Thirteen patients who all had previously inserted temporary or permanent pacemakers (6, VVI; 7, A-V sequential) were studied by two-dimensional echocardiography and radionuclide gated blood pool ventriculography (RVG) for non-invasive evaluation of cardiac performance. Patients were paced in both the VVI mode and during sinus/atrial or A-V sequential pacing. Although there was no objective change of the ejection fraction during V-pacing and atrial/A-V sequential pacing or sinus rhythm, as has been previously reported, A-V sequential pacing did result in significant improvement in overall cardiac function and output as judged by radionuclide ventriculography and blood pressure response in most of our patients. An appropriately timed atrial contribution to ventricular systole resulted in improved ventricular function in those individuals with pre-existing systolic or diastolic myocardial dysfunction and/or sick sinus syndrome in whom pacemaker therapy was indicated. Radionuclide ventriculography appears to be a reliable, accurate, non-invasive method that can be used to evaluate patients before implantation of a permanent ventricular or atrioventricular pacemaker in order to decide which pacing mode is best for that particular individual.

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Teratomas are germinal cell tumors originating from all three germ cell layers. When intracranial in location, they typically occur in the pineal or suprasellar regions. Ruptured intracranial teratomas are exceedingly rare. The authors report a case of a 34-year-old woman with a ruptured fourth ventricular mature teratoma that was treated with open surgery. The patient initially presented complaints of headache, nausea, and dizziness. CT scan demonstrated a mixed density lesion in the fourth ventricle and hypodensity lesions in bilateral lateral ventricles. MRI imaging revealed a complex fourth ventricular lesion and high T1 signal bilaterally in the lateral ventricles. A ruptured fourth ventricular teratoma was suspected and the patient was taken for surgery. Histopathology confirmed the diagnosis. Due to CSF leaking from her wound she ultimately underwent a ventriculoperitoneal shunt procedure several days later for persistent pseudomeningocele and hydrocephalus. A review of the literature is performed. Spontaneous rupture of intracranial mature teratomas is seldom encountered. The later atypical presentation may be attributed to the tumor's unusual location, precluding the more typical visual or endocrine abnormalities which may have otherwise resulted in an earlier diagnosis.