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Biomedical subjects

J A Sobrino

Publications and source records attributed to J A Sobrino.

At least 19 recordsLinked to original sources
PubMed2001

Bundle-branch reentry and the postpacing interval after entrainment by right ventricular apex stimulation: a new approach to elucidate the mechanism of wide-QRS-complex tachycardia with atrioventricular dissociation.

BACKGROUND: Diagnosis of bundle-branch reentry ventricular tachycardia (BBR-VT) by the standard approach is challenging, and this may lead to nonrecognition of this tachycardia mechanism. Because the postpacing interval (PPI) after entrainment has been correlated with the distance from the pacing site to the reentrant circuit, BBR-VT entrainment by pacing from the right ventricular apex (RVA) should result in a PPI similar to the tachycardia cycle length (TCL). This factor may differentiate BBR-VT from other mechanisms of wide-QRS-complex tachycardia with AV dissociation, such as myocardial reentrant VT (MR-VT) or AV nodal reentrant tachycardia (AVNRT), in which the circuit is usually located away from the RVA. METHODS AND RESULTS: Transient entrainment by RVA pacing was attempted in 18 consecutive BBR-VTs and finally achieved in 13. Results were compared with those found in 59 consecutive MR-VTs and 50 consecutive AVNRTs. The mean PPI-TCL difference was significantly (P:<0.0001) shorter in the BBR-VT group (9+/-11 ms) than in the MR-VT (109+/-48 ms) and the AVNRT (150+/-29 ms) groups. No BBR-VT showed a PPI-TCL >30 ms (range -12 to 24 ms). Except for 2 MR-VTs, no MR-VT (range 21 to 211 ms) or AVNRT (range 100 to 215 ms) showed a PPI-TCL <30 ms. CONCLUSIONS: A PPI-TCL >30 ms, after entrainment by RVA stimulation, makes BBR-VT unlikely. Conversely, a PPI-TCL <30 ms is suggestive of BBR-VT but should lead to further investigation by use of conventional criteria.

Bundle-Branch Block↗
PubMed2001

[Variable response to the biological inhibition of platelets by abciximab in patients subjected to percutaneous coronary angioplasty].

INTRODUCTION AND OBJECTIVES: Abciximab has been shown to reduce the risk of thrombotic complications during coronary angioplasty, however there are still many aspects to be resolved. The aim of this study was to investigate the various biological effects of abciximab on platelets during coronary angioplasty. METHODS: The degree of platelet inhibition (with 5 and 20 mol/l concentrations of ADP), occlusion time (measurement of platelet haemostatic capacity, PFA-100), and the platelet activation markers were determined in 15 patients who underwent basal coronary angioplasty and abciximab treatment. Determinations were obtained before, 15 minutes after procedure initiation, at procedure termination, and 24 hours after procedure termination. RESULTS: More than 80% platelet aggregation inhibition was observed in 13 patients during the procedure, but after 24 hours (p < 0.05) was only detected in two. The occlusion time during the procedure was > 300 sec. in 13 patients, 6 of whom evolved to normal values after 24 hours (p < 0.05). A high correlation (p = 0.02) was found between these two parameters during the intervention, but not after 24 hours. No platelet inhibition or occlusion time changes were observed in 2 patients during the study. The expression of p-selectin increased significantly during the procedure (p < 0.05). CONCLUSIONS: The variability of platelet function inhibition and existence of circulating activation during coronary angioplasty following the administration of abciximab support the use of early analytical controls with the objective of modifying guidelines for use in order to optimize its effect or to combine it with other antithrombotic agents.

Abciximab↗
PubMed2000

[Aortic pseudocoarctation complicated by a giant pseudoaneurysm].

Pseudocoarctation of the aorta is an infrequent anomaly caused by the elongation and the congenital kinking of the aorta. We present a case of pseudocoarctation of the aorta with saccular aneurysm complicated with a large pseudoaneurysm. Both, magnetic resonance and aortography showed an aneurysm of the aortic isthmus that extended/progressed as pseudoaneurysm towards the neck. The patient was asymptomatic but due to the high risk of rupture, she underwent surgical reparation. The revision of the literature and our experience with this case show that pseudocoarctation of the aorta is not always a benign pathology and that surgical reparation should be performed in all those cases that are complicated by aneurysm.

Adult↗
PubMed2000

[Cardioinhibitory vagal response not related to pain, and induced by radiofrequency application during ablation of right posteroseptal accessory pathway].

Inappropriate sinus tachycardia is the most common arrhythmia induced by radiofrequency energy delivery in the posteroseptal area. It has been suggested that this could be secondary to parasymphathetic nerve injury. We report a patient with extreme sinus bradycardia and PR interval prolongation induced by radiofrequency energy delivered in the coronary sinus ostium area, but not related to any other stimulus. The most probable mechanism of the disorder was transient stimulation of the vagal afferent nerve fibers located in this anatomical area.

Autonomic Pathways↗
PubMed2000

[Oblique orientation of the accessory pathway demonstrated by radiofrequency application].

Activation mapping of atrial and ventricular insertion has suggested an oblique orientation of some accessory pathways. However, this aspect has not been demonstrated by radiofrequency application. This report presents two patients with Wolff-Parkinson-White syndrome and an accessory pathway with bidirectional conduction and oblique orientation. The accessory pathway oblique orientation was demonstrated by transient and permanent conduction abolition following radiofrequency application in two separate ventricular and atrial sites. These findings may explain the failure to ablate accessory pathway by radiofrequency application in the ventricular side of the mitral annulus guided by retrograde atrial activation occasionally observed in patients with a concealed accessory pathway.

Catheter Ablation↗
PubMed2000

Tricuspid insufficiency and interatrial septum rupture: a cause of persistent systemic hypoxemia after blunt chest trauma.

The case of a 45-year-old man with severe tricuspid insufficiency and interatrial septum rupture caused by a car accident is described. The patient had a rupture of the anterior papillary muscle of the tricuspid valve and right-to-left shunt through an interatrial defect with severe hypoxemia that was difficult to distinguish from that caused by pulmonary damage. Transesophageal echocardiography was extremely useful for early diagnosis.

Echocardiography, Transesophageal↗
PubMed2000

Ablation of idiopathic ventricular tachycardia by bipolar radiofrequency current application between the left aortic sinus and the left ventricle.

BACKGROUND: Failure to ablate idiopathic ventricular outflow tract tachycardia by radiofrequency current is not uncommon and suggests that non-standard approaches may be required to map and suppress idiopathic ventricular tachyarrhythmias in some patients. METHODS AND RESULTS: Left and right ventricular activation and pace mapping proved inadequate for radiofrequency application in a patient with idiopathic ventricular outflow tract tachycardia. Presystolic activity was recorded at the left aortic sinus of Valsalva, and the QRS complex recorded at this location during pacing showed few differences compared with that recorded during tachycardia. Radiofrequency current application at this site transiently suppressed the tachycardia. Following new mapping of the left ventricle outflow tract, radiofrequency application just below the aortic valve in close proximity to the previous aortic application site transiently abolished the arrhythmia. Finally, bipolar radiofrequency application between the distal electrode of the aortic catheter and the distal electrode of a second catheter placed in the left ventricular subaortic area permanently suppressed the tachycardia. CONCLUSION: Bipolar radiofrequency application between the aortic sinus of Valsalva and the left ventricle could be an alternative approach in occasional patients with idiopathic ventricular outflow tract tachycardia resistant to conventional left ventricular and aortic root unipolar radiofrequency application.

Aged↗
PubMed2000

[Coxiella burnetii endocarditis: long-term clinical course in 20 patients].

INTRODUCTION AND OBJECTIVES: Coxiella burnetii is a causative agent of increasingly frequent subacute infective endocarditis, and is associated with elevated morbimortality. Our aim in the present study was to assess the clinical, serological and therapeutic long-term evolution of 20 patients with Coxiella burnetii endocarditis. METHODS: Twenty patients (13 male and 7 female, age 42 +/- 10 years) admitted between 1982 and 1996 were retrospectively studied. All of them fulfilled the Duke criteria modified by Raoult for Q fever endocarditis. RESULTS: Endocarditis involved prosthetic and native valves in 14 and 6 patients, respectively. All patients except one received antibiotic treatment. Patients treated with doxycycline in monotherapy showed worse evolution than those treated with doxycycline in combination with other antibiotics. Valve replacement was performed in 15 patients, due to prosthetic dysfunction in most of them. The overall mortality was 40% (8 patients). At follow-up of 74 months (range 19-156) (mean 74 +/- 47) all patients showed persistent high levels of phase I antibodies. At follow-up of 15 to 65 months (32 +/- 30) antibiotic treatment was suspended in five patients because they were asymptomatic and without microbiologic findings of valvular endocarditis. CONCLUSIONS: Q fever endocarditis was associated with severe complications, which often required valve replacement. All patients showed persistent high serological titers of Coxiella burnetii endocarditis without other signs of active infection. This finding raises the issue of suspending antibiotic treatment in patients with negative microbiologic findings and questions the persistence of abnormal serology as a monitor of treatment efficacy.

Adult↗
PubMed2000

[Demonstration of accelerated growth of heart sarcoma using imaging techniques].

We report the case of a patient presenting a sarcoma of interatrial septum with an accelerated growth and a fulminate clinical course documented by non-invasive image diagnostic techniques, habitual in the cardiologic practice. The natural history of some cardiac malignant tumours, as aggressive as in this case, explains the diagnostic delay, the difficulty to establish a curative treatment such as surgery and/or chemotherapy/radiotherapy and the awful short-term prognosis.

Adult↗
PubMed2000

Quantitative study of metals in bile from patients with cholelithiasis.

OBJECTIVE: Biliary lithiasis is a multifactorial phenomenon that is decisively influenced by the composition of bile. We analyzed the presence of eight metals in bile and compared their concentrations in healthy persons and patients with cholelithiasis. METHODS: We studied bile from 119 patients who underwent cholecystectomy because of symptomatic cholelithiasis, and from 25 control subjects in whom the gallbladder was removed for reasons other than cholelithiasis. Metal concentrations were analyzed by atomic absorption spectrophotometry. The subjects were divided into subgroups according to age, sex and type of stone. RESULTS: Bile from patients with cholelithiasis contained significantly less of the essential element magnesium (Mg) and the toxic element lead (Pb) than bile from control subjects. Calcium (Ca) and strontium (Sr) concentrations were also lower in patients with gallstones than in the control group, although the differences were not significant. CONCLUSIONS: Biliary concentrations of Mg and Pb were significantly lower in patients with cholelithiasis than in the control group. The biliary excretion of Ca and Sr was lower in patients than in controls, although the differences were not statistically significant.

Bile↗
PubMed1999

Transient entrainment of bundle-branch reentry by atrial and ventricular stimulation: elucidation of the tachycardia mechanism through analysis of the surface ECG.

BACKGROUND: Different responses to entrainment have been reported in relation to the pacing site of a variety of tachycardias. However, transient entrainment of bundle-branch reentrant tachycardia (BBRT) has not been investigated systematically. METHODS AND RESULTS: We attempted entrainment of 13 BBRTs in 9 patients by pacing first the right ventricle and then the right atrium. The initial pacing cycle length (CL) was 10 ms faster than the tachycardia CL. Subsequent pacing sequences were performed with 5- to 10-ms CL decrements until tachycardia termination or loss of postatropine 1:1 AV conduction. Both full ventricular-paced and AV-conducted QRS complex references were obtained during sinus rhythm pacing from the same sites and with similar CL as during entrainment. Transient entrainment was achieved by ventricular and atrial stimulation in 11 and 8 tachycardias, respectively. Constant fusion was always present during entrainment by ventricular stimulation. There was no change in the QRS complex (orthodromically concealed fusion) during entrainment by atrial stimulation in 6 of 6 tachycardias with left bundle-branch block morphology and in 1 of 2 tachycardias with right bundle-branch block morphology. CONCLUSIONS: BBRT, especially if it has a left bundle-branch block morphology, can be differentiated from other wide-QRS-complex tachycardia mechanisms through analysis of the ECGs recorded during tachycardia entrainment by atrial and ventricular stimulation. This diagnostic approach may be especially useful when it is difficult to record a stable or sufficiently sized His bundle electrogram or when spontaneous changes in the ventricular CL precede similar changes in the His bundle CL.

Adult↗
PubMed1999

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↗
PubMed1998

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↗
PubMed1998

[Uncommon atrial flutter related to cicatrix from atriotomy surgery: radiofrequency catheter ablation].

A patient with a complex congenital abnormality required the implantation of an interatrial septum patch through a right lateral atriotomy. Nine years later he developed two different morphologies of an incessant uncommon atrial flutter refractory to antiarrhythmic drug treatment. The electrophysiological study localized a site on the right atrium lateral wall where local activation time was 75 ms earlier than the onset of the P wave, transient entrainment with concealed fusion was obtained, the first postpacing interval after transient entrainment was 5 ms longer than tachycardia cycle length and the stimulus to P wave interval was 50 ms. At this site, radiofrequency delivery terminated the atrial flutter in less than 1 second. No further induction or recurrences of any morphology of the atrial flutter were observed after a four month follow up. These findings suggest the existence of a narrow conduction isthmus amenable to interruption by focal delivery of radiofrequency. The isthmus was most probably located between the atriotomy and the crista terminalis, posterior to the former and anterior to the latter.

Adult↗