Atrial natriuretic peptide, aldosterone, and plasma renin activity in peripartum heart failure.

Plasma concentrations of atrial natriuretic peptide and aldosterone and plasma renin activity were measured in patients with peripartum heart failure and in age matched healthy women post partum. Both groups had carried out traditional postpartum practices of salt consumption and body heating. Plasma concentrations (mean (SEM)) of atrial natriuretic peptide were significantly higher in the seven patients with peripartum heart failure (146.9 (24.3) pg/ml) than in the seven controls (4.4 (0.8) pg/ml). Both plasma aldosterone and plasma renin activity were suppressed in the patients with peripartum heart failure. After treatment for the heart failure plasma atrial natriuretic peptide fell considerably and there were associated increases in plasma aldosterone and plasma renin activity. The high plasma concentrations of atrial natriuretic peptide may have been a compensatory response to salt and water retention as well as to the heart failure. These high concentrations could also, in part, have suppressed the release of aldosterone and renin in an attempt to correct for volume overload.

Peripartum cardiac failure. A ten year follow-up study.

A cohort of patients with peripartum cardiac failure (PPCF) was followed for 10 years after the initial illness. The follow up rate was 78%. Fifty two per cent of patients improved without further episodes of heart failure. PPCF recurred in 26 per cent. Heart failure unrelated to pregnancy was seen in 13%, and 9% of the patients progressed to dilated cardiomyopathy. Transient hypertension was seen in 87% of patients on admission, and later hypertension was found in 45%. Late hypertension influenced heart size more when recurrent PPCF or progressive heart failure was present. Anaemia on admission had no effect on subsequent heart size. The electrocardiogram may continue to be abnormal for up to 10 years in normotensive patients who had no heart failure. The abnormal electrocardiogram in patients with persistent cardiomegaly may represent progressive myocardial damage. Mortality rate was highest (11%) in the first year and declined thereafter. Cardiac deaths were common in patients with recurrent PPCF or progressive heart failure.

Echocardiographic assessment and systolic time interval measurements in the evaluation of severe hypertension in Nigerian Africans.

Echocardiograms, systolic time interval measurements and electrocardiograms were obtained before treatment of 15 Nigerian patients with severe hypertension (WHO stage 2) but without overt heart failure. These were compared with the measurements in 12 normotensive controls. In the hypertensive subjects, left ventricular (LV) posterior wall thickness septal thickness, relative wall thickness and LV wall mass were greater than normal (p less than 0.01 respectively). However, the LV cavity size was within the normal range. The increase in LV wall mass correlated positively with the increase in mean blood pressure (r = 0.96, P less than 0.001). The ejection fraction (EF) and mean velocity of circumferential fibre shortening (mVcF) were decreased (P less than 0.01, P less than 0.05) respectively, while the calculated systemic vascular resistance (SVR) was elevated (p less than 0.01). THe pre-ejection period (PEP) was prolonged, but left ventricular ejective time (LVET) was shortened and therefore PEP/LVET was increased. Electrocardiographic criteria did not detect left ventricular hypertrophy in four out of the 15 hypertensive patients, all of whom had left ventricular hypertrophy by echocardiography. These findings are similar to the abnormalities described for non-African hypertensive patients; and show that hypertension causes LV dysfunction before the onset of overt heart failure.

Surgical management of pericarditis in Zaria, Nigeria.

Over eight years, 58 rural Nigerians with pericarditis were treated surgically in Zaria using basic surgical facilities. Eighteen patients had purulent pericarditis, associated with staphylococcal pneumonia in children, or pneumococcal pneumonia in adults. Treatment with antibiotics and prompt pericardiectomy appeared to be superior to drainage, since a quarter of those initially treated with surgical drainage developed early constriction and required pericardiectomy soon after. Thirteen patients had chronic pericardial effusions, of whom one had epicardial constriction and two had cardiomyopathy. Twenty-seven patients had chronic constrictive pericarditis but tuberculosis was confirmed histologically in three only. Echocardiographic findings remained unchanged in five patients evaluated before and after pericardiectomy. Eight of the 13 patients who died had already developed myocardial or hepatic insufficiency before operation, because of late presentation or diagnosis. Greater awareness of the significance of precordial pain in this rural population where ischaemic heart disease is rare would help in making an earlier diagnosis.

Closed digital commissurotomy for mitral stenosis in Northern Nigeria.

Despite the absence of sophisticated thoracic surgical facilities, valuable relief was provided to young patients with progressive symptoms of rheumatic mitral stenosis in Zaria (Nigeria) whose response to the medical regime had been unsatisfactory. Using digital trans-atrial commissurotomy, which is technically straightforward and involves little blood loss and no elaborate surgical equipment 18 patients with a lone mitral stenosis were symptomatically improved but three with mixed mitral stenosis and regurgitation died. There is urgent need to reduce the prevalence of rheumatic fever in this and other parts of the tropics.

Echocardiographic features of congestive cardiomyopathy in Nigerians.

In this study, we compared the echocardiographic features of thirteen patients with chronic congestive cardiomyopathy (COCM) with those of twelve normal subjects. Characteristically, the patients with COCM had larger than normal left ventricular internal dimensions and estimated volumes in enddiastole and endsystole. Qualitatively the septum had a diminished motion, or was flat, similarly the motion of left ventricular posterior wall was less than normal. The diastolic closure rate of the anterior mitral valve (AMV) was less discriminating between normal and COCM patients. However, the distance between the C - point on the AMV and the left side of the septum was significantly greater than normal in COCM. The excursion of AMV was less than normal. Both leaflets of the mitral valves were recorded easily. Although these features are known, they have not been previously reported for Nigerian patients. Echocardiography is useful in the diagnosis of congestive cardiomyopathy, particularly when there are no facilities for Cardiac catheterization.

Postpartum cardiac failure--heart failure due to volume overload?

Ventricular function has been studied in 43 patients with the peripartum cardiac failure (PPCF) syndrome which occurs around Zaria. All patients had an echocardiogram on admission and 10 patients had right heart catheterization. Despite the gross edema, left ventricular function assessed by echocardiography and systolic time intervals was relatively good and the estimated cardiac output were high. At catheterization, although the pressures were high, the cardiac outputs were greater than normal in four out of six patients. No patient had a low cardiac output. These findings are not compatible with a severe heart muscle disorder, or cardiomyopathy. We suggest that the primary event in PPCF of Zaria is fluid retention which leads to a form of high output cardiac failure. The postpartum practices in this area (taking high sodium diets and lying on heated beds) almost certainly cause the fluid to accumulate initially, but the heart may be unable to meet the demands either because of preexisting heart muscle disease or, more likely, because of a rise of the peripheral resistance due to the volume expansion, overburdens such dilated hearts and leads to myocardial damage. Since there are similarities between this condition and PPCF in temperate climates, it is possible that there is a common mechanism which the traditional practices of this area have unveiled.

M-mode echocardiography in the diagnosis of heart diseases in Africans.

The aim of this study was to evaluate the usefulness of M-mode echocardiography as a non-invasive diagnostic tool when facilities for cardiac catheterization were not available. We used this technique to study 275 patients whose clinical diagnosis included hypertension, rheumatic heart disease, cardiomyopathy, peripartum cardiac failure, pericardial disease and some forms of congenital heart disease. Characteristic echocardiographic patterns made specific cardiac diagnoses possible and allowed a distinction to be made between clinically similar conditions. It is concluded that echocardiography is very useful in the African setting because it is safe and repeatable.

Fatal coronary atherosclerotic heart disease in a Nigerian case report with necropsy findings.

This report describes the clinical and necropsy findings in a fatal case of coronary atherosclerotic heart disease with thrombosis occurring in a Nigerian. This entity is very rarely seen in indigenous Africans, except in the setting of hypertension, diabetes mellitus or high socioeconomic status.

Heart muscle performance after experimental viral myocarditis.

As part of an inquiry into possible antecedents of idiopathic cardiomyopathy, acute experimental coxsackie virus myocarditis was studied for late structural and functional sequelae. Myocarditis was induced in 12- and 22-day-old hamsters by inoculation with coxsackie virus B3. Early viremia occurred, followed by virus replication in heart muscle. Maximum peak developed tension (Tpd) of isometrically contracting isolated heart muscle was depressed 17 and 43% in the animals inoculated at 12 days, and studied 18 and 90 days later, respectively, as compared to their uninoculated controls. In both infected groups, less muscle stretch was required to reach the length at which Tpd was produced. Animals studied 180 days after inoculation did not differ from controls. The muscles from animals inoculated at 22 days of age and studied 18 days later showed a 15% depression of Tpd compared to their controls. Glycerinated muscles from this infected group developed 50% less tension than their controls. The muscles of hamsters inoculated with virus at 22 days and studied 90 and 180 days later showed no change in Tpd. The data suggest that contractility and compliance of heart muscle are decreased 18 days after inoculation, but recover by 90 days if the animals are inoculated at age 22 days. However, if the animals are inoculated at a younger age (12 days), depression of myocardial performance persists for at least an additional 90 days. It is concluded that the inflammatory stage of experimental acute coxsackie virus B3 myocarditis in the Syrian golden hamster may be followed by residual alterations in contractile proteins and myocardial function.

Depressed myocardial function in subacute experimental viral myocarditis.

A model of experimental Coxsackie virus B3 myocarditis has been developed in the weaning Syrian golden hamster. The acute infection is characterized by extensive viral replication in the myocardium, associated with transient myocytolysis and leukocytic infiltration. At 2 weeks after inoculation, there is survival without evidence of cardiac hypertrophy or failure, and minimal residual light microscopic changes. In order to evaluate myocardial function during convalescence form this form of myocarditis, muscle mechanics were studied in left ventricular trabeculae careae in 10 infected and 7 control animals, 18 days after inoculation. Maximum developed tension of the infected animals was depressed by 25%, and there was a significant decrease in the time to peak tension. Furthermore, the infected muscles required less stretch to reach that length at which maximal developed tension was produced. These data indicate that myocardial function remains depressed during early convalescence from acute Coxsackie virus B3 myocarditis and suggest that this state is associated with decreased compliance. Studies of myocardial morphology and function at longer intervals after acute experimental viral myocarditis are indicated, to further test the hypothesis that viral myocarditis might be a precursor chronic isiopathic cardiomyopathy.