Heart to Heart

Most GPs carry out ECGs which provide a snapshot of your heart's rhythm, says Paul Nolan, a cardiac physiologist at Galway 
University Hospitals

Most GPs carry out ECGs which provide a snapshot of your heart's rhythm, says Paul Nolan, a cardiac physiologist at Galway University Hospitals

A fish flopping in your heart. A washing machine in your chest. Your heart turning over. That is how patients have described the symptoms of atrial fibrillation (AFib ) or irregular heartbeat.

It is the most common heart rhythm disorder and becomes increasingly common with age. Almost 10 per cent of 80-year-olds have had it at some point in their lives while up to five per cent of 70-year-olds are affected.

While advancing years are the most common risk factor, the condition can occur at any age, according to Professor Jonathan Lyne, a consultant cardiologist and the director of cardiac electrophysiology at the Beacon Hospital in Dublin.

Speaking at a webinar on "Living with Atrial Fibrillation", organised by the Galway based heart and stroke charity Croí recently, Professor Lyne, an internationally recognised heart rhythm specialist, stated that patients with other cardiac conditions such as artery disease, high blood pressure, valve disease, particularly of one of the valves called the mitral valve, or heart failure are at increased risk of having this heart rhythm disorder.

"Really, what atrial fibrillation is, is that in the top chambers of the heart or the atria, there are specialised cells that set the rhythm of the heart. They are the pacemaker cells and, in some patients, extra beats can occur in these top chambers. Sometimes they are very fast and they can disorganise the rhythm of the heart and override that pacemaker group of cells.

"Instead of a single organised electrical activity of the heart, they can actually result in it being chaotic and sending an irregular signal down to the bottom chamber of the heart. [You] end up with an irregular pulse that can be fast and something that people could be aware of in terms of symptoms."

Professor Lyne, a Cambridge University graduate, explained that patients with atrial fibrillation almost always have an irregular pulse and recommended that people check it regularly. "There have been campaigns called 'Know your Pulse' and checking that a couple of times a week to be sure it is regular is a very easy screening tool."

Artery disease

Is atrial fibrillation a side effect of some conditions or does it cause others? He said this can be "either way round".

"Conditions that we mentioned, artery disease, blood pressure, and heart failure can certainly be related in how atrial fibrillation can develop.

"If these top chambers - that become irregular in their activity - are under stretch from valve disease leaking blood back into them, if there is high blood pressure and they are stretched and under pressure, atrial fibrillation is more likely to happen as a secondary effect of that."

Neil Johnson, the chief executive of Croí who hosted the webinar, said when his organisation's health team are speaking to the public, they refer to atrial fibrillation as an "electrical problem" and systemic heart disease as a "plumbing problem". He asked about the impact of AFib and if it were a dangerous condition.

Professor Lyne said when speaking to patients, he talks firstly about the symptoms of the condition. "By that I mean if the heart is irregular and potentially fast they may be aware of palpitations. They may be aware of the heart being fast, they may get breathless from that and we talk about how that may affect them or not affect them. Some patients can be asymptomatic and not know at all. But really we are talking about symptoms in particular.

"Secondary to that I talk about the stroke risk and these things are to a large degree completely independent. By that I mean you may not have symptoms but still have a stroke risk that may be quite high and vice versa. So there is a link to a degree but I would really treat them as being quite independent things.

"The second thing is the stroke risk. In assessing what is the likely or possible level of stroke and how should we manage that, is there somebody that needs to have a blood thinning type of medication, a warfarin type of medication, to thin the blood and reduce the risk and there are several other procedures which can be done to help with that as well."

Larger deficit

Professor Lyne outlined that atrial fibrillation is probably the major cause of stroke in the western world. A patient with it has a five times higher stroke risk on average than a patient without AFib. With atrial fibrillation as a diagnosis, strokes tend to be denser, a larger symptom burden, or larger deficit for patients afterwards than would be from some other conditions. So stroke risk is a significant issue and atrial fibrillation is certainly one of the biggest risk factors."

People with atrial fibrillation may not experience any symptoms or the condition can present with virtually any cardiac or cardiorespiratory symptoms, according to the consultant cardiologist.

"By that I mean it can be breathlessness, it can be palpitations, the Americans [liken it to] a fish flopping in the heart, or the heart turning over, or a washing machine in the chest. It can be a very mild symptom to a very specific symptom like breathlessness or an awareness of the heart pumping in the chest or palpitations. Breathlessness is a relatively common symptom of atrial fibrillation. I'd say probably 20 to 30 per cent of patients present with a degree of breathlessness."

Is there a link between transient ischaemic attacks (TIAs ), also known as mini-strokes, and AFib? The professor said a mini-stroke is a neurological deficit, an alteration maybe in speech or motor function, sensory function, or vision lasting less than 24 hours.

"So, a non-permanent neurological symptom. In relation to atrial fibrillation, there can be small clumps of blood clots that may go up to the brain or the back of the eye and may result in a symptom like this that resolves. The body breaks it down and blood flow is restored by itself without permanent loss of function.

"But I suppose it is a warning sign with respect to the risk of stroke. And in patients who have had TIA, the risk of them suffering a further event or stroke is higher than [those] patients with atrial fibrillation that have not had that event before. Managing them appropriately in terms of blood thinners and other options are important as well as keeping them in normal rhythm as much as possible be that by drug medication or procedures such as ablation [a treatment that aims to correct certain types of abnormal heart rhythms by blocking electrical pathways in the heart]."

Speaking at the webinar, Paul Nolan, the chief 11 cardiac physiologist at Galway University Hospitals [UHG and Merlin Park] explained how AFib is diagnosed. Most GPs can perform a 12-lead electrocardiogram (ECG ) [a test to check the heart's rhythm and electrical activity], he said.

Holter monitor

"This is where they put the stickers on the chest, wrists, and ankles and that gives about a 10 second snapshot. And if you happen to be in AFib at the time it will pick it up. But most of the time that's not the case and there is a suspicion. In general, the most likely test people will have done is a Holter monitor [test] which is a small monitor you will wear for anything from 24 hours maybe up to a week depending on the suspicion or the history.

"In the case of somebody who would have a TIA or mini-stroke typically the best scenario is to monitor them for 72 hours. So typically a Holter monitor or even sometimes a smaller monitor we use in Galway is an R-Test monitor. This has three stickers on the chest. It's smaller than a mobile phone and clips to your belt or somewhere discreet. You come in and get it fitted and go home and return it at the end of the monitoring period and we analyse it and give a report to your clinician."

Professor Lyne said that patients with atrial fibrillation are commonly diagnosed either by ECG or monitor. "They often would have tests such as an ultrasound or echocardiogram to confirm that the heart is structurally normal, there isn't a valve narrowing, a leakage to fix and many patients may have had an exercise test or some assessment of artery function and maybe a CT or MRI scan of the heart.

"After that, when it comes down to treatment we look at symptom control and stroke risk. In terms of symptom control we are looking at giving then the best quality of life possible and freedom of symptoms. So, we would normally start with, if they are in atrial fibrillation all the time, controlling the speed of that heart maybe with medications like beta blockers specifically to slow down the heart not necessarily to regularise it but to give them a better quality of life."

Croi's next free public webinar titled "Living with Cardiovascular Disease: Emotional Recovery" will take place on Thursday Aug 26. To register log on to https://croi.ie/webinar/

 

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