Analysis Of Clinical Characteristics Of Cardiomyopathy In Patients With Sudden Cardiac Death And Cardiac Arrest And Cardiopulmonary Exercise Test In Patients With Chronic Left Heart Failure

Part Ⅰ. Analysis of the clinical features in sudden cardiac death/survivors of cardiac arrest patients with DCMObjective:The patients with DCM (dilated cardiomyopathy) have high mortality and poor prognosis. Approximately40-50%deaths are due to SCD (sudden cardiac death). Therefore, it is crucial to analyze the clinical features of sudden cardiac death/survivors of cardiac arrest patients with DCM to find which patients prone to sudden death.Methods:Patients with DCM hospitalized in our hospital from April2008October2013were screened, and those who had experienced cardiac arrest events (ventricular fibrillation, persistent tachycardia) and received cardiopulmonary resuscitation were recruited(n=100). Patients with DCM hospitalized in same period in our hospital were enrolled as controls if they did not experience cardiac arrest events.Their baseline data and blood tests, electrocardiogram, echocardiography and HOLTER information were collected. All survivors were followed up after discharge, and the all-cause death and SCD were recorded.Results:No significant differences were found in left atrial diameter, left ventricular end-diastolic diameter, left ventricular ejection fraction (LVEF), the proportion of patients with cardiac function classification, serum creatinine, uric acid, electrolyte, NT-proBNP level, QTc between DCM patients with and without cardiac arrest.The limb lead low voltage, abnormal Q wave, the number of atrial fibrillation and bundle brunch block, ventricular premature beat, nonsustained ventricular tachycardia and heart rate variability did not differ betwen two groups. However, patients with SCD/cardiac arrest had higher level of TnI andhsCRP as compared with those without cardiac arrest. Also,more patients with elevated white blood cells, poor R wave progression, Ⅰ-Ⅱ degree atrioventricular block were observed in SCD/cardiac arrest group than the control group (P<0.05).All patients were followed up for6months～70months (the median follow-up period was36months). In cardiac arrest group,5patients died from cardiac causes (7.2%), including4patients had sudden cardiac death (6.0%),1patient died of heart failue during follow-up period. ICDs were implanted in44patients, Among39survivors without receiving ICD, there were4sudden deaths during the follow-up period. In control group,8people died of cardiac causes during follow-up period, and2of them were SCD, the other6patients died from aggravating heart failure, And10DCM patients without SCD received ICD implantation. ICD. During follow-up,2patients had sudden death among93patients who did not receiving ICD during the follow-up period.Conclusions:Our study provide no evidence for the role of the left atrial diameter, left ventricular end-diastolic diameter, LVEF, the number of ventricular premature beat, and non sustained ventricular tachycardia, pairs of premature ventricular beat, heart rate variability and QTc in the warning of sudden death. I-II degree atrioventricular block and elevated blood TnI, HsCRP, elevated white blood cells are more common observed in DCM patients with SCD/cardiac arrest, SCD reoccurrence are more common in cardiac arrest survivors without receiving ICD implantation. Part II. Value of cardiopulmonary exercise test in the cardiac function evaluation of patients with chronic left heart failure caused by dilated cardiomyopathy.Objective:To assess the value of cardiopulmonary exercise test in the evaluation of cardiac function in patients with chronic left heart failure caused by dilated cardiomyopathy.Methods:Fifty-three18-and-older patients with chronic left heart failure caused by dilated cardiomyopathy hospitalized in Fuwai hospital from October2010to October2011were selected and divided into two groups according to the New York Heart Association (NYHA) heart function classification. One group had20cases for class II, and the other33cases for class III. All patients had cardiopulmonary exercise tests. Synchronous measurement and record of gas exchange index were taken during every breath, and so were heart rate, blood pressure, electrocardiogram and blood oxygen saturation. At the same time other routine tests were taken as well. After the exercise test, anaerobic threshold and peak oxygen consumption index were calculated and statistically analyzed. The patients also received follow-ups1month after the tests including clinical manifestation and cardiac adverse events.Results:All53patients accepted CPET check safely, no syncope, bosom frowsty, lower blood pressure, and death occurred.Compared with the cardiac function class II group, the group of cardiac function class III had lower anaerobic threshold level and peak oxygen consumption ((13.7±2.6) vs (20.5±3.6) ml·min-1·kg-1,(10.7±1.5) vs (13.3±2.1) ml·min-1·kg-1, both P=0.000). In the analysis of correlation, the NT-proBNP and cardiac function classification showed positive correlation (OR=1.002, P=0.003), while peak oxygen consumption, anaerobic threshold and cardiac function classification were negative correlated (OR=0.736,0.608; P=0.011,0.001).Conclusions:DCM patients with chronic left heart failure can take CPET check safely. Cardiopulmonary exercise test can objective reflect the cardiopulmonary reserve of the heart failure patients with dilated cardiomyopathy. The parameters of anaerobic threshold and peak oxygen consumption can reflect the patient’s motor ability quantitatively and accurately.