Question: Who developed the prototype pacemaker used by the 34th President of the USA?

Context paragraphs:
Dwight D. Eisenhower: Dwight David "Ike" Eisenhower ( ; October 14, 1890 – March 28, 1969) was an American politician and Army general who served as the 34th President of the United States from 1953 until 1961.  During World War II, he was a five-star general in the United States Army and served as Supreme Commander of the Allied Expeditionary Forces in Europe.  He was responsible for planning and supervising the invasion of North Africa in Operation Torch in 1942–43 and the successful invasion of France and Germany in 1944–45 from the Western Front.

34th Battalion (Australia): The 34th Battalion was an infantry unit of 1st Australian Imperial Force (AIF), which was established in World War I for overseas service.  Formed in Australia in 1916, the battalion fought on the Western Front before being disbanded in 1919.  It was later re-raised as a part-time infantry battalion in the Illawarra region of New South Wales during the inter-war years.  During World War II, the 34th was amalgamated with the 20th Battalion and undertook defensive duties in Australia before being disbanded in 1944.  Post war, the 34th was re-formed in the early 1950s before being subsumed into the Royal New South Wales Regiment in 1960.

2013 America's Cup: The 34th America's Cup was a series of boat races held on San Francisco Bay between the defender Oracle Team USA representing the Golden Gate Yacht Club, and the challenger Emirates Team New Zealand representing the Royal New Zealand Yacht Squadron.  Oracle Team USA defended the America's Cup by a score of 9 to 8.  Oracle had to win the last eight races to come from behind and once again win the oldest trophy in international sport.  Team New Zealand won the right to challenge for the cup by winning the 2013 Louis Vuitton Cup.  The 34th America's Cup was the longest ever cup by both number of days and races, and the first since the 25th America's Cup to feature a winner-take-all final race.

34th Armoured Brigade (United Kingdom): The 34th Armoured Brigade was an armoured brigade of the British Army that saw active service in the Second World War.  It was formed in 1941 as the 34th Army Tank Brigade and subsequently redesignated as the 34th Tank Brigade in February 1945 and became part of the 79th Armoured Division.  It was equipped with Churchill tanks and provided close support for assaults by the infantry.  During the fighting in North-west Europe from July 1944 to May 1945 the brigade served with both the First Canadian Army and the British Second Army.  The brigade was disbanded in early 1946.

Andrés Avelino Cáceres: Andrés Avelino Cáceres Dorregaray (November 10, 1836 – October 10, 1923) served as the President of Peru three times during the 19th century, from 1881 to 1882 as the 34th President of Peru, then from 1886 to 1890 as the 36th President of Peru, and again from 1894 to 1895 as the 38th President of Peru.  In Peru, he is considered a national hero for leading the resistance to Chilean occupation during the War of the Pacific (1879–1883), where he fought as a General in the Peruvian Army.

R Adams Cowley: R Adams Cowley (July 25, 1917 – October 27, 1991), the "Father of Trauma Medicine," was an American surgeon considered a pioneer in emergency medicine and the treatment of shock trauma.  He was the founder of the United States's first trauma center at the University of Maryland, in 1958, after the US Army awarded Dr. Cowley $100,000 to study shock in people—the first award of its kind in the United States.  The trauma unit at first consisted of two beds, and was later expanded to four beds.  Many people called the four-bed unit the "death lab."  Cowley was the creator of the "Golden Hour" concept, the period of 60 minutes or less following injury when immediate definitive care is crucial to a trauma patient's survival.  He was a leader in the use of helicopters for medical evacuations of civilians, beginning in 1969, and founded the Society of Thoracic Surgeons.  He also founded the nation's first statewide EMS system, called MIEMSS by Executive Order of Maryland's Governor Mandel, 1972, as well as the National Study Center for Trauma and EMS, enacted by Congress in 1986 and signed into law by President Ronald Reagan.  He is also known for being one of the first surgeons to perform open-heart surgery and invented both a surgical clamp that bears his name and a prototype pacemaker that was used by Dwight D. Eisenhower.

David Eisenhower: Dwight David Eisenhower II (born March 31, 1948) is an American author, public policy fellow, professor at the University of Pennsylvania, and eponym of the U.S. Presidential retreat, Camp David.  He is the only grandson of 34th President of the United States, Dwight D. Eisenhower, and the son-in-law of the 37th President of the United States Richard Nixon.

Black Bat Squadron: Black Bats () 34th Squadron was the name of a corps of CIA reconnaissance plane pilots and crew based in Taiwan during the Cold War.  Citizens of the Republic of China, they flew missions over mainland China controlled by the People's Republic of China (PRC), to drop agents and gathered military signal intelligences around military sites.  The 34th Squadron was formed in 1953 and flew its last operational mission in 1967.  The squadron's emblem was a bat and seven stars and its formal name was the 34th Squadron of the ROC Air Force.  Unit's aircraft included the Boeing B-17G, Douglas A-26C/B-26C Invader, 7 Lockheed RB-69A, Douglas C-54, 11 Fairchild C-123B/K Provider, Lockheed C-130E Hercules, and 3 "black" Lockheed P-3A Orion (149669, 149673, 149678).  The P-3As and RB-69As were armed with AIM-9 Sidewinder missiles for self-defense.  34th Squadron specialized in very low level air space penetration (100–200 meters altitude) to hug the ground in order to evade enemy radars and fighter interceptions.  Later when operating P-3A, its main mission was flying in international water, 40 miles outside of Mainland China, to collect signal intelligences.

34th Street (IRT Second Avenue Line): 34th Street was a local station on the demolished IRT Second Avenue Line.  It had two levels.  The upper level had three tracks and two side platforms and was used for the Second Avenue line trains.  The lower level had two tracks and one island platform and was used by 34th Street shuttle trains.  The next stop to the north was 42nd Street.  The next stop to the south was 23rd Street.  The next eastbound stop on the shuttle was 34th Street Ferry.  The next westbound stop on the shuttle was Third Avenue.  The shuttle platform closed on July 14, 1930, and the main line station closed on June 13, 1942.

East 34th – Campus (RTA Rapid Transit station): East 34th–Campus Station is station on the RTA Rapid Transit system in Cleveland, Ohio, USA, serving the Red, Blue and Green Lines.  It is located just east of East 34th Street near the intersection of East 34th and Broadway, on the north side of the CSX railway tracks, and below the bridge that carries East 34th Street over the railway tracks.

Supporting paragraphs: R Adams Cowley Dwight D. Eisenhower
Answer: R Adams Cowley