“Hearts
cannot be broken, they're small squishy things
They don't
break like glass but they bruise easily” – The
Judybats
While hearts can’t be broken, their rhythmic beating can go awry – a condition we call arrhythmia. Many people don’t think of the heart as a muscle, but that’s what it is - a muscle that pumps blood around the body through a series of regular contractions. When the ventricles contract, oxygenated blood gets pumped out into circulation; when they relax, they fill back up with blood. Disruption of this routine delays delivery of blood to tissues and organs, including the brain.
Ventricular
fibrillation is caused when a heart disorder leads to a problem with the
electrical impulses running the cardiac muscles, which makes them quiver
instead of contracting. A defibrillator basically sends an electric shock
through the heart, stopping it in hopes that it starts back up with its normal
rhythm restored. A remarkable feat that has saved tens of millions of lives,
but how did we learn to do this?
Ventricular fibrillation usually occurs as a consequence of previous cardiac damage, such as a heart attack. But what about the pain that we feel when someone “breaks” our heart? Believe it or not, stress-induced cardiomyopathy, also known as “broken heart syndrome” is a real thing! |
Long ago, people used to believe muscles expanded and contracted because of air or fluid inside them. This was referred to as the “balloonist” theory. |
As dramatic
as the “shocking” experiment was, the lesson was that electricity would not
reanimate a corpse. So it wasn’t until 1930 that this sort of work was
resurrected with simpler objectives:
using electric currents to kickstart a heart. Enter William
Kouwenhoven, who invented the heart defibrillator, a device that
essentially “restarts” the cardiac engine*. His experiments did not get off to
a promising start. In 1928, high voltage shocks from electrodes placed on the
head and one limb of a rat only resulted in a dead rat. But by 1933, he was
able to restore normal heartbeats to dogs. However, this required direct
contact with the dog’s heart muscle to work. This method of “open chest heart
defibrillation” was practiced on patients until 1957, when Kouwenhoven built a
device capable of delivering the electrical pulses from outside the body.
Kouwenhoven’s
defibrillation studies also led to the development of cardiopulmonary
resuscitation (CPR) as a critical life-saving technique. One fine Saturday –
because all good scientists work through the weekends – a graduate student named
Guy Knickerbocker noted a brief rise in blood pressure when he pressed those
heavy copper defibrillator paddles onto the dog’s chest. This gave rise to the
idea that by forcefully pressing on the chest, one could help circulate blood
through the body until the heart started beating again.
One of the first defibrillators by Kouwenhoven compared to what they look like today. |
*Kouwenhoven’s research stemmed from
earlier findings, most notably those made by Jean-Louis
Prevost and Frederic Batelli. In 1899, they observed that electrical shocks
could induce ventricular fibrillation in dogs, but even larger shocks could
restart their hearts.
Contributed
by: Bill Sullivan
Check out my
other Valentine’s Day treat: What Is Love, Anyway?
References:
Furman S (2002). Early history of cardiac pacing and defibrillation. Indian pacing and electrophysiology journal, 2 (1), 2-3 PMID: 17006571
Bresadola, M. (1998). Medicine and science in the life of Luigi Galvani (1737–1798) Brain Research Bulletin, 46 (5), 367-380 DOI: 10.1016/S0361-9230(98)00023-9
References:
http://www.emsmuseum.org/virtual-museum/by_era/articles/399789-CPR-and-the-First-Defibrillator-Drs-Kouwenhoven-Jude-and-Knickerbocker
http://www.aed.com/blog/a-little-defibrillator-history-and-its-potential-future/#sthash.UjFv3BXE.dpuf
http://www.aed.com/blog/a-little-defibrillator-history-and-its-potential-future/#sthash.UjFv3BXE.dpuf
Furman S (2002). Early history of cardiac pacing and defibrillation. Indian pacing and electrophysiology journal, 2 (1), 2-3 PMID: 17006571
That afforded surge towards concept that by means of forcefully depressing within the breasts, you possibly can guide stream our blood throughout the human body till the cardiovascular system started off busting all over again.
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