QLQ-SHF comprises 26 Likert-type questions used to measure quantitatively physical activity as well as an analogous scale to measure life satisfaction and social/emotional factors. The higher the point score, the more negatively affected is HRQoL. QLQ-SHF has been used in several clinical studies, and its validity has been determined in comparative studies with other questionnaires (e.g., SIP). The validity of the QLQ-SHF is sufficient for the dimensions of physical symptoms and life satisfaction. However, this validity is decreased for somatic complaints and physical activity.

Studies have shown that the QLQ-SHF is moderately sensitive to small changes in the QoL of CHF patients. However, further study is required because it is not known if this questionnaire can be used to differentiate between patients in terms of CHF severity (see Appendix).

CHFQ contains 20 questions which can be applied in an interview with trained personnel. It can be used to differentiate between three problem categories: dyspnea, fatigue, and emotional functioning. A higher score denotes higher HRQoL. CHFQ is highly sensitive to changes in the degree of severity of the main CHF symptoms (i.e., dyspnea and fatigue). Therefore, CHFQ is used in patients at varying levels of CHF advancement (see Appendix).

MLHF was developed for CHF patients to measure how such patients interpret the influence of CHF on their exercise tolerance, socioeconomic functioning, and psychological status (see Appendix). Patients answer 21 questions using a six-level, Likert-type scale, earning 0–5 points for each answer. One can measure the dimensions of physical and emotional functioning separately. MLHF is short, easy to use, and understandable by patients. It can be administered as a survey and completely independently by patients in their homes or in the physician’s office. MLHF has satisfactory validity compared with other scales measuring the influence of CHF on the HRQoL of patients [19].

It can be used to differentiate between subjects with and without symptomatic left ventricular dysfunction (LVD) (i.e., NYHA classes I and II) but it poorly differentiates between advanced stages of symptomatic CHF. Thers are reservations as to whether MLHF can also be used to differentiate between symptoms of heart failure from similar symptoms in other diseases [20]. MLHF is usually employed to measure heart-related QoL in CHF patients, but it is a specific questionnaire that is meant to be used in clinical studies to measure the influence of pharmacotherapy or other interventions on HRQoL. It does not ensure a full measure of HRQoL [20].

Burdensome symptoms reported by 20-75% of heart-failure patients include dyspnea, fatigue, pain, peripheral edema, and lack of appetite. Beyond these typical symptoms of failing health, < 70% of CHF patients experience anxiety and 50% report depressive symptoms, excessive stress, and cognitive dysfunction (i.e., difficulty with concentration). Approximately 50% of patients also experience dry mouth, trouble with taste sensations, excessive sweating, palpitations, and constipation [21].

Dyspnea and fatigue are the basic symptoms reported by CHF patients. Patients also complain about sleep disturbances, described by them as “even worse and more burdensome” than dyspnea [21], leading to even greater fatigue and negative influences on HRQoL [22]. A significant percentage of CHF patients report aggravated sleep disturbances, especially insomnia. These disturbances are associated directly not only with fatigue, but also the frequent occurrence of depression and poor HRQoL [22]. It seems that CHF patients who report chronic fatigue along with tiredness during the day should also be evaluated carefully for sleep disturbances [23].

Worse HRQoL has been linked to a younger age of the CHF patient, greater severity of symptoms, and to a greater number of restrictions on physical activity resulting from CHF [21]. Decreasing the severity or eliminating the symptoms of CHF leads to an improved ability to engage in normal activity and may positively influence HRQoL. Most CHF patients know that their illness is related to reduced longevity, which leads to additional stress.

Female CHF patients are characterized by having lower HRQoL than men [24]. Their HRQoL is also lower than that of women who have experienced a myocardial infarction (MI) or in those with other chronic diseases, such as DM, Parkinson’s disease, or COPD [25]. Compared with men, the HRQoL of female CHF patients is most affected in the dimensions of: sleep; symptoms; the energy that they have every day; physical and psychological functioning; and self-rated health. Improvement in HRQoL after hospitalization due to CHF is also lower in women than in men.

Not all studies confirm the decreased HRQoL of women with heart failure. Compared with women, some authors observe decreased HRQoL in male subjects with heart failure, especially in older age groups [4, 26]. However, these differences disappeared after adjusting for the NYHA classification system, ejection fraction, and age. When explaining differences in the HRQoL of male and female subjects with CHF, the different ways in which the sexes perceive the influence of their disease on everyday functioning must be stated. Men tend to focus most of their attention on the restrictions their disease places on physical functioning. Conversely, women tend to focus their attention on the negative affects of their disease on emotional, family and social functioning. Women with poor social support, who live alone, and who have a pessimistic personality are characterized by especially lower HRQoL [27].

Congestive heart failure is one of the diseases that affects HRQoL most negatively, in which older (compared with younger) patients seem to report higher levels of QoL [22, 24, 26]. This difference is based primarily on the varied way in which health and illness is interpreted at different ages. Younger individuals are affected more greatly by the restrictions placed on them by their illness, even if this involves only their family and professional activities. Sexual dysfunction constitutes an often encountered problem in male CHF patients. This involves loss of libido and an increased incidence of erectile dysfunction [28].

Ejection fraction does not correlate significantly with HRQoL in CHF patients. Austin et al. reported that, at 8 years follow-up in patients living with heart failure, HRQoL scores were similar regardless of systolic function (i.e., the KCCQ scores were not different in the survivors with preserved and reduced ejection fraction ) [29]. Recently, Hoekstra et al. confirmed that QoL measured with generic and diseases-specific questionnaires was impaired by similar amounts in CHF patients with preserved ejection fraction as in CHF patients with reduced ejection fraction [15].

Studies have shown that pharmacological and non-pharmacological (e.g., restricting intake of salt and fluids) treatment options may positively influence the HRQoL of CHF patients (though this effect is not appreciable). In patients with symptomatic left ventricular dysfunction, certain ACEIs, beta-blockers (especially carvedilol) [30], and diuretics yield only a modest advantage over placebo in terms of improving HRQoL. In this respect, differences exist within groups of particular drugs. For example, compared with placebo, one study did not find rampril to significantly improve the HRQoL of patients treated for moderately advanced CHF.

Certain angiotensin-II receptor antagonists called sartans are characterized by their positive influence on the HRQoL of subjects with heart failure as measured using the McMaster questionnaire. The recently published results of the Candesartan in Heart Failure (CHARM) study [31] reported that, after 26 months, the addition of candesartan to current CHF treatment led to significant improvement in HRQoL. Moreover, the Valsartan Heart Failure Trial (Val-HeFT) found that adding valsartan to an ACEI regimen that did not include beta-blockers led to improvement in HRQoL if measured using MLHF [32]. Both studies suggested that, from the viewpoint of patient QoL, sartans may be used in CHF patients already being treated with ACEIs, or even before beginning treatment with beta-blockers.

However, not all studies have confirmed the additional benefits of sartan use on the HRQoL of heart-failure patients. The Losartan Heart Failure Survival Study (ELITE II) measured HRQoL in CHF patients treated with losartan. It found that losartan did not have an advantage over captopril in terms of influencing the QoL of patients in NYHA classes II-IV and decreased left ventricular ejection fraction. The Replacement of Angiotensin Converting Enzyme Inhibition (REPLACE) study also did not find changes to the HRQoL of patients with heart failure treated with telmisartan compared with those treated with enalapril if measured using MLHF [33].

The dimensions most sensitive to pharmacological therapy include the symptoms of CHF and exercise tolerance. Changes to HRQoL influenced by pharmacological treatment are minimal or absent after the administration of drugs that are similar in their clinical effects and side effects. For example, of 10 studies examining the influence of beta-blockers on the HRQoL of patients with heart failure, only 3 reported improvement [34]. A study by Baxter et al. [35] found only modest improvement in general QoL and decreased severity of depression and anxiety if bisoprolol was used in CHF patients aged > 70 years. Also, as part of a prospective study, a direct comparison of carvedilol and metoprolol found that they influenced the HRQoL of CHF patients in a similar way, despite certain hemodynamic differences favoring carvedilol [36]. Even with the use of new-generation betablockers (e.g., carvedilol, nebivolol), heart failure inevitably decreases the longevity and wellbeing of patients [37, 38].

Several drugs used to treat subjects with heart failure can reduce heart rate (HR), but their effects on symptoms are diverse and can be undesirable. Results from the Systolic Heart Failure Treatment with the If Inhibitor Ivabradine Trial (SHIFT) showed that HR reduction with ivabradine in CHF patients reduced cardiovascular mortality or hospital admissions for worsening heart failure. In addition, there was an improvement in NYHA class and in patient-reported QoL measured using the KCCQ [39]. HRQoL at follow-up was better preserved in the ivabradine group compared with placebo (ivabradine reduced HR by 10 bpm versus placebo). This study suggested that the ivabradine-associated reduction in CHF severity (as reflected by a reduced number of hospital admissions and improved NYHA functional class) also translated into a favorable impact on HRQoL. In contrast, treatment with beta-blockers (which were associated with similar HR reduction and reduction in CHF mortality) did not result in improved HRQoL, as reported in a meta-analysis by Dobre et al. [40].

Volterrani et al. found in the Effect of Carvedilol, Ivabradine or their Combination on Exercise Capacity in Patients with Heart Failure (CARVIVA HF) Trial that patients with heart failure treated with a maximal dose of ACEI who then received ivabradine or ivabradine plus carvedilol had better QoL than patients treated only with carvedilol. HR in this relatively small study (n = 121) was reduced in all three groups, but to a graeter extent by the combination [41]. The studies described above suggest that ivabradine alone or in combination with some beta-blockers may be effective in improving exercise tolerance and QoL in CHF patients.

How non-pharmacologic interventions influence HRQoL is even less conclusive. The results of recently published studies concerning different treatment options, beginning from basic nursing and ending with nasal continuous positive airway pressure (NCPAP), noted only a small positive influence of these interventions on the HRQoL of CHF patients. Patient education and regular support from nursing personnel seems to improve the HRQoL of patients at various stages of advanced heart failure [42].