Objective: To observe the association between clinical phenotypes of hypertrophic cardiomyopathy (HCM) patients and a rare calcium channel and regulatory gene variation (Ca2+ gene variation) and to compare clinical phenotypes of HCM patients with Ca2+ gene variation, a single sarcomere gene variation and without gene variation and to explore the influence of rare Ca2+ gene variation on the clinical phenotypes of HCM. Methods: Eight hundred forty-two non-related adult HCM patients diagnosed for the first time in Xijing Hospital from 2013 to 2019 were enrolled in this study. All patients underwent exon analyses of 96 hereditary cardiac disease-related genes. Patients with diabetes mellitus, coronary artery disease, post alcohol septal ablation or septal myectomy, and patients who carried sarcomere gene variation of uncertain significance or carried>1 sarcomere gene variation or carried>1 Ca2+ gene variation, with HCM pseudophenotype or carrier of ion channel gene variations other than Ca2+ based on the genetic test results were excluded. Patients were divided into gene negative group (no sarcomere or Ca2+ gene variants), sarcomere gene variation group (only 1 sarcomere gene variant) and Ca2+ gene variant group (only 1 Ca2+ gene variant). Baseline data, echocardiography and electrocardiogram data were collected for analysis. Results: A total of 346 patients were enrolled, including 170 patients without gene variation (gene negative group), 154 patients with a single sarcomere gene variation (sarcomere gene variation group) and 22 patients with a single rare Ca2+ gene variation (Ca2+ gene variation group). Compared with gene negative group, patients in Ca2+ gene variation group had higher blood pressure and higher percentage of family history of HCM and sudden cardiac death (P<0.05); echocardiographic results showed that patients in Ca2+ gene variation group had thicker ventricular septum ((23.5±5.8) mm vs. (22.3±5.7) mm, P<0.05); electrocardiographic results showed that patients in Ca2+ gene variation group had prolonged QT interval ((416.6±23.1) ms vs. (400.6±47.2) ms, P<0.05) and higher RV5+SV1 ((4.51±2.26) mv vs. (3.50±1.65) mv, P<0.05). Compared with sarcomere gene variation group, patients in Ca2+ gene variation group had later onset age and higher blood pressure (P<0.05); echocardiographic results showed that there was no significant difference in ventricular septal thickness between two groups; patients in Ca2+ gene variation group had lower percentage of left ventricular outflow tract pressure gradient>30 mmHg (1 mmHg=0.133 kPa, 22.8% vs. 48.1%, P<0.05) and the lower early diastolic peak velocity of the mitral valve inflow/early diastolic peak velocity of the mitral valve annulus (E/e') ratio ((13.0±2.5) vs. (15.9±4.2), P<0.05); patients in Ca2+ gene variation group had prolonged QT interval ((416.6±23.1) ms vs. (399.0±43.0) ms, P<0.05) and lower percentage of ST segment depression (9.1% vs. 40.3%, P<0.05). Conclusion: Compared with gene negative group, the clinical phenotype of HCM is more severe in patients with rare Ca2+ gene variation; compared with patients with sarcomere gene variation, the clinical phenotype of HCM is milder in patients with rare Ca2+ gene variation.

Objective:To evaluate the clinical efficacy of percutaneous intramyocardial septal radiofrequency ablation (PIMSRA) in the treatment of obstructive hypertrophic cardiomyopathy (HOCM) with mild septal hypertrophy.Methods:Forty-five HOCM patients with mild septal hypertrophy (the maximal left ventricular wall thickness is 15-19 mm) who were treated with PIMSRA between November 2016 to February 2021 in the Hypertrophic Cardiomyopathy Center of Xijing Hospital of Air Force Military Medical University were enrolled, and their clinical datas were collected and analyzed. The clinical symptoms and NYHA functional class before operation, 6 months and 1 year after operation were collected. Interventricular septum thickness, left ventricular outflow tract pressure gradient, left ventricular outflow tract diameter, mitral regurgitation, left ventricular systolic and diastolic function were evaluated by transthoracic echocardiography before operation, 6 months and 1 year after operation, intraoperative complications were monitored and recorded. Postoperative arrhythmias were monitored by routine 12 lead ECG and 24-hour ambulatory ECG.Results:All patients successfully completed PIMSRA procedure.No clinical adverse events such as death, bleeding and stroke occurred during and around the operation.No left bundle branch block, complete atrioventricular block and malignant arrhythmia occurred after the operation. All patients did not need permanent pacemaker implantation.NYHA functional class and clinical symptoms of patients were significantly improved after 6 months compared with values before operation (all P<0.001, respectively), it remained stable for 1 year after operation; Anterior interventricular septum, posterior interventricular septum, maximal left ventricular wall thickness all significantly decreased (all P<0.001, respectively), left ventricular outflow tract diameter widened ( P<0.001), continuous improvement 1 year after operation; left ventricular outflow tract gradient and provoked left ventricular outflow tract gradient all significantly decreased, mitral regurgitation decreased and SAM classification reduced after 6 months compared with values before operation (all P<0.001, respectively); left ventricular end-diastolic diameter widened and left atrial diameter decreased (all P<0.001, respectively), it remained stable for 1 year after operation. Left atrial volume index decreased ( P<0.001), with continuous improvement 1 year after operation; The ratio of early diastolic mitral valve velocity to early diastolic mitral annulus velocity (E/e′) decreased ( P=0.001), it remained stable for 1 year after operation. There were no significant differences in left ventricular end diastolic volume, left ventricular end systolic volume and left ventricular ejection fraction among the three groups (all P>0.05). Conclusions:PIMSRA is effective in the treatment of obstructive hypertrophic cardiomyopathy with mild ventricular septal hypertrophy.

Objective:To investigate the effect of percutaneous intramyocardial septal radiofrequency ablation (PIMSRA) guided by echocardiography on the Lown classification of ventricular arrhythmias in patients with hypertrophic obstructive cardiomyopathy (HOCM).Methods:A total of 85 patients with HOCM who received PIMSRA treatment at Xijing Hospital of Air Force Military Medical University from May 2017 to October 2019 were retrospectively selected. All patients underwent 24-hour Holter examinations before and 1 year after PIMSRA to obtain parameters related to Lown classification. The changes in Lown grades after PIMSRA were analyzed. The patients were divided into improved group and unimproved group according to whether there was significant improvement in Lowen′s grades, and the difference of the parameters related were compared. The influencing factors of the changes in Lown classification were analyzed.Results:Compared with before PIMSRA, there was a significant improvement in the Lown classification after PIMSRA ( P=0.001). The patients with Lown grade Ⅰ increased significantly ( P=0.001), and the patients with grade Ⅲ decreased significantly ( P=0.005). There were no significant changes in patients with Lown grades 0, Ⅱ, and Ⅳ (all P>0.05). The proportion of patients with family history of hypertrophic cardiomyopathy (HCM), the baseline Lown classes, the reduction rate of the maximum left ventricular wall thickness and the reduction rate of the provocative left ventricular outflow tract gradient (LVOTG) were higher in the improved group than the unimproved group (all P<0.05). Multivariate Logistic regression results showed that HCM family history ( OR=3.95, 95% CI=1.34-11.64, P=0.013), baseline Lown classes ( OR=2.01, 95% CI=1.25-3.22, P=0.004) and the reduction rate of the provocative LVOTG gradient ( OR=1.02, 95% CI=1.00-1.04, P=0.041) were independent factors of postoperative Lown classification improvement. Conclusions:The Lown classes of HOCM patients after PIMSRA is significantly improved.HCM family history, the baseline Lown classes, and the reduction rate of postoperative provocative LVOTG are independent influencing factors for the improvement of Lown grade.