NCC Neonatal Nurse Practitioner (NNP) Practice Tests & Test Prep by Exam Edge - Features

Correct Answer:

premature ventricular contractions (pvcs) are extra heartbeats that begin in one of the ventricles of the heart. these beats disrupt the regular heart rhythm, sometimes causing a noticeable sensation of a skipped or extra beat in the chest. while generally benign, pvcs can be symptomatic of underlying heart conditions or other factors. here is an expanded explanation on potential causes of pvcs, focusing on the options provided in the question.

**digoxin toxicity** digoxin toxicity can cause premature ventricular beats. digoxin is a medication used to treat heart conditions such as atrial fibrillation and heart failure. however, at toxic levels, digoxin increases the automaticity of ventricular cells (making them more likely to initiate impulses) and can lead to various arrhythmias, including pvcs. this occurs because digoxin inhibits the sodium-potassium atpase pump, leading to an increase in intracellular calcium, which enhances the excitability of heart tissue.

**hypoxia** hypoxia refers to a deficiency in the amount of oxygen reaching the tissues. it can be a direct trigger for pvcs as the heart muscle requires a consistent supply of oxygen to function properly. when oxygen levels are low, it can alter the electrolyte balance and lead to abnormal electrical activity in the ventricles, manifesting as premature ventricular beats. hypoxia may result from respiratory disorders, severe anemia, or acute events such as pulmonary embolism.

**surgical procedures** surgery, especially cardiac surgery, can induce pvcs. the trauma from surgical manipulation of the heart or surrounding structures can provoke irritation or inflammation in the ventricular muscle, leading to abnormal electrical impulses. furthermore, the stress of surgery, combined with other factors like anesthesia, can enhance sympathetic stimulation of the heart, which might also contribute to the occurrence of pvcs.

**irritation caused by an invasive catheter** the use of invasive catheters, such as those inserted during cardiac catheterization or electrophysiological studies, can mechanically irritate the heart muscle, particularly the ventricles. this irritation can provoke ectopic beats or pvcs. the physical presence of the catheter, along with any manipulation during the procedure, disrupts the normal electrical pathways, potentially triggering premature beats.

in conclusion, all  listed factors—hypoxia, surgical procedures, and digoxin toxicity—are also well-documented causes of pvcs. understanding the specific cause is crucial for determining the appropriate management strategy for pvcs, which might range from observation and monitoring to addressing the underlying cause or direct treatment of the arrhythmia.