Clinical Research Of Hypertrophic Cardiomyopathy

Part 1 Clinical Feature and Prognosis of 188 Patients with Apical Hypertrophic CardiomyopathyObjective The aim of this study was to describe the clinical characteristics and prognosis of patients with Apical Hypertrophic Cardiomyopathy (AHCM).Methods A retrospective study of 188 patients with AHCM diagnosed at Fuwai Hospital was performed.Clinical characteristics,mortality and cardiovascular morbidity were analyzed.Multiple logistic regression was used to adjust for potential confounding factors.Results(1) Males predominated with a number of 139(73.9%), and the number of female was 49(26.1%).The age ranged from 15 to 81 years(51.9±12.6).(2) 53 patients(28.2%) complained of atypical chest pain,99 patients(52.7%) complained of chest distress,60 patients(31.9%) complained of palpitation,19 patients(10.1%) complained of dizziness,21 patients(11.2%) complained of dyspnea, 13 patients(6.9%) had a history of syncope,14 patients(7.4%) were asymptomatic, the heart function of 11 patients(5.9%) ranged from gradeⅢto gradeⅣ(NYHA).(3) 120 patients(63.8%) were pure type(left ventricular wall thickening limited to the most distal region at the apex below the papillary muscle level),68 patients(36.2%) were mixed type(had a coexistent hypertrophy of the other segments,mostly involving close segments of apex or interventricular septum).(4) The thickness of apex ranged from 15 to 40 mm(20.2±4.3),the thickness of posterior wall ranged from 6 to 14 mm(9.9±1.6).(5) 73 patients(38.8%) had a complication of hypertension,and 31 patients(16.5%) had a complication of coronary atherosclerotic heart disease,16 patients(8.5%) had a complication of diabetes mellitus,35 patients (18.6%) had a complication of hyperlipoidemia.(6) 50 patients(26.6%) had giant negative T waves(depth≥1 mV) in Electrocardiography(ECG),166 patients(89.9%) had only T wave inversion or ST segment depression,115 patients(61.2%) presented left ventricular hypertrophy in ECG,24 patients(12.8%) had atrial fibrillation or flutter;9 patients(4.8%) even had paroxysmal ventricular tachycardia.(7) 26 patients (13.8%) had a "spade-like" configuration of left ventricle and 15 patients(8.0%) had a myocardial bridging of left anterior descending coronary artery in 70 patients who had performed coronary angiography.(8) 171 patients had a mean follow-up of 5.0±3.0 years from been diagnosed,cardiovascular mortality was 1.2%.28 patients(26.2%) had one or more major morbid events including 15 atrial fibrillation events(14.0%),9 syncope events(8.4%),3 cerebral embolism events(2.8%),myocardial infarction events(0.9%),4 paroxysmal ventricular tachycardia events(3.7%),2 sick sinus syndrome with pace maker implanted(1.9%).2 predictors of cardiovascular morbidity were identified:age≥60 years(OR=2.67,95%CI 1.04～6.89,p=0.042), left atrium diameter≥36 mm(OR=4.90,95%CI 1.34～18.00,p=0.017). Conclusions The probability of AHCM in HCM is high.The symptoms are not characteristic.Giant negative T wave is characteristic in AHCM,but most patients present only inversion of T waves.AHCM patients in China have a benign clinical course. Part 2 Inappropriate Drug Therapy of Hypertrophic Obstructive CardiomyopathyObjective To investigate the medical treatment of Hypertrophic Obstructive Cardiomyopathy(HOCM).Methods 303 patients of HOCM in Fu Wai Hospital from January 1992 to December 2006 were studied.The prescriptions of adrenergic beta-antagonists,calcium channel blockers,angiotensin-converting enzyme inhibitors(ACE inhibitors)/angiotensinⅡreceptor blockers(ARB), diuretics,digoxin,nitrates were collected and evaluated.Results(1) 91(30.0%) patients were given single adrenergic beta-antagonists,33(10.9%) patients were given single calcium channel blockers,166(54.8%) patients were given adrenergic beta-antagonists combined with calcium channel blockers,the other 13(4.3%) were given neither adrenergic beta-antagonists nor calcium channel blockers.In 199 patients who received calcium channel blockers,54(27.1%) patients were given verapamil,106(53.3%) were given diltiazem,39(19.6%) were given dihydropyridines.(2) 125(41.3%) patients were given ACE inhibitors/ARB,70 (23.1%) patients were given diuretics,17(5.6%) patients were given digoxin,64 (21.1%) patients were given nitrates,15(5.0%) patients were given amiodarone.102 (33.7%) patients were treated with ACE inhibitors/ARB,diuretics,digoxin,or nitrates inappropriately in all.Conclusion The most popular agents of HOCM were still adrenergic beta-antagonists and calcium channel blockers,but sometimes ACE inhibitors/ARB,diuretics,digoxin,nitrates etc.were prescribed inappropriately. Part 3 Effect of Atenolol on Left Ventricular Function in Patients with Hypertrophic Obstructive CardiomyopathyObjective To investigate the effect ofβ-blocker Atenolol on left ventricular outflow tract pressure gradient,left ventricular diastolic function,and exercise tolerance in patients with hypertrophic obstructive cardiomyopathy(HOCM). Methods 35 patients with hypertrophic obstructive cardiomyopathy were enrolled and prescribed withβ-blocker Atenolol,6.25mg,bid,PO.Heart rate was kept with 60±5 beats/minute in quiescent condition.6-minute walking test(6MWT) was used for provocation before and after the treatment,and heart function was assessed at the same time.The change of the pressure gradient of left ventricular outflow tract (PG_LVOT),Peak E-wave velocity(V_E,m/s) and Peak A-wave velocity(V_A,m/s),left ventricular ejection fraction(LVEF),6-minute walking distance(6MWD),heart rate, blood pressure were observed before and after the treatment.Results In quiescent condition,V_E increased from 0.68±0.17 m/s to 0.82±0.17 m/s(p＜0.05),V_A decreased from 0.99±0.22 m/s to 0.85±0.16 m/s(p＜0.05),V_E/V_A ratio increased from 0.67±0.13 to 0.97±0.15(p＜0.05),but there was no significant difference of PG_LVOT between pre-treatment and post-treatment.After provocation(6MWT),V_E increased from 0.65±0.17 m/s to 0.80±0.19 m/s(p＜0.05),V_A decreased from 1.05±0.24 m/s to 0.89±0.19 m/s(p＜0.05),V_E/V_A ratio increased from 0.62±0.11 to 0.91±0.14(p＜0.05),PG_LVOT decreased from 79.20±23.23 mmHg to 63.60±22.65 mmHg(P＜0.05).6 minute walking distance(6MWD) increased from pre-treatment (466.40±67.27 m) to post-treatment(515.00±67.28 m,p＜0.05).There was no significant difference of heart rate or blood pressure between pre-treatment and post-treatment.Conclusionβ-blocker Atenolol can significantly decrease left ventricular outflow tract pressure Gradient in the condition of provocation,improve diastolic function of left ventricle and elevate exercise tolerance in patients with HOCM.