**1. Introduction**

Congestive heart failure (CHF) is one of the most important epidemics in the current human species era affecting 1–2% of adults and around 10% of >70 years old in developed countries. The lifetime risk of developing heart failure is one in five after 40 years of age. In the United States, it costs around \$39.2 billion in 2010. Sub group of CHF subjects with reduced ejection fraction and electrical dyssynchrony constitutes a true therapeutic challenge. Therapeutic strategies of this CHF sub group witnessed stagnant periods until electrical therapies were introduced to the world communities where cardiac resynchronization therapy (CRT) became available for clinical use first in 2001. Candidates for CRT are CHF subjects with

reduced left ventricular systolic function, QRS duration of >120 ms with left bundle branch (LBB) morphology, and functional classification with NYHA class III–IV. Accumulative knowledge in the last two decades has shown that more than onethird of patients are not responding with lack of echocardiographic reverse remodeling or no improvement in quality of life (QOL). Intelligent CRT subjects selection with multidisciplinary expertise and improved procedural skills and strategies, as well as optimizing post-implant care are the main targets to achieve the improved outcomes for the non-responders. Nowadays, a new CRT imaging techniques and innovative pacing strategies are top priorities for us in CHF electrical therapies arena. This chapter is a journey in the CRT timeline reviewing the past, discussing the current situation, and elaborating in future directions for better psychophysiological well-being of CRT subjects.
