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Potassium Administration Helps Leg Blood Flow in Heart Failure Patients: Presented at AHA
By Jill Stein
CHICAGO, IL -- November 19, 2002 - Potassium administration improves muscle blood flow and metabolism in patients with heart failure, say researchers.
This finding was reported here on Monday at the 2002 Scientific Sessions of the American Heart Association (AHA).
Dr. Javed Butler and colleagues at Vanderbilt University in Nashville, Tennessee, United States, studied the effect of potassium administration on leg circulation and metabolism in eight heart failure patients. The trial excluded patients with exercise limiting angina, valvular heart disease, symptomatic peripheral vascular disease, and intrinsic lung disease.
Central hemodynamics, leg blood flow, and metabolic parameters were measured during maximal treadmill exercise, before, and two hours after intravenous potassium chloride infusion (0.5 mEq/kg). Four additional patients underwent identical testing after placebo infusion and served as controls.
Infusion of potassium chloride increased potassium levels at rest (4.0 ± 0.2 to 4.7 ± 0.3 mEq/L) and throughout exercise.
Compared to controls, potassium increased leg blood flow (matched peak exercise: 1.2 ± 0.2 to 1.7 ± 0.4 L/min) and leg oxygen consumption (matched peak exercise: 174 ± 35 to 264 ± 53 mL/min) and decreased femoral venous lactate (matched peak exercise: 36.3 ± 6.3 to 20.6 ± 4.5 mg/dL).
No significant changes were noted in exercise duration, potassium level, central or peripheral hemodynamic measurements in the placebo group.
Dr. Butler said the data suggest that relatively modest changes in potassium levels can favorably alter lactase release and leg blood flow in heart failure patients. Notably, these improvements after potassium administration were evident even in those patients with baseline potassium levels in the normal range.
Such results, he added, raise the intriguing possibility that more aggressive repletion of potassium levels in patients with heart failure may enhance muscle oxygen delivery and, over time, improve exercise performance.
Conversely, the study raises the possibility that hypokalemia may adversely influence exercise performance in patients with heart failure.
Studies should be conducted to investigate these hypotheses, he said.
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