Question 39 What are the advantages and disadvantages of furosemide in the treatment of cardiac failure? Question 40 In heart failure, can furosemide be given once daily? Question 41 What are the clinical features of a ruptured sinus of Valsalva? Question 42 Does dobutamine (dose range 2.5-10 g/kg/min) cause significant tachycardia? Question 43 Are beta-blockers indicated in heart failure; if yes, in all cases or in selected cases? Question 44 Why does long-term treatment by digitalis cause gynaecomastia? Question 45 Why do toxic doses of digoxin (which cause a decrease in excitability of cardiac tissue) cause arrhythmias, whereas therapeutic levels of digoxin (which cause increase in excitability) cause no arrhythmias? Question 46 Hypokalaemia is one of the complications of digitalis. In treatment we give K. How does the hyperkalaemia enhance the digitalis toxicity? Question 47 Why should we measure serum potassium before we start digoxin? Question 48 The intravenous administration of loop diuretics such as furosemide relieves pulmonary oedema rapidly. Is this due to arteriolar vasodilatation reducing afterload which is an action that is independent of its diuretic effect? I ask this because I have been told that this drug has no effect on arterioles (except on efferent arterioles of the kidney), but rather a venodilatatory effect. What could be the cause of such different opinions