Mr James Hodges, 73 years of age, is brought to the hospital by his wife and admitted to the cardiology unit. As a nursing student, your clinical facilitator has allocated you to care for Mr Hodges. He has a history of hypertension and hyperlipidaemia. He is on perindopril 5 mg daily and atorvastatin 10 mg daily.
Subjective data:
Mr Hodges describes feeling his heartbeat as fast and pounding; he feels fatigued and describes chest discomfort.
Objective data:
Temperature: 36.6°C, pulse: 120 beats per minute (bpm) with an irregular rhythm, blood pressure (BP): 140/90 mmHg, respiratory rate: 20 breaths per minute, SpO2 (oxygen saturation measured by pulse oximetry): 98% on room air. An electrocardiogram (ECG) is performed and shows atrial fibrillation (AF) with a rapid ventricular response (RVR). Blood tests show normal thyroid function tests, no rise in troponin levels, a serum potassium level of 3.1 mmol/L, and a magnesium level of 0.65 mmol/L.
The treating team deliberates whether to provide digoxin or amiodarone. A decision is made to provide a loading dose of 300 mg of amiodarone intravenously over 30 minutes, followed by 900 mg as an infusion over the next 24 hours. The ventricular rate normalises after 1 hour, and the AF resolves to normal sinus rhythm (NSR) at the end of the 24-hour infusion.
At this point, the amiodarone is stopped. During his cardiac monitoring, Mr Hodges experiences AF for shorter intervals, although this reoccurs every few hours. He is diagnosed with paroxysmal AF. 48 hours after his initial admission, Mr Hodges is prescribed bisoprolol and warfarin. He is also advised to continue with his usual perindopril and atorvastatin medications.
1. Describe the pathophysiological basis for the subjective and objective data in relation to pharmacological concepts.
2. The treating team checked the results of his baseline thyroid function test while on amiodarone. Explain why this test is necessary.