Assessment of left ventricular function after sublingual administration of nifedipine in patients with moderate to severe hypertension

Sublingual nifedipine in elderly patients: even a low dose induces myocardial ischaemia

1. Low doses of sublingual nifedipine are still used for the treatment of hypertensive crises, although recent studies have raised concerns that sublingual nifedipine may cause serious dose-dependent adverse effects. The present study was performed to test the safety of low-dose sublingual nifedipine administered to elderly hypertensive patients. 2. Systemic blood pressure measurements and electrocardiographic (ECG) examinations were performed before and 45-60 min after a 5 mg dose of sublingual nifedipine in 93 consecutive hypertensive patients, 65 years of age or older, who were without coronary artery disease. In 33 patients, the effects of nifedipine on myocardial lactate metabolism were studied during cardiac catheterization. 3. In all patients, following nifedipine administration, blood pressure (BP) decreased significantly, while heart rate (HR) increased, and symptoms associated with elevated BP disappeared. However, changes consistent with myocardial ischaemia appeared on the ECG in six of 55 patients with left ventricular hypertrophy (LVH) and in one of 38 patients without LVH, although only two of these seven patients experienced angina-like precordial tightness. Sublingual nifedipine decreased myocardial lactate extraction from 52 +/- 13 to 38 +/- 19% in 20 patients with LVH (P = 0.02), but myocardial lactate extraction remained stable in 13 patients without LVH (49 +/- 7 to 50 +/- 5%; NS). The change in lactate extraction was significantly correlated with the percentage change in diastolic arterial pressure (r = 0.77, P < 0.001). 4. These results suggest that sublingual nifedipine, even at the low dose of 5 mg, may cause myocardial ischaemia in some elderly patients with LVH that is associated with a marked reduction in coronary perfusion pressure.

Contribution of atrial reservoir function to ventricular filling in hypertensive patients. Effects of nifedipine administration

We designed this study to access the importance of left atrial function as a contributor to mitral flow velocity pattern in hypertensive patients. In hypertensive patients the early diastolic flow velocity and ratio of early to late diastolic flow velocity in the mitral flow velocity pattern increase in association with sublingual administration of nifedipine. These changes have been interpreted as signs of improved left ventricular diastolic function; however, the mitral flow velocity pattern is also affected by various other factors. Thus, the nifedipine-induced changes may not necessarily indicate the improvement of left ventricular diastolic function. Transthoracic Doppler echocardiographic parameters of mitral and pulmonary venous flow velocity patterns and left ventricular M-mode echograms were obtained in 16 untreated hypertensive patients before and after sublingual administration of nifedipine (10 mg). Normal values of the parameters were determined in 50 age-matched healthy subjects. After nifedipine peak early diastolic mitral flow velocity increased beyond the normal value, although the peak increasing rate of left ventricular inner dimension, another index of left ventricular diastolic function, did not recover to the normal value. Peak systolic velocity in the pulmonary venous flow velocity pattern increased beyond the normal value, indicating improvement of the reservoir function to the left atrium during systole. Nifedipine-induced normalization of the mitral flow velocity pattern was associated with further abnormalities of the pulmonary venous flow velocity pattern, indicating enhanced left atrial reservoir function.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of disopyramide on left ventricular diastolic function in patients with hypertrophic cardiomyopathy: comparison with diltiazem

Left ventricular diastolic function before and after the administration of disopyramide (100 mg) or diltiazem (30 mg) was assessed in 10 patients with nonobstructive type hypertrophic cardiomyopathy. Left ventricular diastolic function was assessed by Doppler echocardiography. The peak early (E) and late (A) diastolic flow velocities and E/A ratio (E/A) were measured. Three hours after the administration of disopyramide, blood pressure did not significantly change, but heart rate was decreased significantly (p less than 0.01). Disopyramide increased the E velocity and E/A ratio from 43.8 +/- 15.0 cm/sec to 51.3 +/- 16.1 cm/sec and from 0.71 +/- 0.20 to 1.00 +/- 0.24 (each p less than 0.01), respectively, and decreased the A velocity from 63.9 +/- 18.5 cm/sec to 52.1 +/- 14.9 cm/sec (p less than 0.01). Diltiazem increased the E velocity and E/A ratio from 42.8 +/- 12.5 cm/sec to 46.4 +/- 13.4 cm/sec (p less than 0.05) and from 0.74 +/- 0.21 to 0.96 +/- 0.28 (p less than 0.01), respectively, and decreased the A velocity from 60.6 +/- 16.4 cm/sec to 50.2 +/- 15.6 cm/sec (p less than 0.01). These results indicate that disopyramide improved left ventricular diastolic filling in hypertrophic cardiomyopathy, and its effect was similar to that of diltiazem.