Diagnosis of specific arrhythmias, although often straightforward (eg, clear from the ECG), sometimes requires more detailed evaluation, including detailed history, physical examination, and sometimes ancillary testing. If the specific arrhythmia cannot yet be identified, arrhythmias can still be divided into one of the following categories:
Wide-complex tachycardia (QRS > 0.12 msec)
Narrow complex tachycardia
Bradycardia
Patients with arrhythmias may also be hemodynamically stable or unstable (ie, poorly perfused, as with hypotension, suspected myocardial ischemia, or altered consciousness). Pending diagnosis of the specific arrhythmia, patients who are hemodynamically unstable or need urgent treatment can be treated with the following temporizing measures:
Tachycardia with hemodynamic instability: Cardioversion
Wide complex tachycardia with hemodynamic stability: Treat as for ventricular tachycardia
Narrow complex tachycardia with hemodynamic stability: Trial of adenosine, a nondihydropyridine calcium antagonist (verapamil or diltiazem), or possibly IV beta-blockerNarrow complex tachycardia with hemodynamic stability: Trial of adenosine, a nondihydropyridine calcium antagonist (verapamil or diltiazem), or possibly IV beta-blocker
Bradycardia: Transcutaneous pacing, atropine, and/or isoproterenolBradycardia: Transcutaneous pacing, atropine, and/or isoproterenol
Approach to Cardiac Arrhythmias
