**1. Introduction**

106 Chronic Kidney Disease

Watson G, Hill C M, Biggart J D et al. Sarcoidosis and primary systemic vasculitis. Nephrol

Yoshida O, Okada Y. Epidemiology of urolithiasis in Japan: a chronological and

Dial Transplant. 1996;11: 1631-1633. 54.

geographical study. Urol Int 1990: 45: 104-11.

In recent years, the relationship between the heart and the kidneys in disease has received increasing attention from the clinical and scientific medical community. This was initiated by epidemiological observations in the late 1990's of increasing patient numbers with concurrent heart and kidney problems, and the association with a significantly higher mortality ratio. This has led to intense discussions about the value of the recognition of cardiorenal disease on the one hand, and the existence of a specific "cardiorenal syndrome" on the other hand.1-10

The idea of specific interaction between heart and kidneys is not new. There are numerous examples and anecdotes that show that people in the past from various societies considered the heart and the kidneys to have a special relationship.
