【正文】 B. Higher dose: arrhythmias The affects on ECG T wave It is characterized by an descend ST segment on the ECG PR QT PP Directly inhibit or reflected decrease sympathetic activity ? Exciting increase the vagal activity ? Inhibit RAAS system, promote the excrete of ANP ? cause arrhythmias (toxic doses) II. Action of cardiac glycosides on vascular and kidney ? Vasoconstriction, increase in peripheral vascular resistance ? Diuretic， increase the blood flow through kidney and inhibit Na+K+ATPase → Na＋ decreased reabsorb II. Action of cardiac glycosides on neural and hormone Clinical uses 1. Cardiac glycosides are given for CHF Effects： Best go with atrial fibrillation Better hypertension congenital heart disease not good anaemia lack of vitamin B1 not useful pericarditis 心包炎 2. Some kinds of arrhythmias Atrial fibrillation Atrial flutter Supraventricular Tachycardia Toxic effects 1. Responses of stomachintestines : Anorexia 厭食 , nausea， vomiting , Abdominal pain and diarrhoea 2. CNS: visual disturbaces 3. Arrhythmia: 1) Tachycardia 2)AV block 3)Bradycardia 60 beat/min Prophylaxis and treatment of the toxicity ? Clear the signal of toxic and the indication of withdraw ? Inspect the concentration of digoxin (3ng/ml), digitoxin(45ng/ml) ? If necessary ,potassium supplements and antiarrhythmic drugs ( phenytoin ,lidocaine,atropine )administered ? For severe intoxication ,antibodies specific to cardiac glycosides are available Method of administration ? Classical ： whole effect dose quick or slow (have use digoxin within two weeks) The suitable dose to the patients ? Maintain ： 4～ 5 t 189。 Digoxin , 6～ 7 day ( t 189。 the heart, veins, and capillaries are therefore generally dilated with blood. Hence the term “congestive(充血性 )” heart failure, since the symptoms include pulmonary congestion with life heart failure, and peripheral edema with right heart failure. Underlying causes of CHF include arteriosclerotic heart disease, hypertensive heart disease, valvular heart disease(心瓣膜病 ), dilated cardiomyopathy(擴(kuò)張性心肌病 ), and congenital heart disease(先天性心臟病 ). Left systolic dysfunction secondary to coronaryartery disease is the most mon cause of heart failure. Treatment of congestive heart failure Heart Failure ? Final mon pathway for many cardiovascular diseases whose natural history results in symptomatic or asymptomatic left ventricular dysfunction ? Cardinal manifestations of heart failure include dyspnea, fatigue and fluid retention ? Risk of death is 510% annually in patients with mild symptoms and increases to as high as 3040% annually in patients with advanced disease Main causes ? Coronary artery disease ? Hypertension ? Valvular heart disease (心瓣膜病 ) ? Cardiomyopathy (心肌病 ) ? Cor pulmonale Compensatory changes in heart failure ? Activation of SNS ? Activation of RAS ? Increased heart rate ? Release of ADH ? Release of atrial natriuretic peptide心鈉素 ? Chamber enlargement 心室腔擴(kuò)大 ? Myocardial hypertrophy 心室肥厚 Classification of heart failure ? Class I: No limitation of physical activity ? Class II: Slight limitation of physical activity ? Class III: Marked limitation of physical activity ? Class IV: Unable to carry out physical activity without disfort New classification of heart failure ? Stage A: Asymptomatic with no heart damage but have risk factors for heart failure ? Stage B: Asymptomatic but have signs of structural heart damage ? Stage C: Have symptoms and heart damage ? Stage D: End stage disease ACC/AHA guidelines, 2022 心功能障礙 收縮功能 舒張功能 輸出量 神經(jīng)激素 心肌