Ventricular tachycardia in the absence of structural heart disease

### Learning objectives The earliest recorded description of ventricular tachycardia (VT) is credited to Sir Thomas Lewis in 19 091. VT is defined as a rhythm originating in the ventricles ≥3 beats duration, with a heart rate of ≥100 beats/minute.2 It is often associated with structural heart disease (SHD), from any disease process affecting ventricular myocardium, including acute or healed myocardial infarction and cardiomyopathies often associated with reduced ventricular ejection fraction and myocardial scar. Less frequently, VT occurs in the absence of SHD. These may be associated with a defined electrophysiological abnormality that is often genetic or may occur with no definable electrical or structural abnormality in which case they are often referred to as idiopathic ventricular arrhythmias (IVT). Detection and characterisation of underlying SHD and recognition of sudden cardiac death (SCD) risk is a critical component of management. In this article, we review salient features of various types of VTs seen in patients with structurally normal hearts, including some associated with inherited arrhythmia syndromes, and provide an overview of therapy. VT can be classified according to its duration and morphology (figure 1): Figure 1 Classification of ventricular tachycardia in the absence of structural heart disease.