(142 KB)
A closeup view from above looking down on the aortic valve of Peskin and McQueen's computational heart during ejection from the left ventricle. Valve leaflet fibers are white. The red blobs are blood markers, and the red streaks show the recent paths of the blobs.

Happy Birthday

"You gotta have heart,
All you really need is heart."

It's not everyday new life comes into being as a result of calculations on a supercomputer. But it's not much of an exaggeration to say that's what happened when Charles Peskin and David McQueen cranked up their heart model for the first time on the Pittsburgh Supercomputing Center's CRAY C90.

"It worked!" exclaimed Peskin in February 1993 as he watched the visualized results of a "monster calculation" made possible by availability of the C90. As the model heart contracted, red and blue particles streamed from the left and right ventricle into the aorta and pulmonary artery.

The main objective of the computation -- which took nearly a week of C90 single-processor computing and 50 million words of memory -- was to improve flow through the aortic valve. By increasing the number of points in the mesh-like grid used to do the calculations, the researchers created a more realistic match between the detail of the computation and actual heart anatomy. They expected this would solve the aortic valve problem, and they were right.

What they didn't realize was that improved resolution also would fix problems with the right side of their heart model, and the result was a breakthrough in their work. Every part of the model, each chamber and valve, did its job in synchrony through a complete cycle -- a full computational heartbeat. After 15 years of development, beginning with two dimensions and for the last five to six years working on the much more difficult three-dimensional version, Peskin and McQueen have achieved one of their goals: a fully functioning 3-D computational model of the heart, its valves and nearby major vessels.

For this accomplishment, Peskin and McQueen received the 1994 Computerworld Smithsonian Award for Breakthrough Computational Science. Peskin also received the 1994 Sidney Fernbach award. The researchers are now working toward the day when their model can be used to pose important "what if" questions about the heart, many of which are difficult to address in animal research and clinical studies.

Computed flow patterns in a thin slice of Peskin and McQueen's heart model at different times during a single heartbeat. The slice is roughly through the middle of the left ventricle. The mitral valve (inflow) is on the right, and the aortic valve (outflow) is on the left. Red markers indicate oxygen-enriched blood (left-hand side of the heart) and blue indicates oxygen-depleted blood.

ANIMATION: Beating Heart (6,065 KB)
This detailed image and animation show muscle fibers of the heart wall, the mitral valve (purple) and the aortic valve (yellow). The animation, from an educational video produced by the PSC scientific visualization group, shows the heart beating while the viewpoint rotates. The mitral-valve structure extends upward, sealing off the opening to the left atrium, as the left ventricle, the heart's main pumping chamber, contracts.

ANIMATION: Heart Beat with Ejecting Blood (2,765 KB)
In this animation of the beating heart, red markers show blood ejected into the aorta (left) as the left ventricle contracts. The markers on the right show blood forced upward against the sealed mitral valve.

Researcher: Charles S. Peskin and David M. McQueen, New York University, Courant Institute of Mathematical Sciences.
Hardware: CRAY Y-MP C90
Software: Immersed Boundary Method
Keywords: cardiac fluid dynamics, computational fluid dynamics, biological fluid flow, mathematics, immersed boundary method, heart, blood flow, circulation, circulatory system, heart valves, heart disease, heart function, ventricle, aorta.

Related Material on the Web:
PSC News Release, 1994 Computerworld Smithsonian Award.
PSC News Release, 1994 Sidney Fernbach award.
Projects in Scientific Computing, PSC's annual research report.

References, Acknowledgements & Credits