The Clinical Characteristics And Prognosis Of Hypertrophic Cardiomyopathy With Decreased LVEF

Purpose :Diastolic heart failure is the most common clinical manifestation of hypertrophic cardiomyopathy.While some of the patients progress to systolic heart failure,presenting impaired left ventricular contractility,LVEF decrease,even wall thinning and cavity dilatation.The prognosis of these patients is very poor.It’s not clear how to recognize these patients early and whether the early treatment will change the outcomes.The purpose of this study is to investigate the characteristics and prognosis of Hypertrophic Cardiomyopathy with decreased LVEF.Methods :Retrospectively analyze the data of in-hospital Hypertrophic Cardiomyopathy patients in The First Hospital of Dalian Medical University from 2002 to 2014. Based on the left ventricular ejection fraction(LVEF), HCM patients were divided into two groups(one group with LVEF<50%,the other group with LVEF≥50%).Compare the difference of the clinical manifestations and prognosis between the two groups. Then the patients with LVEF<50% were divided into two subgroups according to whether the left ventricular end-diastolic diameter was dilated(LVEDD≥55mm). The clinical characteristics and prognosis between the two subgroups were compared. Data were expressed as mean±SD or as frequencies. Two-detailed paired or unpaired Student t tests were used to study normally distributed data. χ2 Tests and Fisher Exact Test were delivered to compare non-continuous variables expressed as proportions. Binary Logistic Regression Analysis was used to detect the risk factors of sudden cardiac death.Probability values are significant when P<0.05. All the data was analyzed by SPSS19.0software.Results :A total of 578 in-hospital HCM patients had the complete data in 12 years.44( 7.6%) patients excluding 4 cases who had myocardial infarction and severe mitral regurgitation prior to systolic dysfunction, conformed to the diagnostic standards of HCM with left ventricular systolic dysfunction. 20(3.5%) HCM patients developed into D-HCM(56mm≤LVEDD≤72mm). The average age diagnosis with HCM with systolic dysfunction was 60.0±12.0years(from 31 to 78 years. It took 8.7±8.1years for classical HCM developing into left ventricular systolic dysfunction. 61.4%(27)were male.Compared with the patients whose LVEF was normal, the first time to diagnosis with HCM was no significance(51.0±13.8 vs 48.8±10.5,t=1.22,P=0.22), but the family history of sudden death(9.1% vs 2.5%,χ2=4.13,P=0.04)and syncope(36.4% vs 16.8%,χ2=10.4,p=0.001)were significant in the group with reduced LVEF. In the patients with systolic dysfunction, there were more patients with ventricular tachycardia(29.5% vs5.1%, χ2=35.46, P<0.001) and the ratio of atrial fibrillation was higher in this group(40.9% vs 25.5%,χ2=4.95,P=0.026).42.3% patients had abnormal Troponin I at least once in the group with LVEF<50%( 42.3% vs 9.8%,P=0.001). Regarding to the manifestation of echocardiography, the patients with LVEF<50% had larger left atrial diameter(42.1±6.1mm vs 35.2±3.3mm,P<0.05) and thicker largest Left ventricular wall(21.5±4.7mm vs 17.2±3.5mm,P<0.05). In the subgroups, patients with left ventricle dilated were younger at first time of diagnosis with HCM(44.7±10.4 years vs 56.2±14.2years,P=0.005) and more patients had abnormal Troponin I( 70% vs 20.8%,χ2=41.4,P=0.001). It only took 3.4±2.2 years from diagnosis with left ventricular systolic dysfunction to death, and the sudden cardiac death(37.5%)and heart failure(33.3%)were the main cause of cardiac death. The risk factors of sudden cardiac death were analyzed, the patients who were younger at diagnosis with systolic dysfunction(53.6±12.5 years vs 63.5±11.1 years,t=2.4,P=0.021) and had lower LVEF(33.6±6.5%vs 41.4±6.1%,t=3.65,P=0.01) were prone to experience sudden cardiac death. BinaryLogistic Regression Analysis revealed the LVEF was the only one non-independent factor(P=0.018).The incidence of stroke is 23.1%(9/39) in the patients with reduced LVEF when followed up, most of them had atrial fibrillation(persistent or paroxysmal).Conclusions :1.The mortality of HCM with left ventricular systolic dysfunction is relatively low.2.It will take a long time for classical HCM developing into systolic dysfunction.The age of diagnosis with HCM is not associated with systolic dysfunction.3.The dilated left atrial, the greatest wall thickness, ventricular tachycardia, atrial fibrillation, family history of sudden death,syncope and abnormal Toponin I level may be the risk factors of HCM progressing to systolic dysfunction.4.The prognosis of HCM with reduced LVEF is ominous. Heart failure and sudden cardiac death are the main causes of cardiac death.5.The patients who are young at diagnosis with systolic dysfunction and have low LVEF are prone to experience sudden cardiac death.6.All of the HCM patients with systolic dysfunction and atrial fibrillation should receive anticoagulant therapy with VKA or other oral anticoagulant agent,unless contraindicated.