Antecedent risk factors and their control in young patients with a first myocardial infarction.

INTRODUCTION: Identifying and controlling cardiovascular risk factors at an early age may prevent cases of young myocardial infarction (MI). We studied age-related differences in the cumulative incidence of risk factors and the adequacy of primary prevention by surveying 1,556 patients with a first MI admitted to a tertiary hospital in Singapore. METHODS: This is a single centre registry-based study on patients admitted with a first MI to a tertiary hospital in Singapore. We stratified the cohort into younger (45 years of age and younger) and older (older than 45 years of age) groups. The presence of five risk factors, namely: hypertension, diabetes mellitus (DM), smoking, a family history of premature MI, and hyperlipidaemia, was assessed at the point of care by interview and prior medical records when obtainable. We also determined by the same methods, if these patients were receiving active treatment for DM, hypertension or hyperlipidaemia prior to their first MI. Lipid levels were measured within 24 hours of admission. RESULTS: 96 percent of patients 45 years and younger and 92 percent of those older than 45 years had at least one antecedent risk factor. The 45 years and younger age group had a higher incidence of untreated hypertension (odds ratio 2.99, 95 percent confidence interval 2.00-4.46, p-value is less than 0.001) and hyperlipidaemia (odds ratio 1.71, 95 percent confidence interval 1.20 - 2.43, p-value is equal to 0.002). CONCLUSION: A majority of young patients with a first MI have at least one identifiable antecedent risk factor. There is significant undertreatment of hypertension and hyperlipidaemia in this age group.

Electrocardiographic patterns in posterior chest leads (V7, V8, V9) in normal subjects.

The electrocardiographic patterns in leads V7, V8, and V9 were studied in 225 young, normal men (age range 17 to 21 years). The prevalence of 0.5- to 1.0-mm ST-segment elevation in leads V7, V8, and Vg 0.08 second after the J point was 8.9%, 5.8%, and 3.1%, respectively; the ST-segment elevation was not >1.0 mm in any subject.

Usefulness of ST elevation II/III ratio and ST deviation in lead I for identifying the culprit artery in inferior wall acute myocardial infarction.

In a study of 92 patients presenting with inferior wall acute myocardial infarction, the infarct-related artery was the right coronary artery in 72 patients (78%) and the left circumflex artery in 20 (22%). An ST II/III ratio of 1 or an isoelectric ST in lead I are sensitive and specific markers of left circumflex artery occlusion, whereas an ST II/III ratio <1 (ST elevation in lead III >II) or ST depression in lead I are sensitive and specific markers of right coronary artery occlusion.

Two-dimensional and pulsed Doppler echocardiographic abnormalities in coronary artery-pulmonary artery fistula.

We describe two patients who presented with precordial continuous murmurs which were diagnosed clinically as due to patent ductus arteriosus; however, two-dimensional echocardiographic and pulsed Doppler echocardiographic studies showed dilatation of the left main coronary artery with turbulent flow during systole in the lumen in both patients. Subsequent selective coronary angiographic studies showed bilateral coronary artery-pulmonary artery fistula in one patient and left coronary artery-pulmonary artery fistula in the other. This study illustrates that in a patient presenting with a continuous murmur which is suggestive of patent ductus arteriosus, such two-dimensional and pulsed Doppler echocardiographic findings as were seen in our patients should immediately alert the physician that he may be dealing with a case of coronary arterial fistula.

Atrial flutter in Wolff-Parkinson-White syndrome responding to intravenous disopyramide.

Atrial flutter occurring in patients with the Wolff-Parkinson-White syndrome is extremely uncommon. We describe a patient with this arrhythmia which converted to sinus rhythm and normal conduction following intravenous administration of disopyramide.

Right chest electrocardiographic patterns in normal subjects.

Right-sided chest lead ECGs (V3R to V6R) were recorded in 110 normal male subjects who were between the ages of 17 and 22 years old (mean, 17.9 years). The prevalence of the rS pattern decreased from V3R (89 percent) to V6R (37 percent). However, the opposite was the case for the rSr pattern (10 percent in V3R and 36 percent in V6R). The amplitudes of the r wave, S wave and secondary r wave all progressively decreased from V3R to V6R. The prevalence of the qr and qS patterns was 0 and 1 percent, respectively in V3R and 14 and 2 percent, respectively in V6R. A positive ST segment deviation of 0.5 to 1 mm was present in 13 percent of subjects in V3R and 5 percent in V4R. T wave inversion was common and the prevalence increased from V3R (60 percent) to V6R (79 percent).

Two-dimensional echocardiographic abnormalities of right atrial metastatic tumors in hepatoma.

We describe two patients suffering from hepatoma who presented with right atrial metastatic tumors as a result of invasion of the inferior vena cava and extension into the right atrium. Two-dimensional echocardiographic studies detected the right atrial tumor during life in both patients and the invasion of the inferior vena cava in one patient.

Musical murmur and cardiac shudder.

When echocardiographic studies show several structures vibrating at a similar frequency to an associated musical cardiac murmur, the structure vibrating most strongly may localize the origin of the murmur.

Intra-atrial smoke-like echoes and thrombi formation.

Between December 1980 and December 1987, approximately 6,000 two-dimensional echocardiographic examinations were performed in our noninvasive cardiac laboratory. During this period, five cases of intra-atrial smoke-like echoes were diagnosed. The four patients with dense smoke-like echoes in the left atria all had echocardiographic evidence of severe mitral stenosis and thrombi in the left atrial cavity, both of which were confirmed at open-heart surgery. One patient with right-sided cardiomyopathy had echocardiographic evidence of dense smoke-like echoes and thrombus in the right atrial cavity. One of our five patients was receiving anticoagulant therapy, and none had a history of thromboembolism. We conclude that using conventional two-dimensional echocardiographic techniques, smoke-like echoes in the atria are a very infrequent finding and are very commonly associated with formation of thrombi.

Spontaneous aortic laceration causing flail aortic valve and acute aortic regurgitation.

Spontaneous laceration of the aorta is an unusual cause of flail aortic valve. We report a case of acute aortic regurgitation caused by flail aortic valve as a result of spontaneous laceration of the ascending aorta. The role of transesophageal echocardiography in the diagnosis of this condition is discussed.

A comparison between once-daily and twice-daily administration of metoprolol in the management of hypertension.

The efficacy of metoprolol as an antihypertensive agent was assessed in 20 previously untreated Asian patients with mild to moderate hypertension. After a 4-week run-in period when placebo therapy was given, the patients were given oral metoprolol at a starting dosage of 100 mg twice daily. The dosage of metoprolol was increased at fortnightly intervals until either satisfactory blood pressure control, defined as a diastolic blood pressure of less than 90 mmHg or a greater than 10% fall in pre-treatment diastolic blood pressure, was achieved or a total of 400 mg metoprolol was reached. All 20 patients had satisfactory control of their blood pressures on a twice-daily regimen and the average dosage of metoprolol required was 200 mg daily. For the second part of the study, the medication was changed to a once-daily regimen at the same total dosage of metoprolol. Final efficacy of once-daily therapy was assessed after 8 weeks of treatment. All blood pressure and pulse rate reductions were significant (P < 0.001) from the placebo phase. However, twice-daily and once-daily readings were not significantly different from each other. No side-effects were reported during the study.

The immediate hypotensive effect of oral nifedipine.

The immediate hypotensive effect of oral nifedipine was assessed in 15 patients with moderate to severe hypertension. Supine and erect blood pressure and heart rates were measured before and 30 minutes after 10 mg nifedipine. The results showed that there was a significant (p less than 0.001) reduction in both systolic and diastolic pressures. There was a slight increase in heart rate and mild postural hypotension but neither appeared to be significant. It is concluded that nifedipine given by the oral route is an effective agent for the rapid lowering of elevated blood pressure and deserves further evaluation as an agent for the management of hypertensive emergencies.

Right praecordial early repolarization pattern occurring with the Wolff-Parkinson-White pattern.

A 47 year old man presented with simultaneous electrocardiographic manifestation of the right praecordial early repolarization pattern and the Wolff-Parkinson-White pattern. The important features of this combined pattern and helpful clues which will enable the correct diagnosis to be made are discussed in this paper.

Right sided chest lead electrocardiographic abnormalities in acute pulmonary embolism.

Twelve lead electrocardiograms together with right-sided chest leads V4R, V5R and V6R were recorded in four patients with acute pulmonary embolism. All four patients showed ST segment elevation and a qs or qr pattern (with prominent q waves) in one to three of the leads V4R, V5R and V6R. These abnormalities were absent in the repeat electrocardiograms which were recorded after the acute illness.

Sino-atrial Wenckebach conduction in thyrotoxic periodic paralysis: a case report.

A 28-year-old male presented with thyrotoxic periodic paralysis. On admission to hospital the serum potassium level was 1.4 mmol/l. The ECG showed classical features of hypokalaemia. In addition, sino-atrial block with Wenckebach conduction was also present. With the normalization of the serum potassium, the ECG became completely normal and showed no evidence of any arrhythmia.

Isolated right ventricular diverticulum with chest pain.

A 26-year-old man presented with severe chest pain. Subsequent investigations revealed a right ventricular diverticulum communicating with the right atrium. Surgery was performed, following which the chest pain disappeared completely.

Left bundle branch block and increased transverse:frontal plane QRS voltage ratio in severe left ventricular dysfunction.

Six patients with complete left bundle branch block and an increase in the transverse:frontal plane QRS voltage ratio are described. All these patients presented with congestive heart failure which was due to severe left ventricular dysfunction.

Electrocardiographic abnormalities in right ventricular infarction associated with right bundle branch block.

An 80-year-old woman with pre-existing complete right bundle branch block presented with severe chest pain. The 12-lead electrocardiogram, together with right-sided chest leads, showed complete right bundle branch block and ST segment elevation in leads II, III, aVF, V5, V6 and V4R to V6R. These electrocardiographic abnormalities indicate acute 'Q wave' inferolateral and right ventricular infarction coexisting with right bundle branch block.

Digitalis-induced cardiac arrhythmias.

Six cases of digitalis intoxication presenting with cardiac arrhythmias are described. Multiple cardiac arrhythmias consisting of multifocal, or unifocal, multiform ventricular ectopic beats, bidirectional tachycardia, complete heart block, accelerated junctional rhythm with exit block, nonparoxysmal junctional tachycardia, atrial fibrillation, atrial tachycardia with block, and multifocal tachycardia were observed. The presence of such multiple arrhythmias occurring simultaneously should always suggest the high possibility of digitalis intoxication.

Echocardiographic abnormalities in acute rupture of the aortic valve due to infective endocarditis.

The M-mode echocardiographic findings seen in 5 patients with acute rupture of the aortic valve leaflets due to infective endocarditis are described. These findings embrace a wide spectrum of abnormalities seen in the aortic root in diastole and they are (1) fine, high frequency oscillating echoes, (2) thick oscillating bands of echoes, and (3) dense shaggy echoes loosely attached to the aortic valve leaflets. Three patients showed persistence of these aortic root echoes right up to the level of the left ventricular outflow tract. All 5 patients demonstrated early closure of the mitral valve and exaggerated motion of the interventricular septum and the posterior wall of the left ventricle. Two patients died from the illness and the remaining 3 had successful aortic valve replacement after appropriate antibiotic therapy. The aortic valve and the aortic root were carefully examined in all 5 patients either at necropsy or at operation. Two patients had leaflet perforation alone, whereas the remaining 3 had both leaflet perforations as well as vegetations. An attempt was made to correlate morphologic findings with the echocardiographic abnormalities. It is concluded that it is frequently difficult from abnormal echoes in the aortic root alone to differentiate between ruptured leaflets and vegetations. However, the presence of the combination of early closure of the mitral valve, exaggerated motion of the interventricular septum and the posterior wall of the left ventricle, together with abnormal aortic root echoes as described above should strongly suggest acute rupture of the aortic valve leaflets due to infective endocarditis, or in rare cases myxomatous degeneration of the aortic valve.