Background: Changes in resting membrane potential due to extracellular potassium ([K+]e) accumulation are thought to be responsible for TQ segment depression in ischemia. However, the nature of the [K+]e-TQ relationship remains to be fully elucidated. Methods: We created a carotid-coronary shunt in 21 pigs, and recorded [K+]e and TQ-segment potentials simultaneously during graded left anterior descending artery (LAD) flow reduction via 4-6 K+-sensitive electrodes placed in the LAD. Only data from K+ electrodes with calibration slopes of 55-65 mV/decade change in K+ were used. Results: While the correlation between the changes in potassium equilibrium potential (EK) and the TQ shift was linear, the regression slopes initially increased and then decreased during graded flow reduction (S = -0.338, Q = 30 mL/minute, S = -3.253, Q = 10 mL/minute, S = -0.312, Q = 0 mL/minute), i.e., TQ depression at all EK values became larger, then smaller as the flow was decreased in a stepwise manner. The inhomogeneity of changes in [K+]e and TQ potential changes and their relationship also decreased initially then increased during graded flow reduction (R = -0.237, LAD flow = 30 mL/minute; R = -0.819, LAD flow = 15 mL/minute; R = -0.115, LAD flow = 0 mL/minute). Conclusions: Although [K+]e and the TQ shift are related linearly, there is large variability in their relationship in the setting of graded coronary flow reduction. Therefore, local TQ-segment potentials cannot be used as indices of the severity of ischemic changes.
Background: Sites of high dominant frequency (DF) and complex fractionated atrial electrograms (CFAEs) are used as ablation targets to eliminate atrial fibrillation (AF). These sites are identified using spectral and time domain analyses. The frequency spectrum of the signal is determined by its cycle length as well as the morphology and amplitude of the electrogram, and these factors can affect the DF analysis. We determined the DFs, mean AF cycle lengths (fractionation intervals [FIs]), and voltages from bipolar and unipolar electrograms-and compared the values derived from the 2 types of recordings. Methods: Five patients with paroxysmal AF and 5 patients with persistent AF were included in the study. Highdensity unipolar electrograms recorded through a band-pass filter of 1-400 Hz and bipolar electrograms recorded through a band-pass filter of 30-400 Hz were obtained with the use of a 20-pole circular mapping catheter positioned in the left atrium (LA), and DF, AF cycle length, and unipolar and bipolar voltages during sinus rhythm (SR) were analyzed with the use of NavX software. Results: While the unipolar FIs were longer than the bipolar FIs, the bipolar and unipolar DFs were similar. The SR voltages of the unipolar and bipolar electrograms at CFAE sites (FIs <120 msec) were higher than those at the non-CFAE sites, but did not differ between the high DF (>8 Hz) and other DF sites. Overlap between the CFAE sites and the high DF sites identified from both bipolar and unipolar electrograms was only 7.9%. Conclusion: FIs and DFs may represent different electrophysiologic substrates.
Objectives: To improve the survival rate in patients with nasopharyngeal squamous cell carcinoma (NSCC). Material and Methods: A total of 56 patients with NSCC were enrolled in this study, in order to observe the long-term survival. The primary site was treated conservatively with neoadjuvant chemotherapy (NAC) and concurrent chemoradiation therapy (CCRT), using superselective intra-arterial infusion chemotherapy (SSIAC) with cisplatin, docetaxel, and 5-fluorouracil. Cervical lymph node metastasis was treated using neck dissection. Results: The 5- and 10-year overall survival rates were 67.9 and 60.5%, respectively. The 5- and 10-year survival rates improved particularly in patients with T3 cancer (96.5 and 96.5%, respectively), N1 cancer (100 and 100%, respectively), and poorly-differentiated cancer (88.2 and 79.2%, respectively). In contrast, the 5- and 10-year survival rates were worse in patients with T4 cancer (28.7 and 0%, respectively), N3 cancer (11.1 and 0%, respectively), and moderately-differentiated cancer (18.7 and 0%, respectively). There were significant differences in the overall survival rates between patients with stage III and IVA, stage III and IVB, and between IVA and IVB NSSC. Conclusion: We demonstrated that NAC and CCRT using SSIAC, with neck dissection to control cervical lymph node metastasis, were safe and effective in patients with NSCC. The introduction of maintenance therapy and intensity-modulated radiation therapy (IMRT), as well as molecular-targeted drugs and heavy-particle radiotherapy, should be considered.