Hypertension, coronary heart disease and arrhythmia
Hypertension, coronary heart disease and arrhythmia are the common conditions of the heart and circulation: how each is defined, what drives it and how it is treated, set against the risk factors the Framingham Heart Study identified for heart disease.
Risk factors for heart disease
The Framingham Heart Study followed three generations of participants and identified high blood cholesterol, smoking, obesity, diabetes, lack of physical activity and hypertension as the primary risk factors for heart disease.
Hypertension
Hypertension, or high blood pressure, is an elevated measure of the force the blood exerts against the artery walls, and what counts as elevated has evolved over the years and varies with patient characteristics. The American Heart Association blood pressure classification, as given in 2017, sets general guidelines for normal, borderline and elevated values:
| Level | Systolic | Diastolic |
|---|---|---|
| Normal | <120 mm Hg | <80 mm Hg |
| Prehypertension | 120–139 mm Hg | 80–89 mm Hg |
| Hypertension | ≥140 mm Hg | ≥90 mm Hg |
The Eighth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure recommends that clinicians start therapy in patients older than 60 with a blood pressure of 150/90 mm Hg or higher, in patients younger than 60 with a blood pressure of 140/90 mm Hg or higher, and in patients with diabetes and a blood pressure of 140/90 mm Hg or higher.
Coronary heart disease
Coronary heart disease is marked by the accumulation in the coronary arteries of plaque made of cholesterol, fat, cellular waste, fibrin and calcium, and it causes approximately 16% of deaths in the United States, according to one speaker in 2017. Its potential outcomes include ischaemia (insufficient blood flow to the heart muscle), angina (chest pain), atherosclerosis (hardening of the arteries), blood clots, stroke and heart attack. Some of its risk factors, such as age, sex and family history, cannot be modified, but people can control several others: poor diet, obesity, lack of exercise, smoking and elevated cholesterol.
Cholesterol is produced in the liver and is needed for digestion and hormone production, and it circulates in the blood in two forms: low-density lipoprotein (LDL), the "bad" cholesterol, and high-density lipoprotein (HDL), the "good" cholesterol. Excess LDL accumulates within the arteries and narrows them, whereas HDL acts as a scavenger that sweeps LDL back to the liver for recycling. The options for managing cholesterol include, in particular, the statin medications.
Arrhythmias
The American Heart Association defines arrhythmias as changes in the sequence of electrical impulses through the heart, which can make it beat too rapidly (tachycardia), too slowly (bradycardia) or irregularly. Arrhythmias are, in one speaker's characterisation, generally harmless but potentially damaging for organs that do not receive an adequate blood supply. Their treatments include medications, pacemakers and ablation.