Implantable cardioverter-defibrillator

The implantable cardioverter-defibrillator (ICD) emerged on February 4, 1980, when a 57-year-old woman with severe coronary artery disease received the first device at Johns Hopkins Hospital in Baltimore. Michel Mirowski, a Polish-born physician who had immigrated to Israel and then the United States, led the team that developed what many consider the most significant advance in cardiovascular medicine in fifty years—a device that could detect lethal heart rhythms and automatically shock the heart back to normal.

Mirowski's mission was personal. His mentor had died of a heart arrhythmia, a condition where the heart's electrical system malfunctions, causing it to beat erratically or stop effectively pumping blood. External defibrillators could restore normal rhythm—but only if medical help arrived in time. Mirowski asked the obvious question: why not put the defibrillator inside the patient, where it could act instantly?

The adjacent possible for the ICD opened through advances in cardiac pacing and battery technology. Lithium-powered pacemakers, developed in the early 1970s, had proven that implanted electronic devices could function reliably for years. External defibrillators demonstrated that electrical shocks could terminate ventricular fibrillation. What was missing was the engineering to miniaturize a defibrillator small enough to implant and reliable enough to trust with autonomous life-or-death decisions.

Mirowski teamed up with Morton Mower and began research at Sinai Hospital in Baltimore in 1969. The development took eleven years. A 1975 prototype small enough for dog implantation proved the concept, and a famous film of the first successful dog defibrillation brought the ICD into the spotlight. But the medical establishment remained skeptical—some physicians considered the therapy unethical, questioning whether autonomous devices should make resuscitation decisions.

The first human device, installed with cardiac surgeon Myron Weisfeldt and electrophysiologist Philip Reed, weighed 225 grams and required thoracotomy (open-chest surgery) to place electrode patches on the heart. It could only defibrillate, not pace. The patient had recurrent ventricular arrhythmias that had resisted all available antiarrhythmic drugs. The device worked, demonstrating that automatic internal defibrillation was possible.

The cascade from the 1980 implant transformed cardiac care. FDA approval came in 1985. Progressive miniaturization eliminated the need for thoracotomy. Modern ICDs combine pacing, cardioversion, and defibrillation in devices small enough to implant through a vein. By 2024, millions of patients worldwide lived with ICDs, each device standing ready to deliver life-saving shocks within seconds of detecting lethal rhythms. Mirowski, who died in 1990, was posthumously inducted into the National Inventors Hall of Fame for work that extended countless lives.