Sinus bradycardia is a rhythm that originates from the sinoatrial (SA) node with a rate of < 60 beats per minute. The SA node is the heart's normal pacemaker, and sinus bradycardia may be normal in some patients such as conditioned athletes. In these cases, patients will have a resting heart rate of < 60 per minute, but will not exhibit any other symptoms. Other times, sinus bradycardia may be due to organic heart disease such as coronary artery disease, cardiomyopathy, or myocarditis, resulting in symptomatic sinus bradycardia. Therefore, treatment largely depends on whether the patient is symptomatic (unstable) or not. An unstable patient is anyone who shows signs of poor perfusion, such as altered mental status, diaphoresis, dizziness, or syncope. A stable patient may be monitored closely. Initial pharmacologic treatment for an unstable patient is atropine. Since this patient presents with both a syncopal episode and diaphoresis, she is unstable and atropine is the appropriate therapy. After an initial dose of atropine, infusions of epinephrine or dopamine may also be considered, and for more emergent cases transcutaneous pacing may be necessary. Adenosine
A. is the treatment for supraventricular tachycardia, not bradycardia, and so is not appropriate for this patient. Amiodarone
B. is used to treat dysrhythmias, such as ventricular tachycardia, not a sinus rhythm. Amlodipine
C. is a calcium channel blocker that helps to control heart rate and blood pressure
