Ten men repeatedly performed leg exercise (100-150 W) for 7 min with 30-min recovery periods interspersed. Both legs were made ischemic by total occlusion (OCCL), first for 3 min immediately after exercise and second for 30 s before exercise ended and 3 min into recovery. In addition legs were occluded for 3 min at rest (seated). OCCL at rest increased mean arterial pressure (MAP) by 9 Torr but did not affect cardiac output (CO) or heart rate (HR). OCCL at the end of exercise significantly raised MAP and HR above control values during 3-min recovery but CO was unaffected. OCCL 30 s before the end of exercise further increased MAP and HR significantly during recovery; MAP, CO, and HR were significantly increased above control values (CO by 2.1 1-min-1) during the 3rd min of recovery. We conclude that a strong reflex from ischemic legs maintains normal or elevated CO during leg OCCL. Thus CO was too high relative to total vascular conductance so that MAP was elevated.
SUMMARY Autonomic cardiovascular regulation was evaluated in 35 women, 19 with mitral valve prolapse and 16 healthy controls. Heart rate responses to the diving reflex and to phenylephrine infusion were diminished in patients. Noninvasive measures of cardiac output, heart rate, blood pressure, forearm flow and leg volume during lower body negative pressure (LBNP) showed that patients had less lower extremity pooling of blood and had lower forearm conductance. Blood pressures during LBNP rose or remained unchanged despite decreases in cardiac output of 20-25%. These data indicate that mitral valve prolapse patients have an increased venous and arterial vasoconstrictor activity. Cardiac output at rest and echocardiographic indices of contractility were normal. Patients with a history of significant ventricular arrhythmias had higher heart rates and lower forward stroke volumes than the other patients or controls.The combined data demonstrate autonomic dysfunction in women with the mitral valve prolapse syndrome and suggest decreased parasympathetic, increased a-and normal j-adrenergic tone and responsiveness.
Materials and Methods PatientsThe protocol was approved by the institutional Human Research Review Committee. The records of the Cardiographics Laboratory of the University of Texas Southwestern Medical School, Dallas, Texas were reviewed to obtain the names of patients with the diagnosis of mitral valve prolapse. Private cardiologists in the community were also contacted for names of patients who might enter the study. We studied only women because most of our MVPS patients are women and because we wished to avoid problems of data interpretation due to inherent cardiovascular differences between normal men and women. One patient was excluded because she required propranolol for control of arrhythmias. Four additional patients were taking propranolol at the time they agreed to participate, but all medications were discontinued for at least 72 hours before this study. Nineteen female patients (mean age 30 ± 1.8 years) were included.The diagnosis of MVPS was confirmed by echocardiography using the criteria of DeMaria et al.4 or by phonocardiography demonstrating a nonejection systolic click-murmur complex which changed in the typical fashion in response to amyl nitrite inhalation or the Valsalva maneuver.2 The laboratory and clinical findings of the patients are summarized in table 1.None of the patients had clinical findings suggestive of hemodynamically significant mitral regurgitation or echo-or electrocardiographic evidence of left atrial or ventricular enlargement.We graded the severity and frequency of each patient's symptoms and ventricular and supraventricular arrhythmias on a scale of 0-4+ (as defined in table 1) on entry to the study, and used the sum of
Exertional rhabdomyolysis (ER) is a common medical condition encountered by primary care and sports medicine providers. Although the majority of individuals with ER follow an expected and unremarkable clinical course without any adverse long-term sequelae or increased risk for recurrence, in others, the condition can serve as an 'unmasker' of an underlying condition that portends future risk. We present two cases of warfighters with a history of recurrent ER who presented to our facility for further evaluation and a return to duty determination. We describe the definition, pathophysiology, epidemiology, etiology, and clinical course of ER. In addition, we introduce 'high-risk' criteria for ER to assist in identifying individuals needing further testing and work-up. Finally we present a suggested algorithm that details the work-up of these individuals with high-risk ER to help identify underlying conditions that may lead to recurrence.
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