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 | Definition 
 
        | a disruption in cardiac rate or rhythm. |  | 
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 | Definition 
 
        | of heart cells to generate an action potential without an external stimulus. |  | 
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 | Definition 
 
        | a period of cardiac muscle relaxation (diastole) followed by a period of contraction (systole) in the heart.prothrombin;  thrombin then breaks down fibrin threads from fibrinogen to form a clot.formation of thrombin from prothrombin;  thrombin then breaks down fibrin threads from fibrinogen to substances formed in the liver – many requiring vitamin K – that react in a cascading sequence to cause the formation of thrombin from prothrombin;  thrombin then breaks down fibrin threads from fibrinogen to form a clot. |  | 
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        | Term 
 | Definition 
 
        | property of heart cells to rapidly conduct an action potential of electrical impulse. |  | 
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 | Definition 
 
        | an electrical tracing reflecting the conduction of an electrical impulse through the heart muscle; does not reflect mechanical activity. |  | 
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        | Term 
 | Definition 
 
        | the normal pacemaker of the heart; composed of primitive cells that constantly generate an action potential. |  | 
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        | Term 
 
        | Starling’s law of the heart |  | Definition 
 
        | addresses the contractile properties of the heart: the more the muscle is stretched, the stronger it will react, until it is stretched to a point at which it will not react at all. |  | 
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        | Term 
 | Definition 
 
        | discomfort with respirations, often with a feeling of anxiety and inability to breathe, seen with left-sided heart failure. |  | 
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        | Term 
 | Definition 
 
        | rapid and shallow respirations, seen with left-sided heart failure. |  | 
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        | Term 
 | Definition 
 
        | end result of vessel blockage in the heart; leads to ischemia and then necrosis of the area cut off from the blood supply; it can heal, with the dead cells replaced by scar tissue. |  | 
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        | Term 
 | Definition 
 
        | characterized by progressive narrowing of coronary arteries, leading to a decreased delivery of oxygen to cardiac muscle cells; leading killer of adults in the western world. |  | 
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        | Term 
 | Definition 
 
        | drop in blood flow through the coronary arteries caused by a vasospasm in the artery, not by atherosclerosis. |  | 
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        | Term 
 | Definition 
 
        | pain due to the imbalance of myocardial oxygen supply and demand that is relieved by rest or stoppage of activity. |  | 
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        | Term 
 | Definition 
 
        | episode of myocardial ischemia with pain due to the imbalance of myocardial oxygen supply and demand when the person is at rest. |  | 
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        | Term 
 | Definition 
 
        | faster-than-normal heart rate (usually greater than 100 beats/min). |  | 
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        | Term 
 | Definition 
 
        | cardiac arrhythmia originating within the ventricles; isolated ventricular contractions are referred to as premature ventricular contractions. |  | 
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        | Term 
 | Definition 
 
        | any irregularity in rate and rhythm which arises in the atrium. |  | 
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 | Definition 
 
        | an abnormal enlargement of the heart. |  | 
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        | Term 
 | Definition 
 
        | substances effecting the rate or rhythm of the heartbeat. |  | 
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        | Term 
 | Definition 
 
        | substances that alter the force or energy of muscular contractions |  | 
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 | Definition 
 
        | a condition in which a problem with the structure or function of the heart impairs its ability to supply sufficient blood flow to meet the body’s needs. |  | 
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        | Term 
 | Definition 
 
        | the circulation of the blood in the blood vessels of the heart muscle. |  | 
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