No abstract

To explore the mechanisms of the "white coat" phenomenon, the effects of talking, reading, and silence were analyzed. Fifty essential hypertensive patients were randomly allocated to periods of stress talking and relaxing reading, alternating with three periods of silence. While talking, systolic/diastolic blood pressure increased sharply, from 142 +/- 0.7/97.7 +/- 0.5 mm Hg to 159 +/- 0.7/111 +/- 0.5 mm Hg (P < .0001). While reading, systolic/diastolic blood pressure decreased (P < .0001). Moreover, talking and reading had opposite residual effects. The silence and reading periods gave the best approximations of the daytime ambulatory period. The predictive value of clinical blood pressure can be improved if measured during a period without talking, thus decreasing the "white coat" phenomenon.

cause. It would be interesting to know how many of the perinatal deaths in the "anoxic" group in Cardiff corresponded to deaths of unknown cause in mature infants and to know the age, parity, height, and social class of the mothers. Higher induction and section rates in these groups most at risk might have resulted in better figures.Fedrick and Yudkin9 reported a reduction in the number of stillbirths in the Oxford area associated with a rising induction rate. The reduction was more apparent in induced than in noninduced births. As they pointed out themselves, however, when the induction rate is low only pregnancies at very great risk are included in an induced group, but as the induction rate rises, more and more relatively normal cases are induced. It is difficult, therefore, to draw firm conclusions about the benefits of induced labour from their method of analysing their data. Possibly the optimum induction rate will vary from area to area depending on the characteristics of the populations. By detailed analysis of our population and classification of the causes of our perinatal deaths, we were able to show where greatest improvement could be made, and it would be valuable to compare our results with those from other centres. Our present findings strongly suggest that increased use of induction of labour has contributed to a reduction in perinatal mortality.

Talking has been shown to increase blood pressure instantaneously in hypertensive patients and to contribute to the white coat effect. The effects of talking were compared with those of counting aloud in 64 patients with essential hypertension who were randomly assigned to a period of stress talking and a period of counting aloud (active periods), alternating with three periods of silence (control). The same monitor was used for office measurements and 24-hour ambulatory blood pressure analysis. Systolic/diastolic blood pressures increased significantly more during talking (163/110 mmHg) than during counting aloud (152/102 mmHg, both p < .0001) in both treated and untreated patients and in sustained and clinical hypertension. Talking had a residual effect on systolic blood pressure that lasted 5.8 +/- 0.1 minutes. The emotional content seemed to be the only cause of the talking effect. Its instantaneous and residual effects on blood pressure and heart rate should be considered when measuring these variables.

Left ventricular function was investigated in 21 chronic hemodialysis patients with cardiomegaly not due to major pericardial effusion. Angiographic and hemodynamic studies were performed in all, and selective coronary angiography in 16 patients. 5 patients had a history of long-standing arterial hypertension, 5 had clinical evidence of coronary artery disease, 3 had an overfunctioning arteriovenous fistula, and 3 had valvular heart disease. In 10 patients progressive cardiac failure developed without any apparent cause. The diagnosis of congestive cardiomyopathy was established in the latter by left ventricular catheterization. Their myocardial dysfunction was characterized by a significant increase in left ventricular end-diastolic volume when compared to control values. The mean myocardial contractility indices were significantly decreased, as was the index of normalized ventricular rigidity. Of the 10 patients, 6 presented the complete picture of the disease. The remaining 4 also had marked left ventricular dilatation and a decreased normalized rigidity index but their ejection fractions were in the normal range and their myocardial contractility indices only moderately decreased. 7 had coronarography, their coronary arteries were found normal. Of the 5 patients with angina, 3 had significant coronary artery disease as demonstrated by coronary angiography but 2 had angiographic and hemodynamic findings compatible with congestive cardiomyopathy and hypertrophic cardiomyopathy, respectively, in the absence of coronary heart disease. Among the remaining 6 patients with variable underlying etiologies 3 had myocardial dysfunction also compatible with congestive cardiomyopathy while 3 others had left ventricular function near normal. The severe ventricular dysfunction of one of them was possibly related with both aortic and mitral insufficiency. 5 of them had coronary angiography. No significant coronary artery disease could be demonstrated in them. It is concluded that congestive cardiomyopathy in the absence of significant atherosclerotic coronary disease is an important feature of cardiac dysfunction in uremic patients with cardiomegaly undergoing intermittent hemodialysis.