But that was hardly the end of the story. The holy grail of a working mechanical heart never disappeared, though the word “permanent” faded away. New devices have come along, each presented not as an abiding solution but, rather, as a temporary “bridge” to sustain patients until they can receive the transplant of a real heart. (Not that transplantation, first performed in 1967, is guaranteed to work. There is always a risk of a recipient’s body rejecting the new organ.)

In line with its mission to look both back and ahead, Retro Report explores the extent to which artificial hearts remain very much a part of modern life. Among the designs that have emerged, none is more embraced than a Jarvik-7 descendant, the Temporary Total Artificial Heart made by SynCardia Systems of Tucson, Ariz. (A mechanism designed by a French company, Carmat, has also received attention.)

Nearly all the devices in use today in the United States are the SynCardia model, with the number of those who have carried it approaching 1,600. Unlike the unwieldy compressor of the Jarvik-7, the power system is portable, stored in a pouch weighing 13 pounds. Even so, full freedom of movement is elusive. The battery pack has a limited life. Users cannot stray far from a power source.

Thousands of other Americans have years added to their lives with the aid of a smaller artificial apparatus, a partial heart known as a ventricular assist device, or VAD. The VAD is attached to one or both of the ventricles, the heart’s pumping chambers. Most commonly, the left ventricle is the target because it does most of the pumping.

By bolstering the ventricle, the device buys ailing people time to recover. Intriguingly, these patients have no pulse: With most VADs, blood flows in a continuous stream, as opposed to being pumped in the pulsating rhythm of a healthy heart.

The wait for a real heart that can be transplanted requires patience worthy of Job. There are not nearly enough potential donors in this country, where heart disease continues to be the No. 1 killer, with more than 600,000 annual deaths. The number of available hearts in a given year has long hovered around 2,000, not enough to meet the need.

In a sense, developments that amount to good news for most Americans are not necessarily glad tidings for critical heart patients. Victims in fatal car crashes, for instance, can be a prime source of hearts. But with improvements in auto and highway safety, motor vehicle deaths in the United States have declined to fewer than 33,000 a year from a high of more than 54,000 in the early 1970s. The math speaks for itself.