Parallel morning and evening surge in stroke onset, blood pressure, and physical activity.

BACKGROUND AND PURPOSE: A circadian variation with a morning peak on waking and arising is known to occur in both blood pressure (BP) and cardiovascular event onset. A second peak in BP has been described to occur after an afternoon sleep (siesta). This study was designed to investigate the hypothesis that the 2-peak diurnal variation of BP is dependent on physical activity and occurs in parallel with the diurnal variation of stroke onset. METHODS: The diurnal variation of stroke onset was compared with the diurnal variation of BP, pulse rate (PR), and physical activity in 3 independent groups of Greek hypertensives 51 to 80 years of age (633 stroke patients, 379 subjects with 24-hour ambulatory BP monitoring, and 50 subjects with 24-hour physical activity monitoring through wrist devices). RESULTS: The diurnal variation of stroke onset, BP, and PR all showed 1 morning and 1 evening peak with a decline in the afternoon and at night that occurred in parallel with the diurnal variation in physical activity (P<0.001 for differences among morning, afternoon, evening, and nighttime intervals in BP, PR, activity, and stroke). The afternoon decline in BP, PR, and activity was significant only in subjects with a siesta. CONCLUSIONS: The 2-peak diurnal variation in stroke onset occurred in parallel with the variation in BP, PR, and physical activity. These data support the hypothesis that an abrupt change in physical activity is not only a major determinant of the 2-peak diurnal variation of BP but also an important triggering factor for a cerebrovascular event.

White-coat effect in normotension and hypertension.

OBJECTIVES: The difference between clinic and daytime ambulatory blood pressure is referred to as the white-coat effect. In this study, we investigated (i) the magnitude of the white-coat effect in subjects with different daytime ambulatory blood pressure levels, and (ii) the association of the white-coat effect with left ventricular mass. METHODS: A total of 1581 subjects underwent clinic blood pressure readings, 24-h ambulatory blood pressure monitoring and left ventricular echocardiographic assessment. Their mean daytime systolic blood pressure varied from 88.0 to 208.9 mmHg and their mean daytime diastolic blood pressure from 40.3 to 133.0 mmHg. RESULTS: A negative correlation was found between the systolic or diastolic white-coat effect and the systolic or diastolic daytime ambulatory blood pressure (r = -0.22, P < 0.000 and r = -0.50, P < 0.000, respectively). Left ventricular mass significantly correlated with ambulatory blood pressure (P < 0.001), but there was no association between left ventricular mass and clinic blood pressure or white-coat effect. Furthermore, the white-coat effect was reversed at the highest level of systolic or diastolic daytime ambulatory blood pressure (systolic over 170 mmHg or diastolic over 100 mmHg) when systolic or diastolic daytime ambulatory blood pressure was higher than systolic or diastolic clinic blood pressure (ambulatory blood pressure hypertension). CONCLUSIONS: The white-coat effect shows an inverse association with daytime ambulatory blood pressure level (systolic or diastolic), being significantly more prominent for levels below 140/80 mmHg for systolic/diastolic daytime ambulatory blood pressure and reversed with daytime ambulatory blood pressure levels above 170/100 mmHg.

Seasonal variation of hospital admissions caused by acute stroke in Athens, Greece.

Several studies have reported a seasonal variation in stroke incidence with a peak during winter. In a hospital-based study, we investigated the distribution pattern of stroke occurrence in general, as well as its subtypes throughout the year. We studied the monthly and seasonal distribution of acute stroke occurrence among 1299 first ever stroke patients admitted at our hospital and compared it with the assumed equal distribution of stroke over the year (null hypothesis) using chi2 techniques. The seasonal distribution of the different stroke subtypes was also examined. Overall stroke incidence shows a seasonal variation with a significant peak during wintertime. Stroke etiology, cardioembolic stroke, and intracerebral hemorrhage are also characterized from a similar seasonal fluctuation with a significant trough in summer and peak in winter. On the contrary, cases of stroke caused by atherosclerotic large vessel disease, small vessel disease, and stroke caused by unusual or undetermined types show no seasonal periodicity. Seasonal variation of stroke seems to depend primarily on the etiology of stroke. Further studies are necessary in order to clarify this issue and provide useful evidence for stroke prevention and therapy.

Hypothyroidism as a protective factor in acute stroke patients.

OBJECTIVE: It has been reported that hypothyroidism is associated with better survival in elderly persons. We investigated possible associations of thyroid status with clinical outcome in patients with acute stroke. DESIGN: Retrospective analysis. PATIENTS: Consecutive patients (median age 70 years) admitted for acute stroke. MEASUREMENTS: Total T3, T4 and TSH levels. Stroke severity evaluation using the Scandinavian Stroke Scale (SSS) and the Glasgow Coma Score (GCS). Handicap and survival assessment over 12 months. RESULTS: Of 744 patients where thyroid function tests were available within the first 24 h of stroke, 13 had elevated TSH (>or= 10 microU/ml; range 10-42 microU/ml) (hypo-group), 51 had mildly elevated TSH (3.3-9.9 microU/ml) and 680 had nonelevated TSH < 3.3 microU/ml. In the hypo-group transient ischaemic attacks (TIA's) were more prevalent (46.2%) compared to the groups of mildly elevated TSH (11.8%) and nonelevated TSH (12.4%, P < 0.002). Hypo-group had more frequently an adequate level of consciousness (GCS 14-15 = fully alert): 92.3%vs 74.5% and 63.7% (P = 0.033), a milder neurological deficit (SSS score 45-58) 76.9%vs 39.2% and 38.7% (P = 0.02) compared to the other two groups, respectively, and a tendency for lower glucose levels on admission. One year outcome tended to be better with respect to survival and handicap. CONCLUSIONS: Acute stroke patients with laboratory findings compatible with pre-existing hypothyroidism on admission, appear to have better clinical presentation and outcome; we speculate that a reduced response to stress and previous TIA's, possibly related to endogenous 'preconditioning', may contribute to this phenomenon.

Two-peak temporal distribution of stroke onset in Greek patients. a hospital-based study.

A circadian distribution with a single peak of stroke onset in the morning hours has been described in various countries. Analysis of the temporal pattern of symptom onset in a series of 1253 Greek first-ever stroke patients revealed a circadian distribution with two incidence peaks between 08.00 and 10.00 h, and between 16.00 and 18.00 h. Considering the different etiopathogenic types of stroke, the same two-peak time pattern was evaluated in all stroke subgroups with the only exception of lacunar stroke, which seems to predominantly occur during night and sleep. A secondary stroke onset peak in the late afternoon has not been previously described in such detail. A relation between the second, however lower, frequency peak and the traditional Greek habit of afternoon sleep (siesta) could be assumed and deserves further investigation.