| Background and ObjectiveHypertrophic cardiomyopathy (HCM) is a common genetic disease with a prevalenceof1:500. It is characterized by asymmetric myocardial hypertrophy, which is most obviousin the interventricular septum. The common symptoms of HCM are exertional dyspnea andchest pain, and younger individuals may be at higher risk of ventricular fibrillation andsudden cardiac death. Approximately two thirds of patients have significant left ventricularoutflow tract gradient (LVOTG) at rest (≥30mmHg) or at provocation (≥50mmHg), whichreferred to as hypertrophic obstructive cardiomyopathy (HOCM). For drug-refractoryHOCM, a surgical septal myectomy (SSM) or alcohol septal ablation (ASA) isrecommended. However, ASA has been highly praised both at home and abroad as a lessinvasive, effective and safer alternative to the SSM for HOCM patients. In addition, itsclinical efficacy differs from center to center though the short and mid-term effects areencouraging in most studies.The major complications of ASA include atrioventricular block (AVB) and acute mitralinsufficiency, which play an important role in judging the safety of ASA. Intracoronaryelectrocardiogram (IC-ECG) in the target septal perforator was performed before and afterASA, which was helpful to evaluate the myocardial injury immediately by the elevation ofST segment. Real-time three dimensional echocardiography (RT-3DE) is a highly accuratemeans for determining left ventricle volume and function in asymmetric left ventricles thanconventional two-dimensional echocardiography without geometric assumptions. Left atrialenlargement (LAE) is a common pathologic change in HCM patients and closely relates toatrial fibrillation (AF). RT-3DE and left atrial volume (LAV) was calculated in nineteenHOCM patients with ASA. Methods1. Follow-up study of the efficacy of ASA in HOCM patientsForty-six HOCM patients with ASA from March2001to March2014in our hospitalwere analyzed. Meanwhile, sixty non-obstructive HCM patients and twenty-six HOCMpatients without ASA were also analyzed. Ultrasonic cardiography (UCG) and cathetertechnique were performed to assess LVOTG in ASA group before and after operation.Meanwhile, interventricular septum (IVS) thickness, left ventricular posterior wall (LVPW)thickness, left atrial diameter (LAD), left ventricular end-diastolic diameter (LVDD), leftventricular ejection fraction (LVEF), NYHA class, arrhythmia, complication, and mortalitywere also analysed in all groups.2. IC-ECG during the ASA operationEight HOCM cases [3males and5females, aged from32to67(48.62±13.78) years]were treated IC-ECG before and after ASA immediately from December2012to March2014. We measured the decrease of LVOTG in ASA by catheter and the values of creatinekinase (CK) and creatine kinase isoenzyme (CK-MB) in plasma were assayed at0,6,12,24,48and72hours after ASA respectively.3. Evaluate the ASA efficacy by RT-3DE and LAVOn the basis of UCG and ECG, nineteen HOCM patients with ASA [8males and11females, aged from32to67(46.53±11.66) years] from April2012to March2014wereevaluated by RT-3DE and LAV before and3days,6months after ASA additionally.Results1. The mean follow-up time for the ASA-treated group was (35.89±36.54) months.Meanwhile, the HOCM without ASA and HCM group followed for (32.77±21.72) and(34.00±32.98) months respectively. In ASA-treated group, catheterization laboratoryshowed an immediate decrease in both resting and evoked LVOTG after ASA (P<0.01).UCG demonstrated significant reduction in LVOTG three days after ASA (P<0.05) andmarked decreased in IVS thickness one month after the procedure (P<0.05), whichremained lower at the latest follow-up respectively. Meanwhile, both the degree of mitralregurgitation (MR) and NYHA class were improved, and the30-day mortality was0%.Until the latest follow-up, there were no instances of complete heart block, sustainedventricular arrhythmias, and sudden cardiac death (SCD). Meanwhile, only one patient died of lung cancer, and one patient was treated repeated ASA during follow-up period. Inaddition, the mortality was12%in HOCM without ASA group, and30%in HCM group atthe same follow-up period.2. Eight HOCM cases were treated IC-ECG before and after ASA immediately. UCGdemonstrated IVS thickness before and3days after ASA were (20.91±4.16) mm and(20.03±3.89) mm respectively (P<0.05). The resting gradient decreased from (68±15.96)mmHg to (52.25±28.50) mmHg on the third day after ASA (P<0.05). There were nostatistical difference in LVPW, LAD and LVEF (P>0.05). Catheterization laboratorydemonstrated the resting LVOTG decreased from (90.00±42.09) mmHg to (40.88±35.46)mmHg (P<0.01) and the evoked gradient decreased from (171.00±31.70) mmHg to (98.80±35.88) mmHg (P<0.01). The peak values of CK and the area under curve of CK(CK-Area) were (898.73±308.17) IU/L and (33325.13±12895.87) IU.h/L respectively.While the the peak values of CK-MB and the area under curve of CK-MB (CK-MB-Area)were (121.09±49.03) IU/L and (4033.88±1837.67) IU.h/L. IC-ECG showed that STsegment elevated (5.94±3.49) times after ASA (P<0.01). The correlation coefficientbetween the elevation of ST segment and the dosage of alcohol was0.710(P<0.05).3. Both LVESV and LVEDV measured by RT-3DE increased significantly at the sixthmonth after ASA (P<0.05). Meanwhile the LVEF and Tmsv16-SD%obviously decreased(P<0.05). Illustration bull eye (IBE) and time-volume curve of17segments were alsoimproved compared with preoperation. The LAV was significantly reduced at sixth monthafter ASA (P<0.05).Conclusions1. For drug-refractory HOCM patients, ASA could significantly reduce LVOTG, septalthickness and left atrial volume, with an improved NYHA function and degree of mitralregurgitation. The mid and long-term efficacy of ASA are encouraging.2. The application of IC-ECG in ASA is helpful to evaluate the myocardial injuryimmediately by the elevation of ST segment.3. RT-3DE has its unique advantages in evaluating the left ventricular volume, leftventricular function and synchronism, especially for HOCM patients. |
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