This research was a one-stage descriptive - correlation study that was conducted from February to April 2015 in hospitals affiliated in Isfahan University of Medical Sciences, in Iran. The sample size was calculated using
Equation 1 was 227 patients. All 227 patients that were evaluated in the study, suffered from cardiac failure. The patients were randomly assigned to two groups. The inclusion criteria included assignment of consent form, suffering from class two or three of cardiac failure that was confirmed by a cardiologist, patients that were being 18 years or older, passed at least six months after diagnosis of heart failure, non-presence of other threatening physical illnesses such as mental retardation and dementia, self-awareness of their disease, being alert, and familiar with the Persian language (
32,
33).
The information gathering tool was comprised of three parts: the first one containing the questions about demographic subjects and information related to the patient (including age, sex, and occupation, marital status, and education level, duration of illness, hospitalization times, and ejection fraction of the heart, diabetes, hypertension, and cholesterol disorders). The second one includes Sullivan’s self-efficacy questionnaire. This questionnaire is a 16-item scale with a score for each question ranging from zero to four and assesses the level of confidence and self-efficacy of patients about care, controlling disorders symptoms (0 = not at all confident, 1 = somewhat confident; 2 = moderately confident, 3 = very confident, and 4 = completely confident).
The cardiac self-efficiency with changing to appropriate variables were turned into 0-100 and its score was classified in three main groups of 0 - 33 (low), 34 - 66 (medium), and 67 - 100 (high). The cardiac self-efficiency of Sullivan is a valid and reliable questionnaire that has been approved by studies. In the study by Shamsizadeh the validity of this tool was approved and the internal consistency reliability was estimated using Cronbach’s alpha (0.977) (
34). In recent studies, the Cronbach’s alpha coefficient of this tool was determined as 0.87 - 0.90 (
35) and 0.77 (
36).
The third part of the tool was the Ferrans and Powers quality of life index (1999), where its questions are arranged in two parts: measuring the importance and satisfaction of health and functioning, social and economic, psychological/spiritual, and family with values ranging from one to six. In the first part, the scale ranges from very unsatisfied [1] to very satisfied [6]. In the second part, the scale ranges from without any importance [1] to very important [6]. Every section contains 35 questions and the questions related to the importance and consensus was similar. The 35 items are distributed into the four subscales: health/functioning (15 items), social and economic (eight items), psychological/spiritual (seven items), and family (five items) (
16,
37,
38). To determine the score for the quality of life level, first, the satisfaction scores must be recoded with the purpose of centering the scale of zero. This is done by subtracting 3.5 from satisfaction responses, which results in the following scores: -2.5, -1.5, -0.5, +0.5, +1.5, and +2.5 for scores that were originally 1, 2, 3, 4, 5, and 6, respectively. Second, the recoded satisfaction scores are weighted by their corresponding importance items, multiplying each item’s recoded value by the raw importance score (1, 2, 3, 4, 5, 6). Next, the total score is calculated by adding the weighted values of every response and then dividing by the total number of answered items. Up to this stage, the possible variation is from -15 to +15. To avoid the final score having a negative number, we add 15 to the obtained values, resulting in the total score of the instrument, which can vary from zero to 30. Accordingly, the score of nine-zero is considered as unfavorable quality of life, 19 - 10 is relatively favorable, and 20 - 30 is considered desirable (
16). In recent studies, the Cronbach’s alpha coefficient of the Ferrans and Powers quality of life index was determined as 0.86 - 0.9 (
16,
38).
The method of study conduction was so that the researcher, after acquiring the introduction issue from Nursing and Midwifery Faculty of Isfahan University of Medical Science, will refer to cardiovascular medical science university hospital-associated clinics. After presenting the introduction letter and explaining the study aim to the heads of the center and taking their agreements starts to making samples, the researcher goes to study the environment and after taking permissions from heads, if the patients were suitable to study, they were explained the purpose of this study and they would make their agreement to attend in the study. The completion of the three-part questionnaire for collecting patients’ information required an average 20 minutes. It should be noted that participants did not exchange any comments when answering questions. The present study was approved by the Research Council of the faculty of Nursing and Midwifery and the Ethics Committee of Isfahan University of Medical Sciences with code 293270. Objectives and methodology were explained for patients and informed consent was obtained.