**4. Potential deleterious effects of pharmacological therapy**

Understanding and identification of drug deleterious effects are also another important issue for management consideration. Digoxin's ability to reduce heart rate and improving LV function is very tempting; however, digoxin's potential deleterious effects such as arrhythmogenic potential, narrow therapeutic window, increased sympathetic activity, and risk for serious drug interaction. A meta-analysis of nonrandomized trials showed digoxin used in HF and AF is associated with an increased risk of all-cause mortality [15]. Moreover, the use of pharmacological rhythm control also brings risk. Amiodarone carries the risk of thyroid, pulmonary, and hepatic toxicity. Dofetilide therapy is also known for prolonging QT interval and higher rate of torsade de pointes [45, 46].

## **5. Catheter ablation vs pace and ablate**

Biventricular pacing was found to be superior to right ventricular pacing after atrioventricular-node ablation [47]. However, PABA-CHF trial has shown that CA for AF provides superior morphological and functional improvements compared with atrioventricular-node ablation with biventricular pacing in patients with HF who had drug-refractory AF [20].

#### **6. Catheter ablation strategy**

The improvement in LVEF observed following CA may largely be dependent on successful rhythm restoration, rather than the mode of restoration, which enables regular ventricular filling time and coordinated atrial contraction [46]. CA by pulmonary vein isolation (PVI) is proven as the best technique for AF ablation, as no proven benefit shown by additional ablation.

After Haissaguerre et al. found that radiofrequency ablation on PV is efficient in treating AF in 1998, no additional ablation technique (posterior wall ablation, linear lines or ablation of complex fractional aytrial electrograms) has been proven consistently to improve ablation efficacy; however, additional ablation can be done up to the operator's discretion. Future research endeavors should be performed into the field of high-power short duration, pulsed field ablation, and hybrid/convergent AF ablation strategies in patients with AF and HF [11, 48].
