The exact mechanism and the immediate triggers for acute heart attack and brain attacks are not known. Clinical manifestations of these attacks also do not occur at random times but according to a time structure. It is possible that certain external activities, known as triggers, play a major role in the occurrence of these attacks. In one study, half of all heart attack patients reported a temporal relationship between characteristic activities and occurrence of the attack. Emotional stress, sleep deprivation ,large meals, mild and heavy physical exertion were the most frequently reported triggering factors of heart attacks.In the TRIMM STUDY, 76% of all heart attack patients reported an unusual event, shortly before the onset of attack. There appears to be a powerful evidence of a link between these triggers and the sequences of cellular and pathophysiological events that are postulated as being responsible for poor supply of blood in the heart. The morning increase in platelet aggregability is a most frequent trigger of heart attack, which may be the result of increased secretion of cortisol, aldosterone, catecholamines, angiotensin and decreased vagal tone that are known to be enhanced by food and benefited by fasting.

Both clinical and biochemical factors may be related to a molecular clock present in the brains suprachiasmatic nucleus . Apart from above triggers, presence of risk factors of low heart rate variability, such as excess fat, more insulin resistant, obesity and pollution may also act by enhancing triggers and trigger-induced brain-related and hormonal mechanisms in the development of poor supply of blood to heart.
Could a heavy breakfast lead to heart disease?

Heart attack is a highly dynamic event, which is associated with marked neuroendocrinological dusfunction apart form heart damage. The immediate trigger for heart attack is not known exactly. Studies conducted by Lown, Braunwald, Halberg, Otsuka,Singh,Anna and our group have demonstrated, a marked increase in sympathetic activity, oxidative stress and deficiency of magnesium and potassium during heart attack.

Clinical studies have reported an increased incidence of attacks, sudden death and poor blood supply to heart, during first quarter of the day when there is rapid withdrawal of vagal activity and increase in sympathetic tone. In one case control study by Singh etal(Biomed Pharmacother,2004) among 202 patients of heart attack, there was a significant (Pandlt;0.02) increase in cardiac events in the second quarter of the day compared to other quarters respectively (16.8%, 41.0%, 13.8%, 28.2%). This characteristic remained common in both men and women and among patients with and without known heart attack (n=52), diabetes (n=53) and hypertension (n=75). Triggers of heart attack were noted among 162(82.2%) of the patients.Brain related and psychological mechanisms were observed as given : emotional stress (45.5%) , sleep deprivation (27.7%), cold climate (29.2%), hot climate (24.7%), large meals (47.5%) and physical exertion (31.2%). These triggering factors are known to enhance sympathetic activity and decrease vagal tone, resulting into increased secretion of plasma cortisol, noradrenaline, aldosterone, angiotension converting enzyme, interleukin-1,2,6,18 and tumor necrosis factor-alpha, that are pro-inflammatory. There is also a deficinency in the serum levels of vitamin A,E,C,coenzyme Q and magnesium, potassium, melatonin, interleukin-10 (anti-inflammatory). In our study, we found a decrease in magnesium, potassium, vitamin A,E,C and beta carotine and and increase in TBARS, MDA and diene conjugates, TNF-alpha and IL-6 which are indictors of oxidative damage and pro-inflammatory respectively.