Pathophysiology, diagnosis and treatment of tachycardiomyopathy

IntroductIon Tachycardiomyopathies (TCMP) are an important cause of left ventricular (LV) dysfunction that should be recognised by physicians as they are potentially reversible and have a significant impact on morbidity and prognosis. They are classically defined as the reversible impairment of ventricular function induced by persistent arrhythmia. However, it is becoming increasingly evident that they can be induced by atrial and ventricular ectopy promoting dyssynchrony and indeed the term ‘arrhythmia-induced cardiomyopathy’ is emerging to describe the phenomenon. 2 A more current proposed definition highlights aetiology: ‘Atrial and/or ventricular dysfunction—secondary to rapid and/or asynchronous/irregular myocardial contraction, partially or completely reversed after treatment of the causative arrhythmia’ (figure 1). Two categories of the condition exist: the arrhythmia is the only reason for ventricular dysfunction (arrhythmia-induced), and another where the arrhythmia exacerbates ventricular dysfunction and/or worsens heart failure (HF) in a patient with concomitant heart disease (arrhythmia-mediated). The exclusion of underlying structural heart disease can be challenging as current imaging techniques, for example, MRI cannot easily identify diffuse fibrosis which may itself be primary or secondary to the effects of arrhythmia promoting ventricular wall dyskinesis and stretch or valvular regurgitation.