As part of the 2010 focused update of ESC guidelines on device therapy in heart failure, the guidelines on pacemakers in the treatment of heart failure were renewed. A new feature is that cardiac resynchronization therapy (CRT) is indicated for New York Heart Association (NYHA) class III and IV irrespective of the presence of left ventricular dilatation and specified for NYHA class IV (patient ambulatory, stable, life expectancy >6 months). Furthermore, NYHA class II (but not class I) has been added when there is left bundle branch block and QRS duration ≥150 ms. CRT is also indicated for patients in NYHA class III-IV with permanent atrial fibrillation and heart failure [left ventricular ejection fraction (LVEF) ≤ 35%] when QRS is ≥ 130 ms and ventricular rate has slowed either spontaneously or by AV node ablation. In patients with heart failure (NYHA class II-IV, LVEF ≤ 35%) who need a pacemaker for AV block, CRT is generally indicated to avoid progression of heart failure caused by right ventricular stimulation, also in cases of intrinsic QRS <120 ms. For patients with terminal heart failure who are not eligible for heart transplantation, treatment with a left ventricular assist device can be performed as destination therapy. The new guidelines expand the indication for device therapy in heart failure based on the newest study findings, particularly for patients in NYHA class II, and specify the old guidelines. There are still uncertainties that must be investigated in randomized trials regarding patients with permanent atrial fibrillation, the indication for CRT in heart block, and the question of CRT with pacemaker or defibrillator.