Exposure to cobalt in the production of cobalt and cobalt compounds and its effect on the heart.

AIMS: To investigate whether exposure to cobalt in cobalt plants has any measurable effect on the cardiovascular system. METHODS: Occupational, cross sectional study, using a self administered questionnaire, blood pressure measurement, electrocardiography, and laboratory tests in which 203 male workers with at least one year of exposure to cobalt and 94 unexposed controls participated. Echocardiography was performed on a subset of 122 most highly exposed cobalt workers, of which 109 were analysed, and on 60 controls, of which 57 were analysed. Analysis of covariance and a multiple regression analysis were used to evaluate the data. RESULTS: Two of the echocardiography parameters measured were associated with cobalt exposure. In the higher exposure group the left ventricular isovolumic relaxation time (mean 53.3, 49.1, and 49.7 ms in the high exposure, low exposure, and control groups respectively) and the deceleration time of the velocity of the early rapid filling wave (mean 194.3, 180.5, and 171.7 ms for those in the high exposure, low exposure, and control groups respectively) were prolonged, indicating altered left ventricular relaxation and early filling. CONCLUSION: Cumulative exposure to cobalt was found to be associated with the results of Doppler echocardiography measurements, indicating altered diastole. This finding supports the hypothesis that cobalt accumulation in the myocardium could affect myocardial function. Whether this finding has clinical implications remains to be evaluated.

Natriuretic peptide and echocardiography after operation of atrial septal defect.

Patients benefit from surgical seclusion of atrial septal defect but have excessive cardiovascular morbidity after the operation. We evaluated haemodynamics and looked for abnormalities of cardiac structures and function late after surgical seclusion of the defect. Serum N-terminal natriuretic peptide measurement and transthoracic and transoesophageal echocardiography were performed in 61 patients aged 43+/-15 years (mean+/-standard deviation) 21+/-5 years after surgery. The findings were compared with 67 control subjects. The patients had higher serum N-terminal atrial natriuretic peptide concentration than the control subjects (0.40+/-0.32 vs. 0.24+/-0.12 nmol/l, P=0.0001). Peptide levels correlated with current age (P=0.0001) and age at operation (P=0.0014), but not with age in the control subjects. In the patients, echocardiography measurements of cardiac dimensions correlated with hormone levels (atrial natriuretic peptide concentration with left atrial end-systolic diameter (P=0.042), left ventricular end-diastolic (P=0.021) and end-systolic diameter (P=0.042). There were only 10 patients (16%) without any abnormality in echocardiography. Their peptide concentration was 0.25+/-0.18 nmol/l (P=not significant compared to the control subjects). The association between increasing N-terminal atrial peptide levels and operation age together with echocardiography findings support the clinical consensus of treating atrial septal defect patients in their childhood and adolescence.

Thyroid hormone substitution therapy rapidly enhances left-ventricular diastolic function in hypothyroid patients.

OBJECTIVE: Alterations in thyroid status may lead to changes in both systolic and diastolic function of the heart. Pulsed Doppler echocardiography is a reliable non-invasive means of assessing left-ventricular (LV) diastolic function. The aim of the present study was to evaluate LV diastolic function in patients with primary hypothyroidism receiving thyroxine therapy. METHODS: Twelve patients (all females, mean age 47 +/- 17, range 16-69 years) with primary hypothyroidism were studied by pulsed Doppler echocardiography. The first examination was made before the start of thyroxine substitution and the second at 37-68 (mean 53 +/- 10) days after commencing thyroxine treatment (mean dose 136 +/- 22 microg/day). RESULTS: During thyroxine substitution therapy, the hypothyroid patients became clinically euthyroid and serum T4 increased from 51 +/- 21 to 119 +/- 24 nmol/l; TSH decreased from 50.4 +/- 55.3 to 1.2 +/- 1.5 mU/l. During therapy, heart rate increased from 61 +/- 8 to 68 +/- 10 (p = 0.05). The LV posterior wall (7.8 +/- 1.0 mm) and interventricular septum thickness (8.0 +/- 1.4 mm) were significantly greater in hypothyroid patients than in the control subjects (6.4 +/- 1.0 mm, p = 0.007 and 6.8 +/- 1.0 mm, p = 0.04, respectively). There was no significant change in LV dimensions and wall thickness during follow-up. E/A(max) increased significantly during treatment (from 1.679 +/- 0.432 to 1.947 +/- 0.335, p = 0.006). The isovolumic relaxation time shortened significantly (from 88 +/- 23 ms to 75 +/- 24 ms, p = 0.005). CONCLUSIONS: The present study shows that LV diastolic function as assessed by pulsed Doppler echocardiography in hypothyroid patients is enhanced by thyroxine therapy during a rather short follow-up period.

Epidemiology of three cases of severe diphtheria in Finnish patients with low antitoxin antibody levels.

During the 1990-1998 diphtheria epidemic in the newly independent states of the former Soviet Union, more than 150,000 infections and 5,000 deaths occurred. During this period, more than 10 million trips were made from Finland to Russia or vice versa. This resulted in only 10 cases of diphtheria in Finland. There was no secondary spread to healthcare workers or other close contacts. Three patients had severe respiratory tract diphtheria. All three were middle-aged men who had made a short visit to Russia, during which time they had intimate contact with local women. These findings suggest diphtheria was transmitted mainly by direct saliva contact. All patients with severe diphtheria had a non-protective level of antitoxin antibodies during the first days of the disease. Only the patient whose antibody titre rose rapidly to a protective level (>1 IU/ml) had an uncomplicated recovery. The other two, one of whom died, had myocarditis and severe polyneuropathy.

Serum N-terminal atrial natriuretic peptide in adult patients late after surgical repair of atrial septal defect.

BACKGROUND: The purpose of surgical closure of atrial septal defect (ASD) is to relieve the cardiovascular system from a haemodynamic burden. Excessive amounts of atrial peptides are released in congestive heart failure, valvular diseases and congenital heart diseases. AIMS: To examine whether patients after surgical repair of ASD have higher concentrations of N-terminal atrial natriuretic peptide (ANP-N) than age-, sex- and body mass index (BMI)-matched control subjects. METHODS: Medical history, physical examination, standard 12-lead electrocardiogram, and ANP-N concentrations were obtained in 65 adult patients operated for ASD at the age of 21+/-13 years (mean+/-standard deviation), 21+/-6 years after surgical closure of ASD. Sixty-seven healthy subjects matched for age, sex and BMI served as controls. RESULTS: In the patients serum ANP-N was higher than in the control subjects 0.41+/-0.32 nmol/l, median 0.31 nmol/l, interquartile range (IQR) 0.21-0.49 nmol/l vs. 0.24+/-0.12 nmol/l, median 0.23 nmol/l, IQR 0.17-0.29 nmol/l, (P=0.0003). Patients with concomitant diseases had higher ANP-N concentrations (0.51+/-0.39 nmol/l, median 0.34, IQR 0.26-0.73 nmol/l) than ASD patients without any history or signs of disease (0.28+/-0.16 nmol/l, median 0.27, IQR 0.17-0.40 nmol/l, P=0.01). The 'healthy' ASD patients had higher hormone concentrations than age-, sex- and BMI-matched control subjects (0.28+/-0.16 median 0.27 nmol/l, IQR 0. 17-0.40 nmol/l and 0.21+/-0.07 nmol/l, median 0.20 nmol/l, IQR 0. 15-0.27 nmol/l, P=0.01). Multiple stepwise linear regression analysis showed that age at operation was strongly associated with the post-operative ANP-N concentration (r(2)=0.25, P=0.0002). CONCLUSION: ASD patients have higher ANP-N concentrations late after surgical repair. Hormone levels correlate with age at operation. Our finding supports the clinical praxis of operating on these patients in their childhood and adolescence.

Comparison of bicycle, heavy isometric, dipyridamole-atropine and dobutamine stress echocardiography for diagnosis of myocardial ischemia.

Several stress echocardiography (SE) modalities have been introduced for diagnosing coronary artery disease (CAD). Exercise and dobutamine SE are considered to have better diagnostic accuracy than vasodilator or isometric SE, but there are no studies in a single group of patients comparing these 3 tests with heavy 2-arm isometric SE. The purpose of this study was to determine the diagnostic characteristics of 4 SE methods in patients with chest pain. Altogether, 60 patients (age +/- SD 55.1 +/- 2.1 years) were tested with bicycle, heavy 2-arm isometric, dipyridamole-atropine and dobutamine SE. CAD (>50% stenosis) was present in 44 patients; 26 patients had 1-vessel disease. During bicycle SE, the double product at peak stress was higher than during dobutamine and dipyridamole-atropine SE (26.5 x 10(3), p <0.005 vs dobutamine and dipyridamole-atropine SE), and peak wall motion score index (1.40) was higher than during dipyridamole-atropine and isometric SE (1.26 and 1.07, respectively, p <0.05 vs bicycle SE). Bicycle, dipyridamole-atropine, and dobutamine SE had higher sensitivity than isometric SE (90%, 93%, 95%, and 30%, respectively, p <0.05 isometric SE vs others). There were no statistically significant differences with regard to specificity. Similarly, bicycle, dipyridamole-atropine, and dobutamine SE had a higher diagnostic accuracy than isometric SE (78%, 88%, 87% and 47%, respectively, p <0.05 isometric SE vs others). We conclude that bicycle, dipyridamole-atropine, and dobutamine SE have an equal diagnostic accuracy in detecting CAD despite higher double product and ischemic burden at peak stress during bicycle and dobutamine SE over dipyridamole-atropine SE. Heavy isometric SE is inaccurate.

Late postoperative follow-up of ostium secundum defect.

AIM: To perform late postoperative assessment of patients with ostium secundum defect. METHODS: We studied 45 patients 22+/-4 years after operation using clinical examination, transthoracic and transoesophageal echocardiography and electrocardiography. RESULTS: Patients operated on at 24 years reported dyspnoea upon exercise. Mitral regurgitation occurred more frequently in patients operated on at 24 years (29% vs 69%, P<0.05). Tricuspid regurgitation was mild in 20 patients (45%). There was an inter-atrial communication in 13 patients (28%). Eighteen patients (40%) had an enlarged right ventricular diameter. A tricuspid regurgitation gradient >30 mmHg was measured in seven patients (16%). Seventeen patients (38%) had significant electrocardiographic abnormalities. CONCLUSIONS: Late after uncomplicated seclusion of ostium secundum defect patients operated at >24 years have more symptoms than those operated on at an earlier age. Residual lesions are common. Mitral regurgitation is more frequent in patients operated on at >24 years. Our findings support the clinical consensus of operating on these patients in their childhood and adolescence.

Calcium infusion and left ventricular diastolic function in patients with chronic renal failure.

BACKGROUND: Left ventricular (LV) function is sensitive to disorders in calcium metabolism. Most previous reports have focused on the effects of calcium on systolic performance. We studied the acute effect of calcium infusion on LV diastolic function in patients with moderate to severe chronic renal failure (CRF) and secondary hyperparathyroidism (SHP). METHODS: We infused calcium gluconate at a constant rate of 45 mumol/kg/h to 14 patients with severe to moderate CRF and SHP. Our aim was to reach slightly supranormal levels of serum ionized calcium (1.35-1.45 mmol/l). LV diastolic function was assessed by pulsed Doppler echocardiography before and after the calcium infusion. The echocardiographic indices were compared to those of 14 age- and sex-matched healthy controls. RESULTS: Before calcium infusion the patients had significantly greater LV dimensions than the controls, but there was no differences in the diastolic indices. During calcium infusion, serum ionized calcium increased from 1.18 +/- 0.03 to 1.40 +/- 0.03 mmol/l (P < 0.0001) and plasma intact PTH decreased from 38.6 +/- 5.6 to 9.0 +/- 2.2 pmol/l (P < 0.0001). Calcium infusion did not affect the LV dimensions or fractional shortening. The peak early diastolic velocity (Emax) decreased and peak late diastolic velocity (Amax) increased, and their relationship decreased significantly (1.552 +/- 0.586 vs 1.414 +/- 0.535 m/s, P = 0.03). These changes reflect impairment of LV diastolic function. CONCLUSIONS: Induction of acute hypercalcaemia by calcium infusion impairs LV diastolic function in patients with CRF and SHP.

Fatal respiratory tract diphtheria apparently caused by nontoxigenic strains of Corynebacterium diphtheriae.

A major diphtheria epidemic affecting the whole population of St. Petersburg started in 1990. During the period of 1991 to 1995, 4600 patients with clinical respiratory tract diphtheria were treated in Botkin's Hospital. From 112 (2.4%) of these patients only a nontoxigenic strain of Corynebacterium diphtheriae was isolated. Three patients with this strain who were suffering from clinical disease consistent with classical toxic diphtheria died. All had myocarditis, two had asphyxia due to membrane formation in the lower respiratory tract, and one had severe polyneuritis. In two patients the causative agent was of the biotype mitis and in the third intermedius, whereas the prevailing epidemic strain was of the biotype gravis. As the clinical presentation of the disease in the three patients who died was typical of toxic diphtheria, it is considered likely that the immunodiffusion test for toxin production in vitro may fail to detect strains of Corynebacterium diphtheriae producing toxin in vivo.

Echocardiographic follow-up of diphtheric myocarditis.

We report the first case of diphtheric myocarditis documented by serial electrocardiography and echocardiography. The electrocardiographic changes preceded the contraction abnormalities by 3 weeks. During a prolonged neurologic disease with extensive polyneuropathy, the patient had only subtle clinical signs of myocarditis. In patients with diphtheria, electrocardiographic changes may warrant repetitive echocardiographic examinations.

Diphtheria outbreak in St. Petersburg: clinical characteristics of 1860 adult patients.

An epidemic of respiratory tract diphtheria began in Russia in 1989. In 1994 more than 2,500 cases occurred in St. Petersburg alone. We describe clinical findings in the 1,860 adult patients treated in Botkin's Hospital. The study is based on a retrospective review of patient records. In 98% of the patients the diagnosis was confirmed by a positive throat culture growing a toxin producing strain of Corynebacterium diphtheriae. A catarrhal disease without membranes was present in 1,256 (67.5%) patients, 150 patients had membranes on tonsils only, 268 patients on tonsils, the uvula, soft palate and posterior pharynx and 35 patients on larynx or in the lower respiratory tract. 42 patients (2.3%) died. Among the deceased patients 26 were alcoholics, whereby the death rate for non-alcoholics was probably around 1%. 151 patients (8.1%) had a toxic form of the disease with swelling of the neck. This form of the disease carried a high mortality, 25.7%. In a subgroup of 1,045 patients the protective efficacy of vaccination could be evaluated. A 2.2-fold protection was found, but the study may underestimate the efficacy. We conclude, that if a wide diphtheria epidemic affects an industrialized country, it would probably not any more be the big killer that it was in Europe and in the United States in the 1950's and 1960's.

Single right coronary artery assessed by contrast angiography and transoesophageal echocardiography.

Contrast angiography is the gold standard for the assessment of the site and severity of coronary artery narrowing. Transoesophageal echocardiography is recognized as a feasible technique in assessing coronary artery anomalies. Our patient had arteriosclerotic narrowing in a single right coronary artery with poor distal opacification during contrast injection. Combining transoesophageal echocardiography with contrast angiography helped us in visualizing a surgically accessible vessel on the anterior wall of the left ventricle.

Color Doppler myocardial imaging: a new technique for the assessment of myocardial function.

Color Doppler myocardial imaging is a new technique that has been developed specifically to allow color Doppler imaging of myocardial wall motion rather than blood pool imaging. Such a technique has the potential to interrogate velocities, accelerations, and Doppler signal strength within the myocardial wall. Moreover, the concomitant enhancement of the myocardial Doppler signal after an intravenous injection of a transpulmonary echocardiographic contrast agent could permit the noninvasive assessment of regional myocardial perfusion. Thus this new imaging modality could be a valuable adjunct to the ultrasound assessment of myocardial ischemia.

[Value of biplane transesophageal echocardiography in congenital abnormalities of the heart atrium and venous-atrial connection]. / Valore dell'ecocardiografia transesofagea biplanare nelle anomalie congenite dell'atrio e della connessione veno atriale.

BACKGROUND: Transesophageal echocardiography with transversal planes offers many advantages in the evaluation of patients with congenital anomalies of atrium, allowing visualization of obscure areas, not visualized with traditional echocardiography, as appendages, venous connections, upper interatrial defects. The aim of this paper is to check what advantages the transesophageal imaging in longitudinal plane, recently insert in biplane probes, might confer over transversal plane imaging in the evaluation of patients with congenital heart disease of atrium and venous connections. METHODS: We carried out a prospective study on 70 patients (49 adults and 22 children) with congenital heart diseases of this area. Fifty-six studies out of 71 were preoperative diagnostic, 15 were carried out in the late postoperative period. Twenty-two studies were performed under general anaesthesia during concomitant cardiac catheterisation, 49 were carried out in outpatient clinic. All the transesophageal diagnoses were subsequently confirmed at either catheterization or surgery. Lesions studied included 36 atrial septal defects (ASD) ostium secundum, 6 interatrial septal aneurysms, 1 ASD coronary sinus, 5 ASD venous sinus, 5 partial and 2 complete atrioventricular septal defects, 1 double outlet right ventricle; in operated patients 2 ASD ostium secundum, 2 ASD sinus venosus, 11 post Mustard or Senning in TGA. RESULTS: Anomalies either better defined or that obtained important additional informations by long axis scanning (vs transverse scanning) included: ASD ostium secundum 36/36, ASD multiple 1/3, caval obstruction in Mustard or Senning 4/5, anterior mitral valve cleft 2/5, left superior vena cava to coronary sinus 3/3. Features visualized by longitudinal plane alone were: ASD coronary sinus 1/1, caval obstruction in sinus venosus operated 1/1, multiple ASD 2/3, coronary artery fistula to right atrium 1/1; for associated features anterior bringing leaflets 2/2, left ventricular outflow tract obstruction 2/2, right ventricular outflow tract obstruction 1/1. Anomalies better characterized by transversal plane versus longitudinal plane were: ASD ostium primum 2/7, ASD sinus venosus sinus 3/5; for associated anomalies VSD inlet 1/1. Features visualized by transversal plane alone were: right upper pulmonary vein in superior vena cava 4/4, right upper pulmonary vein to right atrium 1/1, DIA ostium primum 5/7, ASD sinus venosus 2/5, superior vena cava obstruction in Mustard 1/5, left juxtaposition of the atrial appendages 1/1. The transversal plane alone provided the correct morphologic and hemodynamic diagnosis in 74/88 (84%) (in this group longitudinal plane gave 68% additional informations), the longitudinal planes in 69/88 (78%). However in 11% of cases longitudinal plane was the only means for identifying the congenital lesion and transversal plane in 16%. It was the combination of longitudinal and transverse scanning which gave in 97% the correct complete morphologic diagnosis. CONCLUSIONS: Thus we conclude that both planes are required for optimal transesophageal evaluation of congenital disease of atrium and venous connection.

Additional value of biplane transoesophageal imaging in assessment of mitral valve prostheses.

OBJECTIVES: To determine whether biplane transoesophageal imaging offers advantages in the evaluation of mitral prostheses when compared with standard single transverse plane imaging or the precordial approach in suspected prosthetic dysfunction. DESIGN: Prospective mitral valve prosthesis in situ using precordial and biplane transoesophageal ultrasonography. SETTING: Tertiary cardiac referral centre. SUBJECTS: 67 consecutive patients with suspected dysfunction of a mitral valve prosthesis (16 had bioprostheses and 51 mechanical prostheses) who underwent precordial, transverse plane, and biplane transoesophageal echocardiography. Correlative invasive confirmation from surgery or angiography, or both, was available in 44 patients. MAIN OUTCOME MEASURES: Number, type, and site of leak according to the three means of scanning. RESULTS: Transverse plane transoesophageal imaging alone identified all 31 medial/lateral paravalvar leaks but only 24/30 of the anterior/posterior leaks. Combining the information from both imaging planes confirmed that biplane scanning identified all paravalvar leaks. Five of the six patients with prosthetic valve endocarditis, all three with valvar thrombus or obstruction, and all three with mitral annulus rupture were diagnosed from transverse plane imaging alone. Longitudinal plane imaging alone enabled diagnosis of the remaining case of prosthetic endocarditis and a further case of subvalvar pannus formation. CONCLUSIONS: Transverse plane transoesophageal imaging was superior to the longitudinal imaging in identifying medial and lateral lesions around the sewing ring of a mitral valve prosthesis. Longitudinal plane imaging was superior in identifying anterior and posterior lesions. Biplane imaging is therefore an important development in the study of mitral prosthesis function.

The transesophageal echocardiographic features of double-orifice left atrioventricular valve.

Three adult patients with a double-orifice left atrioventricular valve (AV) were studied by both precordial and transesophageal ultrasound imaging, (two transverse plane and one biplane studies) to compare and contrast the information obtained by either imaging modality. In two patients, this pathologic condition was associated with other congenital heart malformations--a muscular inlet ventricular septal defect in the first, atrioventricular and ventriculoarterial discordance and an unrestrictive ventricular septal defect in the second. In the third patient, the double-orifice left AV valve existed as an isolated lesion. In the first and second case, both orifices were of similar size; in the third the additional orifice was of diminutive size and was demonstrated only by transesophageal longitudinal plane scanning. In summary, in this adult patient group, transesophageal echocardiography with color flow mapping was superior to precordial scanning in the assessment of both the morphology and functional status of a double-orifice left AV.