Successfully communicating cardiovascular risk to patients is essential for achieving compliance to medication and lifestyle changes. An intuitive way to translate cardiovascular risk is to present a Heart Age; an ECG-based age-estimation from ECG changes which can be contrasted to a patient's chronological age. In this pilot study, the feasibility of a randomized controlled study (RCT) in which hypertensive patients in primary care will receive information about their ECG-based Heart Age in addition to standard care, or standard care alone, will be assessed, in preparation for a larger RCT.

Cardiovascular disease processes begin early and progress silently for many years. Fortunately, several risk-factors are modifiable, and cardiovascular risk can therefore be reduced for example by smoking cessation, dietary changes, increased physical activity in sedentary people and adherence to pharmacological risk factor reduction. To accomplish this, the patient must understand that he or she is at risk. One way to do this could be to present the risk as a "Heart Age", which can be contrasted to the patient's chronological age. In a previous study, an accurate Heart Age could be obtained using conventional, 10-second ECG recordings. The ECG analysis included conventional and basic ECG measurements such as heart rate and waveform amplitudes and durations, but also combinations of advanced ECG measures from 12-lead-ECG-derived vectorcardiography and waveform complexity.

However, it is not known whether the use of Heart Age can improve outcomes if applied in clinical care. To address this issue, a study in which patients, in addition to standard care, are randomized to either being presented with their Heart Age or not should be performed. In order to check the feasibility of such a randomized controlled study (RCT), a pilot study is necessary.

This study will evaluate the feasibility of randomizing patients with hypertension to either being presented with their Heart Age or not, in addition to standard care, by describing the recruitment dropout rate, the quality of the recorded ECG and the tolerability of the intervention (participant experience).

At the baseline visit a standardized resting blood pressure, height, weight and waist circumference will be measured. Baseline characteristics (age, sex, hypercholesterolemia, diabetes, ischemic heart disease, cerebrovascular disease, renal failure, heart failure, medications) will be recorded from the patient records. Unless a recent (<1 month) ECG is available, a new resting ECG recording will be performed, and blood sampling will be done (total cholesterol, high-density lipoprotein [HDL], low-density lipoprotein [LDL] mmol/l, triglyceride mmol/mol, Hba1c (IFCC) mmol/mL, P-Creatinine (µmol/L). The participant will also receive a questionnaire for background information and information about tobacco and alcohol use, level of physical activity, dietary habits, medication adherence, quality of life and self-estimated health including estimating one's own risk of cardiovascular morbidity.

ECG-based Heart Age will be estimated for all participants but presented only to patients in the intervention arm. A follow-up visit will be performed 6 months after the baseline visit. At follow-up, the same measurements including the same questionnaires will be obtained. Participants in the intervention arm will also receive a questionnaire on their experience of receiving information about their Heart Age (tolerability).

Eligibility: Patients with hypertension and systolic blood pressure >140 mm Hg (measured during the inclusion period by doctor or nurse at the primary health care center)

Inclusion Criteria:

• Informed consent
• Diagnosed hypertension (International classification of disease (ICD-10), I10.9)
• 40 - 75 years

Exclusion Criteria:

• ECG findings that are incompatible with or may significantly distort the Heart Age estimation (left/right bundle branch block, atrial fibrillation/flutter, tachycardia (≥100/min), abundant ventricular ectopic beats, misplaced ECG electrodes, missing leads, excessive signal noise/baseline)
• Short life expectancy (<1 year)
• Pregnancy, known secondary hypertension
• Predicted inability to give informed consent due to either language difficulties, cognitive impairment or other.
• Systolic blood pressure <120 mmHg at the baseline visit