ABSTRACT
Heart failure is a condition, often called congestive heart failure (CHF), dened as the inability of the heart to pump enough blood throughout the body due to any structural or functional disorders (Hunt et al. 2009). CHF occurs as a result of myocardial infarction (MI) and other forms of ischemic heart disease, hypertension, valvular heart disease, and cardiomyopathy (Dickstein et al. 2008). In spite of several advances in therapy for CHF and MI, the prevalence of this disease is expected to still rise and predicted to reach 10 million patients by the year 2037 (Rich 1997). Even though several new drugs have been introduced to treat CHF condition and symptoms, still there is a pressing need for new effective drugs and treatment options for patients who may remain symptomatic despite optimal therapy. The inhibitors of phosphodiesterase (PDE) enzymes emerge as a class of cardioprotective drugs for their use in the adjunctive therapy in patients with decompensated heart failure (Cvelich et al. 2011). The main role of the cyclic nucleotide PDE enzymes is to hydrolyze the phosphodiester bonds in the second messenger molecules such as the cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) (Mullershausen et al. 2003). The cyclic nucleotides, cAMP and cGMP (Kass et al. 2007; Movsesian et al. 2009), inuence
23.1 Introduction ......................................................................................................................... 439 23.2 Cyclic Nucleotide Phosphodiesterase .................................................................................440 23.3 Phosphodiesterase Inhibitors and Their Use in Erectile Dysfunction ................................440
