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Lateral Right Atrium (lateral + right_atrium)
Selected AbstractsReversal of Electrical Remodeling After Cardioversion of Persistent Atrial FibrillationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2004MERRITT H. RAITT M.D. Introduction: In animals, atrial fibrillation results in reversible atrial electrical remodeling manifested as shortening of the atrial effective refractory period, slowing of intra-atrial conduction, and prolongation of sinus node recovery time. There is limited information on changes in these parameters after cardioversion in patients with persistent atrial fibrillation. Methods and Results: Thirty-eight patients who had been in atrial fibrillation for 1 to 12 months underwent electrophysiologic testing 10 minutes and 1 hour after cardioversion. At 1 week, 19 patients still in sinus rhythm returned for repeat testing. Reverse remodeling of the effective refractory period was not uniform across the three atrial sites tested. At the lateral right atrium, there was a highly significant increase in the effective refractory period between 10 minutes and 1 hour after cardioversion (drive cycle length 400 ms: 204 ± 17 ms vs 211 ± 20 ms, drive cycle length 550 ms: 213 ± 18 ms vs 219 ± 23 ms, P < 0.001). The effective refractory period at the coronary sinus and distal coronary sinus did not change in the first hour but had increased by 1 week. The corrected sinus node recovery time did not change in the first hour but was shorter at 1 week (606 ± 311 ms vs 408 ± 160 ms, P = 0.009). P wave duration also was shorter at 1 week (135 ± 18 ms vs 129 ± 13 ms, P = 0.04) consistent with increasing atrial conduction velocity. Conclusion: The atrial effective refractory period increases, sinus node function improves, and atrial conduction velocity goes up in the first week after cardioversion of long-standing atrial fibrillation in humans. Reverse electrical remodeling of the effective refractory period occurs at different rates in different regions of the atrium. (J Cardiovasc Electrophysiol, Vol. 15, pp. 507-512, May 2004) [source] Typical Atrial Flutter Ablation: Conduction Across the Posterior Region of the Inferior Vena Cava Orifice May Mimic Unidirectional Isthmus BlockJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2000MARCO SCAGLIONE M.D. Atrial Flutter Mapping. Introduction: The aim of this study was to map the low right atrium before and after radiofrequency ablation of the inferior vena cava-tricuspid annulus (IVC-TA) isthmus in patients with typical atrial flutter (AFI) to better understand the electrophysiologic meaning of incomplete or unidirectional block following the ablation procedure and its relationship with AFI recurrence. Methods and Results: We performed atrial mapping in 12 patients using a "basket" catheter in the IVC orifice, Halo catheter in the right atrium, and multipolar catheters in the coronary sinus (CS) and His region. In patients in sinus rhythm, atrial activation was analyzed during pacing from the CS and low lateral right atrium (KLRA) before and after ablation. Atrial activation propagated across the isthmus and posterior region of the IVC orifice simultaneously before ablation. Mapping during AFI in four patients showed that the crista terminalis was a site of functional block. After ablation, evaluation of Halo catheter recordings in three patients showed apparent unidirectional counterclockwise block, whereas analysis of basket catheter recordings demonstrated complete bidirectional block. The apparent conduction over the isthmus during pacing from proximal CS was due to conduction along the posterior part of the IVC orifice, which activated the LLRA despite complete isthmus block. Conclusion: Our results demonstrate that limited endocardial mapping may yield a pattern compatible with unidirectional block in the IVC-TA isthmus, although bidirectional block is present at this anatomic level. [source] Reentry Within the Cavotricuspid Isthmus: An Isthmus Dependent CircuitPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 8 2005YANFEI YANG Background: We describe a new cavotricuspid isthmus (CTI) circuit. Methods: This study includes 8 patients referred for atrial flutter (AFL) ablation whose tachycardia circuit was confined to the septal CTI and the os of the coronary sinus (CSOS) region. Entrainment mapping was performed within the CTI, CSOS, and other right atrial annular sites (tricuspid annulus (TA)). Electroanatomic mapping was available in 2 patients. Results: Sustained AFL occurred in all patients with mean tachycardia cycle length (TCL) of 318 ± 54 (276 , 420) ms. During tachycardia, fractionated or double potentials were recorded at either the septal CTI and/or the region of CSOS in all, and concealed entrainment with post-pacing interval (PPI) , TCL , 25 ms occurred in this area; but manifest entrainment with PPI > TCL was demonstrated from the anteroinferior CTI and other annular sites in 7/8 patients. In one, tachycardia continued with conduction block at the anteroinferior CTI during ablation. Up to three different right atrial activation patterns (identical TCL) were observed. The tachycardia showed a counterclockwise (CCW) pattern in 6, a clockwise pattern in 2, and simultaneous activation of both low lateral right atrium and septum in 5. Electroanatomic mapping was available in 2, showing an early area arising from the septal CTI in 1, and a CCW activation sequence along the TA in another. Radiofrequency application to the septal CTI terminated tachycardia in 4, and tachycardia no longer inducible in all. Conclusions: We describe a tachycardia circuit confined to the septal CTI/CSOS region, and hypothesize that this circuit involves slow conduction within the CTI and around the CSOS, which acts as a central obstacle. [source] High Density Endocardial Mapping of Shifts in the Site of Earliest Depolarization During Sinus Rhythm and Sinus TachycardiaPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 4p1 2003TIM R. BETTS BETTS, T.R., et al.: High Density Endocardial Mapping of Shifts in the Site of Earliest Depolarization During Sinus Rhythm and Sinus Tachycardia.Previous mapping studies of sinus rhythm suggest faster rates arise from more cranial sites within the lateral right atrium. In the intact, beating heart, mapping has been limited to epicardial plaques or single endocardial catheters. The present study was designed to examine shifts in the site of the earliest endocardial depolarization during sinus rhythm and sinus tachycardia using high density activation mapping. Noncontact mapping of the right atrium during sinus rhythm was performed on ten anesthetized swine. Recordings were made during sinus rhythm, phenylephrine infusion, and isoproterenol infusion. The hearts were then excised and the histological sinus node identified. The mean minimum and maximum cycle lengths recorded were355 ± 43and717 ± 108 ms. A median of three (range two to five) sites of earliest endocardial depolarization were documented in each animal. With increasing heart rate the site of earliest endocardial depolarization remained stationary until a sudden shift in a cranial or caudal direction, often to sites beyond the histological sinoatrial node. The endocardial shift was unpredictable with considerable variation between animals; however, faster rates arose from more cranial sites(r = 0.46, P = 0.023). There was no difference in the mean cycle length of sinus rhythm originating from specific positions on the terminal crest(r = 0.44, P = 0.17). Cranial sites displayed a more diffuse pattern of early depolarization than caudal sites. In the porcine heart the relationship between heart rate and site of earliest endocardial depolarization shows considerable variation between individual animals. These findings may have implications for clinical mapping and ablation procedures. (PACE 2003; 26[Pt. I]:874,882) [source] | ||||||||||