Relationships between verapamil plasma concentrations and its antihypertensive action.

Twenty-seven hypertensive outpatients were studied to evaluate the efficacy of verapamil after a single oral dose as well as following a short-term treatment and also in combination with oxprenolol. Blood pressure was significantly reduced (p 0.01) after verapamil monotherapy and the combined treatment. PR interval was lengthened from 30 min to 4 h during acute testing, and also after short-term treatment. QT was only prolonged after the verapamil monotherapy. Systolic time intervals (STIs) were not modified, except left ventricular ejection time (LVETc). Direct correlations were found among verapamil plasma concentrations and changes provoked on blood pressure and PR interval. The mean side effects found were disturbance of atrioventricular conduction in two patients without ulterior complications. The results suggest that verapamil monotherapy or in combination with oxprenolol could be useful in the treatment of essential hypertension.

Clonidine and prazosin in the treatment of hypertensive outpatients--a preliminary study.

Clinical assessment of a novel antihypertensive drug combination was undertaken in a group of essential hypertensive patients (n = 20). The effects of several doses of clonidine and its association with prazosin on blood pressure (BP), systolic time intervals (STI), and electrocardiogram (ECG) were investigated. Clonidine monotherapy induced a good BP control at 60%. BP was controlled in those patients in which prazosin was combined with clonidine (87.7%). LVETc was reduced by 0.3, 0.6, and 0.9 mg clonidine daily (p less than 0.05). PEPc was increased by only 0.9 mg, and it was diminished after its combination with 20 mg prazosin daily (p less than 0.05). PEP/LVET index was significantly increased by a higher dose of clonidine (p less than 0.05). ECG intervals did not change with the exception of PR, which was prolonged by 0.9 mg clonidine daily (p less than 0.05). Dry mouth, sedation, constipation, and drowsiness were the main side effects observed during the investigation. These results suggest an alternative treatment of essential hypertension, with a novel clinical application of drugs such as clonidine and prazosin, which have pharmacologic action via different alpha-adrenergic mechanisms.

Hypotensive action of verapamil in a group of hydralazine-dependent hypertensive patients.

Sixteen hydralazine-dependent hypertensive patients (7 females) were included in this clinical study. All patients were being treated with hydralazine, cyclopenthiazide and propranolol in the first visit to the laboratory. Two drugs were maintained during the study: the beta blocker and the diuretic. Hydralazine was discontinued and replaced by placebo during 3 weeks and after this period, verapamil was instituted at increasing doses. Replacing hydralazine by verapamil a better control of hypertension was obtained with a daily dose of 400 mg. The calcium entry blocker causes shortening of PEPc interval probably by reducing afterload which was only observed with the highest dose of verapamil (400 mg). ECG intervals were not modified by the different treatments with the exception of PR which was significantly increased by the major dose of verapamil. The calcium antagonist produced a stable reduction of blood pressure without affecting left ventricular function.

Modification of blood pressure and systolic time intervals by diuretics and beta-blockers in essential hypertension.

Heart rate (HR), blood pressure and systolic time intervals (STI), including total electromechanical systole (QS2), left ventricular ejection time (LVETc), pre-ejection period (PEPc), the PEP/LVET index and the time to the peak of carotid upstroke (Ut), were measured in 24 patients with moderate essential hypertension after 15 days of treatment with oral furosemide (F), hydrochlorothiazide (H), propranolol (P), atenolol (A), furosemide + propranolol (F + P) and hydrochlorothiazide + propranolol (H + P). Except F, all treatments significantly reduced blood pressure; maximal reductions were brought about by A and H + P. The heart rate was most reduced by A. THe QS2c interval was reduced only after F and H, LVETc was significantly reduced by H, A and H + P. Drug combinations prolonged PEPc, while the PEP/LVET index was increased only by H + P. Beta-blockers significantly prolonged the Ut. It is concluded that diuretics shorten QS2c mainly through reduction in blood volume. The H + P combination diminishes contractility and cardiac output and should not be employed in heart failure.

Effects of propranolol and atenolol on plasma renin activity and systolic time intervals in borderline hypertension.

Plasma renin activity (PRA) and systolic time intervals (STI), including total electromechanical systole (QS2), left ventricular ejection time (LVET), pre-ejection period (PEP) and isovolumetric contraction time (ICT), were measured in patients with borderline hypertension (n = 23) before and after oral treatment with atenolol and propranolol. Both beta blockers caused a similar fall in blood pressure and heart rate (P less than 0.001). QS2, PEPc and PEP/LVET values did not change after treatment. Propranolol prolonged ICT (p less than 0.001) and reduced LVET (p less than 0.001). No significant changes were detected in PRA after atenolol while a reduction was found after treatment with propranolol (p less than 0.001). No relationship was found between PRA and STI, however a linear correlation was recorded between systolic pressure and PRA (r = 0,91; p less than 0.01) before beta-blockade. These results suggest that: a) only beta 2-adrenoceptors are involved in the release of renin; and b) the effect of beta-blockers on STI follows a reduction of blood pressure and heart rate which in turn affect afterload.

Comunicación interauricular ostium secumdum con hendidura de la válvula mitral. Informe de tres casos operados y revisión de la literatura / Interauricular ostium secumdum communication with mitral valve cleavage. Report on three cases surgical treated and literature review

Se estudian 3 pacientes operados que presentaron comunicación interauricular (CIA) tipo ostium secumdum (OS) asociada con hendidura de la valva septal de la mitral (HVM). Se indican las distintas causas de la regurgitación mitral (RM) que se pueden presentar en el OS. Se comenta sobre la embriología de esta malformación. Se hace énfasis en los datos clínicos y de los exámenes complementarios para el diagnóstico de dicha entidad. La profilaxis antibiótica adecuada es una indicación en esta combinación de anomalías, para evitar la endocarditis bacteriana (AU)

Comparison of the effects of atenolol and propranolol in labile hypertension.

The effects of a single daily dose of 100 mg. of atenolol and an equivalent dose of propranolol were compared during a crossover, 15 day blind trial in a group of young labile hypertensives. Arterial pressure, heart rate, systolic time intervals and the carotid pulse upstroke time, recorded by external non-invasive procedures, were measured before and 4 and 8 hours after the last dose of both drugs. Both beta blocking agents significantly reduced and stabilized the arterial BP and the heart rate to normal values. However, a tendency to return to abnormal values was observed 8 hours after propranolol administration. Both drugs provoked an increase in the pre-ejection period, but with propranolol this increase was related to a larger isovolumetric contraction time, pointing to a negative inotropic action. The carotid pulse upstroke time was increased to normal values with atenolol. Propranolol failed to alter this value. Atenolol in a single oral daily dose is recommended in the treatment of labile hypertension.