Archive For November 30, 2016

RESTRICTIVE CARDIOMYOPATHY

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RESTRICTIVE CARDIOMYOPATHY

Restrictive cardiomyopathy is a rare heart muscle disease that may affect both ventricles and is characterized by small ventricular cavity size, diastolic dysfunction, and elevated ventricular filling pressures. Systolic function is usually normal, especially early in the coarse of the disease. Restrictive cardiomyopathy may result from various systemic disorders, as well as exposure to several…

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Myocarditis

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Myocarditis

Myocarditis is an inflammatory disease of the myocardium. Although associated with a number of infections and systematic diseases, myocarditis is most frequently the result of a viral infection, with coxsackievirus B and echovirus being the most frequently implicated infectious agents. However, any virus may replicate in the heart and induce myocardial inflammation. The true incidence…

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Principles of Cardiopulmonary Resuscitation

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Principles of Cardiopulmonary Resuscitation

Most cases of sudden cardiac death do not occur in the hospital and, thus, immediate medical therapy may not be available. Over two thirds of patients who suffer an out-of-hospital cardiac arrest die before ever reaching a hospital. Less than half of the remainder survive to hospital discharge. Basic cardiac life support(BCLS) performed by civilian…

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SYNCOPE

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SYNCOPE

Syncope is defined as the sudden, transient loss of consciousness and may be the result of a variety of cardiac and noncardiac conditions. Presyncope is a feeling of impending syncope without true loss of consciousness. Cardiovascular causes are responsible for the vast majority of cases and produce loss of consciousness by means of a drop…

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Heart Block

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Heart Block

Heart block refers to an impairment in impulse conduction. The block may occur at any point in the conduction system, although it is most commonly recognized at the level of the Av node or system. The incidence of heart block increases with a and may result from fibrosis of the AV infarction of the AV…

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VENTRICULAR RHYTHM DISTURBANCES

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VENTRICULAR RHYTHM DISTURBANCES

Ventricular premature complexes(VPCs) result from the spontaneous depolarization of the ventricular myocardium. The result a QRS complex that wide 120 has a bizarre morphology, and occurs earlier than expected. The repolarization phase is also abnormal and results in ST segment and T wave changes opposite the major deflection of the QRS complex. The AV node,…

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ATRIOVENTRICULAR RECIPROCATING ARRHYTHMIAS

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ATRIOVENTRICULAR RECIPROCATING ARRHYTHMIAS

Normally, the AV node is the only pathway that allows the wave of depolarization to conduct from the atria to the ventricles. However, anomalous bands of tissue( accessory pathways or bypass tracts) may exist and form an additional conduction pathway. The conductive properties of these bypass tracts differ from those Av of the node in…

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ATRIOVENTRICULAR NODAL(JUNCTIONAL) RHYTHM DISTURBANCES

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ATRIOVENTRICULAR NODAL(JUNCTIONAL)  RHYTHM DISTURBANCES

If the atrial heart rate falls sufficiently, the Av node will emerge as the dominant pacemaker at a rate of 40 to 60 beats/ min. This is termed a junctional escape rhythm. Occasionally, the junctional pacemaker may inappropriately overtake the atrial pacemaker for a single beat(premature junctional complex), for sustained periods of time at rates…

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ATRIAL RHYTHM DISTURBANCES

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ATRIAL RHYTHM DISTURBANCES

Atrial premature complexes(APCs) result from the premature discharge of nonsinus atrial pacemakers and generate P waves on the surface ECG that are distinct from those generated by the sinus node(Fig. 10-5B). Atrial premature complexes(APCs) result from the premature discharge of nonsinus atrial pacemakers and generate P waves on the surface ECG that are distinct from…

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Specific Arrhythmias SINUS NODAL RHYTHM DISTURBANCES

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Specific Arrhythmias SINUS NODAL RHYTHM DISTURBANCES

The sinus node is located high in the right atrium and depolarizes the atria in a superior-to-inferior direction, resulting in a P wave on the surface ECG that is positive in the inferior leads(I, III, avF) and negative in a VR. Normal sinus rhythm denotes a rhythm that originates from the sinus node and has…

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