The present invention relates to compounds of Formula (Ia) and pharmaceutical compositions thereof that modulate the activity of the beta-3 adrenergic receptor. Compounds of the present invention and pharmaceutical compositions thereof are directed to methods useful in the treatment of a beta-3 adrenergic receptor-mediated disorder, such as, heart failure； cardiac performance in heart failure； mortality, reinfarction, and/or hospitalization in connection with heart failure； acute heart failure； acute decompensated heart failure； congestive heart failure； severe congestive heart failure； organ damage associated with heart failure； heart failure due to left ventricular dysfunction； heart failure with normal ejection fraction； cardiovascular mortality following myocardial infarction； cardiovascular mortality in patients with left ventricular failure or left ventricular dysfunction； left ventricular failure； left ventricular dysfunction； class II heart failure； class III heart failure； class IV heart failure； LVEF ＜ 40% by radionuclide ventriculography； LVEF £35% by echocardiography or ventricular contrast angiography； and conditions related thereto.本發明係關於調節β-3腎上腺素受體活性之式（Ia）化合物及其醫藥組合物。本發明之化合物及其醫藥組合物係針對適用於治療β-3腎上腺素受體介導之病症的方法，所述病症諸如心臟衰竭；心臟衰竭時之心臟效能；與心臟衰竭有關之死亡、再梗塞及/或住院；急性心臟衰竭；急性失代償心臟衰竭；充血性心臟衰竭；重度充血性心臟衰竭；與心臟衰竭相關之器官損傷；因左心室功能障礙所致之心臟衰竭；射血分數正常之心臟衰竭；心肌梗塞後的心血管死亡；患有左心室衰竭或左心室功能障礙之患者的心血管死亡；左心室衰竭；左心室功能障礙；II類心臟衰竭；III類心臟衰竭；IV類心臟衰竭；藉由放射性核種心室顯像術LVEF＜40%；藉由超音波心動描記術或心室對比血管造影LVEF≤35%；及與其相關之病狀。
