RESUMEN
Three patients had carotid sinus syncope secondary to malignant neoplasms in the neck. Pacemaker therapy controlled the cardioinhibitory reflex with bradycardia, but the patients manifested varying episodes of hypotension due to a vasodepressor reflex that most likely resulted from persistent irritation of the carotid sinus by the tumor. These episodes seemed to be self-limiting. Surgical treatment in resistant cases is a possibility.
Asunto(s)
Estimulación Cardíaca Artificial , Seno Carotídeo , Neoplasias de Cabeza y Cuello/complicaciones , Hipotensión/etiología , Síncope/etiología , Carcinoma de Células Escamosas/complicaciones , Carcinoma de Células Escamosas/radioterapia , Estimulación Cardíaca Artificial/efectos adversos , Constricción Patológica , Neoplasias de Cabeza y Cuello/radioterapia , Humanos , Masculino , Persona de Mediana Edad , Neoplasias Nasofaríngeas/complicaciones , Neoplasias Nasofaríngeas/radioterapia , Síncope/terapiaRESUMEN
The possibility that DL-carnitine has a protective effect during myocardial ischemia was evaluated by performing two rapid coronary sinus pacing studies 15 minutes apart in 21 patients with coronary artery disease. Eleven patients received DL-carnitine (20 or 40 mg/kg) before the second pacing study. The treated group had a significant increase in mean heart rate (12.5 beats/min, P less than 0.001), pressure-rate product (1,912 units, P less than 0.01) and pacing duration (3.2 minutes, P less than 0.001) after the administration of carnitine. The treated group also had improvements in percent myocardial lactate extraction (8.8 percent increase, P less than 0.001) and left ventricular end-diastolic pressure (a decrease of 5.3 mm Hg, P less than 0.05). There was significantly less S-T segment depression during the second pacing period in both the untreated and treated groups. The results of this study suggest that in ischemic human hearts with reasonably well preserved left ventricular function, DL-carnitine may improve the tolerance for stress associated with an increase in heart rate and pressure-rate product.
Asunto(s)
Estimulación Cardíaca Artificial , Carnitina/uso terapéutico , Enfermedad Coronaria/fisiopatología , Corazón/fisiopatología , Dióxido de Carbono/sangre , Cateterismo Cardíaco , Enfermedad Coronaria/tratamiento farmacológico , Electrocardiografía , Hemodinámica , Humanos , Concentración de Iones de Hidrógeno , Lactatos/metabolismo , Persona de Mediana Edad , Miocardio/metabolismo , Oxígeno/sangre , Presión Parcial , Esfuerzo Físico , Factores de TiempoRESUMEN
A patient with moderate aortic stenosis, left ventricular hypertrophy, and a permanent right ventricular pacemaker for a sick sinus node presented with hypotension, dizziness, and angina pectoris with paced beats. The hemodynamics of pacing were documented with non-invasive and invasive studies. The patient was successfully treated with a programmable generator and pacing at a lower rate. The neccessity of evaluating the effects of a temporary pacemaker before insertion of a permanent one and of a reevaluation of the hemodynamic status in the presence of unexplained cardiac failure in a patient with permanent pacemaker are emphasized in this case report.