The significance of cardiac normal variants such as patent foramen ovale (PFO), mitral valve prolapse (MVP) and atrial septal aneurysm (ASA) as potential intracardiac sources of embolism in patients with cerebral ischemia is still discussed controversially. In the present study, we determined the prevalence of PFO, MVP and ASA in patients with suspected embolic cerebral events after exclusion of cerebrovascular disease. Therefore, 164 consecutive patients with suspected embolic cerebral events as suggested by cranial computer tomography or clinical neurological examination were divided into two groups: patients with "classical" potential cardiac source of embolism (group I, n = 81, age 52 +/- 10 years) and patients without such potential cardiac sources of embolism (group II, n = 83, age 56 +/- 12 years). The prevalence of PFO, but not that of MVP and ASA, was significantly higher in group I than in group II (group I: 33.3% vs. group II: 2.4%; chi-square 88.5, p < 0.0001). In the absence of "classical" potential cardiac sources of embolism transesophageal echocardiography reveals a PFO in approximately 30% of the cases. This finding supports the significance of PFO as a potential cardiac source of embolism.