Extreme externalisation of a Riata defibrillator lead conductor cable with prolapse into the left pulmonary artery.

The Riata family of defibrillator leads (St. Jude Medical, Sylmar, CA) has been recalled because of externalisation of conductor cables and increased electrical failure. We describe the case of a man with an incidental finding of extreme externalisation of a conductor from the right ventricular defibrillator lead (Riata family) with prolapse into the left pulmonary artery.

Mechanisms of increased right and left ventricular oxygen uptake during inotropic stimulation.

AIMS: Few studies have investigated oxygen supply/demand relations in right ventricle (RV). The current study compared changes in myocardial oxygen uptake (MVO2) and its determinants, myocardial blood flow (MBF) and oxygen extraction (EO2), in RV and left ventricle (LV) during stimulation with inotropic drugs. MAIN METHODS: Twenty-one anesthetized dogs were studied. MBF was measured with radioactive microspheres. A-VO2 difference was determined separately for RV and LV, and used to calculate MVO2 (Fick equation) and EO2. Responses to iv. infusions of isoproterenol (0.1 µg/kg/min), dobutamine (5 µg/kg/min), and amrinone (1mg/kg+10 µg/kg/min) were assessed. KEY FINDINGS: Baseline MVO2 in RV was 50-60% of that in LV. The inotropes increased MVO2 in both RV and LV (range 32-63%; P<0.05). With isoproterenol, the increased MVO2 in the RV was due to increases in both MBF and EO2, whereas in LV it was due only to increases in MBF. With dobutamine and amrinone, the increased MVO2 in RV was due to increased MBF while EO2 was constant (dobutamine) or decreased (amrinone), and that in the LV was due to increased MBF while EO2 decreased. SIGNIFICANCE: RV possesses EO2 reserve that contributed to increased MVO2 during isoproterenol infusion, whereas LV depended on increased MBF alone. Because dobutamine and amrinone caused direct coronary vasodilation, i.e., "luxuriant perfusion," it was not necessary to recruit the EO2 reserve. Thus, it remained available to meet further increases in MVO2 or to maintain MVO2 in the face of reductions in MBF.

The false assumption of lung cancer based upon a positive positron emission tomographic scan.

OBJECTIVE: To show that positron emission tomography (PET) can have false positive results from inflammatory lesions. METHODS: We present a complicated, elderly patient who underwent an extensive work-up that failed to provide a diagnosis for a radiographic abnormality. RESULTS: A PET scan was positive and the patient was believed to have lung carcinoma until eventual surgical excision was performed. Final pathology revealed that the patient had exogenous lipoid pneumonia. CONCLUSIONS: PET scans that are positive cannot be assumed to show a malignancy. Inflammatory lesions will also be positive with PET scanning.