The aim of our pilot study is to evaluate the feasibility, acceptance and efficacy of motivational interviewing (MI) to support elderly patients with heart failure with preserved ejection fraction (HFpEF) in maintaining or starting physical activity (PA).

Patients discharged from the Ex-DHF trial were recruited from June 2013 to December 2015 and offered participation in a controlled add-on pilot study. The treatment group (n=19) received 5 sessions of MI, each lasting 15-30 min over 6 months to enhance physical activity.

For the first two and the last sessions participants met with the psychologist-counsellor face-to-face for about 45 minutes. The remaining three sessions could be conducted via telephone or face-to-face, depending on participants' preferences, and typically lasted 15-30 minutes. Per study protocol, counsellors (physicians and psychologists trained in motivational interviewing) assisted the participants in: (1) Setting goals for their physical activity; (2) developing a plan to increase physical activities; (3) setting specific plans for the implementation of the plan; and (4) overcoming possible barriers. Participants were also asked to keep track of their daily physical activity in a diary, which counsellors then discussed with them during the sessions.

After patients had given their written informed consent, counsellors assessed all participants via structured interview and self-rating scales. At baseline only, sociodemographic information was recorded.

At baseline and at the final 6-month visit participants' motivation to be physically active in the upcoming weeks was assessed using the SSK-scale ("Sportbezogene Selbstkonkord" = sports-related self-concordance, Seelig and Fuchs 2006) to assess the self concordance of sport- and exercise-related goals.

The kind and extent of patients' daily physical activity was recorded using patient diaries. At baseline and 6 months we also conducted a symptom-limited cardiopulmonary exercise test on a bicycle ergometer, in order to assess changes in maximum rate of oxygen consumption during the last 30 seconds before the termination of the exercise (peak oxygen consumption (VO2 [ml/min/kg])) as measure of maximal exercise capacity. Participants also completed the 6-minute walk test on flat surface (6-MWT) as an additional parameter to assess submaximal exercise capacity.

Additionally, at the 6-month assessment, intervention participants filled out a questionnaire about their subjective evaluation of the counseling program.

The control group (n=20) received usual care.

Inclusion Criteria:

• preserved left ventricular systolic function (left ventricular ejection fraction >= 50%),
• echocardiographically determined diastolic dysfunction (grade ≥ 1),
• New York Heart association functional classes I, II or III,
• at least one cardiovascular risk-factor (overweight, diabetes, hypertension, smoking or hyperlipidemia)
• participation in Ex-DHF main study
• written informed consent

Exclusion Criteria:

• Non-cardiac causes for heart failure-like symptoms
• Chronic obstructive pulmonary disease GOLD stages ≥II
• Anaemia (haemoglobin <11 mg/dL)
• Significant renal dysfunction (eGFR <30 mL/min/1.73 m**2 indexed to BSA)
• Significant peripheral artery disease (Fontaine ≥IIb)
• Musculoskeletal disease that contributes to reduced exercise performance
• Specific cardiomyopathy (e.g. amyloidosis)
• Haemodynamically significant valvular disorders
• Significant coronary artery disease (current angina pectoris Canadian Cardiovascular Society Class ≥II or positive stress test, myocardial infarction or coronary artery bypass graft within the last 3 months)
• Any inability or contraindication to participate in cardiopulmonary exercise testing or in an exercise programme (e.g. physiological, mental) or to supply essential information (e.g. questionnaire, diary)
• Ineffective control of resting blood pressure (≥140/90 mmHg or ≥160/100 mmHg with ≥3 antihypertensive drugs) or of resting heart rate (≥100 b.p.m.)
• Expected low adherence (e.g. by travel distance to trial site; planned absences longer than 4 weeks during follow-up) or ongoing drug abuse
• Pregnant or nursing women
• Concomitant participation in other interventional clinical trials