Acute Effect of One Single Bout of High Intensity Exercise on the Tendency for Ventricular Arrhythmia

This study is a substudy of a planned study involving participants with an implantable cardioverter defibrillator (ICD), who will be randomly assigned to either take part in a exercise program for 12 weeks or serve as control and live as usual (Clinical Trials Unique Protocol ID: 2018/1592). In that study all participants will complete an exercise treadmill test to determine maximum oxygen uptake (VO2 peak).

In this study we wish to examine the acute effect of one single bout of high intensity exercise (i.e the VO2 peak test) on the tendency for ventricular arrhythmia. The study will evaluate changes in ICD-parameters and the number of premature ventricular contractions the first 24 hours after VO2 peak testing compared to the average number of the 48 hours prior to the test.

The study will also examine if the acute effect after VO2 peak testing alters after completing 12 weeks of aerobic interval training or control respectively.

Inclusion criteria

• Patients with ICD and dilated cardiomyopathy or coronary heart disease as cause for implantation
• ICD implanted at St Olavs hospital, Trondheim

In case of difficulties with patient inclusion for the study, the criteria might be broadened to include patients with idiopathic ventricular arrhythmia as cause for implantation.

Exclusion criteria

• inability to accomplish the exercise program due to serious comorbidity or to participate in regular training within the next 3 months due to other reasons
• signs of severe cardiac ischemia or persistent ventricular tachycardia during individualized treadmill O2 peak test, which after individual assessment is to be found at risk
• comorbidity where endurance training at more than moderate intensity is discouraged
• severe cardiac valve disease
• planned surgery within the next 3 months
• inability to give informed consent