RESUMEN
We studied with M-mode echocardiography the morphology and function of the left ventricle in a group of 36 juvenile hypertensives with borderline hypertension, whose cuff arm pressure exceeded 150/90 mmHg in at least three separate sessions. The results were compared with those of 23 age-matched normotensives with no evidence of any cardiovascular disease. Left ventricular hypertrophy (i.e. septum and/or posterior wall thicknesses in diastole greater than or equal to 12 mm) was present in 13 subjects of the hypertensive group (36%). Significant increase of interventricular septal thickness together with higher septum/posterior wall ratio and a higher incidence of asymmetric septal hypertrophy were the most characteristic findings in juvenile hypertensives. Of the functional parameters the only observed difference between the two groups was an elevated peak velocity of left ventricular contraction in hypertensives which tended to correlate inversely with the values of septum/posterior wall ratio. Additional comparison of electrocardiographic and echocardiographic detection of left ventricular hypertrophy in young hypertensives revealed a lower sensitivity but a satisfactory specificity of electrocardiography (31 and 87% respectively). The results indicate that besides an elevated systemic arterial pressure, other factors such as increased sympathetic or humoral activity may play a role in the incipient stage of essential hypertension and that isolated septal hypertrophy seems to be an early sign of cardiac involvement.
Asunto(s)
Cardiomegalia/diagnóstico , Ecocardiografía/métodos , Hipertensión/diagnóstico , Contracción Miocárdica , Adolescente , Adulto , Gasto Cardíaco , Volumen Cardíaco , Cardiomiopatía Hipertrófica/diagnóstico , Femenino , Tabiques Cardíacos/patología , Ventrículos Cardíacos/patología , Hemodinámica , Humanos , MasculinoAsunto(s)
Hemodinámica , Hipertensión/fisiopatología , Adolescente , Adulto , Presión Sanguínea , Gasto Cardíaco , Prueba de Esfuerzo , Femenino , Humanos , Masculino , Consumo de Oxígeno , Postura , Descanso , Resistencia VascularAsunto(s)
Angina de Pecho/complicaciones , Insuficiencia de la Válvula Aórtica/complicaciones , Estenosis de la Válvula Aórtica/complicaciones , Enfermedad Coronaria/complicaciones , Hemodinámica , Adulto , Anciano , Angina de Pecho/fisiopatología , Insuficiencia de la Válvula Aórtica/fisiopatología , Estenosis de la Válvula Aórtica/fisiopatología , Enfermedad Coronaria/fisiopatología , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Significant structural, functional and metabolic differences between the right and left ventricles are present already in control animals. Intermittent high altitude (IHA) hypoxia (4 hr daily, 5 days a week, stepwise up to an altitude of 7000 m in a hypobaric chamber) induced in adult rats pulmonary hypertension and right ventricular hypertrophy; prolonged hypoxia also increased the relative left ventricular mass. Both chambers show proportionate increase in concentration of myofibrilar and collagenous proteins; the right-left difference, characteristic of animals living in normoxic environment, remains unaffected. The relative right and left ventricular bloodflow in hypoxic animals increases and so doses also the activity of glycolytic enzymes in both ventricles. Necrotic lesions, localized predominantly in the right ventricle, develop only at the beginning of adaptation to IHA. Parallel changes in the structure and enzyme activity of the myosine molecule in both ventricles can be observed. Administration of beta-blocking agent (Trimepranol, Spofa) significantly decreased pulmonary hypertension and right ventricular hypertrophy; the relative left ventricular mass normalized. Furthermore, Trimepranol significantly reduced necrotic changes in the right ventricle after a dose of 10 mg/kg, in the left ventricle - after 1 mg/kg. These results support the hypothesis of a possible impairment of left ventricular function in the presence of a primary right ventricular disturbance.
Asunto(s)
Mal de Altura/etiología , Ventrículos Cardíacos/fisiopatología , Hipoxia/etiología , Animales , Circulación Sanguínea , Gasto Cardíaco , Cardiomegalia/tratamiento farmacológico , Cardiomegalia/etiología , Enfermedad Crónica , Colágeno/biosíntesis , Circulación Coronaria , Ventrículos Cardíacos/crecimiento & desarrollo , Ventrículos Cardíacos/patología , Hipertensión Pulmonar/tratamiento farmacológico , Metipranolol/farmacología , Proteínas Musculares/biosíntesis , Ratas , Factores de TiempoRESUMEN
Adult male Wistar rats were used for studying the effect of Ca2+ antagonist verapamil on pulmonary hypertension, right ventricular hypertrophy and the medial thickness of pulmonary arterioles, induced by intermittent high altitude (IHA) hypoxia. This was simulated in a hypobaric chamber (7,000, 8 h daily, 5 days a week, 24 exposures). Verapamil was injected subcutaneously in a single dose of 8 mg/kg before each IHA exposure. Administration of verapamil to IHA-exposed animals significantly reduced right ventricular systolic pressure, right ventricular hypertrophy and pulmonary arteriolar medial thickness. Our results support the hypothesis that the transmembrane influx of extracellular calcium is an important component of the mechanisms of hypoxic pulmonary vasoconstriction.
Asunto(s)
Mal de Altura/complicaciones , Cardiomegalia/tratamiento farmacológico , Hipertensión Pulmonar/tratamiento farmacológico , Hipoxia/complicaciones , Verapamilo/farmacología , Animales , Peso Corporal/efectos de los fármacos , Cardiomegalia/etiología , Hematócrito , Hemodinámica/efectos de los fármacos , Hemoglobinas/análisis , Hipertensión Pulmonar/etiología , Masculino , Circulación Pulmonar/efectos de los fármacos , Ratas , Ratas EndogámicasRESUMEN
The pulsed Doppler echocardiography (PDE) was used to evaluate the character of mitral valve flow in a large atrial tumor. The tumor obstructed the mitral orifice during diastole. PDE findings, however, showed normal triphasic diastolic flow within the actual mitral orifice and no changes typical for mitral stenosis. The same turbulence pattern as in mitral stenosis was detected in the left ventricle. In addition, PDE revealed the presence of mild mitral regurgitation in agreement with angiography.