sudden death

Monday, April 21, 2014

There may be nothing better than the NHL’s sudden death overtime for excitement, drama and the finality as the winning goal is scored. Sudden death has a totally different meaning in medicine and the end game is not a positively anticipated event. And yet there are people who survive sudden death because of a confluence of fortunate circumstances.

The purpose of the body is to take the brain around to experience life and for that to happen, the heart has to circulate blood and deliver oxygen and nutrients to the far reaches of the body. It’s a simple pump that depends upon its electrical system to deliver rhythmic impulses that allow the heart muscle to squeeze in a coordinated fashion. The body is very forgiving and it can tolerate an occasional hiccup where an irregular heartbeat or two is unable to pump blood, but without adequate blood flow, the body shuts down very quickly and the brain is perhaps the most unforgiving of all organs. No blood flow and it turns off in an instant; no blood flow for 4-6 minutes and damaged forever.

The heart is a two stage electrical pump. A group of pacemaker cells generates an electrical signal that is transmitted through the heart’s wiring to allow the heart muscle to beat in a coordinated fashion. It’s a continuous lifelong process, where the natural pacemaker tells the atrium, the upper chambers of the heart to contract and send blood to the ventricle. The electrical signal is also sent to the ventricle but before it arrives, there is a split second delay at a junction box called the AV node (atrioventricular node), so blood can actually fill the ventricle before the muscle squeezes to send the blood off to the body.

There are a variety of rhythm disturbances that can affect the heart and an occasional skipped or missed beat can be a normal variant but in some people, the electrical system can short circuit and not deliver a coordinated electrical impulse to the heart muscle. When this occurs, each heart muscle cell has the potential to generate its own electrical signal and the end result is chaos. Instead of having one coordinated beat, the heart just quivers or fibrillates. If this occurs in the atrium (atrial fibrillation), the AV node can filter the chaos and allow the ventricle to beat normally, though irregularly. Though A Fib has its own issues, sudden is not one of them. However, if it is the ventricle that fibrillates, then blood flow to the body stops and death is almost immediate.

Ventricular fibrillation or V Fib is one of the complications of a heart attack or myocardial infarction, where a blocked artery causes some heart muscle to lose its blood supply and become irritated. This may affected the electrical system leading to fibrillation and it is what kills a heart attack victim in the immediate time frame. In some unfortunate souls, V Fib and sudden death happens just because…there is no warning.

Those who survive sudden death do so because of circumstance. They are fortunate that their heart stopped when other people were around, that those people knew how to perform cardiac resuscitation and that an AED was soon available to shock the heart back into a normal rhythm. It’s an electric problem that kills and it is electricity that saves. Should a victim survive sudden death, a defibrillator is often implanted that can detect future V Fib rhythms and automatically deliver a shock.

An implantable carioverter defibrillator is a lifesaver but it is also meant to allow the body to return to normal function, allowing it to take the brain to the many places it wants to go.  The Twin Cities Marathon is a gathering place for runners who continue their passion for running and for those who decide to embark on their running career even after surviving sudden death. The Global Heroes program sponsored by Medtronics, one maker of ICDs, celebrates those athletic souls.

Sudden death strikes without warning and without regard to age, body size or level of fitness. My brother’s keeper is the treatment, where people take the time to learn life saving techniques and are willing to us them on family or stranger alike. In sports, there is always another game after sudden death even if it need to wait till next season. In life, sudden death may actually mean death.

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