Hypertension is also associated with decreased peripheral venous compliance which may increase venous return, increase cardiac preload and, ultimately, cause diastolic dysfunction. Pulse pressure (the difference between systolic and diastolic blood pressure) is frequently increased in older people with hypertension. This can mean that systolic pressure is abnormally high, but diastolic pressure may be normal or low, a condition termed isolated systolic hypertension. The high pulse pressure in elderly people with hypertension or isolated systolic hypertension is explained by increased arterial stiffness, which typically accompanies aging and may be exacerbated by high blood pressure.Many mechanisms have been proposed to account for the rise in peripheral resistance in hypertension. Most evidence implicates either disturbances in the kidneys salt and water handling (particularly abnormalities in the intrarenal renin–angiotensin system) or abnormalities of the sympathetic nervous system. These mechanisms are not mutually exclusive and it is likely that both contribute to some extent in most cases of essential hypertension. It has also been suggested that endothelial dysfunction and vascular inflammation may also contribute to increased peripheral resistance and vascular damage in hypertension. Interleukin 17 has garnered interest for its role in increasing the production of several other immune system chemical signals thought to be involved in hypertension such as tumor necrosis factor alpha, interleukin 1, interleukin 6, and interleukin 8.Excessive sodium or insufficient potassium in the diet leads to excessive intracellular sodium, which contracts vascular smooth muscle, restricting blood flow and so increases blood pressure. Diagnosis
Hypertension is diagnosed on the basis of a persistently high resting blood pressure.
In the famous Baltimore-Washington Study, it was reported that smoking more than one pack per day while pregnant was associated with two specific cardiac deflects, both part of TOF: pulmonary stenosis and transposition with VSD. Maternal diabetes: Maternal diabetes, diabetes Mellitus, and gestational diabetes are well-known risk factors of fetal CHD, including TOF. Maternal diabetes has been shown to increase the risk of cardiovascular deformations, namely the transposition of great arteries, one of the four deformations in TOF. Studies have also looked at whether diabetes increases the risk of malformation or poor sugar regulation and have found that sugar regulation does not significantly affect cardiac malformations. Retrospective studies have shown that diabetic mothers with good glucose control still retained the elevated CHD risk. Rubella: Rubella is characterized as mild, contagious viral disease with often unnoticed consequences. Infection with rubella during the first trimester has been seen to cause various fetal malformations, including TOF. Maternal Age: Older maternal age, especially after 35 can have various pregnancy risks due to existing co-morbidities such as hypertension, diabetes, hypothyroidism, and consanguinity. These risk factors can effect fetal development and lead to various fetal conditions such as CHD (including TOF), Down Syndrome and Autism.Embryology studies show that anterior malalignment of the aorticopulmonary septum results in the clinical combination of a ventricular septal defect (VSD), pulmonary stenosis, and an overriding aorta. : 200  Right ventricular hypertrophy develops progressively from resistance to blood flow through the right ventricular outflow tract.