Table 2. Studies demonstrating the prophylactic effect of beta blockers.

LVEF - left ventricular ejection fraction; LV - left ventricle; HF - heart failure; BB - beta-blockers; HER2 - human epidermal growth factor receptor 2

References	Design	Cases	Treatment aims	Diagnostic criteria	Conclusion
Kalay et al. [80]	Randomized controlled study	25 patients	Carvedilol vs. placebo	LVEF, systolic and diastolic	Prophylactic use of carvedilol in pts with anthracycline protects both systolic and diastolic functions of LV
Kaya et al. [81]	Prospective randomized controlled trial	45 patients with breast cancer	Nebivolol vs. placebo	Change in LVEF from baseline, N-terminal brain natriuretic peptide.	LVEF change; pre/post placebo: 66.6%/57.5%; nebivolol: 65.6%/63.8%. Nebivolol protects the myocardium against anthracycline-induced cardiotoxicity
Seitan et al. [82]	Follow-up study	920 patients with breast cancer	Beta-blockers	LVEF, HF incidence	Continuous use of BB lowers the incidence of HF in patients
Gulati et al. [83]	Randomized controlled study	130 women with breast cancer	Candesartan vs. metoprolol vs. candesartan+metoprolol	Change in LVEF on completion of adjuvant therapy	Mean LVEF % point reduction: placebo:2.6; candesartan:0.8; metoprolol:1.6. Concomitant treatment with candesartan protects against an early decline in LVEF
Pitkin et al. [84]	Randomized controlled study	33 petients with HER2-positive early breast cancer	Perindopril vs. bisoprolol vs. placebo	Change in LV volume and LVEF	No difference in the primary outcome
Cardinale et al. [23]	Clinical trial	201 patients with LVEF <45% due to anthracycline-induced cardiomyopathy	Enalapril vs. no treatment	Recovery in LVEF	Cardiotoxicity incidence control 25/58 (43%), enalapril 0/56 (0%)