Per2 knockout mice show arrhythmic locomotor activity. Causes of cardiogenic shock include cardiomyopathic, arrhythmic, and mechanical. Mice with one NPAS2 allele showed shorter periods at first, but eventual arrhythmic behavior. Both entrained to external light cues, but were largely arrhythmic in constant conditions. It is often used to induce arrhythmic contraction in patients suspected of having Brugada syndrome. These mutant flies were also found to display arrhythmic eclosion. Influenced by African music, arrhythmic drumming and jazz were common at Dada gatherings. His death was due to Sudden Arrhythmic Death Syndrome (SADS).