Platypnea-orthodeoxia: an unusual indication for surgical closure of a patent foramen ovale.

Platypnea-orthodeoxia is an infrequently reported clinical form of position dependent dyspnea and oxygen desaturation. There are several diverse etiologies for this syndrome. This case report of a patient with platypnea-orthodeoxia is the first known presentation of a case secondary to a patent foramen ovale and idiopathic hemidiaphragm paralysis. A major problem with this disease is the clinical recognition of its existence. Full recovery is possible with proper assessment of clinical signs and symptoms, appropriate noninvasive diagnostic tests, and corrective surgery in selective cases.

Effect of a total artificial heart on adaptive hormonal responses in humans with end-stage heart failure.

The J-7 total artificial heart (TAH) can restore normal vascular hemodynamics in humans treated for end-stage heart failure, but less is known regarding its effect on hormones elevated under these conditions. A 49-year-old man with NYHA Class IV end-stage heart failure received a J-7-70 TAH as a bridge to transplantation. Pre-TAH cardiac index was less than 2 L/min/m2 with end organ dysfunction, increased venous and pulmonary pressures, and a low arterial pressure. The TAH provided an immediate cardiac index greater than 3 L/min/m2 with normal hemodynamics and organ function. Pre-TAH renin, aldosterone, and atrial natriuretic factor (ANF) levels were markedly elevated: 147 ng/dl, 29.4 ng/dl, and 380 pg/ml, respectively. All values declined dramatically by the fifth postoperative day, with the aldosterone and ANF values returning to normal at 11.5 ng/dl and 37 pg/ml, respectively. Renin levels reached normal values by the fourth postoperative week. Once normal values were obtained, they remained in this range for the 57 days of TAH function. The TAH, used in end-stage heart failure, restores normal hemodynamics and compensatory hormonal levels. These hormones can be used as indicators of proper TAH function in such patients.

The role of beta receptors in the peripheral vasculature of calves with a total artificial heart.

Drugs given to a total artificial heart (TAH) calf isolate their vascular effects independent of the myocardium. During experiments, the TAH maintains full ejection, constant heart rate, and percent systole, and uses no vacuum. Cardiac output (CO) varies solely and directly with preload. Six calves received an infusion of isoproterenol, a beta agonist, and three calves received propranolol, a beta antagonist. The isoproterenol was resumed after beta blockade. Isoproterenol alone caused a significant increase in CO, an effect that was attenuated but not eliminated with beta blockade. Both isoproterenol and propranolol decreased AoP, but only isoproterenol increased preload. Beta receptors play a significant role in decreasing venous capacitance with increased preload and CO, independent of the myocardium.