Are all hearts the same?

Risposta: Genetics, sex and age are non-modifiable determinants of cardiovascular health. They can influence the functional status of our heart: genetic abnormalities can predispose us to numerous conditions affecting the coronary arteries, the heart muscle or the heart’s electrical conduction system. Having a parent or sibling who has suffered an acute coronary syndrome at a young age – that is, under the age of 55 – may indicate a genetic predisposition to atherosclerotic disease. Each genetic condition has its own typical age of onset and may affect one sex more than the other. As for the incidence of coronary atherosclerosis – the leading cause of cardiovascular death – in the absence of a genetic predisposition, it increases with age. Women are less affected by this condition during their childbearing years, but their risk rises rapidly after the age of 70. It is important to remember that ‘modifiable’ risk factors (high blood pressure, high cholesterol, diabetes, smoking) and a sedentary lifestyle are genuine accelerators of the progression of atherosclerotic disease. Moving from the coronary arteries to the heart muscle, there are numerous genetically inherited conditions. These conditions may manifest predominantly as arrhythmias or be predominantly associated with a loss of the muscle’s ability to contract. In the first case, predominantly ventricular arrhythmias develop, with an increased risk of sudden death. In the latter case, there is a progressive reduction in the ejection fraction and the onset of heart failure. Heart failure manifests as the onset of dyspnoea, or shortness of breath, which occurs even during mild exertion. Finally, there are genetically inherited conditions that affect ion channels. These are the fundamental components of the cardiac excitation-conduction system, as they regulate the movement of negative and positive ions across the plasma membranes of cells. Genetic abnormalities affecting sodium channels cause Brugada syndrome, which increases the risk of sudden arrhythmic death, particularly between the ages of 30 and 50. This condition is more common in men than in women. In contrast, long QT syndrome, predominantly caused by the malfunctioning of potassium channels, affects women more than men, as men have a higher concentration of potassium channels. Long QT syndrome increases the risk of sudden arrhythmic death from as early as the first decade of life. As can be seen from the above examples, the gender most affected and the age at which the condition manifests vary depending on the specific condition under consideration.