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Ventricular Tachycardia

Ventricular Tachycardia or VT refers to any rhythm faster than 100 beats per minute arising distal from the bundle of His. The rhythm may arise from working ventricular myocardium and/or the distal conduction system. VT may cause important symptoms such as syncope, palpitations, and dyspnea. With a few exceptions, VT is associated with increased risk of sudden death. The most common setting for VT is ischemic heart disease, in which myocardial scar is the substrate for electrical reentry. It is often, but not always, associated with hemodynamic compromise, particularly if the left ventricle is impaired or the heart rate is especially fast. When sustained VT causes signs or symptoms of diminished perfusion, emergent treatment is necessary. In this essay I will discuss the pathophysiology, frequency, race, sex, age, history, and symptoms of ventricular tachycardia.
Pathophysiology is the study of the disturbance of normal mechanical, physical, and biochemical functions, either caused by a disease, or resulting from a disease or abnormal syndrome, or condition that may not qualify to be called a disease. In VT it is a general term that includes any rapid rhythm, faster than 100-120 beats per minute, arising in the ventricle. Regardless of the arrhythmia mechanism, the severity of clinical symptoms determines the urgency with which VT must be treated. During VT, cardiac output is reduced due to the rapid heart rate and lack of a properly timed or coordinated atrial contraction. Ischemia and mitral insufficiency may also contribute to hemodynamic intolerance. Hemodynamic collapse is more likely when underlying left ventricular dysfunction is present or with very rapid rates. Diminished cardiac output may result in diminished myocardial perfusion, worsening inotropic response, and degeneration to VF, resulting in sudden death.
The frequency of VT in the United States is not well quantified because of the clinical...