Arrhythmic Outcomes in Catecholaminergic Polymorphic Ventricular Tachycardia

Abstract

IntroductionLong QT syndrome (LQTS) and catecholaminergic ventricular tachycardia (CPVT) are less prevalent cardiac ion channelopathies than Brugada syndrome in Asia. The present study compared paediatric/young and adult patients with these conditions.MethodsThis was a territory-wide retrospective cohort study of consecutive patients diagnosed with LQTS and CPVT attending public hospitals in Hong Kong. The primary outcome was spontaneous ventricular tachycardia/ventricular fibrillation (VT/VF).ResultsA total of 142 LQTS (mean onset age= 27±23 years old) and 16 CPVT (mean presentation age=11±4 years old) patients were included. For LQTS, arrhythmias other than VT/VF (HR=4.67, 95% confidence interval=[1.53-14.3], p=0.007), initial VT/VF (HR=3.25 [1.29-8.16], p=0.012) and Schwartz score (HR=1.90 [1.11-3.26], p=0.020) were predictive of the primary outcome for the overall cohort, whilst arrhythmias other than VT/VF (HR=5.41 [1.36-21.4], p=0.016) and Schwartz score (HR=4.67 [1.48-14.7], p=0.009) were predictive for the adult subgroup (>25 years old; n=58). All CPVT patients presented before the age of 25 but no significant predictors of VT/VF were identified. A random survival forest model identified initial VT/VF, Schwartz score, initial QTc interval, family history of LQTS, initially asymptomatic, and arrhythmias other than VT/VF as the most important variables for risk prediction in LQTS, and initial VT/VF/sudden cardiac death, palpitations, QTc, initially symptomatic and heart rate in CPVT.ConclusionClinical and ECG presentation vary between the pediatric/young and adult LQTS population. All CPVT patients presented before the age of 25. Machine learning models achieved more accurate VT/VF prediction.

Clinical Characteristics, Genetic Findings and Arrhythmic Outcomes of Patients with Catecholaminergic Polymorphic Ventricular Tachycardia from China

“…In China, cases of CPVT have been limited to small case reports or case series. In this study, we performed a systematic search of the published literature, identifying CPVT cases that have been reported in the following cities: Beijing (n=22) [11,[32][33][34], Hong Kong (n=16) [25], Guangzhou (n=8) [35,40], Nanjing (n=6) [36], Shanghai (n=3) [37,38] and Sichaun (n=1) [39].…”

“…Of these, 12 have been reported outside China: c.490C>T [58], c.2410C>T (RCV000639160.2), c.7202G>A [41], c.7258A>G [31], c.7420A>G [28], c.10046C>T [30,42], c.11836G>A [43,46], c.12272C>T (RCV00182811.1), c.12475C>A [44], c.13933T>C [45], c.14159T>C (RCV000182842.2), c.14848G>A [46]. By contrast, c.14861C>G is a novel RyR2 variant that gives rise to the A4954G amino acid change [25]. This mutation affects the cytoplasmic domain of the RyR2, is expected to produce abnormalities in calcium handling, possible diastolic calcium leak and triggered arrhythmogenesis [54].…”

“…A systematic search of the PubMed and MedRvix databases yielded 1049 and 12 articles, respectively. After the exclusion of overlapping cohorts, a total of 56 unique cases from six cities by 11 studies were included [11,25,[32][33][34][35][36][37][38][39][40]. Their clinical characteristics and test results are shown in Table 1.…”

“…Another Japanese reported on the findings of 29 patients [23]. However, to date, case descriptions from China have been limited to case series [11,[24][25][26] and there is no established registry nationally. Moreover, many of these reports were also published in Chinese, and have limited accessibility to researchers beyond the country.…”

Clinical Characteristics, Genetic Findings and Arrhythmic Outcomes of Patients with Catecholaminergic Polymorphic Ventricular Tachycardia from China

“…Another Japanese reported on the findings of 29 patients [23]. However, to date, case descriptions from China have been limited to case series [11,[24][25][26] and there is no established registry nationally. Moreover, many of these reports are published in Chinese, and have limited accessibility to researchers beyond the country.…”