Jussi Hernesniemi’s research may save your heart

Jussi Hernesniemi first intended to become a M.Sc. in engineering. However, his background in sports turned his interest to the workings of the human body. Hernesniemi applied to study medicine and completed advanced studies in the field of cardiovascular genetics, which spiked his interest in cardiology.

Now he is working as Professor of Cardiology at Tampere University. In his research, Hernesniemi focuses on atrial fibrillation and atrial flutter. He also strives to find means to predict the risk of sudden cardiac death and stroke in patients with coronary artery disease.

Atrial fibrillation increases with age and is diagnosed in some 10% of people over the age of 75.

In the atria of the heart, the sinoatrial node leads the show as it triggers an electrical impulse that causes the atria to contract. This contraction pushes the accumulated blood into the ventricles of the heart. When the electrical impulse from an atrium enters the blood-filled ventricle with a slight delay, it is their turn to contract and pump the blood forward. After contraction, the ventricles expand again, and the same blood flow process begins again. This is when things are normal.

“If the atrial tissue has deteriorated, atrial fibrillation takes over more easily. That is when the electrical impulse starts to spin chaotically around the atrium, and there is no contraction. When the impulse hits a point where it can enter the ventricles, they contract, but irregularly,” Hernesniemi says.

“Atrial flutter is a rarer arrhythmia, but unhealthy atrial tissue is a risk factor in that too. Atrial flutter wreaks havoc when the electric impulse travels around the atria 250–300 times per minute making them flutter in the same rhythm. Usually, every second or every fourth of these impulses is mediated into the ventricles,” Hernesniemi explains.

Both atrial flutter and atrial fibrillation are associated with an increased risk of stroke.

We all have a higher or lower susceptibility to arrhythmia, and atrial fibrillation and flutter can also hit a healthy heart. A typical young atrial fibrillation patient is a man in his twenties with a hangover that has triggered an existing predisposition.

An occasional guest often moves in permanently

Two treatment strategies are used to treat atrial fibrillation. The first one aims to restore the rhythm to normal and keep it that way. Lifestyle plays a key role: the treatment of high blood pressure and cholesterol levels, weight loss, and the minimisation of significant exposures. Depending on the situation, antiarrhythmic medications and catheter ablation therapy may also be considered.

Another strategy is heart rate control.

“Atrial fibrillation is like an unpleasant relative who sometimes comes calling. But at some point, the guest will begin to drop in so frequently that it will need a room of its own. When the heart rate is controlled, it is irrelevant whether the heart has a normal rhythm or atrial fibrillation. Attention is only paid to the fact that the rhythm should not be too fast,” Hernesniemi says.

In the long run, most patients with atrial fibrillation have a similar quality of life regardless of which treatment strategy has been selected.

Photo: Jonne Renvall

An interesting feature is associated with atrial fibrillation. A high body mass index is a risk factor, but atrial fibrillation does not distinguish whether the mass consists of fat or muscle. What is essential is the total amount of blood flow required in the body. The more weight there is relative to one’s height, the harder the heart must work.

In middle age, moderation is also worth remembering in endurance sports. Weekly high-energy endurance sports — and we are now talking about amounts that a regular fitness enthusiast cannot not reach — increase the daily blood flow so much that it increases the risk of atrial fibrillation considerably.

Investments in the development of professional research

In the prevention of sudden cardiac deaths, Hernesniemi emphasises the importance of the regular electrocardiogram (ECG), which can be a very effective tool for finding risks if a lot of data can be gathered. And especially if more than human observations can be used to aid the screening. As an important leap forward, he mentions Lauri Holmström’s research at the University of Oulu, which utilised machine learning in connection with analysing patients’ ECGs.

“Over time, the ECG may change in ways that are not detected at the time of measurement. Holmström’s research demonstrated that if you compare the latest ECGs of patients who have died of a heart attack with the ECGs of a control group, there are many differences. That is also very a promising result for our research,” Hernesniemi points out.

Hernesniemi is currently doing research with Esa Räsänen, Antti Vehkaoja and Mark van Gils utilising a large cohort data of the ECGs of coronary artery disease patients. It enables conducting a corresponding screening study — and because of the high quality of the data, the results may be even better. They should become available in autumn 2024.

Despite promising projects and successes Hernesniemi says that Finland lags behind in cardiological research. One of the obstacles is the recent legislation on the secondary use of social and health data and its strict interpretation.

“Legislation has been enacted to protect people’s trust and rights and freedoms when their personal data is processed for secondary purposes, such as research. In practice, the act and its extremely strict interpretations add an absurd amount of bureaucracy, create costs and, at worst, hinder research. It paralyses rapid development,” Hernesniemi says.

Further tensions are caused by, for example, the fact that drug development is so expensive that only large multinational companies can do it.

“Vaccine development is a rare example of drug development that can still be driven by academics. In cardiovascular diseases, often the most we can see is whether the old tricks also work in new indications,” Hernesniemi point out.

In fact, he would like university funding models to be overhauled to support professional research activities better instead of emphasising publication and dissertation numbers.