Abstract

Introduction

Materials & Methods

Results

Discussion & Conclusion

References

Discussion
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Study patients. Fifty patients with CHF caused by ischemic heart disease or idiopathic dilated cardiomyopathy were studied. Only patients with restrictive patterns of LV filling as assessed by pulsed Doppler echocardiography were included. Patients were excluded from the study if they had structural valvular heart disease, atrial fibrillation, or myocardial infarction within 6 months. All patients signed informed consent before participation in the study.

Study protocol. The initial examination took place during a hospital stay for evaluation and treatment of CHF after a period of stabilization therapy. Each patient was examined after overnight fasting. Only diuretics were withdrawn on the day of study. Upon completion of the initial examination, twenty five patients were randomized to standard treatment (angiotensin-converting enzyme inhibitors, diuretics and digitalis) and 25 to nitrate (isosorbide-5-mononitrate 20 mg b.i.d.) in addition to standard therapy. Patients were discharged from the hospital and the next examination was performed 6 months later. Two patients randomized to standard treatment and 1 patient in the nitrate group died before 6 months of follow-up. As mortality was not an end-point in this study, these patients were excluded from the follow-up. Consequently, 23 patients in the standard therapy group and 24 patients in the nitrate group completed 6 months follow-up examination.

Clinical examination. Each patient underwent an assessment of clinical status according to the classification of the New York Heart Association. The six-minute walk test was performed to assess exercise capacity.

Echocardiographic and Doppler examination. Complete M-mode, B-mode echocardiography and Doppler ultrasound examination were performed in all patients. Measurements of LV end-diastolic and end-systolic volumes were performed using the biplane area-length method. Ejection fraction was calculated with the standard formula. Pulsed Doppler studies were performed by using apical windows. Recordings of mitral inflow velocity were made from an apical four-chamber view with the sample volume positioned adjacent to the tip of mitral leaflets in diastole. The following Doppler-derived parameters were calculated: peak velocity of early filling (PE), peak velocity of atrial filling (PA), ratio of early wave to atrial wave peak velocity (PE/PA ratio), and deceleration time of early filling. All measurements were made in at least five cardiac cycles and analyzed off-line by two independent observers. The data were averaged.

In this study, the pattern of LV filling was considered restrictive if the PE/PA ratio was > or = 1 and deceleration time of early filling was < or = 140 ms. Mitral regurgitation was semiquantitatively assessed as none, mild, moderate or severe, depending on the maximal Doppler jet area seen from multiple orthogonal views.

Statistical analysis. Results were expressed as mean +/- standard deviation. An unpaired Student’s t test and a chi-squared test were used for analysis of differences between groups in continuous and categorical variables, respectively. A paired Student’s t test and McNemar’s chi-squared test were used for the intragroup comparisons (at study entry and after a period of treatment). A probability value < 0.05 was considered to indicate statistical significance.

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