1/50. AV reentrant and idiopathic ventricular double tachycardias: complicated interactions between two tachycardias.An electrophysiological study was performed in a 61 year old man with Wolff- Parkinson-White (WPW) syndrome. At baseline, neither ventricular nor supraventricular tachycardias could be induced. During isoprenaline infusion, ventricular tachycardia originating from the right ventricular outflow tract (RVOT) with a cycle length of 280 ms was induced and subsequently atrioventricular reentrant tachycardia (AVRT) with a cycle length of 300 ms using an accessory pathway in the left free wall appeared. During these tachycardias, AVRT was entrained by ventricular tachycardia. The earliest ventricular activation site during the ventricular tachycardia was determined to be the RVOT site and a radiofrequency current at 30 W successfully ablated the ventricular tachycardia at this site. The left free wall accessory pathway was also successfully ablated during right ventricular pacing. The coexistence of WPW syndrome and cathecolamine sensitive ventricular tachycardia originating from the RVOT has rarely been reported. Furthermore, the tachycardias were triggered by previous tachycardias.- - - - - - - - - - ranking = 1keywords = cycle (Clic here for more details about this article) |
2/50. adenosine-induced atrial pro-arrhythmia in children.adenosine has become the preferred acute treatment for common types of supraventricular tachycardia because of its efficacy and safety. There have been a few reports of serious proarrhythmic events associated with its use, including the induction of atrial fibrillation in adult patients. Three instances of adenosine-induced atrial proarrhythmia (two atrial fibrillation and one atrial flutter) have been observed in children with manifest or concealed wolff-parkinson-white syndrome at the Hospital for Sick Children, Toronto, ontario since 1990, which indicates a previously unreported risk of atrial arrhythmia for children as well. Because adenosine may enhance antegrade bypass tract conduction, its use carries a risk of ventricular acceleration, including progression to ventricular fibrillation. Because of such rare and potentially life-threatening adverse effects, appropriate monitoring and precautions are required during the administration of the drug to children and adults.- - - - - - - - - - ranking = 0.0023308144325657keywords = life (Clic here for more details about this article) |
3/50. Electrophysiologic characteristics of accessory atrioventricular connections in an inherited form of wolff-parkinson-white syndrome.INTRODUCTION: A familial form of wolff-parkinson-white syndrome (WPW) occurs in association with hypertrophic cardiomyopathy and intraventricular conduction abnormalities. This syndrome, demonstrating autosomal dominant inheritance and segregating with a high degree of penetrance but variable expressivity, has been genetically linked to chromosome 7q3. The purpose of this study is to detail the electrophysiologic characteristics of accessory atrioventricular connections (AC) in four members of a kindred with this syndrome. methods AND RESULTS: We clinically evaluated 32 members of a single kindred and identified 20 individuals with ventricular preexcitation, abnormal intraventricular conduction including complete AV block and/or ventricular hypertrophy. genetic linkage analysis mapped the disease gene in this kindred to the chromosome 7q3 locus (maximum logarithm of the odds score = 6.88, theta = 0); recombination events in affected individuals reduced the genetic interval from 7 centimorgans (cM) to 5 cM. Electrophysiologic study of four individuals with preexcitation, identified seven AC (1 right sided, 3 septal, and 3 left sided). All four individuals had inducible orthodromic tachycardia; while three had multiple AC. Bidirectional conduction was demonstrated in 6 of 7 AC. Successful ablation was accomplished in 5 of 7 AC. CONCLUSION: The electrophysiologic characteristics and location of AC in family members having this complex cardiac phenotype are similar to those seen in individuals with isolated WPW. Identification of WPW in more than one family member should prompt clinical evaluation of relatives for additional findings of ventricular hypertrophy or conduction abnormalities.- - - - - - - - - - ranking = 0.22197569339257keywords = family (Clic here for more details about this article) |
4/50. A wide "gap" in retrograde conduction through a concealed accessory atrioventricular pathway depending on ventricular pacing sites.We present a 57-year-old man with wolff-parkinson-white syndrome who exhibited a wide "gap" in retrograde conduction through a concealed atrioventricular accessory pathway. The appearance of the wide "gap" depended on the ventricular pacing sites. While ventricular extrastimuli at a basic cycle length of 600 msec from the right ventricular outflow tract consistently conducted to the atria, retrogradely through the accessory pathway, those from the right ventricular apex repeatedly revealed disappearance of the retrograde conduction at the wide coupling intervals from 550 to 380 msec. The mechanisms of this rare "gap"-like phenomenon are discussed in this paper.- - - - - - - - - - ranking = 0.5keywords = cycle (Clic here for more details about this article) |
5/50. Development of rapid atrial fibrillation with a wide QRS complex after neostigmine in a patient with intermittent wolff-parkinson-white syndrome.We report the case of a 67-yr-old man with intermittent Wolff-Parkinson-White (WPW) syndrome in whom neostigmine produced life-threatening tachyarrhythmias. The patient was scheduled for microsurgery for a laryngeal tumour. When he arrived in the operating room, the electrocardiogram showed normal sinus rhythm with a rate of 82 beat min-1 and a narrow QRS complex which remained normal throughout the operative period. On emergence from anaesthesia, the sinus rhythm (87 beat min-1) changed to atrial fibrillation with a rate of 80-120 beat min-1 and a normal QRS complex. We did not treat the atrial fibrillation because the patient was haemodynamically stable. neostigmine 1 mg without atropine was then administered to antagonize residual neuromuscular block produced by vecuronium. Two minutes later, the narrow QRS complexes changed to a wide QRS complex tachycardia with a rate of 110-180 beat min-1, which was diagnosed as rapid atrial fibrillation. As the patient was hypotensive, two synchronized DC cardioversions of 100 J and 200 J were given, which restored sinus rhythm. No electrophysiological studies of anticholinesterase drugs have been performed in patients with WPW syndrome. We discuss the use of these drugs in this condition.- - - - - - - - - - ranking = 0.0023308144325657keywords = life (Clic here for more details about this article) |
6/50. Demonstration of phase-3 and phase-4 retrograde block in a second concealed accessory pathway after an initial successful radiofrequency ablation of a 'normal' concealed accessory pathway.We report a patient with concealed wolff-parkinson-white syndrome who, following catheter ablation, demonstrated phase-3 and phase-4 retrograde block in a concealed accessory pathway. After an initial 'apparently successful' ablation, retrograde conduction was through the atrioventricular node during constant ventricular pacing. Ventricular extrastimulus testing was performed at a basic drive cycle length of 600 ms. Unexpectedly, ventricular extrastimuli at coupling intervals of 440-380 ms were conducted retrogradely over an accessory pathway, consistent with a phase-3 and phase-4 retrograde block in the accessory pathway. Residual accessory pathway conduction was eliminated in a single ablation session.- - - - - - - - - - ranking = 0.5keywords = cycle (Clic here for more details about this article) |
7/50. Transient appearance of antegrade conduction via an AV accessory pathway caused by atrial fibrillation in a patient with intermittent wolff-parkinson-white syndrome.A 55 year old man with intermittent Wolff-Parkinson-White (WPW) syndrome had an episode of atrial fibrillation (AF) that lasted for 117 days. After interruption of the AF a Delta wave appeared that lasted for two days and then disappeared. exercise stress and isoprenaline infusion could not reproduce the Delta wave, but after another episode of AF which lasted for seven days a persistent Delta wave appeared that lasted for six hours. In an electrophysiological study performed on a day without a Delta wave, neither antegrade nor retrograde conduction via an accessory pathway was seen, but after atrial burst pacing (at 250 ms cycle length) for 10 minutes, a Delta wave appeared lasting for 16 seconds. Atrial electrical remodelling-that is, the shortening of the atrial effective refractory period caused by AF, is a possible mechanism of the appearance of the Delta wave.- - - - - - - - - - ranking = 0.5keywords = cycle (Clic here for more details about this article) |
8/50. Medically complex pregnancy: a case report illustrating CNM/MD collaborative management.In contemporary society, many women with complex medical conditions are attempting fertility and becoming pregnant. The patient presents with an impressive medical complication, yet many of her key educational and psychosocial needs are typical of those for any pregnant woman. Striving for "normalcy," she may actively seek midwifery care to help her create a family-centered birth experience. Indeed, the midwife practicing with physician colleagues may have the opportunity to collaboratively manage increasingly complex cases. This article describes the case of collaborative management during pregnancy and delivery of a patient with the cardiac syndrome Wolff-Parkinson White syndrome (WPW). First diagnosed with WPW at the age of 13, the patient's condition was initially controlled with oral medication. Eventually, the patient's symptomology worsened and required repeated treatment by cardiac ablation of the accessory pathway. Illustrative of the possibilities for enhanced care of the medically complex pregnant patient via collaborative management, the discussion details not only the pertinent physiologic events but the benefits and process of care. A review of the cardiophysiology of WPW is also presented.- - - - - - - - - - ranking = 0.11098784669629keywords = family (Clic here for more details about this article) |
9/50. Novel PRKAG2 mutation responsible for the genetic syndrome of ventricular preexcitation and conduction system disease with childhood onset and absence of cardiac hypertrophy.BACKGROUND: We recently reported a mutation in the PRKAG2 gene to be responsible for a familial syndrome of ventricular preexcitation, atrial fibrillation, conduction defects, and cardiac hypertrophy. We now report a novel mutation in PRKAG2 causing wolff-parkinson-white syndrome and conduction system disease with onset in childhood and the absence of cardiac hypertrophy. methods AND RESULTS: dna was extracted from white blood cells obtained from family members. PRKAG2 exons were amplified by polymerase chain reaction and were screened for mutations by direct sequencing. The genomic organization of the PRKAG2 gene was determined using inter-exon long-range polymerase chain reaction for cDNA sequence not available in the genome database. A missense mutation, Arg531Gly, was identified in all affected individuals but was absent in 150 unrelated individuals. The PRKAG2 gene was determined to consist of 16 exons and is at least 280 kb in size. CONCLUSIONS: We identified a novel mutation (Arg531Gly) in the gamma-2 regulatory subunit (PRKAG2) of AMP-activated protein kinase (AMPK) to be responsible for a syndrome associated with ventricular preexcitation and early onset of atrial fibrillation and conduction disease. These observations confirm an important functional role of AMPK in the regulation of ion channels specific to cardiac tissue. The identification of the cardiac ion channel(s) serving as substrate for AMPK not only would provide insight into the molecular basis of atrial fibrillation and heart block but also may suggest targets for the development of more specific therapy for these common rhythm disturbances.- - - - - - - - - - ranking = 0.11098784669629keywords = family (Clic here for more details about this article) |
10/50. Wolff Parkinson White (WPW) syndrome: what the critical care nurse needs to consider when administering antiarrhythmics.This paper discusses the importance of critical care and emergency nurses having an understanding of why pre-existing cardiac disorders can influence antiarrhythmic treatment. The patient with a pre-excitation syndrome is usually managed in a coronary care unit. However, these patients may be admitted to an intensive care unit (ICU) with complications of Wolff Parkinson White (WPW) syndrome; for example post cardiopulmonary arrest or WPW as a co-morbidity. It is common practice in critical care areas for registered nurses to administer antiarrhythmics without a doctor's prescription in life-threatening situations. Therefore, the critical care nurse must have knowledge of the implications of administering standard antiarrhythmic agents if this patient reverts into a tachyarrhythmia. If antiarrhythmics are administered that are contraindicated in patients with WPW syndrome, then there is potential for deleterious effects. This case study highlights the different pharmacological agents for treating tachyarrhythmias in a patient with WPW syndrome. The paper outlines the correct treatment and discusses the deleterious effects of incorrect administration of drugs in WPW syndrome.- - - - - - - - - - ranking = 0.0023308144325657keywords = life (Clic here for more details about this article) |
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