Lewis: Medical-Surgical Nursing, 7th Edition
Answer Guidelines for Case Studies in Textbook- Chapr 36: Nursing Management: Dysrhythmias
Dysrhythmia
1. J.M. is at risk for sudden cardiac death from ventricular tachycardia or fibrillation because the
frequent PVCs indicate continued electrical instability of the myocardium that caused the
initial ventricular tachycardia. Sudden cardiac death is also more common in those patients
with an ejection fraction of >40% and a history of ventricular dysrhythmias and myocardial
infarction.
1.
Amiodarone is used to control ventricular dysrhythmias that commonly lead to ventricular
tachycardia or fibrillation, such as premature ventricular contractions. Although J.M. was
successfully defibrillated once, the underlying myocardial ischemia and heart failure causing
the tachycardia are still present, indicating a need for drug therapy to control dysrhythmias
and maintain cardiac output.
2.
Continuous cardiac monitoring is the standard method of assessing the effectiveness of
antidysrhythmia drug therapy, but several other methods may also be used. An
electrophysiologic study (EPS), which is scheduled for J.M., involves introducing several
electrode catheters transvenously to the right side of the heart to induce dysrhythmias,
identify the mechanisms of dysrhythmias, and evaluate the effectiveness of treatment. A
signal-averaged ECG (SAECG) may also be used to identify the patient’s risk for complex
ventricular dysrhythmias and response to treatment. For ambulatory patients, a Holter
monitor, event monitors, and exercise treadmill testing may be used to evaluate dysrhythmias
and the effectiveness of their treatment.
3.
Rhythm strip interpretation: bradycardia (rate = 50) with unifocal PVCs. The serum potassium
level is significantly low (normal is 3.5 to 5.5 mEq/L [3.5 to 5.5 mmol/L]), and hypokalemia
may be a cause of PVCs. Treatment of the hypokalemia with intravenous potassium would
decrease his risk for life-threatening ventricular dysrhythmias. Serum cardiac markers are
negative indicating that J.M. did not suffer another myocardial infarction with this event.
Serum b-type natriuretic peptide (BNP) is elevated and supports the diagnosis of heart
failure.
4.
J.M. may be a candidate for an implantable cardioverter-defibrillator (ICD) because this
device is indicated to control life-threatening ventricular dysrhythmias in cardiac arrest
survivors, patients with recurrent sustained ventricular tachycardia, and individuals at risk for
sudden cardiac death.
Nursing diagnoses: decreased