Clinical Effect Analysis Of Alcohol Septal Ablation For Hypertrophic Obstructive Cardiomyopathy

Background:Alcohol septal ablation（ASA）is an effective interventional therapy for hypertrophic obstructive cardiomyopathy（HOCM）.Compared with the traditional resection of interventricular septum,ASA has the advantages of less trauma and faster recovery,and is more acceptable to patients.A large number of studies have shown that ASA has good safety and efficacy,but there are still some patients with poor ablation effect and prognosis.Further study of the adverse factors affecting the ablation effect will help to further improve the efficacy of ASA.Previous studies have found that patients’age,family genetic history,degree of myocardial hypertrophy,hemodynamic status,alcohol dose,selection of ablation target vessels and physician’s technical experience may affect the efficacy of ASA,but most of them are single-center retrospective studies.Due to the heterogeneity of HOCM and the bias of ASA technology in different medical centers,different research conclusions are quite different,even contradictory.Therefore,the factors affecting the ablation effect still need to be further studied.Since the beginning of the ASA,it has been controversial whether this technique increases the risk of ventricular arrhythmias in patients with HOCM.Some research data show that the incidence of ventricular arrhythmias after ASA is low,but it still does not seem to dispel people’s concerns,especially the positive reaction of late gadolinium enhancement（LGE）significantly associated with ventricular arrhythmias detected by cardiac magnetic resonance imaging in myocardial scars after ablation.This concern has been magnified.However,the evaluation of arrhythmia in patients with HOCM after ASA has always been a difficult problem.Some studies use traditional 24-hour ambulatory ECG monitoring,which is easy to lead to missed diagnosis of positive cases,and its conclusions are not convincing.At present,it seems biased to evaluate the effect of ASA on ventricular arrhythmias by the incidence of sudden cardiac death（SCD）after ASA.Although ventricular arrhythmias are the main cause of SCD in patients with HOCM,but patients without SCD may also have ventricular arrhythmias and spontaneous remission.Therefore,how to accurately evaluate the effect of ASA on ventricular arrhythmias is still a problem worthy of discussion.Based on the single-center data,this study analyzed the ablation effect and influencing factors of ASA for HOCM.By collecting the reliable data recorded by implantable cardioverter defibrillator（ICD）after ASA,the occurrence and influencing factors of fatal ventricular arrhythmias after ASA for HOCM were analyzed,so as to provide clinical experience.Objectives1.To analyze the ablation effect and influencing factors of HOCM treated with ASA.2.To analyze the occurrence and influencing factors of fatal ventricular arrhythmias after ASA for HOCM.Methods:1.A total of 58 cases of HOCM patients treated by ASA in our hospital from August2011 to August 2019 were collected,The changes of New York Heart Association（NYHA）functional class（a median follow-up period was 17 months）,echocardiography（a median follow-up period was 34 days）and electrocardiogram（a median follow-up period was 2days）before and after ASA were compared,and the ablation effect of ASA was analyzed.According to whether left ventricular outflow tract gradient（LVOTG）decreased by 50%,the patients were divided into good ablation effect group（LVOTG decrease≥50%）andpoor ablation effect group（LVOTG decrease<50%）.the independent influential factors of ablation effect were analyzed by comparing the clinical data of the two groups,the receiver operating characteristic（ROC）curve analysis was also made for the influential factors.2.A total of 40 cases of HOCM patients treated by ASA and received ICD in our hospital from August 2011 to January 2019 were collected,The data of ICD were collected（a median follow-up period was 1 year）.The fatal ventricular arrhythmias and the intervention of ICD after ASA for HOCM were analyzed.According to whether ICD intervention occurs,the patients were divided into ICD intervention group and non-intervention group,the independent influential factors of fatal ventricular arrhythmias were analyzed by comparing the clinical data of the two groups,the ROC curve analysis was also made for the influential factors.（In this study,fatal ventricular arrhythmias were defined as VT,FVT,VF events requiring ICD intervention.）Results:1.The ablation effect and influencing factors of HOCM treated with ASA.⑴Compared to preoperative,the NYHA functional class was significantly decreased in 58 patients.The postoperative LVOTG,interventricular septum thickness（IVST）,left atrial diameter（LAD）,mitral regurgitation area,systolic anterior motion（SAM）sign were all significantly reduced after ablation,Postoperative QRS duration and QTc interval were all significantly prolonged,RV₅+SV₁ were significantly decreased,the incidence of right bundle branch block（RBBB）and atrioventricular block（degree I～III）were significantly increased（all P<0.05）.⑵The alcohol dose（OR 3.222,95%CI:1.345～7.717,P=0.009）is an independent influencing factor of ablation effect in short term.The area under the ROC curve is 0.707（95%CI:0.573～0.841,P=0.009）.When the alcohol dose cut-off value is 2.5ml,the sensitivity is 46%,and the specificity is 86%.2.The occurrence and influencing factors of fatal ventricular arrhythmias after ASA for HOCM.⑴The annual incidence of fatal ventricular arrhythmias after ASA for HOCM was35%,the occurrence rates of VT,FVT and VF are 73.0%,14.9%and 12.1%respectively,all of them were terminated by ICD.⑵Age（OR 0.908,95%CI:0.835～0.988,P=0.025）is an independent predictor of fatal ventricular arrhythmias after ASA.The area under the ROC curve is 0.756（95%CI:0.601～0.910,P=0.008）.When the age cut-off value is 54 years old,the sensitivity is 57%,and the specificity is 81%.⑶IVST（OR 1.347,95%CI:1.002～1.811,P=0.048）is an independent predictor of fatal ventricular arrhythmias after ASA.The area under the ROC curve is 0.761（95%CI:0.602～0.920,P=0.007）,when the IVST cut-off value is 20mm,the sensitivity is 79%and the specificity is 69%.⑷Age combined with IVST is more reliable in predicting the occurrence of fatal ventricular arrhythmias after ASA.The area under the ROC curve of age combined with IVST is 0.816（95%CI:0.682～0.950,P=0.001）.the sensitivity is 57%and the specificity is 96%when the Youden index is at its peak.⑸The basic HCM Risk-SCD risk（OR 1.550,95%CI:1.081～2.222,P=0.017）is an independent predictor of fatal ventricular arrhythmias after ASA.Conclusions:1.ASA can effectively improve the NYHA functional class of HOCM patients.It can reduce the IVST,LVOTG,LAD,mitral regurgitation area and SAM sign.The RBBB and atrioventricular block are common complications of ASA.Patients received high-dose alcohol ablation during ASA had a better reduce in LVOTG.2.The incidence of fatal ventricular arrhythmias after ASA for HOCM is higher.ICD is an effective method to prevent SCD in patients with HOCM after ASA.HOCM patients with younger age,thicker interventricular septum or higher risk of basic HCM Risk-SCD are more likely to occur fatal ventricular arrhythmias after ASA.