Quivering Heart

The heart is a hollow muscular basket which begins to beat about ten days after conception and stops only with death. The cavity consists of four chambers. Two of them, called auricles, receive blood from the veins. Two, called ventricles, push blood into the arteries.

Although the heart is an automatic motor, it cannot govern its own speed. Two nerves and two body chemicals do that. The accelerator nerve and adrenalin (hormone of the adrenal glands) speed up the heart. The vagus nerve and acetylcholine (hormone produced by the vagus nerve) slow down the heart.

In certain cases of disease and poisoning, however, the heart behaves like a badly timed automobile engine. It goes into an uncontrollable quiver. Every fibre of the complex heart muscle twitches without any apparent relation to the twitching of other fibres. This condition is called fibrillation. When fibrillation concentrates around the auricles, it becomes a serious heart disorder. Fibrillation around the ventricles quickly ends in death.

Cardiologists have a hard time coping with auricular or ventricular fibrillation, primarily because they are not certain how the condition develops. Only positive factor known was that the vagus and accelerator nerve controls were involved. Last week Dr. Louis Herman Nahum, Yale associate physiologist, and H. E. Hoff, onetime Yale physiology instructor and now a Harvard medical student, set forth before the New Haven Medical Association a theory and a treatment based on new research.

In angina pectoris, in electric shock, in chloroform or benzol poisoning, a certain toxic factor is developed in the blood which upsets the heart's regular timing. From two first stages of disorganization the heart can ordinarily recover. But if something mental or physical excites the accelerator nerve or stimulates the adrenals to pour an excess of adrenalin into the blood, the ventricles begin to fibrillate. And shortly the heart tires and stops.

Overactivity of the vagus nerve is tied up with overactivity of the thyroid. Goitres, said Drs. Nahum and Hoff last week, "change the heart in such a way as to make it susceptible to overactivity of the vagus nerve. Some patients are naturally subject to vagus action. Some develop it reflexly from high blood pressure and it is probable that all hyper-thyroids are sensitive to the vagus nerve. In this way, overactivity of this nerve develops, which precipitates auricular fibrillation."

Digitalis is the only treatment for auricular fibrillation.

To prevent ventricular fibrillation and sure death, Drs. Nahum and Hoff advise elimination of poisons, physical disturbances and excitements; use of barbiturates or other drugs which reduce the heart's activity; administration of oxygen. In extremity, a surgeon might cut the nerves which cause the adrenal glands to excrete their exciting adrenalin. But drugstores now carry acetylcholine, the vagus hormone, with which a desperate doctor can often quiet ventricular fibrillation, set the heart pulsating smoothly again.

This file is automatically generated by a robot program, so reader's discretion is required.