**7.1 Medical management**

CHF medical management for the ccTGA patient with systemic RV has been extrapolated from CHF therapy for LV failure. This primarily includes β-adrenergic receptor blockade (βblockers), diuretics and afterload-reducing agents with an angiotensin-converting enzyme (ACE) inhibitor (Winter et al., 2009). Digoxin may also be useful for its inotropic and antiarrhythmic effects. Angiotensin receptor blockade with losartan was evaluated in a multicenter, randomized, placebo-controlled clinical trial by Dore and colleagues (2005) but found to have no improvement on exercise capacity and no reduction in neurohormonal levels in patients with systemic right ventricles. Overall, evidence-based therapy for optimal CHF treatment in patients with systemic RV is lacking. Beyond medication, cardiac resynchronization has emerged as a therapy for patients with impaired systemic RV function and widened QRS morphology on ECG. Increased QRS duration as a result of bundle branch block or conventional pacemaker is typically greater than 120-140 ms with some patients having QRS duration >200 ms. Such electromechanical dyssynchrony creates inefficiency in ventricular ejection, whereas restoring synchrony has been shown to decrease QRS duration with improvement in RV filling time, ejection fraction, and overall CHF symptoms (Diller et al., 2006; Janousek et al., 2004; Kordybach et al., 2009). Takemoto et al. (2010) reports the use of transvenous permanent para-Hisian pacing in an 8 year old with ccTGA. Restoration of cardiac synchrony decreased the QRS duration from 198 ms to 94 ms, decreased interventricular conduction delay from 137 ms to 37 ms, and improved the patient's CHF symptoms from NYHA (New York Heart Association) class III to NYHA class II over a period of 6 months. Limitations in cardiac resynchronization therapy include difficulty in percutaneous lead delivery, although this has successfully been accomplished even in ccTGA cases of dextrocardia (Malecka et al., 2010).
