repeat ablations (AOR 4.72, 95% CI 2.36-9.44) compared to AVNRT. CONCLUSIONS: Contemporary PSVT ablation is safe with high acute success rates. Long-term outcomes differed by nature of the PSVT.

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.

Therapeutic temperature management (TTM): post-resuscitation care for adult cardiac arrest, with recommendations from the National TTM Workgroup.

Therapeutic temperature management (TTM) was strongly recommended by the 2015 International Liaison Committee on Resuscitation as a component of post-resuscitation care. It has been known to be effective in improving the survival rate and neurologic functional outcome of patients after cardiac arrest. In an effort to increase local adoption of TTM as a standard of post-resuscitation care, this paper discusses and makes recommendations on the treatment for local providers.

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.

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.

Clinical quality improvement: eliminating unplanned extubation in the CCU.

PURPOSE: This article aims to explore coronary care unit (CCU) extubation structures, processes and outcomes. There were 13 unplanned-extubation cases (UE) among 251 intubated patients (5.2 per cent) in a cardiologist-led CCU in 2008. Seven did not require re-intubation, implying possible earlier extubation. A quality improvement project was undertaken with a goal to eliminate CCU UE within 12 months. DESIGN/METHODOLOGY/APPROACH: Using the clinical practice improvement (CPI) method, the most significant root causes were missing sedation/analgesia protocol, no ventilator weaning protocol and absent respiratory therapist during the CCU morning rounds. Non-physician directed sedation/analgesia and ventilation weaning protocols were created and put on trial in Plan-Do-Study-Act cycles before formal implementation. Arrangements were made to allocate a respiratory therapist to the CCU daily for morning rounds. FINDINGS: For 12 months after fully implementing the interventions, UE incidence dropped from 5.2 per cent to 0.9 per cent (p = 0.006). There were no adverse outcomes, re-intubation and/or readmission to CCU within 48 hours. PRACTICAL IMPLICATIONS: Through a multi-disciplinary CPI approach, adopting non-physician directed protocols has successfully streamlined and improved airway management in mechanically ventilated patients in a cardiologist-led CCU. ORIGINALITY/VALUE: There is little published data on improving intubated patient care in cardiologist-led CCUs. Previous studies centered on intensive care units managed by critical care specialists.

Coronary artery calcification across ethnic groups in Singapore.

INTRODUCTION: In Singapore, the age-standardised event rates of myocardial infarction (MI) are 2- and 3-fold higher for Malays and Indians respectively compared to the Chinese. The objectives of this study were to determine the prevalence and quantity of coronary artery calcification (CAC) and non-calcified plaques across these 3 ethnic groups. MATERIALS AND METHODS: This was a retrospective descriptive study. We identified 1041 patients (810 Chinese, 139 Malays, 92 Indians) without previous history of cardiovascular disease who underwent cardiac computed tomography for atypical chest pain evaluation. A cardiologist, who was blinded to the patients' clinical demographics, reviewed all scans. We retrospectively analysed all their case records. RESULTS: Overall, Malays were most likely to be active smokers (P = 0.02), Indians had the highest prevalence of diabetes mellitus (P = 0.01) and Chinese had the highest mean age (P <0.0001). The overall prevalence of patients with non-calcified plaques as the only manifestation of sub-clinical coronary artery disease was 2.1%. There was no significant difference in the prevalence of CAC, mean CAC score or prevalence of non-calcified plaques among the 3 ethnic groups. Active smoking, age and hypertension were independent predictors of CAC. Non-calcified plaques were positively associated with male gender, age, dyslipidaemia and diabetes mellitus. CONCLUSION: The higher MI rates in Malays and Indians in Singapore cannot be explained by any difference in CAC or non-calcified plaque. More research with prospective follow-up of larger patient populations is necessary to establish if ethnic-specific calibration of CAC measures is needed to adjust for differences among ethnic groups.