NCLEX-PN

●​ Premature Atrial Contractions (PACs) : These occur when atrial depolarization occurs prematurely, followed by a compensatory pause. The heart rate is typically normal, rhythm irregular due to the pause, P waves precede each QRS complex but may not be uniformly shaped, PR interval is within the normal range (0.12-0.20 seconds), QRS complexes are uniform (0.06-0.12 seconds). PACs can result from various causes, including hypertension, ischemia, hypoxia, electrolyte imbalances, medications (e.g., digitalis), stress, fatigue, stimulant use (e.g., caffeine, nicotine), valve abnormalities, infectious diseases, or may occur in clients without underlying cardiac conditions. Symptoms are often palpitations and a sensation of a "missed beat." Treatment depends on symptoms and may involve addressing underlying causes or medications like calcium channel blockers and beta-blockers.

●​ Supraventricular Tachycardia (SVT): This includes all tachyarrhythmias with a heart rate exceeding 150 beats per minute. The atrial and ventricular rates range from 150 to 250 beats per minute, rhythm is regular, P waves may not be visible due to their proximity to the QRS complex, PR interval is not discernable, QRS complexes are uniform (0.06-0.12 seconds). Risk factors include atherosclerosis, hypokalemia, hypoxia, stress, and stimulant use. Symptoms may include polyuria, palpitations, syncope, dizziness, chest tightness, diaphoresis, fatigue, and shortness of breath. Complications may include heart failure. Treatment options include vagal maneuvers (e.g., Valsalva maneuver, coughing), oxygen supplementation, medications (e.g., adenosine, cardioversion), and addressing underlying causes.

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