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Bundle Branch (bundle + branch)
Kinds of Bundle Branch Terms modified by Bundle Branch Selected AbstractsIs the Fascicle of Left Bundle Branch Involved in the Reentrant Circuit of Verapamil-Sensitive Idiopathic Left Ventricular Tachycardia?PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 10 2003JEN-YUAN KUO The exact reentrant circuit of the verapamil-sensitive idiopathic left VT with a RBBB configuration remains unclear. Furthermore, if the fascicle of left bundle branch is involved in the reentrant circuit has not been well studied. Forty-nine patients with verapamil-sensitive idiopathic left VT underwent electrophysiological study and RF catheter ablation. Group I included 11 patients (10 men, 1 woman; mean age 25 ± 8 years) with left anterior fascicular block (4 patients), or left posterior fascicular block (7 patients) during sinus rhythm. Group II included 38 patients (29 men, 9 women; mean age 35 ± 16 years) without fascicular block during sinus rhythm. Duration of QRS complex during sinus rhythm before RF catheter ablation in group I patients was significant longer than that of group II patients (104 ± 12 vs 95 ± 11 ms, respectively, P = 0.02). Duration of QRS complex during VT was similar between group I and group II patients (141 ± 13 vs 140 ± 14 ms, respectively, P = 0.78). Transitional zones of QRS complexes in the precordial leads during VT were similar between group I and group II patients. After ablation, the QRS duration did not prolong in group I or group II patients (104 ± 11 vs 95 ± 10 ms, P = 0.02); fascicular block did not occur in group II patients. Duration and transitional zone of QRS complex during VT were similar between the two groups, and new fascicular block did not occur after ablation. These findings suggest the fascicle of left bundle branch may be not involved in the antegrade limb of reentry circuit in idiopathic left VT. (PACE 2003; 26:1986,1992) [source] Cells migrating from the neural crest contribute to the innervation of the venous pole of the heartJOURNAL OF ANATOMY, Issue 1 2008Victoria Hildreth Abstract Cells migrating from the neural crest are known to septate the outflow tract of the developing heart, and to contribute to the formation of the arterial valves, their supporting sinuses, the coronary arteries and cardiac neural ganglia. Neural crest cells have also been suggested to contribute to development of the venous pole of the heart, but the extent and fate of such cells remains unclear. In this study, in the mouse, it is shown that cells from the neural crest contribute to the parasympathetic and, to a lesser extent, the sympathetic innervation of the venous pole of the heart. Nerves within the venous pole of the heart are shown to be of mixed origin, with some being derived from the neural crest, while others have an alternative origin, presumably placodal. The neurons innervating the nodal tissue, which can exert chronotropic effects on cardiac conduction, are shown not to be derived from the neural crest. In particular, no evidence was found to support previous suggestions that cells from the neural crest make a direct contribution to the myocardial atrioventricular conduction axis, although a small subset of these cells do co-localize with the developing left bundle branch. We have therefore confirmed that cells from the neural crest migrate to the venous pole of the heart, and that their major role is in the development of the parasympathetic innervation. In addition, in some embryos, a population of cells derived from the neural crest persist in the leaflets of the atrioventricular valves, but their role in subsequent development remains unknown. [source] The Surface Electrocardiogram Predicts Risk of Heart Block During Right Heart Catheterization in Patients With Preexisting Left Bundle Branch Block: Implications for the Definition of Complete Left Bundle Branch BlockJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2010BENZY J. PADANILAM M.D. LBBB and Heart Block.,Background: Patients with left bundle branch block (LBBB) undergoing right heart catheterization can develop complete heart block (CHB) or right bundle branch block (RBBB) in response to right bundle branch (RBB) trauma. We hypothesized that LBBB patients with an initial r wave (,1 mm) in lead V1 have intact left to right ventricular septal (VS) activation suggesting persistent conduction over the left bundle branch. Trauma to the RBB should result in RBBB pattern rather than CHB in such patients. Methods: Between January 2002 and February 2007, we prospectively evaluated 27 consecutive patients with LBBB developing either CHB or RBBB during right heart catheterization. The prevalence of an r wave ,1 mm in lead V1 was determined using 118 serial LBBB electrocardiographs (ECGs) from our hospital database. Results: Catheter trauma to the RBB resulted in CHB in 18 patients and RBBB in 9 patients. All 6 patients with ,1 mm r wave in V1 developed RBBB. Among these 6 patients q wave in lead I, V5, or V6 were present in 3. Four patients (3 in CHB group and 1 in RBBB group) developed spontaneous CHB during a median follow-up of 61 months. V1 q wave ,1 mm was present in 28% of hospitalized complete LBBB patients. Conclusions: An initial r wave of ,1 mm in lead V1 suggests intact left to right VS activation and identifies LBBB patients at low risk of CHB during right heart catheterization. These preliminary findings indicate that an initial r wave of ,1 mm in lead V1, present in approximately 28% of ECGs with classically defined LBBB, may constitute a new exclusion criterion when defining complete LBBB. (J Cardiovasc Electrophysiol, Vol. pp. 781-785, July 2010) [source] An Autopsy Case of Brugada Syndrome with Significant Lesions in the Sinus NodeJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2005SHIN-ICHIRO MORIMOTO M.D. A 30-year-old man with Brugada syndrome died suddenly. The heart weighed 380 g. The left ventricular wall showed mild thickening, and marked fatty tissue deposition was noted in the right ventricular outflow tract. Neither ventricle was enlarged. Contraction band necrosis was diffuse in both ventricles. In the ventricles no cardiac muscle cell hypertrophy or atrophy, or significant interstitial fibrosis was observed. In the sinus node the number of nodal cells was reduced by half, with fatty tissue and fibrosis prominent. But no lesions were evident in the right bundle branch. [source] Latent Mahaim Fiber as a Cause of Antidromic Reciprocating Tachycardia: Recognition and Successful Radiofrequency AblationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 1 2002M.R.C.P., NEIL C. DAVIDSON M.B. Latent Mahaim Fiber. The term "Mahaim fiber" usually is applied to an atriofascicular fiber that inserts distally into the right bundle branch and forms the anterograde limb of a reciprocating tachycardia. One of the features that has been used to describe the physiology of Mahaim fibers is the presence of anterograde preexcitation. We describe two patients who had a clinical tachycardia consistent with a "Mahaim tachycardia" in whom there was no evidence or minimal evidence of anterograde preexcitation during sinus rhythm or atrial pacing. In both patients, the tachycardia was rendered noninducible by radiofrequency ablation at the site of Mahaim potentials at the tricuspid annulus, and a long-term cure was achieved. This is the first description of a "latent Mahaim fiber" that does not cause preexcitation but which can support antidromic reciprocating tachycardia. [source] Exact Location of the Branching Bundle in the Living HeartPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2009MASAMITSU ADACHI M.D., Ph.D. Aims: The His bundle electrogram is believed to reflect the exact location of the His bundle. However, the distinction between distal His bundle potential and proximal right bundle branch potential is challenging. The aim of this study was to pinpoint the location of the branching point of the His bundle, and to compare that site with the site of recording of the largest His bundle electrogram (LH) during sinus rhythm. Methods: We hypothesized that the site of earliest His activation (EH) during retrograde conduction via the left bundle branch is the branching point. We studied 15 nonconsecutive patients (mean age = 40 ± 22 years; eight men). We performed a programmed stimulation from right ventricular apex until retrograde right bundle branch block appeared. At that point we measured (1) the distance between antegrade LH site and retrograde EH site and (2) the atrial-to-ventricular amplitude ratio (A/V ratio) at both sites. Results: EH was recorded at the proximal electrode of the His bundle catheter in all patients. Mean distance between EH and LH was 9.8 ± 2.5 mm. The mean A/V ratios at the EH site and the LH site were 1.01 ± 0.42 and 0.08 ± 0.06, respectively. Discussion: This study showed that the EH site is located approximately 10-mm proximal to the LH site. The mean A/V ratio at the EH site during sinus rhythm is approximately 1.0. These observations suggest that the majority of His potentials reflect proximal right bundle activation. Before delivering radiofrequency energy in the para-Hisian area, attention should be paid to the presence of a His potential and to the A/V ratio, rather to the amplitude of the His electrogram. [source] Is the Fascicle of Left Bundle Branch Involved in the Reentrant Circuit of Verapamil-Sensitive Idiopathic Left Ventricular Tachycardia?PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 10 2003JEN-YUAN KUO The exact reentrant circuit of the verapamil-sensitive idiopathic left VT with a RBBB configuration remains unclear. Furthermore, if the fascicle of left bundle branch is involved in the reentrant circuit has not been well studied. Forty-nine patients with verapamil-sensitive idiopathic left VT underwent electrophysiological study and RF catheter ablation. Group I included 11 patients (10 men, 1 woman; mean age 25 ± 8 years) with left anterior fascicular block (4 patients), or left posterior fascicular block (7 patients) during sinus rhythm. Group II included 38 patients (29 men, 9 women; mean age 35 ± 16 years) without fascicular block during sinus rhythm. Duration of QRS complex during sinus rhythm before RF catheter ablation in group I patients was significant longer than that of group II patients (104 ± 12 vs 95 ± 11 ms, respectively, P = 0.02). Duration of QRS complex during VT was similar between group I and group II patients (141 ± 13 vs 140 ± 14 ms, respectively, P = 0.78). Transitional zones of QRS complexes in the precordial leads during VT were similar between group I and group II patients. After ablation, the QRS duration did not prolong in group I or group II patients (104 ± 11 vs 95 ± 10 ms, P = 0.02); fascicular block did not occur in group II patients. Duration and transitional zone of QRS complex during VT were similar between the two groups, and new fascicular block did not occur after ablation. These findings suggest the fascicle of left bundle branch may be not involved in the antegrade limb of reentry circuit in idiopathic left VT. (PACE 2003; 26:1986,1992) [source] John B. Barlow: Master clinician and compleat cardiologistCLINICAL CARDIOLOGY, Issue 1 2000Tsung O. Cheng M.D. Abstract 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 refractory 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. [source] Sunao Tawara: A Father of Modern CardiologyPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1 2001KOZO SUMA SUMA, K.: Sunao Tawara: A Father of Modern Cardiology. Knowledge of the conduction system of the heart was greatly advanced by Tawara's work carried out in Aschoff's laboratory in Marburg at the beginning of this century. In his monograph, The Conduction System of the Mammalian Heart, published in 1906, Tawara indicated that the treelike structure of specific muscle fibers comprising the atrioventricular node, His bundle, bundle branches, and Purkinje fibers served as the pathway for atrioventricular conduction of excitation in the mammalian heart. From his own anatomic and histological findings of the conduction system, he assumed precisely that the conduction velocity of excitation in the system, except in the atrioventricular node, would be fast and that contraction as the result of excitation would take place at the various sites of the ventricles almost simultaneously. According to Tawara, a long pathway to each contracting unit and a fast conduction velocity of excitation would be a prerequisite for the effective contraction of the ventricles. Tawara's findings and assumptions provided Einthoven the theoretical basis for interpreting the electrocardiogram, resulting in rapid popularization of electrocardiography. This century has witnessed the rapid progress of cardiology, including cardiac pacing and its related sciences. This progress has its roots in the discovery of the conduction system and the development of electrocardiography that took place almost in the same period at the beginning of this century. Tawara's pioneering work on the conduction system still serves as an invaluable reference for basic and clinical research. [source] Spatiotemporal pattern of commitment to slowed proliferation in the embryonic mouse heart indicates progressive differentiation of the cardiac conduction systemTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 1 2003David Sedmera Abstract Patterns of DNA synthesis in the developing mouse heart between ED7.5,18.5 were studied by a combination of thymidine and bromodeoxyuridine labeling techniques. From earliest stages, we found zones of slow myocyte proliferation at both the venous and arterial poles of the heart, as well as in the atrioventricular region. The labeling index was distinctly higher in nonmyocardial populations (endocardium, epicardium, and cardiac cushions). Ventricular trabeculae showed lower proliferative activity than the ventricular compact layer after their appearance at ED9.5. Low labeling was observed in the pectinate muscles of the atria from ED11.5. The His bundle, bundle branches, and Purkinje fiber network likewise were distinguished by their lack of labeling. Thymidine birthdating (label dilution) showed that the cells in these emerging components of the cardiac conduction system terminally differentiated between ED8.5,13.5. These patterns of slowed proliferation correlate well with those in other species, and can serve as a useful marker for the forming conduction system. Anat Rec Part A 274A:773,777, 2003. © 2003 Wiley-Liss, Inc. [source] | |||||||||||||