Changes in components of kinin system and hemodynamics in acute myocardial infarction

Kinin is known to have potent pain-producing and hypotensive actions and has been suggested as one of the causes of chest pain and shock in acute myocardial infarction. Since most of the previous reports^3–7 have been based on measurements of kininogen, the inactive precursor of kinin, peripheral blood kinin as well as kininogen was measured in this study. Kinin and kininogen levels were determined over a period of one month or until death from the onset in 23 cases of acute myocardial infarction, along with simultaneous measurements of hemodynamic indices. Sixteen of the 23 cases survived more than one month, and seven patients died of pump failure within 3 days of the infarction. In the survival group, increased kinin and decreased kininogen levels were observed in the initial stage, reaching a maximal change on the second day. The alterations in kinin levels were significantly correlated with concomitant lowering of blood pressure, decreased total vascular resistance, and prolongation of circulation time. In the non-survival group, there was no increase in kinin levels in spite of a decrease in kininogen. Accordingly, no significant correlation was found between kinin and hemodynamic changes. The lack of change in kinin in the latter group was thought to account for the strong kininase activity. Thus, these data indicate that kinin is not the cause of cardiogenic shock. Rather, the increased kinin level observed in survivors might indicate beneficial vasodilation effects, possibly by increasing coronary flow and reducing the afterload of the left ventricle.     

Changes in bradykinin level in coronary sinus blood after the experimental occlusion of a coronary artery

In order to study whether bradykinin is responsible for anginal pain, its level in the coronary sinus blood was determined in the dogs after experimental ligation of the anterior descending artery. A marked elevation of bradykinin level and a slight decrease of bradykininogen occurred after the ligation, while bradykininase increased to some extent. The bradykinin content in the ischemic area, estimated from its level in the coronary sinus blood and coronary sinus blood flow, was in the range reportedly sufficient to produce pain. The elevated bradykinin level continued for about 10 minutes, almost coinciding with the duration of the attack of angina pectoris. The results obtained showed also that the increase of bradykinin is induced directly or indirectly by lowering of pH and Po₂ in the ischemic area.     

Evaluation of a QRS scoring system in acute myocardial infarction: Relation to infarct size,early stage left ventricular ejection fraction,and exercise performance

Recent studies suggest that the QRS scoring system (QRSs) using observations of Q- and R-wave duration and $\text{R}\text{Q}$ and $\text{R}\text{S}$ amplitude ratios in the standard electrocardiogram (ECG) is useful in estimating left ventricular function after acute myocardial infarction (AMI).The correlation of QRSs with infarct size determined by serum creatine kinase MB changes and early stage left ventricular ejection fraction (LVEF) determined by multiple gated equilibrium cardiac blood pool scintigraphy was studied in 32 patients with AMI using ECGs taken 3 and 7 days after onset. The relation of QRSs to exercise performance was also examined in 45 other patients who underwent heart rate limited low level exercise test (LLET) soon after AMI (12.3 ± 5.6 days, mean ± standard deviation).The QRSs of 7 days after onset significantly correlated with both infarct size and LVEF; infarct size (CK·g·Eq) = 5.24 QRSs + 8.50 (r = 0.72, p < 0.001), LVEF (%) = ? 2.16 QRSs + 59.58 (r = ? 0.71, p < 0.001).Patients with exercise tolerance of < 6 minutes had significantly higher QRSs than patients with exercise tolerance of 6 to 12 minutes or >12 minutes (9.0 ± 3.3 versus 4.5 ± 2.4 and 3.6 ± 2.2, p < 0.001, respectively). All patients with QRSs < 6 (24 of 45 patients) achieved exercise tolerance of > 5 minutes, whereas all patients who could not exercise for > 5 minutes (10 of 45 patients) had QRSs > 5.The relation between QRSs and the reasons for termination of LLET showed that patients with fatigue or dyspnea, or both, had significantly higher QRSs (8.7 ± 4.6) than those in target heart rate (5.4 ± 2.2, p < 0.05) and those in completed protocol (3.0 ± 1.7, p < 0.01), whereas patients with chest pain had intermediate QRSs (5.3 ± 2.7). The QRSs was significantly higher in patients with S-T changes during LLET (8.2 ± 4.5 versus 4.7 ± 2.8, p < 0.05).These data suggest that QRSs will be clinically useful not only as a variable correlating with infarct size and LVEF but also as an aid in early identification of exercise performance soon after AMI.     

Persistent atrial standstill, report of three cases

Three cases, of which two are brothers, of persistent atrial standstill are reported. The diagnosis was made by the lack of P wave in routine 12 leads and right atrial cavity lead, no response of atrium to electrical stimulation and absence of "a" wave in right atrial pressure curve.     

Clinical features and course of aortitis syndrome in Japanese women older than 40 years

The clinical features and course of aortitis syndrome were studied in 11 women older than 40 years of age. The patients were Japanese women, mean age 57 +/- 6 years old, who were followed for 6.9 +/- 3.8 years. Data from 24 young patients were used for comparison. In the older patients, systemic hypertension (73%), calcification of the aorta (73%), left ventricular hypertrophy (92%) and cardiomegaly (82%) were frequent, whereas the erythrocyte sedimentation rate was normal in 5 patients and only slightly accelerated in 6. C-reactive protein was positive in 2. The incidence of cardiac involvement and inflammatory signs was significantly different from findings in the young patients. Aortic regurgitation (AR) (55%) was significantly more frequent and renal artery stenosis was not observed. Other arterial lesions revealed a pattern similar to those seen in the young patients. An irregular luminal surface, kinking and calcification were present in the lesions in the older patients. The survival rate at 5 years was 80%. Five of 6 patients with AR had congestive heart failure, 4 of whom died. One died after a stroke. Thus, aortitis syndrome in older patients has a long course. There is usually an associated AR, renal artery stenosis is rare and other arterial lesions do not change a great deal. The prognosis may be good, but depends on the association of AR.