by Colin Michie
Valentine’s Day is over, but the month of February keeps hearts centre stage. Our heart is an organ we know well – we feel it pulsing at our wrists; it beats in our ears as we go to sleep, or in our chest when we sprint; its pumping connects us with oxygen, with life. But heart disease is the most common cause of death in those living in Caribbean nations.
We are mostly made up of oxygen. This gas is our most common element. Most of our oxygen is in the form of water – up to 70% of our weight is water. Water is made of two atoms of hydrogen (these are very small) and one large oxygen atom, with the formula of H2O. Water is collected by blood from our gut by vast webs of tiny blood vessels. At the same time, all the time, oxygen is collected as a gas in the lungs in equally fine, lace-like meshes of capillaries. Oxygen is loaded into red cells then transported. Our beating hearts pump about 5 litres of this oxygenated blood every minute when we are at rest, reaching our most distant tissues. All cells use this oxygen to release energy from glucose.
Heart pumping respond within seconds too: Nerve supplies to the pacemaker, along with a stimulus from adrenaline, helps hearts adapt to what is needed for a Valentine rave, a quiet night with the family or a run down the street. You can assess your vital signs, your cardiac performance, with some numbers. How fast are your heart beat and your breathing? What is your blood pressure? Coronary arteries can supply five times more oxygen to the heart muscle to increase its output for these moderate or vigorous activities. And heart muscle itself benefits from the action. These are healthy habits, to be learned by heart!
Should you wish to improve your chances of celebrating Saint Valentine’s Day in 2050, your blood pressure is a critical measure. It is particularly helpful when added into “Life’s Essential 8.” The other elements include measures of your weight, blood glucose and lipids, together with four of your health behaviours: Physical activity levels, diet, sleep pattern and tobacco use. Each has a score to help predict your risk of heart disease or stroke. This combined system provides positive advice and guidance to help avoid premature death. It works for all ethnicities and income groups.
Cardiovascular disease is common. This is a global pattern too. Numbers of patients in the Caribbean have increased over the last 20 years, particularly younger people. High blood pressure and tobacco smoking are powerful heart risks in this region; they are not helped by sedentary lifestyles and unhealthy diets. All of these reduce the elasticity of blood vessels and promote deposits of atherosclerosis. This fatty material narrows blood vessels, including those that carry oxygen into the heart. Lumps of atherosclerotic plaque can break off inside a coronary artery and block it, causing death of heart muscle cells. If a large artery is involved, damaging a large area of muscle, this can result in a heart attack – a myocardial infarction.
Heart muscle is not like skeletal muscle or the smooth muscles in our bladder. First, it needs more oxygen – it must continue to beat! This makes it very sensitive to any reduction in its blood supply. Second, it lacks a system to repair itself. Whereas a tear in a calf muscle can be successfully repaired by local stem cells, this process is limited in the heart. Dead heart muscle is replaced mostly by fibrous tissues that do not contract or support the electrical pacing processes required for regular, efficient heartbeats. So heart disease can lead to pump or heart failure. Creating small personalised cultured muscle patches to repair hearts may become a possibility in the future. Meanwhile, advances in keeping coronary arteries open with stents, reinforcing heartbeats with pacemakers and using medications can manage some heart failure.
Hospitals from different Caribbean islands each report a distinctive pattern of heart problems. Disorders such as sickle cell, rheumatic heart disease, amyloidosis and tropical infections vary in their populations. Surveys suggest that the region successfully delivers urgent care and pharmacological treatments for heart diseases to its citizens. However, longer-term therapies to prevent complications from heart disorders are not always available. For instance, rates of depression following a heart attack were found in just over a third of Caribbean patients – a figure almost double that reported from the US.
Just remember, Looking after our hearts is a very personal, physical and mental venture. Love, together with a sound oxygen supply, can take us a long way towards better health!
Useful resources:
https://www.who.int/news-room/fact-sheets/detail/cardiovascular-diseases
https://www.heart.org/en/healthy-living/healthy-lifestyle/lifes-essential-8
https://www.cdc.gov/heart-disease/about/index.html
