Rlands. Fredwittkampf@mac. cheap viagra Com abstract the present treatment of atrial fibrillation by radiofrequency catheter ablation requires long continuous lesions in the thin walled left atrium where side effects may lead to serious complications. canada viagra generic Better understanding of the physical processes that take place during ablation may help to improve the quality, safety, and outcome of these procedures. These processes include the distribution of power between blood, tissue, and patient; the mechanisms of tissue heating and coagulum formation; the relation between tissue and electrode temperatures; and the effects of increased electrode size and internal and external electrode cooling. With normal electrode-tissue contact, only a fraction of all power is effectively delivered to the tissue. buy viagra canada Due to the variability of blood flow cooling, applied power and electrode temperature rise are poor indicators of lesion formation. With a longer electrode, the efficiency of tissue heating is decreased and the greater variation in tissue contact caused by electrode orientation makes lesion formation even more unpredictable. do you need a prescription to buy viagra in canada The absence of impedance rise during ablation does not guarantee the absence of blood clot formation on the tissue contact site. Blood clots may unnoticeably be created on the lesion surface and are caused by thermal denaturization of blood proteins, independent of heparinization. Irrigated ablation with external flush may prevent blood clot formation. buy cheap viagra Irrigation minimally affects lesion size by cooling the tissue surface. Larger lesions may only be created by the application of higher power levels. what is viagra tadalafil 20mg Electrode cooling, however, impedes electrode temperature feed back and blinds the operator for excessive tissue heating. buy brand viagra no prescription External cooling alone with preservation of temperature feed back is a promising concept that may lead to improved procedural safety and success. generic viagra Pmid: 17100685 [pubmed - indexed for medline] mesh terms mesh terms animals arrhythmias, cardiac/physiopathology* arrhythmias, cardiac/surgery* catheter ablation/instrumentation* catheter ablation/methods* catheter ablation/trends electrodes, implanted* equipment design heart conduction system/physiopathology* heart conduction system/surgery* humans technology assessment, biomedical temperature linkout - more resources full text sources blackwell publishing ebsco ingenta plc ohiolink electronic journal center ovid technologies, inc. viagra online Other literature sources labome researcher resource - exactantigen/labome medical arrhythmia - medlineplus health information miscellaneous swets information services supplemental content save ite. buy brand viagra no prescription mixing zoloft viagra