The existence of a lower common pathway in AV nodal reentrant tachycardia: a controversy reluctant to die.
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Atrioventricular Node↗
Biomedical subjects
J L Merino
Publications and source records attributed to J L Merino.
Successful treatment of prosthetic aortic valve mucormycosis.
Mucor endocarditis after cardiovascular surgery is rare and usually fatal. We report the first known case of prosthetic aortic valve mucormycosis in a patient without predisposing risk factors who was successfully treated using a combination of early antifungal drug therapy and surgical removal of infected material.
Aortic Valve↗
Randomized, prospective comparison of four burst pacing algorithms for spontaneous ventricular tachycardia.
"Less aggressive" burst stimulation is more effective in terminating spontaneous monomorphic ventricular tachycardia with a lesser acceleration rate. Higher ventricular tachycardia cycle length and use of 91% coupling interval were independent predictors for pacing termination.
Adult↗
Mechanisms of sustained ventricular tachycardia in myotonic dystrophy: implications for catheter ablation.
BACKGROUND: Ventricular arrhythmias have been documented and linked to the high incidence of sudden death seen in patients with myotonic dystrophy. However, their precise mechanism is unknown, and their definitive therapy remains to be established. METHODS AND RESULTS: We studied 6 consecutive patients with myotonic dystrophy and sustained ventricular tachycardia by means of cardiac electrophysiological testing. Particular attention was paid to establish whether bundle-branch reentry was the tachycardia mechanism, and when such was the case, radiofrequency catheter ablation of either the right or left bundle branch was performed. Clinical tachycardia was inducible in all patients and had a bundle-branch reentrant mechanism. In 1 patient, 2 other morphologies of sustained tachycardia were also inducible, neither of which had ever been clinically documented, and both had a bundle-branch reentrant mechanism. Ventricular tachycardia was no longer inducible after bundle-branch ablation, except for a nonclinically documented and nonsustained ventricular tachycardia in the only patient who had apparent structural heart disease. CONCLUSIONS: A high clinical suspicion of bundle-branch reentrant tachycardia is justified in patients with myotonic dystrophy who exhibit wide QRS complex tachycardia or tachycardia-related symptoms. Because catheter ablation will easily and effectively abolish bundle-branch reentrant tachycardia, myotonic dystrophy should always be considered in patients with sustained ventricular tachycardia. This is especially true if no apparent heart disease is found.
Adult↗
Implantable cardioverter defibrillator as therapeutic option for sudden cardiac death secondary to severe coronary vasospasm.
We report a case of a patient with angina at rest followed by sudden cardiac death secondary to ventricular fibrillation. Cardiac catheterization did not show significant coronary stenosis but after an acetylcholine test, a severe coronary spasm was induced. Despite intensive medical therapy, vasospasm was not prevented. Finally, the patient received an implantable cardioverter defibrillator (ICD) to avoid the risk of sudden cardiac death. In our opinion, ICD in addition to medical therapy may be useful in patients with sudden cardiac death secondary to coronary vasospasm.
Aged↗
Complete coding sequence of a serologically undefined HLA-B antigen: HLA-B*1537.
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Amino Acid Sequence↗
Complete coding sequence of HLA-B*2712: a serologic B27-negative antigen associated to Bw6.
We report the complete coding sequence of a new HLA-B27 subtype, B*2712, which was found in a Caucasian Spanish family within the chromosome A2-Cw2-B*2712-DR15-DQ6. B*2712 was first detected as a segregating B blank Bw6-associated antigen. Extensive serologic analysis demonstrated that this new B27 subtype was not recognised by any of the B27-monospecific antibodies, giving positive reactions only with some monoclonal reagents against B40 or B27,40. Sequencing analysis showed a high similarity with B*2708, only differing in three clustered amino acid residues at positions 69 to 71 located in the alpha helix of the alpha1 domain. Residues 69 and 71 point towards the T-cell receptor, while amino acid 70 points to the antigen binding site. Loss of the conserved structure of pocket B as well as the differentiated pocket F configuration suggests that B*2712 does not confer ankylosing spondylitis susceptibility. Misleading serologic definition supports the usefulness of DNA-typing methods to complement HLA class I typing.
Amino Acid Sequence↗
Characterization of a new HLA-B18 allele, B*1806, which lacks expression of the Bw6 epitope.
HLA-B18 is a well defined Bw6-associated serologic specificity. Up to now, four different sequences have been characterised in Caucasian populations (B*1801,3,4,5), and one in Orientals (B*1802). We report a new HLA-B18 subtype (B*1806) which was serologically detected in a Spanish Caucasian individual as a B18 Bw4-associated antigen. Complete coding region sequencing showed that B*1806 differs from B*1801 in a unique nucleotide at position 299 (A to T), giving rise to an amino acid replacement in residue 76 (glutamic acid to valine) placed at the alpha1 domain. Therefore, in contrast to the serologic results, B*1806 possesses the canonical Bw6 motif at position 77-83. Subsequent flow cytometric assays proved that B*1806 evidences neither Bw4 nor Bw6 epitopes. Only three additional HLA-B alleles encode valine at codon 76, B*4601, B*7301 and B*5503, and like B*1806, all of them would include a Bw6 motif associated to the negative recognition by Bw6 antibodies. These findings support that valine at position 76 will modify the Bw6 epitope drastically, and suggest that this group of HLA-B alleles would define a third, Bw4 and Bw6-negative, lineage of molecules. Furthermore, valine 76 will also prevent the binding of Bw6 antibodies to those HLA-C antigens with the canonical Bw6 epitope (Cw*1,3,7,8,12,13,14,16).
Alleles↗
It is bundle branch reentry linked to any kind of muscular dystrophy?
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Bundle of His↗
Unipolar mapping and magnetic resonance imaging of "idiopathic" right ventricular outflow tract ectopy.
Radiofrequency catheter ablation of symptomatic ventricular ectopy guided by unipolar mapping was successfully accomplished at the right ventricular outflow tract in a patient who did not exhibit apparent structural heart disease. A "QS" morphology with a fast slope of the downstroke deflection at the successful ablation site was observed on the unipolar electrogram. Focal thinning of the lateral wall of the right ventricular outflow tract was shown in the magnetic resonance image, similar to that reported in patients with "idiopathic" right ventricular outflow tract tachycardia.
Adult↗
[Indications and surgical techniques in the acute phase of infective endocarditis].
Infectious endocarditis is increasingly resistant to antibiotic therapy, due to the increasing number of patient with cardiovascular prostheses or those who are severely immunosuppressed. Frequently, this syndrome and its complications can only be solved with surgery. In this article, which is based on the international literature plus own observations in 77 patients, the indications for surgery and the different technical approaches during the acute phase of infectious endocarditis are reviewed. Surgery to control infectious endocarditis is indicated when there is one of the following situations: a) persistence of infection despite an adequate antibiotic treatment, usually due to a specific pathogen (Staphylococcus aureus, fungus, etc.) or to a low antibiotic penetration into the infected issues (abscess); b) progressive hemodynamic deterioration due to tissular destruction and development of valvular incompetence or fistulous communications or c) development of other complications (repetitive embolism, cardiovascular aneurysms, conduction blocks, etc.). Hemodynamic deterioration due to heart failure refractory to medical treatment is the most frequent indication for cardiovascular surgery, and this was present in 61% of our patients. The timing for surgery is still controversial, although scheduling it at an early stage is generally preferred. The specific surgical technique is chosen according to the degree of tissular destruction and is aimed to remove the infected tissue and to repair the damaged structures or, if this is not feasible, to implant cardiovascular prosthesis.
Acute Disease↗
Mechanism and location of atrial flutter in transplanted hearts: observations during transient entrainment from distant sites.
OBJECTIVES: This study was designed to elucidate the location and mechanism of typical atrial flutter in the transplanted heart. BACKGROUND: Although the F wave morphology in atrial flutter is similar in nontransplanted and transplanted hearts, the surgical incision needed for the atrial anastomosis may create a distinct electrophysiologic substrate of atrial flutter. METHODS: Entrainment from the lateral wall of the right atrium and interatrial septum was used to determine the location of atrial flutter in five patients with a transplanted heart and six patients with a nontransplanted heart. The difference between the first postpacing interval (FPPI) and the flutter cycle length (FCL) was used as an index of proximity to the circuit. RESULTS: In the transplant group, the FPPI was equal to the FCL at sites located close to the tricuspid annulus (TA); the mean differences (+/-SD) were 1 +/- 5 and -1 +/- 2 ms at the lateral wall and interatrial septum, respectively. However, from sites close to the surgical incision at the lateral wall and at the interatrial septum, these differences were significantly longer (29 +/- 12 and 27 +/- 9 ms, respectively, p < 0.05). In the nontransplant group, the FPPI was similar to the FCL at points in the lateral wall and interatrial septum close to the TA (mean difference 7 +/- 6 and 6 +/- 11 ms, respectively) and at sites close to the crista terminalis (CT) in the lateral wall (mean difference 4 +/- 4 ms). However, in sites separated from the TA at the interatrial septum the difference was markedly longer (35 +/- 11 ms, p < 0.05). CONCLUSIONS: Atrial flutter in transplanted hearts may best be explained by macroreentry around the tricuspid ring. In non-transplanted hearts a different structure (perhaps the CT?) may be the basis for atrial flutter at the lateral wall.
Atrial Flutter↗
HLA-B44 subtyping in a Spanish population: further evidence of Caucasian population diversity.
HLA-B44 is the most frequent HLA-B allele in Caucasian populations. Several B44 subtypes, B*4402-B*4406, have been identified in individuals with this ethnic origin. Mismatches among B44 subtypes have been described as major targets for allogeneic responses in bone marrow transplantation. We have developed a PCR-SSO method, based on a B12- specific DNA amplification of exon 2 through exon 3 and subsequent non radioactive hybridization with eight probes, which allow us to discriminate all B12 homozygous combinations. We applied this method to determine the frequency of B44 subtypes in a Spanish population, as well as their HLA-A,-C,-DRB1,-DRB3/DRB4/ DRB5,-DQA1 and -DQB1 associated haplotypes. A total of 141 healthy unrelated Spanish individuals and 31 B44-bearing haplotypes were investigated. Four B44 alleles were identified, B*4402 (33%), B*4403 (66%), B*4404 (0.7%), and B*4405 (0.7%). Haplotype analysis showed a clear differentiated distribution pattern for the two major B44 subtypes. B*4402 is associated with Cw5 (11/13) and A2 antigens (10/13). In contrast, B*4403 is mainly found together with DRB1*0701 (14/16). An inverted B*4402/B*4403 frequency in comparison with other European and North American Caucasian populations, revealed the existence of an extended haplotype diversity between populations of the same ethnic origin. Apart from anthropological studies, high resolution typing for HLA class I antigens presenting molecular polymorphism will be of great relevance in unrelated bone marrow transplantation.
HLA-B Antigens↗
Identification by polymerase chain reaction and hybridization with sequence-specific oligoprobes and complete exon-2 cDNA sequencing of a new DRB1 (DRB1*1131) allele.
HLA-DRB1 is the most polymorphic gene described so far, and their encoded molecules disclose a major role in allogeneic responses. We describe in this report a new DRB1 allele in a Spanish Caucasian bone marrow donor, initially defined by PCR-SSO as a DRB1*11-like allele. Complete exon 2 cDNA-sequencing reveled that this allele was identical to DRB1*1119 except for a single substitution at position 178, which generates an amino acid change (Tyr-His) at position 60. This residue is shared by several DRB1*14 subtypes and DRB1*0808. The new allele was officially named DRB1*1131.
Alleles↗
HLA-B14 subtyping by semi-nested PCR-SSP and haplotype distribution in a Spanish population.
HLA-B14 serological subtyping is very limited probably due to the internal position of the unique amino acid residue that differentiates B64 and B65 molecules. In order to carry out an accurate B14 subtyping we have designed a semi-nested PCR-SSP procedure that can differentiate B*1401 and B*1402 in any HLA-A, -B or -C antigen combination. A panel of 133 B14-positive and 31 B14-negative healthy and unrelated Spanish individuals were studied. Additionally, 45 B14-bearing haplotypes (-A,-B,-C,-DRB1,-DRB3/DRB4/DRB5,-DQA1,- DQB1) were available through family studies. The relative frequencies of HLA-B14 subtypes were 74% for B*1402 and 26% for B*1401, in agreement with those found in other Central European populations, but differing from those in Wales, where the relative presence of B64 goes to 41%. A total of 11/17 and 18/28 different haplotypes for B*1401 and B*1402, respectively, were identified. Both alleles showed the strongest association to Cw8 (43/45), indicating a primary ancestral B14-Cw8 association. However, B14 subtypes evidenced very distinguishable haplotype distributions. B*1401 is strongly associated with the common HLA class II haplotype DRB1*0701-DQA1*0201-DQB1*02 (13/17), while B*1402 is mainly associated to DRB1*0102 (16/28). Three major haplotypes were identified: A32-Cw8-B*1401-DR7-DQ2 (5/17), A33-Cw8-B*1402-DRB1*0102-DQ5 (5/28) and A2-Cw8-B*1402-DRB1*0102-DQ5 (5/28).
HLA-B Antigens↗
[Determination of the cytokine level during storage of partially leukocyte-depleted (<0.5 x 10(9)) or totally leukocyte-depleted (<0.5 x 10(6)) platelets].
PURPOSE: To evaluate the levels of interleukin 1 beta (IL-1 beta), interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-alpha) during the storage of pools of PCs obtained after removing the buffy-coat, in comparison with the amount of leukocytes present in these components. MATERIAL AND METHODS: Blood was collected in quadruple-bag-system containing 63 mL of CPD as anticoagulant and 100 mL of SAG-M solution as additive for the red cells. Approximately twelve hours after collection, blood separation was made automatically by Compomat (NPBI) and platelet concentrates were prepared from the buffy-coat fraction. Five or six PCs were mixed to obtain a pool (n = 28). Eight pools were WBC reduced by filtration (PXL-8, Pall España). Before storage a sample of each pool was obtained in order to count platelets and WBC as basal values. All kind of pools were stored at room temperature with continuous agitation during a period of 10 days. Volumes were measured by weight and specific gravity. Platelets and leukocytes were counted in the Coulter-counter (STKR Counter. Izasa) or in Nageotte chamber for the filtered products. On days 1, 4 and 7 interleukins were measured by ELISA (EASIA Kits, Medgenix Diagnostics, Brussels), Lecture was done at 450 nm using a spectophotometer (ANTHOS 2001). Lower limits of sensitivity were 2 pg/mL for IL-1 beta and 3 pg/mL for IL-6 and TNF-alpha according to the manufacturer. Wilcoxon test was used for statistical analysis. RESULTS: The average volume of the pools was 460 mL and 374 for the filtered ones. The total platelet amount was 3.63 x 10(11) and 2.8 x 10(11) respectively, with a WBC contamination of 380 x 10(6) and 0.54 x 10(6) for the filtered. The yield of platelets after filtration was 84% with a loss of 99.90% of WBC (3-log). The measures of interleukins were not homogeneous, but a great variability was found shown among the different pools, not always in relationship with the amount of leukocytes. The levels of IL-1 beta were 3.58 pg/mL on day 1, 6.36 pg/mL on day 4 and 8.76 pg/mL on day 7 (p < 0.005). For the IL-6 we found 13.08 pg/mL on day 1, 15.43 pg/mL on day 4 and 19.77 on day 7 (p < 0.05). For the TNF-alpha, 13.65 pg/mL an day 1,24.33 pg/mL on day 4 and 30.10 pg/mL on day 7 (p < 0.05). In the filtered pools the detections of IL-1 beta and IL-6 were always under the sensibility threshold, but there was an increment of TNF-alpha on day 7 (16.91 pg/mL). Microbiologic cultures were always negative. CONCLUSION: The accumulation of IL-1 beta, IL-6 and TNF-alpha is not prevented by the fact of removing the buffy-coat layer when preparing PCs, although these levels are considerably lower in comparison with those obtained by the PRP technic. Filtration of pooled PCs avoids the presence of these cytokines except TNF-alpha, where a low amount can be detected.
Blood Platelets↗
Radiofrequency catheter ablation of ventricular tachycardia from right ventricle late after myocardial infarction.
In summary, this case illustrates how complex VT circuits may be. If the findings of this case are substantiated with additional cases, mapping and radiofrequency energy application from right ventricle would have to be considered in VT with left bundle branch blocks QRS morphology, whenever ablation from the left ventricule is ineffective.
Aged↗
"Pseudodisappearance" of atrial electrogram during orthodromic tachycardia: new criteria for successful ablation of concealed left-sided accessory pathways.
OBJECTIVES: This study sought to analyze two new criteria along with other known predictors of success of radiofrequency ablation. Background. Although the overall success rate of radiofrequency ablation of accessory pathways is high, the individual predictive value of each of the established criteria is low. METHODS: We prospectively studied the local electrograms obtained before the application of radiofrequency energy in 33 patients with a left-sided concealed accessory pathway successfully ablated. Two new criteria ("pseudodisappearance" during tachycardia of a bipolar atrial electrogram visible during sinus rhythm and the presence of an "atrial notch" in the ascending limb of the unipolar ventricular electrogram during tachycardia) were studied along with other known predictors. Electrograms recorded at a total of 157 sites were analyzed (33 successful applications, 124 failures). RESULTS: Electrogram characteristics that were predictive of success during ablation on the basis of univariate analyses were a pseudodisappearance criterion (p<0.001), the presence of a Kent potential (p<0.005) and the presence of an "atrial notch" (p<0.005). After adjustment for between-patient differences, logistic regression analysis showed that only the "pseudodisappearance" criterion (odds ratio [OR] 7.2, 95% confidence interval [CI] 1.2 to 42.5, p<0.03) and the presence of a Kent potential (OR 2.4, 95% CI 1.01 to 5.79, p<0.05) had independent predictive value. CONCLUSIONS: The pseudodisappearance during tachycardia or ventricular pacing of a bipolar atrial electrogram present during sinus rhythm is associated with a good outcome during radiofrequency ablation of concealed accessory pathways. These observations may help to ablate accessory pathways and to avoid missing appropriate sites for ablation when the atrial activation is not clearly visible at the local electrogram.
Adolescent↗