Arrhythmias Flashcard 10

C. Rationale: Sinus bradycardia is a rhythm that has fewer than the normal number of impulses arising from the sinoatrial node at a rate of < 50 bpm.

D. Rationale: The vital decision point in managing bradyarrhythmia is determining whether a patient is stable or unstable. Patients with symptomatic bradyarrhythmia’s will have symptoms such as palpitations, dyspnea, and light-headedness. Unstable patients will show these symptoms plus altered sensorium; compromised perfusion, oxygenation, and ventilation; and shock. The presence of unstable symptoms means that cardiac arrest is imminent.

B. Rationale: Bradycardia may be caused by antiarrhythmics (quinidine and amiodarone) and antihypertensive agents (methyldopa).

A. Rationale: AV nodal blocking agents (i.e., beta-blockers, calcium channel blockers, digoxin, adenosine) should be avoided in patients with an irregular wide complex tachycardia. If the rhythm is pre-excited atrial fibrillation, these drugs may cause a paradoxical increase in the heart rate (ventricular response).

C. Rationale: The Valsalva maneuver is one of the vagal maneuvers that make up the preferred initial management of paroxysmal supraventricular tachycardia (PSVT). The effect of these maneuvers is temporary unless the underlying cause of PSVT is treated.

C. Rationale: Adenosine can terminate wide-complex tachyarrhythmias only if the ECG tracing is regular and monomorphic.

A. Rationale: Emergency cardiovascular care guidelines suggest that atropine remains the first-line drug treatment for acute symptomatic bradycardia. Transcutaneous pacing and dopamine may be used if atropine is not effective. (ACLS Case: Symptomatic Bradycardia)

B. Rationale: Synchronized cardioversion is the mainstay of treatment for unstable patients that have tachyarrhythmias with a pulse.

B. Rationale: In recent studies, lidocaine has now become a second-line antiarrhythmic therapy for monomorphic ventricular tachycardia.

A. Rationale: Cardiac output is caused by myocardial contractility and heart rate. Heart rate is severely compromised in symptomatic bradyarrhythmia, and the hypoxemia in these patients is caused by ineffective cardiac output.