This entry reviews the health condition known as Roemheld syndrome, or gastrocardiac syndrome in modern medicine. A pathology of gastrointestinal origin, the syndrome relies on a gut–brain–heart triad, interconnected by the vagus nerve. Pressure from the intestines pushes the stomach into the diaphragm and activates the vagus nerve, which affects the heart rate and gives the perception of cardiac issues. This distressing sensation, which usually comes after meals or with other digestive problems, causes anxiety or panic. Although events not arising from anatomic abnormalities are relatively harmless, hypersensitivity to these uncomfortable sensations may precipitate psychiatric problems (anxiety or depression) that cause repeated gastrocardiac events through sympathetic activation and the disruption of peristalsis. Treatment is usually symptomatic and may include diet, lifestyle changes, probiotics, or prescriptions that increase gut motility, but this specific set of reproducible symptoms may also be caused by hiatal hernia or side effects from medication/surgery and treated with respect to those mechanical causes. This review highlights details from the most current knowledge of the condition and offers suggestions for clinical management based on the literature.