We report two cases in which intra-aortic balloon pump (IABP) was used successfully as a bridge to cardiac resynchronization therapy (CRT) to treat patients with refractory systolic heart failure. The study was designed to assess the acute haemodynamic effects of IABP coupled with CRT using standard haemodynamic monitoring. In both cases, a marked elevation of V-wave in pulmonary capillary wedge pressure (PCWP) was shown, and a moderate-to-severe functional mitral regurgitation was observed. IABP and CRT resulted in a significant acute improvement in aortic pressure, PCWP, and V-wave amplitude compared with baseline measurements and IABP alone. These results provide a basis for studies examining the haemodynamic effects of IABP support associated with CRT in patients with heart failure refractory to medical therapy.