Geraniol is a monoterpene present in several essential oils, and it is known to have a plethora of pharmacological activities. In this study, we explored the contractile and electrophysiological properties of geraniol and its antiarrhythmic effects in the heart. The geraniol effects on atrial contractility, L‐type Ca²⁺current, K⁺currents, action potential (AP) parameters,ECGprofile and on the arrhythmia induced by ouabain were evaluated. In the atrium, geraniol reduced the contractile force (~98%,EC = 1,510 ± 160 μM) and diminished the positive inotropism of CaCl₂andBAYK8644. In cardiomyocytes, theI_Ca,Lwas reduced by 50.7% (n = 5) after perfusion with 300 μM geraniol. Moreover, geraniol prolonged theAPduration (APD) measured at 50% (n = 5) after repolarization, without changing the resting potential. The increasedAPDcould be attributed to the blockade of the transient outward K⁺current (I_to) (59.7%, n = 4), the non‐inactivation K⁺current (I_ss) (39.2%, n = 4) and the inward rectifier K⁺current (I_K1) (33.7%, n = 4). In isolated hearts, geraniol increasedPRi andQTi without affecting theQRScomplex (n = 6), and it reduced both the left ventricular pressure (83%) and heart rate (16.5%). Geraniol delayed the time to onset of ouabain‐induced arrhythmias by 128%, preventing 30% of the increase in resting tension (n = 6). Geraniol exerts its negative inotropic and chronotropic responses in the heart by decreasing both L‐type Ca²⁺and voltage‐gated K⁺currents, ultimately acting against ouabain‐induced arrhythmias.

In infants with phenylketonuria (PKU), dietary management is based on lowering and titrating phenylalanine (Phe) intake from breast milk or standard infant formula in combination with a Phe-free infant formula in order to maintain blood Phe levels within target range. Professionals use different methods to feed infants with PKU and our survey aimed to document practices across Europe. We sent a cross sectional, survey monkey® questionnaire to European health professionals working in IMD. It contained 31 open and multiple-choice questions. The results were analysed according to different geographical regions. Ninety-five centres from 21 countries responded. Over 60% of centres commenced diet in infants by age 10 days, with 58% of centres implementing newborn screening by day 3 post birth. At diagnosis, infant hospital admission occurred in 61% of metabolic centres, mainly in Eastern, Western and Southern Europe. Breastfeeding fell sharply following diagnosis with only 30% of women still breast feeding at 6 months.53% of centres gave pre-measured Phe-free infant formula before each breast feed and 23% alternated breast feeds with Phe-free infant formula. With standard infant formula feeds, measured amounts were followed by Phe-free infant formula to satiety in 37% of centres (n = 35/95), whereas 44% (n = 42/95) advised mixing both formulas together. Weaning commenced between 17 and 26 weeks in 85% centres, ≥26 weeks in 12% and < 17 weeks in 3%. This is the largest European survey completed on PKU infant feeding practices. It is evident that practices varied widely across Europe, and the practicalities of infant feeding in PKU received little focus in the PKU European Guidelines (2017). There are few reports comparing different feeding techniques with blood Phe control, Phe fluctuations and growth. Controlled prospective studies are necessary to assess how different infant feeding practices may influence longer term feeding development.