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W S Teo

Publications and source records attributed to W S Teo.

At least 19 recordsLinked to original sources
PubMed2006

Electrocardiographical case. An elderly lady with chest pain. Diagnosis: isolated posterior myocardial infarct (MI).

A 72-year-old woman with diabetes mellitus, hypertension and dyslipidaemia presented with severe chest pain of four hours duration. Her electrocardiogram (ECG) showed tall R waves in leads V1-2, and ST segment depression in leads V1- 4, consistent with an isolated posterior myocardial infarction (MI). Emergency coronary angiogram showed an occluded left circumflex coronary artery, and primary angioplasty and stenting was performed. The ECG criteria for isolated posterior MI and pitfalls in using the conventional 12-lead ECG are discussed.

Aged↗
PubMed2006

Electrocardiographical case. Acute severe chest tightness.

The early diagnosis of acute myocardial infarction is crucial for the institution of appropriate reperfusion therapy. We describe a 56-year-old man who developed sudden onset of severe chest tightness. Inferior, posterior and right ventricular ST elevation myocardial infarction was diagnosed on electrocardiography (ECG). The ECG interpretation, differential diagnosis and management are discussed.

Acute Disease↗
PubMed2005

Electrocardiographical case. Elderly woman with sudden onset of post-operative dyspnoea.

A 70-year-old Chinese woman developed breathlessness, tachycardia and hypotension on the fourth day after total hip replacement. 12-lead electrocardiogram (ECG) showed sinus tachycardia with ST depression in I, II, V5 and V6. The ECG changes of sinus tachycardia along with a typical history is suggestive of pulmonary embolism. Diagnosis, treatment and the use of IVC filter for pulmonary embolism are discussed.

Aged↗
PubMed2004

Electrocardiographical case. Asymptomatic patient with ST-segment elevation.

A 46-year-old man complained of recurrent episodes of giddiness which was not associated with chest pain or breathlessness. There was no family history of sudden death. Clinical examination was unremarkable.12-lead electrocardiogram (ECG) showed ST segment elevation in the right precordial leads, with coved ST segment elevation at its J point followed by a negative T wave with no isoelectric separation, specifically in V2. These ECG features are characteristic of the Brugada syndrome. He underwent a flecanide challenge which produced further elevation of ST segment at its J point and spontaneous ventricular ectopy. Electrophysiological studies induced ventricular fibrillation with 3 extra stimuli. An implantable cardioverter-defibrillator was implanted for prevention of sudden cardiac death. The Brugada syndrome is discussed.

Bundle-Branch Block↗
PubMed2003

Immediate and mid-term safety and efficacy of single lead VDD pacemakers for patients with atrioventricular block and normal sinus node function--a single centre experience.

INTRODUCTION: Single lead atrial synchronous ventricular pacing (VDD) is increasingly being used in place of conventional dual chamber pacing (DDD) for patients with atrioventricular block and preserved sinus node function. Compared to the latter, VDD pacemakers provide similar haemodynamic benefits derived from atrial synchronous pacing, with the added benefit of an easier implant procedure. OBJECTIVE: To review the use, safety and efficacy of VDD pacing in a single tertiary referral centre. MATERIALS AND METHODS: A review of all patients with atrioventricular block and normal sinus node function implanted with a VDD pacemaker over a 2-year period at a local tertiary cardiac referral centre. Data on complications, atrial sensing performance and maintenance of atrioventricular synchrony during implant and at subsequent follow-up visits were obtained from a prospectively maintained registry and analysed. RESULTS: Forty-one patients (17 males, 24 females) with a mean age of 72 +/- 9 years received VDD pacing for various forms of high-grade atrioventricular block. The average implantation time was 46.8 +/- 17.1 minutes, and a pneumothorax in 1 patient was the only complication. Electrical measurements at implantation and subsequent follow-up visits revealed an initial rapid decrease in atrial signal amplitude (mean atrial P wave at implant 3.1 +/- 1.1 mV, predischarge 1.9 +/- 1.3 mV) which began to stabilise after 3 months, reaching a mean atrial P wave value of 1.3 +/- 0.3 mV at 24 months. The atrial sensing performance (percentage of atrial synchronous ventricular complexes) was 97% over a mean follow-up period of 9.9 months. Four patients (10%) developed paroxysmal atrial tachyarrhythmias. Sinus node dysfunction was not observed in any of our patients during the follow-up period. CONCLUSION: In patients with atrioventricular block and preserved sinus node function, single lead VDD pacing is safe and effective in maintaining a physiological atrial synchronous pacing mode.

Adult↗
PubMed2003

A case series of sotalol-induced torsade de pointes in patients with atrial fibrillation--a tale with a twist.

INTRODUCTION: Sotalol is a potent antiarrhythmic often used in patients with atrial fibrillation. However, it has been associated with a risk of provoking other potentially dangerous arrhythmias, especially if used in high doses and in patients with uncorrected electrolyte imbalance or impaired renal and cardiac function. CLINICAL PICTURE: We present 4 patients with atrial fibrillation treated with sotalol who developed torsade de pointes due to marked prolongation of the QT interval. While 1 patient had renal failure, all had normal left ventricular function. One patient had been treated with sotalol for more than 10 months before developing torsade de pointes precipitated by hypokalaemia, while another had tolerated sotalol for a 3-month period before the drug was discontinued, and only developed torsade de pointes when the drug was restarted 2 years later. Significantly, the doses used in all patients were relatively low, in contrast to most other reported cases where higher doses were used. CONCLUSION: As with all antiarrhythmic therapy, these cases illustrate the need for close follow-up of patients treated with sotalol, even if relatively low doses are used. In addition, patients who had previously tolerated the drug well are still susceptible to its proarrhythmic effects.

Aged↗
PubMed2003

Treatment of heart failure--role of biventricular pacing for heart failure not responding well to drug therapy.

OBJECTIVE: Patients with heart failure may have conduction abnormalities in up to 30%, further aggravating cardiac output. Drugs worsen these abnormalities and resynchronisation therapy with biventricular pacing improves cardiac function by effecting a more coordinated and efficient ventricular contraction. We report here the technique of biventricular pacing and its results. METHODOLOGY: Patients with NYHA Class III to IV heart failure, widened QRS (> or = 130 ms) complex on the ECG and impaired LVEF < or = 40% were enrolled. RESULTS: Biventricular pacing was performed in 29 patients (26 males, three females) from August 1999 to December 2001. The mean age of the patients was 59.6 +/- 12.8 years and 62% had underlying ischemic heart disease. All were in NYHA class III or more. Twenty-three had LBBB, four RBBB and two had widened paced QRS complex. The QRS duration was 161 +/- 21 ms and LVEF was 22 +/- 8%. All the left ventricular leads were implanted successfully. The procedure time was 167.0 +/- 79.6 mins and the fluoroscopy time was 43.8 +/- 41.4 mins. There were no significant complications. The NYHA class improved from a mean of 3.1 to 2.0 and exercise time from 252 +/- 95 seconds to 392 +/- 152 seconds at six months post implant (p=0.049). On follow-up (one month to 28 months), 25 (86%) patients had improvement in heart failure symptoms and 26 (90%) of the patients remained alive. CONCLUSION: Biventricular pacing can be safely performed and results in improvement in symptoms and exercise tolerance in heart failure patients with ventricular dyssynchrony not responding to drug therapy.

Cardiac Pacing, Artificial↗
PubMed2002

Slow-infusion of calcium channel blockers in the emergency management of supraventricular tachycardia.

OBJECTIVE: To compare the efficacy of verapamil and diltiazem as slow infusions in terminating spontaneous supraventricular tachycardia (SVT) in the emergency department (ED). METHOD: Patients of at least 10 years of age who presented to our ED with regular narrow complex tachycardia not converted with a vagal manoeuvre with an ECG diagnosis of SVT were included. Those who were haemodynamically unstable were excluded. Patients were randomized to undergo either verapamil infusion at a rate of 1 mg/min to a maximum of 20 mg or diltiazem infusion at a rate of 2.5 mg/min to a maximum of 50 mg. RESULTS: Eighty-one patients were randomized to receive verapamil infusion and 80 were randomized to receive the diltiazem infusion. There is no difference in success rate between verapamil (98.8%) and diltiazem (96.3%) infusion. The dose of medication required to convert 25,50 and 75% of SVTs were 4.0,5.0 and 8.0 mg for the verapamil infusion and 10.0,12.5 and 17.5 mg for the diltiazem infusion. There was one complication in each group. CONCLUSION: Calcium channel blockers infusions were safe and efficacious in terminating spontaneous SVT. There was no difference between the success rates of verapamil and diltiazem infusions.

Calcium Channel Blockers↗
PubMed2002

Clinical outcomes of patients with diabetes mellitus and acute myocardial infarction treated with primary angioplasty or fibrinolysis.

OBJECTIVE: To compare the early and late outcomes of primary percutaneous transluminal coronary angioplasty (PTCA) with fibrinolytic treatment among diabetic patients with acute myocardial infarction (AMI). DESIGN: Retrospective observational study with data obtained from prospective registries. SETTING: Tertiary cardiovascular institution with 24 hour acute interventional facilities. PATIENTS: 202 consecutive diabetic patients with AMI receiving reperfusion treatment within six hours of symptom onset. INTERVENTIONS: Fibrinolytic treatment was administered to 99 patients, and 103 patients underwent primary PTCA. Most patients undergoing PTCA received adjunctive stenting (94.2%) and glycoprotein IIb/IIIa inhibition (63.1%). MAIN OUTCOME MEASURES: Death, non-fatal reinfarction, and target vessel revascularisation at 30 days and one year were assessed. RESULTS: Baseline characteristics were similar in these two treatment groups except that the proportion of patients with Killip class III or IV was considerably higher in those treated with PTCA (15.5% v 6.1%, p = 0.03) and time to treatment was significantly longer (103.7 v 68.0 minutes, p < 0.001). Among those treated with PTCA, the rates for in-hospital recurrent ischaemia (5.8% v 17.2%, p = 0.011) and target vessel revascularisation at one year (19.4% v 36.4%, p = 0.007) were lower. Death or reinfarction at one year was also reduced among those treated with PTCA (17.5% v 31.3%, p = 0.02), with an adjusted relative risk of 0.29 (95% confidence interval 0.15 to 0.57) compared with fibrinolysis. CONCLUSION: Among diabetic patients with AMI, primary PTCA was associated with reduced early and late adverse events compared with fibrinolytic treatment.

Abciximab↗
PubMed2002

Two case reports on incessant left ventricular tachycardia: curative therapy with radiofrequency ablation.

INTRODUCTION: Incessant ventricular tachycardia is a rare arrhythmia which can be life threatening. Treatment with anti-arrhythmic agents may occasionally fail. CLINICAL PICTURE: We report 2 cases of incessant ventricular tachycardia. The first case was a young man with idiopathic left ventricular tachycardia who was in incessant ventricular tachycardia despite treatment with multiple anti-arrhythmic drugs and developed dilated cardiomyopathy. The second case was an asymptomatic girl with the incidental finding of an incessant ventricular tachycardia which originated from the left ventricular outflow tract. TREATMENT AND OUTCOME: Both patients underwent electrophysiologic study and radiofrequency ablation with complete termination of the tachycardia. CONCLUSION: Radiofrequency catheter ablation in experienced centres should be the first-line therapy for incessant ventricular tachycardia.

Adolescent↗
PubMed2002

Myocardial infarction in Singapore: a nationwide 10-year study of multiethnic differences in incidence and mortality.

INTRODUCTION AND METHODS: Cardiovascular diseases have progressively increased in importance as a major contributor of morbidity and mortality in Asia. However, many countries in Asia do not have nationwide systematically-collected and standardised data on myocardial infarction (MI). To accurately document the extent of atherosclerotic coronary heart disease in Singapore, a nationwide myocardial infarct registry was established in the mid-1986. Possible myocardial infarct events were identified through daily national lists of cardiac enzymes, hospital discharge codes, mortuary records and the national death registry. Data obtained from clinical history, cardiac enzymes and 12-lead electrocardiogram Minnesota codes were entered into an algorithm based on the WHO MONICA study. Cases identified as "definite" MI were included in the decade's review for this study. RESULTS: From 1988 to 1997, 13,048 myocardial infarct events were diagnosed with 3367 deaths. There was a 39.1% decline in mortality, with an average decline of 6.5% per year [95% confidence intervals (CI), -3.9% to -9.1%]. However, the decline in incidence was only 20.8% with an average decline of 2.4% per year (95% CI, -6.6% to -1.2%). The highest incidence and mortality rates for both genders were seen in the Indians, followed by the Malays and the Chinese. CONCLUSION: Over 10 years, from 1988 to 1997, we documented a significant fall in mortality from MI in Singapore. There was a smaller decline in the incidence of infarction. Singapore implemented a National Healthy Lifestyle Programme in 1992 as a 10-year effort. The disparity in the incidence and mortality may suggest that a more dramatic and immediate impact has taken place in mortality through therapeutic programmes; primary preventive programmes would be more difficult to evaluate and have a more gradual impact. Only with continual accurate data collection through the whole country, over a much longer period, can the relative value of preventive and therapeutic programmes in coronary heart disease be assessed.

Adult↗
PubMed2001

Dual-site atrial pacing for atrial fibrillation in patients without bradycardia.

Atrial pacing has been shown to delay the onset of atrial fibrillation (AF) when compared with ventricular pacing in patients with sick sinus syndrome. The role for pacing in the control of AF in patients without bradycardia is uncertain. We performed a randomized, crossover, single-blinded study in 22 patients (14 women, aged 63 +/- 10 years) with paroxysmal AF refractory to treatment with oral sotalol (202 +/- 68 mg/day) and no bradycardic indication for pacing. All patients received a dual-chamber pacemaker with 2 atrial pacing leads positioned at the high right atrium and coronary sinus ostium, respectively. Patients were randomized in a crossover fashion to be paced for 12 weeks, either with high right atrial (RA) pacing at 30 beats/min ("Off") or dual-site RA pacing with an overdrive algorithm that maintained atrial pacing at a rate slightly above the sinus rate ("On"). Treatment on resulted in a significantly higher percentage of atrial pacing and a reduction in atrial ectopic frequency than the treatment off period. The time to the first clinical AF recurrence was prolonged (15 +/- 17 to 50 +/- 35 days, p = 0.006), and total AF burden was reduced (45 +/- 34% vs 22 +/- 29%, p = 0.04) in the on-treatment phase. However, there was no difference in AF checklist symptom scores or overall quality-of-life measures. Dual-site RA pacing with continued sinus overdrive prolonged the time to AF recurrence and decreased AF burden in patients with paroxysmal AF. The absence of a major impact on symptom control suggests that pacing should be used as an adjunctive therapy with other treatment modalities for AF.

Adolescent↗
PubMed2001

A case series of drug-induced long QT syndrome and Torsade de Pointes.

INTRODUCTION: Torsade de Pointes (Tdp) is a form of polymorphic ventricular tachycardia in the setting of prolonged QT interval. Any drug that prolongs repolarisation, and hence QT interval, may cause Tdp. Predisposing factors of drug-induced Tdp include female sex, bradyarrhythmia and hypokalaemia. METHODS: We retrospectively analysed the case notes of 13 patients with drug-induced LQTS from 1991 to 2000 from National Heart Centre and Changi General Hospital. RESULTS: Causative drugs in the series were amiodarone (seven patients, 54%), sotalol (two patients), quinidine (one patient), phenothiazine (two patients) and astemizole (one patient). There were eight females and all were Chinese. The mean age was 72 +/- nine years. The patients commonly present with syncope (38%) and cardiac arrest (38%). The mean corrected QTC interval was 545 ms. The most common precipitating factor was hypokalaemia (31%). Nine patients require cardiopulmonary resuscitation and two patients (15%) died. Nine patients (69%) had underlying structural heart disease such as ischaemic heart disease, valvular heart disease and hypertensive heart disease. The left ventricular ejection fraction was normal in six patients. The onset of Tdp ranged from Day 2 to Day 5 in the seven patient with amiodarone-induced LQTS. These were inpatients who were given intravenous loading doses of amiodarone. Both patients with sotalol-induced LQTS were females on sotalol 80 mg and 240 mg per day with Tdp occurring on Day 2 and 10 months respectively. CONCLUSION: Tdp is a potentially life-threatening arrhythmia. The list of torsadogenic drugs is ever expanding. Physicians need to know the drugs which can lead to Tdp. Careful assessment of risk-benefit ratio is important before prescribing such drugs. Amiodarone-induced Tdp is not uncommon in our local population. Initiation of a class III agent, especially amiodarone, should be done judiciously, with monitoring of the QT interval and avoidance of hypokalaemia.

Aged↗
PubMed2000

Electrocardiographic case: diagnosis of acute myocardial infarction in the presence of left bundle branch block.

The electrocardiographic features associated with acute myocardial infarction (AMI) are often easily recognised. However, interpretation is made more difficult in the presence of confounding patterns such as a left bundle branch block (LBBB). This may result in missed cases which may otherwise have benefited from acute revascularisation therapy. Though not straightforward, the diagnosis of AMI in the presence of LBBB can be made with a reasonable amount of accuracy. We report a case of acute myocardial infarction with LBBB that was appropriately diagnosed and underwent acute revascularisation by angioplasty. A detailed knowledge of the typical electrocardiographic features associated with LBBB, especially the ST segment morphologies, is very important. This will greatly aid recognition of an evolving AMI and help us decide on the most appropriate therapy.

Bundle-Branch Block↗