Circadian variation in stroke - a prospective hospital-based study

Abstract

A particular pattern of circadian variation of cardiovascular and cerebrovascular diseases has been reported in the literature. The circadian periodicity of ischaemic stroke with peak onset in the morning hours may not be a random event and could depend on some underlying precipitating and associated cardiovascular risk factors. In a prospective observational study, we observed that ischaemic stroke onset was significantly higher in late morning hours between 6.00 and 12.00 hours. Ischaemic heart disease and hypertension were significantly associated with the occurrence of late morning ischaemic strokes. Further studies in the future are needed to understand the significance of this association and whether these risk factors are implicated in the pathogenesis of stroke.

Circadian Variation in the Incidence of Stroke-Induced Aphasia Types in Ahvaz, South-West of Iran

“…However, a study in New Zealand found that strokes were less likely to occur during the summer and autumn than in the winter or spring (33). Researchers mentioned some reasons such as changes in blood pressure, viscosity, fibrinogen levels, the effect of the air pressure on blood circulation and the increase of infectious diseases in some seasons to justify these issues (30,34,35). There is evidence that lowering of blood pressure in the night either naturally or through the use of antihypertensive medications could cause ischaemic brain damage especially in the elderly patients with associated ischaemic heart disease and occlusive carotid disease (36).…”

Circadian variation in the occurrences of ventricular tachyarrhythmias: Differences between coronary artery disease and dilated cardiomyopathy

“…The analysis of ischemic patients with Implantable Cardioverter Defibrillators (ICDs) evidence a morning peak and a secondary afternoon peak [1,2]. Similar circadian pattern has been noted in acute myocardial infarction [3] and stroke [4]. The circadian distribution of non-ischemic patients treated with ICDs led to controversial results: while in some studies CAD and non-CAD subjects lead to similar conclusions [5], in other paper the morning peak was not observed, but a more uniform distribution of the VT episodes during day-light in non-CAD patients.…”

Influência das variações circadianas e de temperatura no AVEi

“…Os efeitos da hiperglicemia sobre a área de isquemia e infarto cerebral podem ser variados: aumenta permeabilidade da barreira hematoencefálica e eleva o risco de degeneração hemorrágica. Já as cardiopatias favorecem a estase e turbulência sanguíneas intracardíacas e arritmias, podendo causar eventos cardioembólicos [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] . Ao avaliar o horário de instalação, encontrou-se 65,3% de AVEi entre 06h00 e 11h59 (p<0,0001), sendo condizente com a literatura atual.…”

“…Da mesma maneira, fatores protetores, como atividade fibrinolítica, estão reduzidos neste período do dia [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] . Além disso, foi demonstrado que nas épocas mais frias do ano, pressão arterial, número de plaquetas e hemácias, viscosidade do sangue e níveis de fibrinogênio e colesterol estão 23% mais elevados, principalmente em indivíduos idosos [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] É reconhecido também que a incidência de eventos isquêmicos aumenta nos períodos do ano em que são registradas as temperaturas mais baixas 16 . Em adição, no inverno pode ser observado aumento no número de internações hospitalares devido ao infarto agudo do miocárdio [5][6][7][8][9][10][11]…”