Heart failure is a physiological state in which cardiac output is insufficient to meet the needs of the body and lungs. Therefore, the sympathetic nervous system become overactive and provides a crucial level of compensation for the failing heart. To remove this by using a beta blocker would risk precipitating or exacerbating heart failure. Consequently, Metoprolol impairs the patient's ability to increase heart rate when needed to maintain cardiac output. Furthermore, Metoprolol is a beta-selective adrenergic receptor blocker, which works by reducing the heart rate and cardiac output, so the use of beta blockers in patients with heart failure should be monitored carefully (Feldman,
