BACKGROUND: The clinical significance of conduction recurrences in isolated pulmonary veins of patients with atrial fibrillation is not established. METHODS: Twenty-two patients with paoxysmal atrial fibrillation underwent successful pulmonary vein isolation. Six months after the procedure, 14 patients were free of atrial fibrillation. Two of these patients were subjected to repeat mapping of the left superior pulmonary vein. RESULTS: There was recurrence of pulmonary vein to left atrium conduction despite complete lack of symptoms or evidence of recurrent atrial fibrillation. CONCLUSION: Successful pulmonary vein isolation with abolition of paroxysmal atrial fibrillation does not confer permanent disconnection of the pulmonary vein musculature from the left atrium. 相似文献
OBJECTIVE--To assess the accuracy of measurement of area of the lumen, and sensitivity, and specificity of detection of atheroma in coronary arteries in vitro with a commercially available 20 MHz intravascular ultrasound system. SETTING--A teaching hospital department of cardiology with the support of the department of cardiovascular pathology. PROCEDURE--10 segments of coronary artery were removed from cadaver hearts. Intravascular ultrasound imaging was performed at fixed levels and the vessels were then sectioned and photographed before histological preparation. An independent blinded observer measured luminal area and assessed the presence of atheroma on the intravascular ultrasound images of 76 vessel sections (304 quadrants). The sensitivity and specificity of detection of atheroma was assessed in comparison with the histologically prepared sections. Luminal areas from intravascular ultrasound, photographs of cross sections of the vessels and histological sections were compared with the technique of limits of agreement. RESULTS--Overall 36% of the 304 quadrants studied histologically had identifiable atheroma. Intravascular ultrasound sensitivity for atheroma was 0.593 and the specificity was 0.839. The positive predictive value was 0.674, and the relative risk 3.139. Values for area of the vessel lumen were on average 9.4 mm2 (confidence interval (CI) 8.6-10.2 mm2) larger than those measured from photographs and 10.7 (CI 9.8-11.6 mm2) larger than those measured from the histological sections. CONCLUSIONS--The intravascular ultrasound system assessed in this study significantly overestimated coronary vessel luminal area and had low sensitivity and specificity for detection of atheroma. Improvements in image resolution are required before this system can provide useful information on coronary artery size and morphology. 相似文献
OBJECTIVE: This study aimed at comparing three-dimensional (3-D) reconstruction with two-dimensional coronary angiograms with respect to anatomical parameters that might affect plaque formation and rupture. METHODS: Sixty patients with stable left anterior descending (LAD) lesions and 60 patients with an anteroseptal myocardial infarction and recanalized LAD were studied. RESULTS: Conventional angiography significantly underestimated the distance of the stenosis from the ostium of the LAD, 29.4+/-14.5 versus 35.3+/-18.5 mm, P<0.001. Vessel curvature at the site of the lesion was overestimated by conventional angiography compared with 3-D reconstruction, 147.6+/-30.6 degrees versus 162.3+/-11.2 degrees , P<0.001, as was axial bending of the LAD owing to ventricular contraction (17.8+/-7.78 degrees vs. 8.9+/-8.9 degrees , P<0.001). No agreement was observed between two-dimensional and 3-D analysis for either curvature on lesion or axial bending assessment, with intraclass correlation coefficient values 0.155 (-0.009, 0.315) and -0.022 (-0.183, 0.174), respectively. No significant agreement was found between the two methods in the detection of on-stenosis bifurcations (1.7%, kappa=0.086, P=0.349). CONCLUSION: Conventional coronary angiography cannot provide accurate estimates of anatomical parameters, such as distance of a coronary stenosis from the ostium of the vessel, coronary artery curvature at the site of stenosis, axial deformity and bending because of ventricular contraction, and classification of bifurcations. Reconstruction of the coronary tree in 3-D space is necessary for such estimations. 相似文献
BACKGROUND: Comparisons between segmental ostial disconnection of the pulmonary veins (PV) and circumferential ablation have produced conflicting results in patients with paroxysmal atrial fibrillation (AF). The aim of this study was to evaluate a staged ablation procedure, every step of which was assessed by means of AF inducibility. METHODS: Twenty-two patients with paroxysmal AF were subjected to three ablation stages during one session: (1) circumferential ablation around the PV ostia, (2) segmental ostial PV isolation, and (3) ablation of areas within the circumferential lines with fractionated electrograms or voltage >0.2 mV as well as linear ablation at the mitral isthmus and the left atrial roof. Endpoint of the procedure was noninducibility of AF at any stage. RESULTS: Average radiofrequency energy delivery, fluoroscopy, and procedure times were 43 +/- 11 minutes, 40 +/- 11 minutes, and 3.8 +/- 0.5 hours, respectively. At 6-months follow-up, four patients experienced recurrence of AF (18%), whereas two additional patients (9%) had left atrial arrhythmias not registered before the procedure. Ninety-five percent of the patients who did not have inducible AF (regardless of the stage of ablation at which noninducibility was achieved) were free of recurrent AF, as opposed to none of the patients in whom AF was inducible at the end of the procedure (log-rank test, P < 0.001). CONCLUSIONS: A staged ablation procedure combing circumferential and ostial PV ablation with AF noninducibilty as endpoint may result in high success rates without the need of prolonged ablation sessions in certain patients with paroxysmal atrial fibrillation. 相似文献
Background: Cannulation of the coronary sinus usually has been accomplished by advancing a catheter through the subclavian or internal jugular veins. Hypothesis: We have developed a new technique for cannulation of the coronary sinus with a modified 6F Judkins L5 coronary catheter positioned through the femoral vein. Results: The technique was tried successfully in 20 consecutive patients by the same operator and the average fluoroscopy time for coronary sinus cannulation was 1.6 ± 1.0 min. Conclusion: Analysis of the results showed evidence of a learning curve with improvement of time with an increasing number of patients. The method provides a safe and inexpensive solution for catheterization of the coronary sinus, easily accessible to every catheter laboratory. 相似文献
BACKGROUND--Idiopathic ventricular tachycardia (VT) occurs in a small but important subset of patients without clinically overt heart disease. The mechanism of the arrhythmogenesis remains unclear in these patients. This study examines modulation of the QT interval by the autonomic nervous system in a group of patients with idiopathic ventricular tachycardia. METHODS--Cardiac autonomic activity and ventricular repolarisation were studied in 27 patients with VT associated with a clinically normal heart (NHVT) and in 20 normal subjects. All the patients were in sinus rhythm, had normal atrioventricular conduction, and were in a drug free state. Cardiac efferent autonomic activity was measured by spectral analysis of heart rate variability from 24 hour ambulatory electrocardiograms on a Holter analysis system (Marquette). Ventricular repolarisation was evaluated by measuring the QT intervals from the same 24 hour Holter tapes at one hour intervals. RESULTS--There was no difference in any of the QT interval variables including the maximum, minimum, and mean of both the QT interval and its corrected value (Bazett's formula) between patients with NHVT and normal subjects. The high frequency component (0.04-0.15 Hz) of heart rate variability was significantly decreased in patients with NHVT compared with normal subjects (16 (8) v 21 (12) ms, p < 0.05). There was a significant correlation between the spectral variables of heart rate variability and the mean, maximal, and minimal QT intervals in normal subjects, whereas the relation was lost in patients with NHVT. No difference was found in mean heart rate between normal subjects and patients with NHVT (70 (9) v 72 (13) beats/min, NS). CONCLUSIONS--The high frequency component of heart rate variability is significantly decreased and the relation of QT interval to heart rate variability is significantly altered in patients with NHVT as compared with normal subjects. These findings suggest that abnormal modulation of the QT interval by the autonomic nervous system may play an important part in the arrhythmogenesis of NHVT. This might result from impaired vagal efferent cardiac activity in these patients. 相似文献
Objective—To assess the accuracy of measurement of area of the lumen, and sensitivity, and specificity of detection of atheroma in coronary arteries in vitro with a commercially available 20 MHz intravascular ultrasound system.
Setting—A teaching hospital department of cardiology with the support of the department of cardiovascular pathology.
Procedure—10 segments of coronary artery were removed from cadaver hearts. Intravascular ultrasound imaging was performed at fixed levels and the vessels were then sectioned and photographed before histological preparation. An independent blinded observer measured luminal area and assessed the presence of atheroma on the intravascular ultrasound images of 76 vessel sections (304 quadrants). The sensitivity and specificity of detection of atheroma was assessed in comparison with the histologically prepared sections. Luminal areas from intravascular ultrasound, photographs of cross sections of the vessels and histological sections were compared with the technique of limits of agreement.
Results—Overall 36% of the 304 quadrants studied histologically had identifiable atheroma. Intravascular ultrasound sensitivity for atheroma was 0·593 and the specificity was 0·839. The positive predictive value was 0·674, and the relative risk 3·139. Values for area of the vessel lumen were on average 9·4 mm2 (confidence interval (CI) 8·6–10·2 mm2) larger than those measured from photographs and 10·7 (CI 9·8–11·6 mm2) larger than those measured from the histological sections.
Conclusions—The intravascular ultrasound system assessed in this study significantly overestimated coronary vessel luminal area and had low sensitivity and specificity for detection of atheroma. Improvements in image resolution are required before this system can provide useful information on coronary artery size and morphology.