[Tachycardias. What must the emergency physician know?]

Clinical characteristics and the surface electrocardiogram (ECG) are important diagnostic tools for patients with tachycardias. Tachycardias are characterized by a ventricular heart rate > 100/min and have been divided into those with narrow (QRS width < 0.12 s) or wide QRS complex tachycardias (QRS width ≥ 0.12 s). In broad complex tachycardias, AV dissociation, negative or positive concordant pattern in V(1)-V(6), a notch in V(1) and qR complexes in V(6) in tachycardias with left bundle-branch block morphologies are findings indicating ventricular tachycardia (VT). In addition, an R/S relation <1 in V(6) favors VT when right bundle-branch block tachycardia morphologies are present. By analyzing the surface ECG in the right way with a systematic approach, the specificity and sensitivity of correctly identifying supraventricular tachycardia or VT can be > 95%. Therapeutic options in supraventricular or ventricular tachyarrhythmias are preferentially adenosine, ajmaline, amiodarone, and adrenaline. If antiarrhythmic drugs fail, electric cardioversion using short-acting anesthesia is recommended.