Those who faced turbulence and launched the era of flow dynamic concepts for cardiac investigation.

This paper puts emphasis on pioneers who developed cardiac flow dynamics concepts during the second half of the 20th century at a period where pressure measurements were the rule. Thinking flow instead of pressure dynamics corresponded to in-depth conceptual changes: whereas blood pressure generally has a single positive sign and a similar pattern at all points of a cardiac chamber or a vessel, flow fluctuates around the zero line and its pattern changes within a given cardiac chamber or vessel level. These specific changes and fluctuations were the exciting tools needed to renew our pathophysiological insights, just in time with the take off of Doppler ultrasound making noninvasive investigation of fluid dynamics easily available. Each decade was marked by a specific historical contribution to evolving concepts. Instead of a merely phenomenological approach to flow dynamics, pioneers assigned a value of paradigms to basic flow patterns. They generated a system of heuristical hypotheses which turned out to underlay a modernistic understanding of flow dynamics in normal and diseased hearts. So far, flow investigation had definitely gained acceptance completing pressure data at the middle of the 1980s, widely opening a breakthrough for future pathophysiological insights.