BACKGROUND: The Cochrane Collaboration is an independent organization  that performs systematic reviews in order to assess the scientific  validity of research findings. Music interventions have been theorized  to help patients with heart disease, but no clear consensus exists.
METHODS:  This systematic review looked at the effect of music interventions in  patients with coronary artery disease. There were  23 trials with 1461  patients included in the evaluation. In most  studies, the main intervention was simply listening to music. A trained  music therapist was not utilized in the intervention group in 21 of the  23 trials.
RESULTS:  Although the results were inconsistent, overall, listening to music  appeared to have a moderate and positive effect on anxiety in patients  with coronary heart disease. There wasn't any clear evidence for an  overall reduction of psychological stress by listening to music.  Listening to music, however, did appear to lower the heart rate,  respiratory rate, and blood pressure. In addition, there was evidence  that two or more therapeutic music sessions led to a small but  consistent reduction in pain. 
CONCLUSION:  listening to music appears to have a beneficial effect upon blood  pressure, heart rate, respiratory rate, anxiety, and pain in persons  with coronary heart disease. It should be noted that the scientific  evidence is not strong and the clinical impact of these findings  unclear. More research is needed looking at the possible impact of using  trained music therapists.
Cochrane Database Syst Rev. 2009 Apr 15;(2):CD006577.Read More  
 
