Research Design and Procedure:
In a pre-test post-test experimental design, subjets were randomly assigned to listen to relaxing music of their choice, or be part of the control group. Data (before and after listening to music) were collected in the morning  on the ambulatory care unit (before patients were transferred to the catherization laboratory), or in the evening for those at ER waiting to be hospitalized or send be home.

Subjects:
Convenience sample included 196 patients between age 21 and 85 years (6+11 years), where 137 (70%) come from the ambulatory care unit, and 57 (30%) from the ER. Most patients were men (68%), many experienced their first major angina episode(46%) and were hospitalized for their first time (58%). Identified music producing positive impact included :  classical (69%), popular (80%), country-western (64%) and jazz (48%). At pre-test, no difference were found between subjects listening to music and the control group (p > 0.05). However certain patientís characteristics were different between the ambulatory care department and the ER, as well as between participants and non-participants (p < 0.05).

Instrument:
Eight numeric Likert Scales (0 to 10) (Visual Analogue Scales) were utilized to evaluate patientís perceived relaxation level. This instrument has 0.71 Crombach alpha coefficient. Anxiety levels were positively correlated with levels of frustration (r=0.41), worries (r = 0.61) and negatively with relaxation (r = -0.38). Frustation levels correlated positively with irritation due to noise (r = 0,31) and worries (r = 0.44). Relaxation levels were associated with comfort (r = 0,54), control (r = 0.30) and  negatively with anxiety (r = -0.38) and worries (r = -0,38) (p < 0.05).

Results: 
Listening to relaxing music had beneficial effect on CHD patientís perceived relaxation level (p = 0.0004), indicated by : decreased anxiety (p = 0.01), and increased control (p = 0.003) and relaxation (p = 0.001). No differences existed on perceived levels of frustration, comfort, irritation to noise, worries, retrosternal pain, number of angina and anxiety- relieving  medication consumed, heart rate, blood pressures, premature ventricular  and supra ventricular arrhythmias, and ST segment depression(p > 0.05). At the ER, all relaxation measures remained similar (p > 0.05), with the exception of frustration levels (p = 0.005). In both departments, more women (p = 0.0002) and persons who were not in the habit to listen to music (p = 0.001), decided not to participate in this study. The proportion of women not willing to participate was higher in the ER (55%) than in the ambulatory care unit (38%) (p = 0.0002). At the ER, the non participants were older (p = 0.006). At the ambulatory care unit, non-participants had been previously hospitalized (p = 0.04).

Conclusion:
Listening to relaxing music is an inexpensive nursing intervention which increases CHD patientís perceived relaxation level while waiting for cardiac catherization. These results were not observed in the ER. Non participantís characteristics differed from participantís.

Sylvie Robichaud-Ekstrand, R.N., PhD. Montreal University, Montreal Heart Institute.

Ambulatory care unit, emergency department (ER) of Heart Institute of Montreal (Qc) Canada affiliated to Montreal University.

Main researcher: Sylvie Robichaud-Ekstrand, RN, PhD.
Sylvie.Robichaud-Ekstrand@umontreal.ca