High-Pressure Heart Surgery

Not long ago I watched a delicate heart operation. It was performed in a hermetically sealed high pressure chamber at the Moscow Research Institute for Clinical and Experimental Surgery.

The operated man was 48 years old. He had been hardly able to move because he was suffering from a serious congenital valve defect.

Now this operation is considered not a very complex one. But in this patient there was a serious risk of blood clotting in the brain.

The risk became quite insignificant when the operation was performed in the high-pressure chamber. At normal air pressure the amount of oxygen in the patient’s blood remains unchanged even if he breathes in pure oxygen. In a pressure chamber the oxygen amount in the blood increases considerably. The oxygen prevents dangerous after-effects in many parts of the body, including the brain cells, which are particularly delicate. In a pressure chamber the surgeon is able to operate with greater freedom on vital organs such as the brain, heart and blood vessels.

But it is very hard to work under high pressure. When operations are performed at seven or eight atmosphere pressures, the operation can only last two and a half hours. The personnel in the chamber have to be changed.

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Arrhythmias

Definition: An arrhythmia is any disorder of heart rate or rhythm.

Alternative Names: dysrhythmias; abnormal heart rhythms.

Causes, incidence, and risk factors: Arrhythmias are caused by a disruption of the normal electrical conduction system of the heart. Normally, the four chambers of the heart (two atria and two ventricles) contract in a very specific, coordinated manner.

The signal for the heart to contract in a synchronized manner is an electrical impulse that begins in the sinoatrial node, which is the body’s pacemaker. The signal leaves the sinoatrial node and travels through the two atria, stimulating them to contract. Then the signal passes through another node, and finally travels through the ventricles and stimulates them to contract in synchrony.

Problems can occur anywhere along the conduction system, causing various arrhythmias. There can be a problem in the heart muscle itself, causing it to respond differently to the signal, or causing the ventricles to contract independently of the normal conduction system.

Arrhythmias include tachycardias, bradycardias, and “true” arrhythmias. Arrhythmias can be life-threatening if they cause a severe decreased for more than a few seconds, blood circulation is essentially stopped, and organ damage (such as brain damage) may occur within a few minutes.

People at higher risk for arrhythmias and complications from arrhythmias include the following:

those who have a history of cardiac conditions such as coronary artery disease or heart valve disorders;

those with imbalances of blood chemistries;

Arrhythmias can also be caused by some substances or drugs. These include beta blockers, psychotropic medication, caffeine, amphetamines, and cocaine. Sometimes antiarrhythmic medications – prescribed to treat one type of arrhythmia – can actually cause another type of arrhythmia.

Prevention: Methods of preventing other heart diseases (e.g., coronary artery disease) may decrease the likelihood of developing an arrhythmia. These include not smoking; eating well-balanced, low-fat diet; and exercising regularly.