CHF treatment options

Why are calcium channel blockers (CCB) contra-indicated in congestive heart failure, while beta-blockers aren't? I understand that CCB may worsen the situation with a significant drop in cardiac output (CO), since they're negative inotropes and can further deteriorate the cardiac function.... but don't beta-blockers ultimately do the same thing? They're negative chronotropes, so they will also cause a decrease in CO. Why can they be used in heart failure while CCB cannot? Thanks in advance.
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Tags: Medical Students (MD) Source Type: forums