**5. Therapy**

Therapeutic approach to the tachycardia-induced cardiomyopathy includes two steps: 1. tachyarrhythmia correction as it represents causal therapeutic intervention and 2. heart failure treatment.

Due to the potential reversibility of hemodynamic and structural changes in tachycardiainduced cardiomyopathy, all efforts should be made to achieve **heart rate correction or appropriate rate control.** Rhythm or rate control may be achieved using both pharmacological and non-pharmacological tools. Depending on the type of arrhythmia and presence/absence of concomitant structural heart disease, various antiarrhytmic drugs may be used to terminate the arrhythmia or to achieve adequate rate control. Especially, betablockers and class III antiarrhythmics play an irreplaceable role regarding this treatment. It is very important to avoid drugs with higher pro-arrhythmic effect (e.g. flecainide) in the presence of systolic dysfunction or drugs that may contribute to further progression of systolic dysfunction (e.g. disopyramide). Most arrhythmias that lead to tachycardia-induced cardiomyopathy are currently treatable using catheterization ablation, success rate of which reaches 60–90% depending on the type of arrhythmia. This therapeutic approach should be therefore consid‐ ered as a first-line treatment in the absence of contraindication.

In atrial fibrillation, rate and rhythm control strategy have been shown to be comparable with respect to quality of life, mortality or stroke rate [64, 69]. The decision to favor rhythm control over rate control should thus be made on an individual basis, and discussed with the patient [70]. In case rate control strategy is chosen, repeated long-term ECG monitoring is instrumental to decide whether the selected treatment is appropriate and ensures acceptable rate control (strict rate control requires 60–80 bpm at rest and 90–115 bpm at moderate exercise; lenient rate control requests resting rate < 110 bpm). Atrial arrhythmias are often refractory to antiarrhythmic drugs and an acceptable rate control may be then achieved only with higher doses of AV nodal blocking agent. In such cases, catheter ablation is an option. By other supraventricular tachyarrhythmias, which lead to tachycardia-induced cardiomyopathy, restoration of sinus rhythm is usually preferred. Rhythm correction may be achieved through either pharmacological or electrical cardioversion or (preferably) via catheter ablation of the arrhythmia in these patients.

In rare cases, failing to restore sinus rhythm (even using catheter ablation) and to achieve adequate ventricular control, an ablation of AV node with insertion of a permanent pacemaker may be considered. Because of the present ventricular dysfunction prior to pacemaker insertion, biventricular systems are usually favored [71].

**Treatment of heart failure** symptoms due to tachycardia-induced cardiomyopathy includes standard regimen and drug spectrum as in heart failure of other origin, i.e. ACE inhibitors, beta-blockers, angiotensin-receptor blockers, diuretics and digoxin.
