Clinical application of the nitroglycerin lingual spray

Acute hypertensive pulmonary edema: a new paradigm

Although acute hypertensive pulmonary edema is sometimes regarded as the most severe form of heart failure, at the peak of symptoms, hearts perform well above resting levels and cannot be said to be failing. Another characteristic of the condition, the rapidity of its onset and reversal when properly treated, suggests positive feedback as a causal mechanism. It is proposed that the syndrome results from a feedback loop with increased sympathetic tone as the efferent output, increased pulmonary vascular pressure as the stimulus to increased sympathetic tone, and positive feedback occurring because elevated sympathetic tone constricts systemic veins, thereby transferring blood from peripheral veins to the pulmonary vasculature. Evidence for the proposed mechanism derives from all the empirical treatments that have evolved. All remove blood from the pulmonary circuit, and all but the oldest, bloodletting, do so by transferring blood from the pulmonary circuit to the peripheral veins.

Effects of long-term transdermal nitrate treatment on left ventricular function in patients following myocardial infarction

BACKGROUND

[corrected] Nitrates are widely used for the treatment of myocardial infarction (MI). The large megatrials (GISSI-3 and ISIS-4) did not in fact demonstrate a significant decrease in mortality in the nitrate-treated group. However, examination of the number of postinfarction angina episodes and the occurrence of cardiogenic shock in the GISSI-3 study did reveal significant decreases.

HYPOTHESIS

It was hypothesized that chronic nitrate treatment after an MI preserves left ventricular systolic and/or diastolic functions.

METHODS

Patients were divided into two groups: those receiving chronic nitrate treatment for 6 months after an MI (n = 30), and those without such treatment (n = 29). Echocardiography was performed 3, 14, 42, and 180 days after the infarction. The changes in early diastolic and atrial contraction-related mitral valve inflow pattern and deceleration time were assayed. Alterations in systolic, diastolic, and atrial reverse flow velocities in the pulmonary vein were measured, as were ejection fraction (EF), the number of registered angina episodes, and the maximal ST-segment depression in response to the stress test.

RESULTS

During the 6-month study period, the increase in systolic pulmonary venous flow velocity was significantly larger in the nitrate group than in the controls. The decreases in the velocities of the diastolic and the atrial reverse flow were also more pronounced in the nitrate group than in the controls. The EF was improved only in the nitrate group. Examination of the maximal ST-segment depression in response to the stress test revealed a significant decrease in the nitrate group only. There were no significant differences between the two groups in the number of registered angina episodes or mitral inflow pattern.

CONCLUSIONS

The study showed that prolonged nitrate treatment after an MI may help preserve diastolic left ventricular function.