The U-wave: A remaining enigma of the electrocardiogram.

The U-wave's electrophysiological origin remains unknown and is subject to debate. It is rarely used for diagnosis in clinical practice. The aim of this study was to review new information regarding the U-wave. Further to present the proposed theories behind the U-wave's origin along with potential pathophysiologic and prognostic implications related to its presence, polarity and morphology. METHOD: Literature searches were conducted to retrieve publications related to the electrocardiogram U-wave in the literature database Embase. RESULTS: The review of the literature revealed the following major theories that will be discussed; late depolarisation, delayed or prolonged repolarisation, electro-mechanical stretch and IK1 dependent intrinsic potential differences in the terminal part of the action potential. Various pathologic conditions were found to correlate with the presence and properties of the U-wave, such as its amplitude and polarity. Abnormal U-waves can, for example, be observed in coronary artery disease with ongoing myocardial ischemia or infarction, ventricular hypertrophy, congenital heart disease, primary cardiomyopathy and valvular defects. Negative U-waves are highly specific for the presence of heart diseases. Concordantly negative T- and U-waves are especially associated with cardiac disease. Patients with negative U-waves tend to have higher blood pressure and history of hypertension, higher heart rate, cardiac disease and left ventricular hypertrophy compared to subjects with normal U-waves. Negative U-waves have been found to be associated with increased risk of all-cause mortality, cardiac death and cardiac hospitalisation in men. CONCLUSIONS: The origin of the U-wave is still not established. U-wave diagnostics may reveal cardiac disorders and the cardiovascular prognosis. Including the U-wave characteristics in the clinical ECG assessment may be useful.

Identifying barriers to decreasing meat consumption and increasing acceptance of meat substitutes among Swedish consumers.

A key lifestyle change people could make to reduce their environmental impact is to reduce their meat consumption. However, meat is still a staple in many people's diet, and some consumers are reluctant to cut down. Meat substitutes, if accepted as adequate replacements for meat, may offer a suitable alternative without leaving consumers feeling dissatisfied. The aim of the present study was to identify psychological barriers to reducing meat consumption and increasing use of meat substitutes among Swedish consumers. Participants engaged in focus group discussions around purchasing, preparing, and consuming meat and meat substitutes. Four main themes were identified through thematic analysis: uncertainty, scepticism, health, and identity. These are discussed in relation to previous work on the barriers to reducing meat consumption. Strategies to communicate the environmental impact of meat to consumers and effect change through behavioural interventions are considered.