A cardiac arrest is quite a different diagnosis than that of a heart attack.

Blood vessel dilators and constrictors: Lidocaine, a local anesthetic has dual properties. It acts as a vasodilator or a vasoconstrictor depending on the sight and type of injection. Nitroglycerin is a blood vasodilator - a drug that opens the blood vessel by relaxing the muscular wall of the blood vessel. Nitroglycerin is usually given by pill under the tongue for rapid uptake or intravenously to prevent blood vessel spasm and to minimize the area of damage from the heart attack.

When paramedics are call to a life threatening situation or accident they rely on lidocaine in combination with other drugs to stabilize the injured until they are passed off to E.R. Lidocaine has gained the trust and safety properties of this agent. One must understand there is a clinical difference between a heart attack and cardiac arrest. In a word, there is more time to deal with a heart attack victim as opposed to a one who suffered cardiac arrest. Paramedics are never with out this drug because of its efficacious properties.

Clot busters. Most heart attacks are caused by a blood clot blocking a coronary artery. Using thrombolytic agents or "clot busters" that can break down blood clots and restore blood flow through the artery can limit heart muscle damage. Medications, if given early, also can be effective in reopening arteries. Clot-dissolving medications, also called thrombolytic agents or clot-busters, can open 80 percent of the blocked arteries within 90 minutes. There are many of these agents from which clinicians can use depending on the situation of the patient.

The most commonly used clot-dissolving drugs are tissue plasminogen activators (Activase and Retavase), streptokinase (Streptase and Kabikinase) Inohep and anistreplase (Eminase); all are given intravenously. The earlier these drugs are given, the better the chance of opening the artery quickly. If these drugs are given too late (more than 6 hours after the onset of chest pain), most of the damage to the heart muscle has already occurred.

There is another class of vasodilators, which are given orally after a heart attack to improve the heart muscle healing process. These medications reduce the stress on the heart, thereby allowing damaged muscles to recover.

Opening the artery quickly. If these drugs are given too late (more than 6 hours after the onset of chest pain), most of the damage to the heart muscle has already occurred. Clot-dissolving drugs may be combined with antiplatelet agents, such as aspirin and ReoPro, or anticoagulants, such as heparin and Coumadin. By reducing the tendency of blood platelets to clump and initiate clot formation, antiplatelet drugs lessen the possibility that the artery will reclose and improve chances of survival. An anticoagulant, such as heparin, often given intravenously in the hospital, thins the blood to prevent blood clots and to maintain an open artery during the initial 24 hours after a heart attack. The most serious complication associated with clot-dissolving drugs is excessive bleeding. A small number of patients who receive clot-busting drugs for a heart attack will experience some spontaneous bleeding. Such bleeding is most serious when it occurs in the brain.

A cardiac arrest , As reported what Michael Jackson suffered, also known as cardiopulmonary arrest or circulatory arrest, is the abrupt cessation of normal circulation of the blood due to failure of the heart to contract effectively during the pumping stage.

A cardiac arrest is different from (but may be caused by) a heart attack or, where blood flow to the still-beating heart, is interrupted as in cardiogenic shock. Cardiogenic shock is based upon an inadequate circulation of blood due to primary failure of the pumping valves (ventricles) of the heart to function. To put it bluntly the muscular integrity of the heart has failed due to possibly atrophy. Since this is a category of shock there is insufficient muscle mass tissue (i.e. the heart) to meet the required demand for oxygen and nutrients. This leads to cell death from oxygen starvation and nutrient starvation (e.g. hypoglycemia). Because of this it may lead to cardiac arrest.

"Arrested" blood circulation prevents delivery of oxygen to all parts of the body. Cerebral lack of oxygen supply to the brain causes victims to lose consciousness and to stop breathing, although breathing is abnormal or characterized as shallow may still occur. Brain injury is likely if cardiac arrest is untreated for more than 5 minutes.

by : Haynes Darlington M.SC.PharmD.
Source : www.amazines.com

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