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Nitrates effectively treat congestive heart failure (CHF) by dilating blood vessels and reducing heart pressure. High doses are well-tolerated, improving exercise capacity and symptoms in CHF patients.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Nitrates are used to treat congestive heart failure (CHF).
- Their efficacy stems from dilating capacitance vessels and reducing ventricular diastolic pressure.
Purpose of the Study:
- To review the use of nitrates in congestive heart failure (CHF) treatment.
- To discuss the hemodynamic and clinical efficacy of nitrates, alone and in combination therapy.
Main Methods:
- Review of existing clinical trials and hemodynamic studies on nitrate therapy in CHF.
- Assessment of nitrate efficacy based on ventricular filling pressure, jugular venous pressure, and clinical outcomes like exercise tolerance.
Main Results:
- Nitrates reduce preload and ventricular filling pressures, improving cardiac function in CHF.
- High doses of nitrates are generally well-tolerated in CHF patients.
- Combination therapy with potent arteriolar dilators shows enhanced hemodynamic benefits.
Conclusions:
- Nitrate therapy, at doses normalizing ventricular filling pressure, is recommended for CHF.
- Monitoring jugular venous pressure is key to optimizing nitrate dosage.
- Sustained hemodynamic effects may require high doses of isosorbide dinitrate or transdermal nitroglycerin.
Abstract:
The use of nitrates in various sublingual, oral, topical and intravenous forms of treatment of patients with congestive heart failure (CHF) is based on their efficacy in dilating capacitance vessels and reducing elevated ventricular diastolic pressure on both the left and right sides of the heart. Their modest arteriolar and arterial dilating effect may also decrease aortic impedance and produce a slight increase in stroke volume despite the reduction in preload. This favorable hemodynamic response requires relatively large doses of the nitrates but these doses are remarkably well tolerated in the majority of patients with CHF. In chronic CHF there has been evidence from small controlled trials of clinical efficacy (increased exercise tolerance and reduction in symptomatology) as well as hemodynamic efficacy. The combination of nitrates with a more potent arteriolar dilator such as hydralazine or minoxidil has produced a more striking acute hemodynamic benefit. Long-term response to such combined therapy is currently the subject of a Veterans Administration cooperative study. The current recommended approach to nitrate therapy in patients with CHF is to use the dosage necessary to normalize ventricular filling pressure. This can be best assessed in the clinic by monitoring jugular venous pressure. This response often requires dosages of isosorbide dinitrate of 160 to 320 mg daily. Transdermal preparations of nitroglycerin may give more constant blood levels but a large dosage is usually required to produce a sustained hemodynamic effect (40 to 80 cm2).(ABSTRACT TRUNCATED AT 250 WORDS)