NCLEX-PN

●​ Torsades de Pointes Torsades de pointes

It is characterized by a long QT interval and upward and downward deflections of QRS complexes. The rate can range from 150 to 250 beats per minute , and the rhythm can be regular or irregular. P waves are often not visible, and PR intervals are not measurable. Causes include tricyclic antidepressant overdose, hypomagnesemia, and hypokalemia. It may resolve spontaneously but can progress to ventricular fibrillation if left untreated. Symptoms may include loss of consciousness, shortness of breath, chest pain, nausea, and dizziness. Treatment includes CPR and ACLS protocols, magnesium sulfate administration, cardioversion, and correction of underlying causes.

●​ Heart Block (Atrioventricular Block) Heart block is a conduction disturbance that affects the transmission of electrical impulses between the atria and ventricles. There are several types, including first-degree atrioventricular block, second-degree atrioventricular block (Type I and Type II), and third-degree heart block (complete heart block). a.​ First Degree Atrioventricular Heart Block ○​ PR interval >0.20 seconds. ○​ All P waves followed by QRS complexes. ○​ Causes : AV node dysfunction, myocardial infarction, myocarditis, electrolyte disorders, medications (e.g., beta-blockers, cardiac glycosides, calcium channel blockers, cholinesterase inhibitors).

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