Effects of diltiazem on cardiovascular responses during exercise in systemic hypertension and comparison with propranolol.

Sixteen patients with uncomplicated systemic hypertension were treated with placebo, diltiazem (180 mg/day) and propranolol (60 mg/day) for 1 month each. Each patient performed multistage symptom-limited treadmill exercise tests during each period of administration. There was no significant difference in maximal exercise duration between placebo, diltiazem and propranolol. Diltiazem significantly decreased both systolic and diastolic blood pressure (BP) and heart rate at rest, during submaximal exercise at the same work load and maximal exercise. Propranolol produced similar changes in systemic BP and heart rate at rest and during exercise. However, the reductions in systolic BP, heart rate and pressure-rate product with diltiazem during exercise were smaller than those with propranolol at small doses, suggesting that diltiazem in its usual therapeutic dose was almost devoid of beta-blocking activity. Thus, diltiazem may be of benefit to hypertensive patients because it reduces systemic BP even during exercise. It is particularly useful when systemic hypertension occurs in association with coronary artery disease because of its effects of coronary artery dilatation and heart rate reduction.

[Quantitative electromyographic analysis of the external urethral sphincter using automatic decomposition electromyography on normal subjects].

Motor unit action potentials (MUPs) of the external urethral sphincter muscle during cystometry were analysed on six normal males. Electrodes were of concentric needle type having the exposed tip surface of 0.07 mm2, and the potential changes were analysed by automatic decomposition electromyography (ADEMG), for isolation and characterization of unit discharges. Number of analysed units was as follows: Two at rest, 4 at first desire to void, and 6 at maximum desire to void. Number of the recorded units and the firing rate were increased along with the degree of bladder filling. Average MUP figures as follows: Amplitude of 206 microV, 8.3 msec. duration, and 5.4 Hz firing rate at rest; 246 microV, 9.7 msec and 7.3 Hz at first desire to void; 277 microV. 9.7 msec and 7.2 Hz at maximum desire to void, respectively. It is concluded that external urethral sphincter maintains its urinary continence by excitation of the neuromuscular units, and by the increase in the firing rate of individual MUP during bladder filling.

[Anticholinergic therapy of urinary incontinence and urinary frequency associated with the elderly--with special reference to dementia].

Pharmacotherapy with anticholinergic agents was studied in a total of 80 patients aged 65 years or older with chief complaints of urinary frequency (4 patients) and/or ugency incontinence (76 patients). The subjects were 45 men and 35 women at the age ranging between 65 and 92 (mean 73.7). The patients received anticholinergic agents (terodiline hydrochloride 24 mg/day, oxybutynin hydrochloride 6 mg/day, propantheline bromide 60 mg/day separately or in combination) for more than two weeks. Subjective symptoms and objective findings were assessed before and after the administration. In addition, according to the result of Hasegawa's dementia rating scale the patients were divided into dementia group and non-dementia group for further evaluation of the study drugs. As a result, cystometrogram revealed significant increase of maximum bladder capacity in either dementia group or non-dementia group. There was no significant difference in rate of objective improvement between both groups. On the other hand, rate of subjective improvement was significantly higher in non-dementia group (40%) than in dementia group (15%). As mentioned above, improvement of cystometrogram findings was not associated with improvement of subjective symptoms in the demented patients. This suggests that the major cause of incontinence in demented patients is not the bladder dysfunction but the specific conditions of demented patients such as agnosia and apraxia.

Effects of nifedipine and diltiazem on hemodynamic responses at rest and during exercise in hypertensive patients.

Twelve patients with uncomplicated systemic hypertension were treated with nifedipine (30 mg/day) and diltiazem (180 mg/day) for 1 month each, and performed two stage (50 watt and 100 watt) of bicycle ergometer exercise before and after each period of administration. Both drugs produced significant reduction in systolic and diastolic blood pressure at rest and during exercise, while the mean values of systolic blood pressure tended to be less with nifedipine than with diltiazem. Nifedipine caused a nonsignificant increase in heart rate at rest and during exercise, but diltiazem significantly decreased it at rest and during exercise. Cardiac output was significantly increased at rest and during mild exercise (50 watt), but not during more strenuous exercise (100 watt) with both drugs. Thus, different actions in arterial vasodilation and chronotropism between nifedipine and diltiazem in usual clinical doses were noted. However, nifedipine and diltiazem may be effective in hypertensive patients, probably with left ventricular dysfunction, because both drugs reduced systemic blood pressure even during exercise with simultaneous increase in cardiac output at rest and during mild exercise.

Estimation of ventricular source parameters and its load matching state in vivo.

Ventriculo-arterial coupling states were estimated by calculating left ventricular hydromotive pressure (Ps), source impedance (Zs) and input impedance (Zl) in 24 mongrel dogs with Fourier transforms of ventricular pressure and aortic flow immediately before and after instantaneous changes of arterial load. Calculated Ps (Psc) were compared with measured left ventricular isovolumic pressures (Psm) in various inotropic and loading states. Psc waveforms coinciding closely with those of Psm were obtained by cutting off higher frequencies within the fifth to tenth harmonics prior to the inverse Fourier transformation. The regression equation was Psc = 1.08 Psm +0.68 (r = 0.978). In control conditions, the ratio of Zs (0) / Zl (0) (function of frequency, 0 = zero Hz) was close to the ratio of ejection phase to one whole cardiac cycle, and the ratio of peak Psm to left ventricular ejection pressure was 1.85 +/- 0.25 SD. These results imply the presence of a ventriculo-arterial load matching state in control conditions.