Background - Risk stratification in catecholaminergic polymorphic ventricular tachycardia (CPVT) remains ill defined. Heart rate reduction (HRR) immediately after exercise is regulated by autonomic reflexes, particularly vagal tone, and may be associated with symptoms and ventricular arrhythmias (VAs) in patients with CPVT. Our objective was to evaluate whether HRR after maximal exercise on the exercise stress test (EST) is associated with symptoms and VAs. Methods - In this retrospective observational study, we included patients ≤ 65 years with an EST without antiarrhythmic drugs (AAD) who attained at least 80% of their age- and gender-predicted maximal HR. HRR in the recovery phase was calculated as the difference in heart rate (HR) at maximal exercise and at one minute in the recovery phase (ΔHRR1'). Results - We included 187 patients (median age 36 years, 68 [36%] symptomatic before diagnosis). Pre-EST HR and maximal HR were equal among symptomatic and asymptomatic patients. Patients that were symptomatic prior to diagnosis had a greater ΔHRR1' after maximal exercise (43 [IQR, 25-58] vs. 25 [IQR, 19-34] beats/minute, p<0.001). Corrected for age, gender and relatedness, patients in the upper tertile for ΔHRR1' had an odds ratio of 3.4 (95% confidence interval, 1.6-7.4) of being symptomatic before diagnosis (p<0.001). In addition, ΔHRR1' was higher in patients with complex VAs at EST off AADs (33 [IQR, 22-48] beats/minute vs. 27 [IQR, 20-36], p=0.01. After diagnosis, patients with a ΔHRR1' in the upper tertile of its distribution had significantly more arrhythmic events as compared to patients in the other tertiles (p=0.045). Conclusions - CPVT patients with a larger HRR following exercise are more likely to be symptomatic and have complex VAs during first EST off AAD.