1954

Electrodyne releases commercial version of Zoll’s external pacemaker, and external pacing came into use in U.S. hospitals, esp. teaching hospitals, in 1950s. The version of pacing provided emergency resuscitation in hospital from ventricular standstill. A pulse generator was plugged into the AC electrical system at patient’s bedside, supplying high voltage for very short periods (minutes to hours) (Jeffrey, loc 251-52). At Univ. Minnesota, Lillehei asks resident Roland DeWall to design a practice bubble oxygenator, simpler than other designs being tested elsewhere; prototype ready in May 1955. Also in mid-1955, Lillehei switches from epinephrine to newly available asthma drug Isuprel (isoproterenol), which speeds up heart rate and improves his success rate in the 10% of patients who develop post-surgical heart block after repair of ventricular septal defect owing to surgical stitches damaging conduction cells (Jeffrey, ch 3).