Repeatability of abnormal heartbeats on the exercise-stress test in CPVT
When someone exercises or has stress, hormones, called catecholamines, are released. Amongst other effects, the catecholamines result in a faster heart rate. In patients with catecholaminergic polymorphic ventricular tachycardia (CPVT), the heart is more sensitive to catecholamines. In periods of stress or exercise, the catecholamines can trigger the heart to beat too fast, irregular and ineffective. The main function of the heart – pumping oxygenated blood through the body, is therefore hampered. This can lead to syncope (‘blackouts’) or – if the rhythm is not returned to normal – even death.
The exercise-stress test is used to diagnose CPVT and to evaluate the treatment. In this test, the heart is monitored while the patient is cycling on a home trainer or running on a treadmill. The effort slowly increases until the patient makes maximum effort. In a patient with CPVT, abnormal heartbeats can be seen during the exercise-stress test. The abnormal heartbeats increase in severity when effort increases. The CPVT diagnosis and the type and efficacy of therapy is based on the presence and severity of abnormal heartbeats.
In this study, we looked at repeated exercise-stress tests of patients with CPVT. We collected data of all exercise-stress-tests performed in one patient. We evaluated the exercise-stress test and made five categories based on the severity of the abnormal heartbeats (category 1-5). The lowest category (1) is no arrhythmia at all or only a few extrasystoles and the highest category (5) is ventricular tachycardia. We compared exercise-stress tests in a patient performed under the same circumstances (most importantly same type and dosage of medication). In total, we looked at 349 exercise-stress tests pairs of 104 patients with CPVT. In half of the exercise-stress tests the severity of the abnormal heartbeats differed at least one category (for example category 1 in the first test and category 2 or 3 in the second test performed under the same circumstances). This difference in severity of abnormal heartbeats was especially high in patients using medication. This information can help to improve the diagnosis and treatment and improve research in patients with CPVT. Firstly, a single exercise-stress test to diagnose CPVT might not be enough. Secondly, a sudden increase of abnormal heartbeats should lead to a change in the type of therapy. Finally, a change of abnormal heartbeats can be used as endpoint to study potential new medication in CPVT research.
Translated by Puck Peltenburg, Amsterdam UMC, Amsterdam, The Netherlands
Peltenburg PJ, Pultoo SNJ, Tobert KE, Bos JM, Lieve KVV, Tanck M, Clur SB, Blom NA, Ackerman MJ, Wilde AAM, van der Werf C. Repeatability of ventricular arrhythmia characteristics on the exercise-stress test in RYR2-mediated catecholaminergic polymorphic ventricular tachycardia. Europace. 2022 Nov 12:euac177. doi: 10.1093/europace/euac177. Online ahead of print. PMID: 36369981