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Cardiac Pacing (cardiac + pacing)
Selected AbstractsInternational Consensus on Nomenclature and Classification of Atrial Fibrillation: A Collaborative Project of the Working Group on Arrhythmias and the Working Group of Cardiac Pacing of the European Society of Cardiology and the North American Society of Pacing and ElectrophysiologyJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2003SAMUEL LÉVY M.D. No abstract is available for this article. [source] Practices and Outcome of Artificial Cardiac Pacing in 154 DogsJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 3 2001Mark A. Oyama Artificial pacing (AP) is a treatment for symptomatic bradyarrhythmias unresponsive to medical therapy. This retrospective study was designed to define the practices and outcome of AP in dogs at 7 referral institutions participating in the Companion Animal Pacemaker Registry and Repository (CANPACERS). The indications, implantation techniques, complications, long-term outcome, and owner satisfaction were examined. One hundred fifty-four dogs were identified as undergoing AP from January 1, 1991, to January 1, 1996. Third-degree atrioventricular (AV) block (n = 91; 59%) and sinus node dysfunction (n = 45; 29%) were the most common indications for AP. Transvenous endocardial AP systems were implanted in 136 dogs (88%), and epicardial systems were implanted in 18 (12%). Complications associated with AP were reported in 84 dogs (55%). Major complications occurred in 51 dogs (33%), including dislodgement of the pacing lead (n = 15; 10%), generator failure (n = 10; 6%), cardiac arrest during implantation (n = 9; 6%), and infection (n = 7; 5%). Minor complications occurred in 47 dogs (31%), including seroma formation (n = 18; 12%), muscle twitch (n = 17; 11%), and inconsequential arrhythmias (n = 15; 10%). Fourteen dogs (9%) experienced both major and minor complications. Survival analysis revealed 1-, 2-, and 3-year survival rates of 70, 57, and 45%, respectively. Age and presence of preexisting congestive heart failure (CHF) had a negative effect on survival (P= .001). Sixty percent of dogs with preexisting CHF died within 1 year of implantation, whereas 25% of dogs without heart failure died during the same period. Owners rated their satisfaction with the procedure as high in 80% of the dogs. [source] Cardiac Pacing: Memories of a Bygone EraPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 9 2008HARRY G. MOND M.D. The first cardiac pacemaker implants occurred in the late 1950s and involved insertion of epicardial or epimyocardial leads and abdominal pulse generators. By the mid 1960s, cardiologists were making attempts to insert transvenous leads into the right ventricle. These early unipolar leads had large, polished, high polarization electrodes, no fixation device, and no lumen in which to place a stylet for lead positioning. The lead implantation procedures were usually long and the irradiation to both patient and operator excessive. Pulse generators were powered by zinc-mercury cells, which were large, unreliable, and prone to sudden output failure. Postoperative complications such as lead dislodgement, exit block, and premature power source failure were very common with most patients requiring further surgery within a year. Little has been written of this period and in particular the experiences of the operators, such that today's pacemaker implanters have virtually no knowledge of this bygone era. This historical report by four Australian cardiologists details the operative procedures and follow-up management of those original pacemaker recipients. [source] Primary Prevention of Heart Failure in Cardiac PacingPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 3 2006S. SERGE BAROLD No abstract is available for this article. [source] The Twelfth World Symposium of Cardiac Pacing and ElectrophysiologyPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1p1 2003SEYMOUR FURMAN No abstract is available for this article. [source] The baroreflex is counteracted by autoregulation, thereby preventing circulatory instabilityEXPERIMENTAL PHYSIOLOGY, Issue 4 2004Roberto Burattini The aims of this study were (a) to apply in the animal with intact baroreflex a two-point method for estimation of overall, effective open-loop gain, G0e, which results from the combined action of baroregulation and total systemic autoregulation on peripheral resistance; (b) to predict specific baroreflex gain by correcting the effective gain for the autoregulation gain; and (c) to discuss why the effective gain is usually as low as 1,2 units. G0e was estimated from two measurements of both cardiac output, Q, and mean systemic arterial pressure, P: one in the reference state (set-point) and the other in a steady-state reached 1,3 min after a small cardiac output perturbation. In anaesthetized cats and dogs a cardiac output perturbation was accomplished by partial occlusion of the inferior vena cava and by cardiac pacing, respectively. Average (±s.e.m.) estimates of G0e were 1.4 ± 0.2 (n= 8) in the cat and 1.5 ± 0.4 (n= 5) in the dog. The specific baroreflex open-loop gain, G0b, found after correction for total systemic autoregulation, was 3.3 ± 0.4 in the cat and 2.8 ± 0.8 in the dog. A model-based analysis showed that, with G0e as low as 1.4, the closed-loop response of P to a stepwise perturbation in Q results in damped oscillations that disappear in about 1 min. The amplitude and duration of these oscillations, which have a frequency of about 0.1 Hz, increase with increasing G0e and cause instability when G0e is about 3. We conclude that autoregulation reduces the effectiveness of baroreflex gain by about 55%, thereby preventing instability of blood pressure response. [source] Contribution of a Pacemaker Bradycardia Detection Algorithm in the Study of Patients with Carotid Sinus SyndromePACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 6 2001PIERRE GRAUX GRAUX, P., et al.: Contribution of a Pacemaker Bradycardia Detection Algorithm in the Study of Patients with Carotid Sinus Syndrome. While carotid sinus syndrome (CSS) is often suspected as a cause of syncope in the elderly, whether it represents an indication for cardiac pacing may remain uncertain. Bradycardia algorithms included in pacemakers are now able to establish a precise relationship between spontaneous asystole and occurrence of symptoms and strengthen the indication for permanent pacing. This study included seven men and three women (70.5 ± 7.3 years of age) who, over an average period of 54.1 ± 17 months, had suffered from syncope (12.6 episodes/patient) and presyncope (11.2 episodes/patient) attributed to pure cardioinhibition (2 patients) or mixed CSS (8 patients). Other sources of symptoms were excluded by thorough clinical evaluations, including Holter monitoring, echocardiography, and electrophysiological testing. All patients received a CHORUS 6234 pacemaker, the memory of which includes a dedicated bradycardia detection algorithm capable of storing atrial and ventricular chains, and date and time of the last ten pauses and/or bradycardic events. After a initial period of 14.7 ± 8 months, during which symptoms were suppressed, the bradycardia algorithm was activated. From then on, a cumulative increase in the number of patients presenting with diurnal pauses was measured (1 month, n = 0; 3 months, n = 6; 9 months, n = 7; 2 years, n = 8). Fourteen episodes of diurnal asystole were recorded. The mean duration of the longest episodes of spontaneous ventricular standstill was 6,319 ± 1,615 ms and was due to sinoatrial block (n = 7), atrioventricular block (n = 5), and a combination of both (n = 2). In conclusion, activation of the CHORUS bradycardia algorithm allowed confirmation of the appropriateness of permanent pacing in a majority of patients suffering from CSS. [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] Unresponsive asystolic cardiac arrest responding to external cardiac pacing in a patient with phaeochromocytomaANAESTHESIA, Issue 8 2007M. J. Taylor Summary An anaesthetised 48-year-old woman became haemodynamically unstable following biopsy of a thoracic mass suggesting a diagnosis of a thoracic phaeochromocytoma. Surgery was postponed to allow confirmatory investigations and pre-operative adrenoceptor blockade with phenoxybenzamine and labetalol. Nine days later, following resection of her phaeochromocytoma, she suffered an intra-operative asystolic cardiac arrest which was unresponsive to standard resuscitation protocols and required external cardiac pacing. We discuss the issues involved and suggest that the competitive ,1 adrenoceptor antagonist doxazosin may be preferable to the covalently bound mixed alpha adrenoceptor antagonist phenoxybenzamine in the pre-operative preparation of patients with phaeochromocytoma. [source] Sildenafil (Viagra) reduces arrhythmia severity during ischaemia 24 h after oral administration in dogsBRITISH JOURNAL OF PHARMACOLOGY, Issue 4 2004Orsolya Nagy Sildenafil (Viagra) prolongs repolarisation in cardiac muscle, an effect that could lead to ventricular fibrillation (VF). Sildenafil (2 mg kg,1) was given by mouth to 12 mongrel dogs and, 24 h later, these dogs were anaesthetised, thoracotomised and subjected to a 25 min occlusion of the anterior descending coronary artery. Haemodynamic parameters were similar in this and the control group, but there were fewer and less serious ventricular arrhythmias during occlusion in the sildenafil group (VF 17 vs 60%; ventricular premature beats 140±52 vs 437±127% and episodes of ventricular tachycardia 4.0±3.2 vs 19.3±7.7%, all P<0.05). However, reperfusion VF and indices of ischaemia severity (epicardial ST-segment mapping, inhomogeneity) were not modified by the drug. Sildenafil increased the QT interval, especially during ischaemia. Our conclusion is that ischaemia-induced ventricular arrhythmias are reduced by sildenafil, but this protection is less pronounced than that following cardiac pacing or exercise. British Journal of Pharmacology (2004) 141, 549,551. doi:10.1038/sj.bjp.0705658 [source] Cardiac veins: A review of the literatureCLINICAL ANATOMY, Issue 1 2009Marios Loukas Abstract Cardiac veins have long stood in the shadow of their more extensively studied counterparts, the coronary arteries. The clinical importance of the coronary venous system, nonetheless, should not be underestimated. Intricate and beneficial therapeutic options are increasingly being developed that depend on knowledge of the structure of this venous network. Such interventions have been shown greatly to promote cardiac health, and to enhance the efficacy of cardiac pacing. A comprehensive appreciation of the architecture of the coronary venous system, therefore, is crucial to optimal cardiac care. It is possible to provide an overview of the arrangement of the cardiac veins, with the larger veins draining to the coronary sinus, and thence to the right atrium, but with smaller and minimal veins draining directly to the cavities of the atrial chambers. The venous pathways, nonetheless, are highly variable, making exceptions the commonly accepted rule. As such, unique solutions for imaging, and simple attentiveness to possible venous variations, can greatly enhance clinical outcomes. For example, identifying the diameter, course, and valves of the cardiac veins allows for anticipation of impediments during interventional procedures, and allows for informed clinical decision-making. Also of significance is awareness of alternate arrangements that may be encountered in terms of venous drainage, and the importance of intramural venous collecting spaces in these patterns. The objective of our review, therefore, is to explore and describe the anatomical distribution of the coronary veins Clin. Anat. 22:129,145, 2009. © 2008 Wiley-Liss, Inc. [source] | |||||||||||||