Electrically unstable heart

Although death may be attributable to many tmderlying conditions, the final common pathway remains the cessation of the heart electrical activity. With hospitalized patients, cardiac arrest is usually manifested by ventrieular fibrillation, from which the patient may or may not be resuscitated. Sudden eardiae death, which claims over 350,000 lives annually in the United States, results from abrupt disruption of heart rhythm, also primarily in the form of ventricular fibrillation. Death in those instances is due not to extensive cardiac injury, but rather, to transient triggers that impinge on the electrically unstable heart (65-67). Identification of individuals at risk for sudden cardiac death remains a major objective in cardiology. Similarly, the specific mechanism linking ambient air particle exposure to death is unknown. 

Drying, usually by physical methods, is one of the most common unit operations in both laboratory or industrial scale process chemistry, and since heating is usually employed to remove volatiles, thermally unstable materials may decompose if overheated. As a light-hearted example, when a faulty oven thermostat led to overheating of mercuric thiocyanate, a monstrous Pharaoh s serpent resulted. Drying moist cadmium propionate in an electric oven led to explosive ignition of the diethyl ketone vapour produced as an unforeseen by-product. Drying 3,5-dinitro-2-toluamide had more serious consequences. 

In synchronized cardioversion, an electric current is delivered to the heart to correct an arrhythmia. This procedure may be done electively in a stable patient with recurrent atrial fibrillation or urgently in an unstable patient with such arrhythmias as PSVT, atrial flutter, atrial fibrillation, and VT with a pulse. 

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