Europe and North America differ in their use of implantable cardioverter-defibrillators (ICDs), which are advanced pacemakers for people with an increased risk of sudden cardiac death. New research shows that European cardiac centres implant ICDs much less often, but those who do not get an ICD have fewer serious events in Europe than in North America.
Europe and North America differ in their use of implantable cardioverter-defibrillators (ICDs), which are advanced pacemakers for people with an increased risk of sudden cardiac death. New research shows that European cardiac centres implant ICDs much less often, but those who do not get an ICD have fewer serious events in Europe than in North America.
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited heart disease often discovered early in life among elite athletes, with massive training putting the heart under pressure.
Once ARVC is confirmed, a cardiologist assesses whether the person needs an ICD to prevent sudden cardiac death and other serious cardiac events.
A new study now shows considerable trans-Atlantic differences in the proportion of people with ARVC who have an ICD implanted.
Cardiac centres in the United States and Canada do this more often than those in Europe, and there might therefore be concern about more serious cardiac events among people with ARVC in Europe, but the study refutes this.
“Although in Europe we feel that we are very liberal in giving ICDs to people with ARVC, we do this less often than in North America but still have good outcomes. We therefore conclude that we should probably continue to be cautious about using ICDs for people with ARVC – if we have any doubts that they are needed,” explains Henrik Kjærulf Jensen, Clinical Professor, Department of Clinical Medicine, Aarhus University and Consultant Cardiologist, Department of Cardiology, Aarhus University Hospital.
The research has been published in the European Heart Journal.
ARVC often affects young athletes
ARVC is a relatively rare inherited heart disease. About 1,000 people are diagnosed with it in Denmark.
Unlike other types of arrhythmias, ARVC is more serious because it involves the heart’s ventricles, and this can be fatal if they do not pump sufficient blood.
ARVC typically starts already in adolescence, often because of continual heavy strain on the heart. ARVC often emerges among athletes in sports with high stress on the heart, such as distance runners, swimmers and cyclists – but it can remain undetected for a long time among people who do not exercise at a high level.
A genetic defect means that some proteins (desmosomes) that normally hold the heart muscle cells together do not function properly.
Severe strain on the heart can then lead to inappropriate signals being sent to some of heart muscle cells, transforming normal heart muscle into fatty-fibrous tissue.
“Fatty-fibrous tissue in the heart muscle can interrupt electrical signals in the heart, which may cause irregular and potentially life-threatening arrhythmia. In the worst case, this can trigger cardiac arrest and sudden cardiac death. People diagnosed with ARVC should avoid training intensively for long periods. Then the task is to determine who should get an ICD to prevent future problems and when – and who can manage without one,” says Henrik Kjærulf Jensen.
Europe versus North America
The researchers investigated the treatment and outcomes over five years for 1,098 people with ARVC: 725 from 29 cardiac centres in Europe and 373 from a centre in the United States and a centre in Canada.
The researchers also stratified them according to high risk and low risk of complications.
The cohort in Europe averaged 42 years old versus 36 years in North America.
“We only have data from two centres in North America, and the data may not be completely representative. But the data still indicate whether the treatment approach differs across the Atlantic,” explains Henrik Kjærulf Jensen.
ICDs three times as often in North America
The results show that 50% of the study group received a primary prevention ICD, and 26% experienced ventricular arrhythmia requiring treatment.
The researchers found that the cohort in North America was 3.1 times as likely to receive ICDs as that in Europe.
Nevertheless, the cohort in Europe had only 1.4 times the increased risk of sustained ventricular arrhythmia of that in North America.
The researchers also found that the people with ARVC in North America without an ICD had 2.1 times the risk of sustained ventricular arrhythmia of those in Europe without an ICD.
“We conclude that people with ARVC in North America get an ICD more often, but the fact that we are a little more reluctant to implant them in Europe is not disadvantageous to the people with ARVC. Perhaps we should take a cautious approach towards people with mild ARVC, and instead of giving them an ICD, monitor them more closely with more frequent checks,” explains Henrik Kjærulf Jensen.
He elaborates that he is quite satisfied with the approach in Europe, since implanting an ICD can risk infection, inappropriate therapy, and psychological side-effects..
“We would like to take a cautious approach to implanting ICDs, and we would prefer to avoid doing this if it is not necessary. Our study indicates that we have the right approach in Europe,” concludes Henrik Kjærulf Jensen.
