Erythrityl tetranitrate, a long-acting organic nitrate, was compared with isosorbide dinitrate in a double-blind, placebo-controlled complete crossover study in 15 healthy male volunteers. A digital plethysmogram and ear densitogram were used to assess the physiologic response to these two sublingual nitrates, with the intensity and duration of drug effect calculated by differences in diastolic amplitude intensity before and after drug administration. Both 5 mg sublingual erythrityl tetranitrate and 5 mg isosorbide dinitrate produced significant increases in diastolic amplitude intensity for up to 3 hours. The erythrityl tetranitrate peak effect was less than that of the isosorbide dinitrate, but the incidence of headaches was also less. The ear densitogram was found to be an effective means of assessing the diastolic amplitude intensity changes.

Adult↗

PubMedDate not supplied

Erythrityl tetranitrate compared with isosorbide dinitrate. Effects on systolic time intervals and nitrate modification of effects of food.

The pharmacologic effects of erythrityl tetranitrate (ETN) and isosorbide dinitrate (ISDN) were compared to placebo using systolic time intervals (STI) in a randomized, double-blind study in 15 fasted male volunteers. Sublingual doses of ETN 5 mg, ISDN 5 mg, and placebo were administered to each volunteer at weekly intervals, and measurements of heart rate and STI [pre-ejection period (PEP), left ventricular ejection time (LVET), and PEP/LVET ratio] were made serially for up to 6 hours after each dose. STI were determined using ear densitography. Evaluation of the pharmacologic effects of ETN and ISDN were based on placebo-corrected changes from baseline values. Ejection time index (ETI) [LVET corrected for heart rate] was shortened, but the changes were not statistically significant for either drug. However, after ETN and ISDN, statistically significant (p less than 0.05) changes in PEP and PEP/LVET ratio were demonstrated for up to 240 minutes after dosing. Unexpected marked changes in the baseline corrected PEP/LVET ratio were observed following food at 4 hours after dosing. This suggests increased inotropy during the postprandial period.

Adult↗

PubMedDate not supplied

Cardiac effects of hemodialysis: noninvasive monitoring by systolic time intervals.

The effects of hemodialysis on cardiac performance were evaluated by systolic time intervals measured blindly in 15 chronic renal failure patients maintained free of circulatory congestion. After a mean dialysis of 8.7 hours, levels of blood urea nitrogen, serum creatinin, and potassium and body weight showed statistically significant decreases and serum calcium and hematocrit values increased; heart rate and both diastolic and systolic blood pressure did not change significantly. Left ventricular ejection time (LVET) and ejection time index (ETI) were significantly shorter, falling from within normal limits to below normal. Pre-ejection period (PEP) rose significantly. These changes are consistent with a two-fold immediate effect of hemodialysis: (1) reduction of stroke volume as reflected by decreased ETI; and (2) reduced Starling effect, with or without decreased contractility, as reflected by increased PEP.

Adolescent↗

PubMedDate not supplied

The effect of near-maximal isometric stress on the presence and amplitude of fourth heart sounds.

Near-maximal isometric exercise (IHG) was employed to provoke new, or alter pre-existing fourth heart sounds (S4s) in ambulatory middle-aged normal subjects (N), hypertensive patients (HHD), and patients with coronary disease (CAD). S4 amplitudes and systolic time intervals (STIs) were measured blindly. No subjects without a resting S4 developed a new S4 during IHG. Increases and decreases of pre-existing S4 provoked by IHG were not statistically different among all groups. Among subjects matched for presence of S4, STIs during IHG showed significant shortening of the ejection time index and prolongation of Q-Im in the HHD group only. When the subjects who increased a resting S4 during IHG were compared with the subjects who decreased their resting S4 during IHG there were no significant differences in the responses of STIs. Thus, in these ambulatory, hypertensive patients, coronary patients, and normal subjects, near-maximal IHG did not induce new S4s and had variable effects on pre-existing S4s. Neither type of S4-response could be associated with corresponding changes in systolic time intervals.

Aged↗

PubMedDate not supplied

Development of an ambulatory systolic time interval monitoring system.

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Ambulatory Care↗