The Naked Heart

Chronotropic Incompetence

A young and healthy heart can double its stroke volume in a heartbeat. However, this capability diminishes with an ageing heart, especially one that has been subjected to high blood pressure, heart valve issues or metabolic conditions such as poor glucose control over many years. These factors cause the left ventricle to stiffen in many people as they age, limiting their left ventricle's  ability to change its stroke volume. Consequently, any change in cardiac output in older individuals, or those with a stiff heart, increasingly relies on increasing the heart rate.

If the heart rate fails to increase with physical activity, cardiac output becomes constrained. Somewhat scarily, doctors call this "Chronotropic Incompetence" or "CI" for short. 

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Left ventricular suction, stiffness and heart failure

Getting your head around the difference between heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF) is a challenge for everyone. This is a technical discussion about why a stiff heart causes poor left ventricular suction and diastolic dysfunction.

In part 2 of the podcast their is a major focus on what lifestyle measures during mid life may help fend off the risk of heart failure in later life. 

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Starting Betablockers?

Beta blockers work on the beta receptor situated on the surface of cells that are affected by circulating adrenaline which the body releases in times of stress. Small amounts of adrenaline circulate, even at rest and help determine the resting heart rate and cardiac output. They also have a direct action on the Sinoatrial node which sets the heart rate and the AV node, which becomes very important in patients prone to atrial fibrillation and flutter. Beta blockers have been developed over 50 years and are used to treat a wide range of conditions, including palpitations due to arrhythmia, high blood pressure, anxiety, migraine to name just a few. For a cardiologist, beta blockers are a commonly used medication, possibly because we live in a high stress world and patients come to us with symptoms that are often improved by taking blockers. Cardioselective beta blockers are more popular as they are far less likely to trigger bronchoconstriction or asthma. Here are a few points that are often raised by our patients.

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Bradycardia: When does a Slow Heart Rate Becomes a Health Concern?

Bradycardia, or a slow heart rate, is a term you might have come across in a medical report or perhaps during a routine checkup. For many, hearing that their heart rate is "too low" can trigger concern. But what does bradycardia actually mean? And when does a slow pulse become something to address with a healthcare professional? Let’s dive deeper into the causes, symptoms, and treatment options, to help demystify bradycardia and highlight when it is a natural variation and when it requires medical attention.

Blog article

 

Why do patients with AFib feel breathless?

In atrial fibrillation, the atrial tissue quivers at approximately 600 cycles per minute, which means that it has no useful pumping function. The left atrium in patients with atrial fibrillation, merely acts as a passive conduit between the lungs and the left ventricle. It no longer serves to prime the left ventricle, and as a result, there may be less blood entering the heart during diastole and thus less 'priming' occurs, so cardiac output may fall. If ever you have experienced a car's turbo charger going 'on the blink' you will know that the car still GOES, but not very well, since it too suffers loss of output.  The left atrial pressure in many such cases will increase, causing oedema or fluid in the alveolar space, reducing gas exchange and contributing to the symptom of breathlessness.

Any stiffening of the left ventricle that for example accompanies old age, poor glycaemic control or indeed any condition that causes thickening of the left ventricle, such as hypertension or cardiomyopathy, therefore has a big impact on the ability of the left ventricle to relax and suck blood through from the left atrium and joining pulmonary veins, creating  backup of blood into the lung tissue.

For more on this topic and other related blog articles and podcasts see

https://www.scvc.co.uk/naked-heart/why-do-patients-in-atrial-fibrillation-get-breathless/

Glucose: A Matter of Life and Death

There is increasing evidence that high blood and tissue glucose levels may be an important risk factor for many non communicable diseases.

CGM monitoring should be considered in all patients affected by heart disease, in order to define glucotype and current glucose profile- both easily treated if 'unhealthy' .

Read more about glucose here

https://www.scvc.co.uk/news/why-glucose-may-be-the-most-important-modifiable-risk-factor-for-humans/

 

Why is Atrial Fibrillation a risk factor for heart attacks and stroke?

By 75 yrs of age 8.3 % of men and 5.7% of women are in AFib

Many people are not aware they have it

AFib is the cause of 20% of all stroke and upto half of all disabling hemiparetic stroke 

AFib can cause heart attacks and heart failure

For every case of permanent AFib there are 100s of cases of intermittent Afib called paroxysmal atrial fibrillation or ‘PAF’

Your blood pressure: how low is low enough?

Emerging evidence suggests that lower blood pressure targets may offer substantial benefits for cardiovascular health, particularly in those at higher risk. However, individual patient factors and potential side effects must be carefully considered. Further research is needed to refine optimal targets and individualise treatment strategies for long-term benefit.

https://www.scvc.co.uk/naked-heart/optimal-blood-pressure-how-low-is-low-enough/