N

Options (in this order if control not achieved):

' IV loop diuretic + metolazone • Short-term inotrope (dobutamine/PDE inhibitor)

■ Cardiac transplant

Continue:

■ ACE inhibitor

■ Loop diuretic

■ Spironolactone

Continue: •ACE inhibitor

■ Loop diuretic

Fig. 24.5 Management of chronic cardiac failure (N = no,Y = yes, Rx = treatment, PDE = phosphodiesterase). Reproduced with permission from Lancet.

heart failure. The benefit is seen at a surprisingly low dose of spironolactone (25 mg/d); it probably reflects both improved potassium and magnesium conservation (both are antiarrythmic) and reversal of fibrosis in the myocardium by aldosterone.

None of the available oral phosphodiesterase inhibitors has become established in routine therapy, because the short-term benefit of the increased contractility has been offset by an increased mortality (presumably due to arrhythmias) on chronic dosing. A similar fate befell flosequinan, a positive inotrope which acted through the phosphatidylinositol system. Their use is restricted to short-term symptom control prior to, for example, transplanation.

Acute left ventricular failure

This is a common medical emergency (despite some possible lessening in frequency with the advent of thrombolysis for myocardial infarction). The approach should be to reassure the intensely anxious patient, who should sit upright with the legs dependent to reduce systemic venous return. A loop diuretic, e.g. frusemide (furosemide) 40-80 mg i.v., is the mainstay of therapy and provides benefit both by a rapid and powerful venodilator effect reducing preload, and by the subsequent diuresis. Oxygen should be given, if the patient can tolerate a face mask, and diamorphine or morphine i.v. which in addition to relieving anxiety and pain, have a valuable venodilator effect.

While there can be a case for short-term use of inotropic drugs (see Ch. 22) for cardiac failure where low output is a predominant feature, it is important to remember that most such drugs substantially increase the risk of arrhythmias when the heart is hypoxic. The pharmacokinetics of digoxin do not lend themselves to emergency use. Aminophylline (5mg/kg over 20 min) may be administered i.v., following with great care the precautions regarding dose and monitoring (c.f. acute severe asthma, p. 562). By this stage, the possibility of assisted ventilation should be considered: where pulmonary oedema is the main problem, ventilation is likely to be both safer and more effective than inotropic drugs.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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