Cat's Claw and Heart Disease

Can cat's claw be used safely if you have irregular heart beat, and a leaking heart valve?

From the research literature on cat's claw, it appears to be beneficial to blood circulation by improving the health of the blood vessels, improving peripheral blood circulation, lowering heart rate and blood pressure. Cat's claw also appears to have a calming action on the nervous system, which may beneficial in an irregular heart beat.
I can't say specifically whether cat's claw is safe in an irregular heart beat and a leaky heart valve. For these, we would use herbs that strengthen the heart (like hawthorn) and herbs that strengthen the nervous system (the particular herbs depend on the individual's condition).