Approach to bradyarrhythmias: A proposed algorithm

Bradyarrhythmias are commonly encountered in clinical practice. While there are several electrocardiographic criteria and algorithms for tachyarrhythmias, there is no algorithm for bradyarrhythmias to the best of our knowledge. In this article, we propose a diagnostic algorithm that uses simple concepts: (1) the presence or absence of P waves, (2) the relationship between the number of P waves and QRS complexes, and (3) the regularity of time intervals (PP, PR and RR intervals). We believe this straightforward, stepwise method provides a structured and thorough approach to the wide differential diagnosis of bradyarrhythmias, and in doing so, reduces misdiagnosis and mismanagement.

Association of face mask use with self-reported cardiovascular symptoms during the COVID-19 pandemic

INTRODUCTION@#Countries are mandating the use of face masks to stem the spread of coronavirus disease 2019 (COVID-19). Face mask use has been associated with discomfort due to its effects on thermoregulation, breathing and oxygenation. We evaluated the prevalence and severity of self-reported cardiovascular symptoms before and during face mask use.@*METHODS@#This was a cross-sectional study of 1,001 participants residing in Singapore, who participated in a self-administered questionnaire between 25 April 2020 and 4 May 2020. Symptom severity before and during mask use, and health-seeking behaviour information were collected. The study outcome was self-reported worsening of cardiovascular symptoms and its association with the type of mask worn, duration of mask worn per day, and intensity of physical activities during mask use.@*RESULTS@#The most common symptom reported during mask use was dyspnoea. Independent predictors for self-reported cardiovascular symptoms during mask use were moderate-high physical activity during mask use (odds ratio [OR] 1.634, 95% confidence interval [CI] 1.176-2.270, P = 0.003), duration of mask use for ≥3 h (OR 1.672, 95% CI 1.189-2.352, P = 0.003) and type of mask used, after adjusting for age, sex, healthcare-based worker status and presence of comorbidities. N95 mask was associated with worse symptoms when compared to surgical mask. Participants with ≥3 worsening symptoms or worsening dyspnoea, palpitations, fatigue and dizziness were more likely to seek medical help.@*CONCLUSION@#Face mask use has been proven to be an effective way in curbing COVID-19 transmission. However, participants in this study had concerns regarding its use and these concerns should be urgently addressed to enable mask use policies to be enacted.

Cost-Effectiveness of Transcatheter Aortic Valve Implantation in Intermediate and Low Risk Severe Aortic Stenosis Patients in Singapore

INTRODUCTION@#Singapore has the world's second most efficient healthcare system while costing less than 5% GDP. It remains unclear whether transcatheter aortic valve implantation (TAVI) is cost-effective for treating intermediate-low risk severe aortic stenosis (AS) patients in a highly efficient healthcare system.@*MATERIALS AND METHODS@#A two-phase economic model combining decision tree and Markov model was developed to assess the costs, effectiveness, and the incremental cost-effectiveness ratio (ICER) of transfemoral (TF) TAVI versus surgical aortic valve replacement (SAVR) in intermediate-low risk patients over an 8-year time horizon. Mortality and complications rates were based on PARTNER 2 trial cohort A and Singapore life table. Costs were mainly retrieved from Singapore National University Health System database. Health utility data were obtained from Singapore population based on the EuroQol-5D (EQ-5D). A variety of sensitivity analyses were conducted.@*RESULTS@#In base case scenario, the incremental effectiveness of TF-TAVI versus SAVR was 0.19 QALYs. The ICER of TF-TAVI was S$33,833/QALY. When time horizon was reduced to 5 years, the ICER was S$60,825/QALY; when event rates from the propensity analysis was used, the ICER was S$21,732/QALY and S$44,598/QALY over 8-year and 5-year time horizons, respectively. At a willingness to pay threshold of S$73,167/QALY, TF-TAVI had a 98.19% probability of being cost-effective after 100,000 simulations. The model was the most sensitive to the costs of TF-TAVI procedure.@*CONCLUSION@#TF-TAVI is a highly cost-effective option compared to SAVR for intermediate-low risk severe AS patients from a Singapore healthcare system perspective. Increased procedure experience, reduction in device cost, and technology advance may have further increased the cost-effectiveness of TF-TAVI per scenario analysis.

Percutaneous pulmonary valve implantation as an alternative to repeat open-heart surgery for patients with pulmonary outflow obstruction: a reality in Singapore

Right ventricle to pulmonary artery (RV-PA) conduits have been used for the surgical repair of congenital heart defects. These conduits frequently become stenosed or develop insufficiency with time, necessitating reoperations. Percutanous pulmonary valve implantation (PPVI) can delay the need for repeated surgeries in patients with congenital heart defects and degenerated RV-PA conduits. We presented our first experience with PPVI and described in detail the procedural methods and the considerations that are needed for this intervention to be successful. Immediate and short-term clinical outcomes of our patients were reported. Good haemodynamic results were obtained, both angiographically and on echocardiography. PPVI provides an excellent alternative to repeat open-heart surgery for patients with congenital heart defects and degenerated RV-PA conduits. This represents a paradigm shift in the management of congenital heart disease, which is traditionally managed by open-heart surgery.

Mid-term study of transcatheter aortic valve implantation in an Asian population with severe aortic stenosis: two-year Valve Academic Research Consortium-2 outcomes

<p><b>INTRODUCTION</b>Transcatheter aortic valve implantation (TAVI) is an effective treatment for high-risk or inoperative patients with severe aortic stenosis. Given the unique characteristics of Asian populations, questions regarding mid-term outcomes in Asians undergoing TAVI have yet to be addressed. We evaluated the two-year clinical outcomes of TAVI in an Asian population using Valve Academic Research Consortium-2 definitions.</p><p><b>METHODS</b>This prospective study recruited 59 patients from a major academic medical centre in Singapore. The main outcomes were two-year survival rates, peri-procedural complications, symptom improvement, valvular function and assessment of learning curve.</p><p><b>RESULTS</b>Mean age was 76.8 years (61.0% male), mean body surface area 1.6 mand mean logistic EuroSCORE 18.7%. Survival was 93.2%, 86.0% and 79.1% at 30 days, one year and two years, respectively. At 30 days post TAVI, the rate of stroke was 1.7%, life-threatening bleeding 5.1%, acute kidney injury 25.0%, major vascular complication 5.1%, and new permanent pacemaker implantation 6.8%. 29.3% of TAVI patients were rehospitalised (47.1% cardiovascular-related) within one year. These composite outcomes were measured: device success (93.2%); early safety (79.7%); clinical efficacy (66.1%); and time-related valve safety (84.7%). Univariate analysis found these predictors of two-year all-cause mortality: logistic EuroSCORE (hazard ratio [HR] 1.07; p < 0.001); baseline estimated glomerular filtration rate (HR 0.97; p = 0.048); and acute kidney injury (HR 5.33; p = 0.022). Multivariate analysis identified non-transfemoral TAVI as a predictor of cardiovascular-related two-year mortality (HR 14.64; p = 0.008).</p><p><b>CONCLUSION</b>Despite the unique clinical differences in Asian populations, this registry demonstrated favourable mid-term clinical and safety outcomes in Asians undergoing TAVI.</p>

Demographics of severe valvular aortic stenosis in Singapore

<p><b>INTRODUCTION</b>The treatment of aortic valve stenosis (AS) is seeing renewed interest mainly due to the availability of transcatheter therapies. However, the number of epidemiological studies of this disease in Singapore is limited. We aimed to describe the aetiology and clinical presentation of AS in Singapore, as well as patients' attitudes toward it. Our findings may facilitate the future planning and utilisation of resources to better manage these patients.</p><p><b>METHODS</b>249 consecutive patients who underwent transthoracic echocardiography (from April 1999 to April 2008) and diagnosed with severe AS were assessed. Demographic and clinical data were collected, and patients' decisions on surgery were determined.</p><p><b>RESULTS</b>The mean patient age was 71 (range 23-98) years. 50.2% of patients were male. The commonest presenting symptom was dyspnoea, and 40 (16.0%) patients had coexistent atrial fibrillation. The aetiology of AS was degenerative in 216 (86.7%), rheumatic in 11 (4.4%) and related to a bicuspid valve in 22 (8.9%) patients. The average peak velocity across the aortic valve was 4.2 ± 0.8 m/s and the mean aortic valve area was 0.76 ± 0.13 cm2. The overall mean logistic EuroSCORE was 10.7 ± 12.3. 105 (42.2%) patients who were offered surgery refused. 87 (35%) deaths were seen during the follow-up period (mean duration 14.5 months), which also saw 68 (27%) patients undergo surgery and 86 (34%) patients hospitalised for heart failure.</p><p><b>CONCLUSION</b>Degenerative AS was the commonest aetiology in this contemporary cohort of patients. Despite the known benefits of surgery, the refusal rate for surgery remained high.</p>

Framingham risk score inadequately predicts cardiac risk in young patients presenting with a first myocardial infarction

<p><b>INTRODUCTION</b>The Framingham Risk Score (FRS) is a well-validated epidemiologic tool used to assess the risk for a fi rst cardiac event. Because young patients presenting with a fi rst myocardial infarction (MI) tend to have less significant risk profiles compared with older patients, we hypothesized that FRS may underestimate cardiac risk in these patients.</p><p><b>MATERIALS AND METHODS</b>We studied 1267 patients between January 2002 and November 2007 presenting with a fi rst MI. Patients with pre-existing diabetes mellitus and vascular disease were excluded. FRS was calculated for each patient. Patients were divided based on their age: group A (<40 years), group B (40 to 64 years) and group C (> or =65 years).</p><p><b>RESULTS</b>The mean age was 54.7 +/- 11 years, 88.4% of the patients were males. Younger patients were more likely to be assigned with lower scores. Based on FRS, 63.0%, 29.3% and 14.2% of group A, B and C patients were classified as low risk (10-year risk for cardiac events<10%) respectively, P <0.001. The sensitivity of FRS in identifying at least intermediate risk subjects (10-year risk for cardiac events >10%) was 37.0% in group A vs 85.8% in group C (P <0.001). The incidence of newly diagnosed diabetes mellitus was higher in younger patients (12.0% vs 13.2% vs 7.1 % in groups A, B and C respectively, P = 0.027).</p><p><b>CONCLUSIONS</b>FRS inadequately predicts cardiac risk in young patients presenting with a fi rst MI. This could be because a significant proportion of these young patients have undiagnosed diabetes mellitus, a coronary artery disease risk equivalent.</p>

Reperfusion strategy and mortality in ST-elevation myocardial infarction among patients with and without impaired renal function

<p><b>INTRODUCTION</b>Several randomised controlled trials have demonstrated better outcomes with primary percutaneous coronary intervention (PCI) over fibrinolytic therapy in the treatment of patients with ST-segment elevation myocardial infarction (STEMI) and normal renal function. Whether this benefit extends to patients with impaired renal function is uncertain.</p><p><b>MATERIALS AND METHODS</b>We studied 1672 patients with STEMI within 12 hours of symptom onset who were admitted to 2 major public hospitals in Singapore from 2000 to 2002. All patients received either upfront fibrinolytic or PCI as determined by the attending cardiologist. Serum creatinine was measured on admission and the glomerular filtration rate (GFR) was determined using the Modification of Diet in Renal Disease equation. The impact of reperfusion strategy on 30-ay mortality was then determined for patients with GFR > or =60 mL min-(1) 1.73 m-(2) and GFR <60 mL min-(1) 1.73 m-(2).</p><p><b>RESULTS</b>The mean age was 56 +/- 12 years (85% male) and mean GFR was 81 +/- 30 mL min-(1) 1.73 m-(2). Unadjusted 30-day mortality rates for fibrinolytic-treated vs primary PCI-treated patients were 29.4% vs 17.9%, P <0.05, in the impaired renal function group and 5.4% vs 3.1%, P <0.05, in the normal renal function group. After adjusting for covariates, primary PCI was associated with a significantly lower mortality in the normal renal function group [odds ratio (OR), 0.41; 95% confidence interval (CI), 0.19-0.89] but not in the impaired renal function group [OR, 0.70; 95% CI, 0.31-1.60].</p><p><b>CONCLUSIONS</b>Primary PCI was associated with improved 30-day survival among patients with normal renal function but not among those with impaired renal function. Randomised trials are needed to study the relative efficacy of both reperfusion strategies in patients with impaired renal function.</p>

Risk factor profile and treatment patterns of patients with atherothrombosis in Singapore: insight from the REACH Registry

<p><b>INTRODUCTION</b>Atherothrombosis is the leading cause of cardiovascular mortality. The Reduction of Atherothrombosis for Continued Health (REACH) Registry provided information on atherosclerosis risk factors and treatment. Singapore was one of the 44 participating countries in the REACH Registry. The objective of this study was to determine the atherosclerosis risk factor profile and treatment patterns in Singapore patients enrolled in the REACH Registry.</p><p><b>MATERIALS AND METHODS</b>The REACH Registry is an international prospective observational registry of subjects with or at risk for atherothrombosis. Patients aged 45 years or older with established vascular disease [coronary artery disease (CAD), cerebrovascular disease (CVD), peripheral arterial disease (PAD)] or 3 or more atherosclerosis risk factors were recruited between 2003 and 2004.</p><p><b>RESULTS</b>A total of 881 patients (64.4% male) were recruited in Singapore by 63 physicians. The mean age was 64 +/- 9.8 years (range, 45 to 95). Seven hundred and one (79.6%) patients were symptomatic (CAD 430, CVD 321, PAD 72) while 180 (20.4%) patients had > or =3 risk factors. Approximately 13% of symptomatic patients had symptomatic polyvascular disease. There was a high proportion of diabetes mellitus (57%), hypertension (80.6%) and hypercholesterolemia (80.1%). A substantial proportion of symptomatic patients were current smokers (14.1%). Approximately half of the patients were either overweight or obese [abdominal obesity, 54.3%; body mass index (BMI) 23-27.5, 45.9%; BMI > or =27.5, 23.3%]. Patients were undertreated with antiplatelet agents (71.9% overall; range, 23.9% for > or =3 risk factors to 84.7% for PAD) and statins (76.2% overall; range, 73.6% for PAD to 82.1% for CAD). Risk factors remained suboptimally controlled with a significant proportion of patients with elevated blood pressure (59.4% for > or =3 risk factors and 48.6% for symptomatic patients), elevated cholesterol (40% for > or =3 risk factors and 24.4% for symptomatic patients) and elevated blood glucose (45% for > or =3 risk factors and 19.8% for symptomatic patients).</p><p><b>CONCLUSION</b>Established atherosclerosis risk factors are common in Singapore patients in the REACH Registry; and obesity is a major problem. Most of these risk factors remained suboptimally controlled.</p>