Entry 5

Coronary Occulsion and Conducting System of Heart

            The normal electrical conduction of the heart allows electrical propagation to be transmitted from the Sinoatrial Node (SA Node), the pace maker of the heart, through both atria to the Atrioventricular Node (AV Node). Baseline physiology allows the further propagation from the AV node to the purkinje fibers and repective bundle branches and fascicles. The SA and AV nodes stimulate the myocardium and proper, time ordered stimulation of the myocardium allows efficient contraction of all four chambers of the heart.

            Damage to the conducting system of the heart, often a result from ischemia, improper blood flow, caused by coronary artery disease. This produces disturbance in the myocardium, and since the anterioter intraventricular branch of the left coronary artery and the right coronary artery supply the AV and/or SA node a heart block could occur. There are several circumstances that could affect the AV and/or SA. When the AV node is affected the ventricles will begin to contract independently at their own rate but allowing the atria to contract at a normal rate. Under these circumstances a cardiac pacemaker would be implanted to control the rate of the ventricles.

http://en.wikipedia.org/wiki/Electrical_conduction_system_of_the_heart

 

Coronary Angioplasty

            Angioplasty is the surgical technique of mechanically widening a narrowed or obstructed blood vessel. An empty and collapsed balloon catheter, guided by a wire, is passed into the narrowed location and then inflated to a fixed size using water pressure normal to blood pressure. The balloon is responsible for crushing the fatty deposits and opening the blood vessel allowing for improved flow. The balloon is then collapsed and withdrawn.

            Percutaneous transluminal coronary angioplasty is a surgical approach for the treatment of stenotic coronary artery disease, and is caused by cholesterol-laden plaques that form due to atherosclerosis. Access to these blood vessels is gained through the femoral artery called percutaneous access. Real time X-ray visualization is used to guide the guiding catheter, which is pushed through the femoral artery ascending until it reaches the coronary artery that is infected. The guide wire is then pushed through the guiding catheter and this serves as the pathway for the balloon. A pharmaceutical aid called Heparin is used to thin the blood and reduce blood clots to help maintain blood flow.

http://en.wikipedia.org/wiki/Percutaneous_coronary_intervention

Fibrillation of Heart

Fibrillation is the rapid, irregular, and unsynchronized contraction of muscle fibers. Two types of cardiac fibrillation exist: artial fibrillation and ventricular fibrillation. During atrial fibrillation the normal rhythmical contractions of the atria are replaced by rapid irregular and uncoordinated twitching of different parts of the atrial walls. During ventricular fibrillation the ventricular contractions are replaced by rapid irregular twitching movements; stop the pumping action of the heart.

Artial fibrillation is usually easily treated with anticoagulation drugs and sometime with a conversion to normal sinus rhythm. The use of drugs are using sufficient in controlling either rate or rhythm, different. Ventricular fibrillation is the most serious condition because it inhibites the proper pumping of blood by the heart. One treatment of V-fib uses an electric defibrillator which can reverse the fibrillation by an electric discharge of direct current to the heart. This method is not always successful. Another treatment method is the implantation of a cardioverter defibrillator, which has been shown to be beneficial. 

http://en.wikipedia.org/wiki/Fibrillation