1/16. tachycardia-dependent right bundle-branch block with supernormal conduction.This paper reports the case of a 76-year-old man in whom atrial flutter with varying atrioventricular block and intermittent right bundle-branch block was found. This is the first report on tachycardia-dependent right bundle-branch block associated with supernormal conduction in a case of atrial flutter. When an impulse is conducted to the ventricles beyond 0.72 s after a QRS complex of right bundle-branch block configuration, the impulse falls after the abnormally long effective refractor period of the right bundle branch and passes through the right bundle branch. When the conducted impulse occurs within 0.72 s after a QRS complex of right bundle-branch block configuration, the impulse usually falls in the refractory period and is blocked in the right bundle branch; however, only when the impulse occurs 0.48 or 0.49 s after that does it fall in the supernormal period and passes through the right bundle branch. The findings in the present report strengthen our previous suggestion that the presence of supernormal conduction plays an important role in the initiation of reentrant ventricular tachycardia.- - - - - - - - - - ranking = 1keywords = complex (Clic here for more details about this article) |
2/16. syncope in patients with atrial flutter during treatment with class Ic antiarrhythmic drugs.We describe 2 atrial flutter (AFL) patients with syncope during treatment with class Ic antiarrhythmic drugs. During the syncope, 1:1 atrioventricular (AV) conduction during AFL preceded a wide QRS tachycardia. The class Ic drugs, flecainide and pilsicainide, slowed the atrial rate, resulting in AFL with 1:1 AV conduction, and the width of the QRS complexes became wider during the tachycardia. syncope was abolished after successful radiofrequency catheter ablation of the AFL. These potential proarrhythmic effects of the class Ic drugs should be taken into account in AFL patients, and concomitant use of beta-blocking agents would be critical to prevent proarrhythmias.- - - - - - - - - - ranking = 0.5keywords = complex (Clic here for more details about this article) |
3/16. Characterization of the anatomy and conduction velocities of the human right atrial flutter circuit determined by noncontact mapping.OBJECTIVES: This study was done to characterize human right atrial (RA) flutter (AFL) using noncontact mapping. BACKGROUND: atrial flutter has been mapped using sequential techniques, but complex anatomy makes simultaneous global RA mapping difficult. methods: Noncontact mapping was used to map the RA of 13 patients with AFL (5 with previous attempts), 11 with counterclockwise and 2 with clockwise AFL. "Reconstructed" electrograms were validated against contact electrograms using cross-correlation. The Cartesian coordinates of points on a virtual endocardium were used to calculate the length and thus the conduction velocity (CV) of the AFL wave front within the tricuspid annulus-inferior vena cave isthmus (IS) and either side of the crista terminalis (CT). RESULTS: When clearly seen, the AFL wave front split (n = 3) or turned in the region of the coronary sinus os (n = 6). Activation progressed toward the tricuspid annulus (TA) from the surrounding RA in 10 patients, suggesting that the leading edge of the reentry wave front is not always at the TA. The IS length and CV was 47.73 /- 24.40 mm (mean /- SD) and 0.74 /- 0.36 m/s. The CV was similar for the smooth and trabeculated RA (1.16 /- 0.48 m/s and 1.22 /- 0.65 m/s, respectively [p = 0.67]) and faster than the IS (p = 0.03 and p = 0.05 for smooth and trabeculated, respectively). CONCLUSIONS: Noncontact mapping of AFL has been validated and has demonstrated that IS CV is significantly slower than either side of the CT.- - - - - - - - - - ranking = 0.5keywords = complex (Clic here for more details about this article) |
4/16. Noncontact mapping for radiofrequency ablation of complex cardiac arrhythmias.Radiofrequency (RF) catheter ablation is the current treatment of choice for several cardiac arrhythmias. The conventional approach utilizing intracardiac electrograms during sinus rhythm and during tachycardia has inherent limitations, including limited two-dimensional fluoroscopic imaging and limited ability to evaluate several potential sites for ablation then go precisely to the most suitable site. Recently, a noncontact mapping system has been developed that can be used to perform single beat high resolution mapping of cardiac arrhythmias. In this report, we describe the advantage of utilizing the system in facilitating a successful outcome in 5 patients with different complex arrhythmias.- - - - - - - - - - ranking = 2.5keywords = complex (Clic here for more details about this article) |
5/16. Torsade de pointes induced by ajmaline.ajmaline, a reserpine derivative, is an effective class I antiarrhythmic agent. Herein we report two cases of ajmaline-induced abnormal QT prolongation accompanied by polymorphic ventricular tachycardia of the torsade de pointes type. Since ajmaline is increasingly used for the acute termination of wide complex tachycardia and as a diagnostic tool after syncope and in patients with idiopathic ventricular tachyarrhythmias, our observations suggest that caution should be exercised with regard to the effects of the drug on the QT interval and its potency to induce proarrhythmia of the torsade de pointes type.- - - - - - - - - - ranking = 0.5keywords = complex (Clic here for more details about this article) |
6/16. Failure of atrial flutter detection by a pacemaker with a dedicated atrial flutter detection algorithm.Detection of atrial flutter may be difficult for pacemakers with automatic mode switching algorithms. The Medtronic Kappa 700 device pacemakerfamily offers a dedicated Blanked Flutter Search algorithm specifically designed for the detection of atrial flutter. This report describes how spontaneous atrioventricular conduction, resulting in a sensed QRS complex at a critical time, inhibited the function of the Blanked Flutter Search algorithm to sense "concealed" or "blanked" atrialflutter. This observation underscores the need for further refinement of pacemaker algorithms for the detection of atrial tachyarrhythmias.- - - - - - - - - - ranking = 0.5keywords = complex (Clic here for more details about this article) |
7/16. Masquerade: a malignant arrhythmia masquerading as benign.Pseudoatrial flutter has been reported to have benign causes, but this is the first report of a malignant arrhythmia presenting as a benign arrhythmia. An 82 year old patient presented with ventricular tachycardia and electrical artefact appearing as atrial flutter. In this case, comparing the morphology of the QRS complexes in the rhythm strip with those in lead II showed the arrhythmia to be ventricular in origin and points to the importance of comparing all leads of the ECG before arriving at a diagnosis.- - - - - - - - - - ranking = 0.5keywords = complex (Clic here for more details about this article) |
8/16. Flutrer-like P waves in a case of atrioventricular reciprocating tachycardia.Typical atrial flutter is characterized by its sawtooth flutter wave in leads II, III, aVF, and V1. Atrioventricular reciprocating tachycardia is characterized by its small retrograde P wave after completion of QRS complex, where sawtooth flutter-like P waves are rarely seen in the electrocardiogram during atrioventricular reciprocating tachycardia. We report on a 62-year-old patient who presented the characteristic sawtooth flutter-like P waves in the electrocardiogram during attack of supraventricular tachycardia. By electrophysiologic study, the mechanism of his supraventricular tachycardia was atrioventricular reciprocating tachycardia using the left posterior lateral concealed accessory pathway for retrograde conduction. The accessory pathway was successfully ablated by radiofrequency ablation therapy.- - - - - - - - - - ranking = 0.5keywords = complex (Clic here for more details about this article) |
9/16. One heart, two minds.A case of complex atrial tachyarrhythmias following orthotopic heart transplantation is presented. The ablation strategy in such a situation and the outcome achieved are discussed.- - - - - - - - - - ranking = 0.5keywords = complex (Clic here for more details about this article) |
10/16. Bundle branch block in alternate beats during 2:1 atrial flutter.This presentation deals with a case of atrial flutter. During 2:1 A/V conduction, the QRS complexes showed a regular alternation of narrow beats and wide beats with a typical configuration of left bundle branch block. In contrast, pauses resulting from 4:1 A/V conduction ratio always resulted in narrow beats. Disappearance of left bundle branch block with long R-R intervals demonstrated that the block was tachycardia-dependent or phase 3. Analysis of the tracing suggested that narrowing of QRS complexes in alternate beats was due to supernormal left bundle branch conduction associated with retrograde concealed conduction into the anterogradely blocked bundle branch.- - - - - - - - - - ranking = 1keywords = complex (Clic here for more details about this article) |
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