Ischaemic Heart Disease

A lot of times, the pathologist puts ischaemic (same as ‘ishemic’) Heart Disease down as the cause of death. It’s a term that encompasses a whole host of related conditions, all of which are caused by chronic lack of blood to the heart muscle. I’d better explain the medical meaning of ‘chronic’, which is confined to the meaning ‘long term’. ‘Acute’ means ‘short term’. When a doctor uses those words, there is no implication of strength.

So, ischaemic Heart Disease (often shortened to IHD) merely means the heart muscle (‘myocardium’, remember?) has not had enough blood over a long period of time – years, even decades. The cells that make up the myocardium (‘myocytes’) die but, unlike in a myocardial infarction, they don’t die all at once. The body’s response to any long-term shortage of blood is to make fibrous tissue (‘fibrosis’), but the heart still has a job to do.

The problem is, fibrous tissue is useless as a pump, which means that the surviving myocytes have to work harder. To put it simply, it’s a bit like bench-pressing weights day in and day out; the muscle gets bigger. When the patient dies, the pathologist finds a big heart and when the heart muscle is examined, it’s pale because of the high content of fibrous tissue.

The problem is that the fibrous tissue isn’t an efficient electrical conductor. As a result, arrhythmias occur; an ‘arrhythmia’ is a rhythm that is different to the normal regular ‘sinus’ rhythm. Sometimes, the patient can live with an arrhythmia, and therefore the patient may came to the attention of a healthcare professional. If the first arrhythmia is asystole (the heart just stops) or ventricular fibrillation (see before), then the chances are, the patient dies

But why is there not enough blood? Because of coronary atheroma again. When doctors talk of ‘coronary artery disease’ they almost always mean ‘atheroma’.

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