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Biomedical subjects

J Brugada

Publications and source records attributed to J Brugada.

At least 73 records · Page 4Linked to original sources
PubMed1998

[Radiofrequency ablation of multiple atrioventricular accessory pathways in a patient with syncope, atrial fibrillation and fasciculoventricular fibers].

Multiple accessory pathways in patients with the Wolff-Parkinson-White syndrome are infrequent and are associated with a higher risk of ventricular fibrillation. We present an exceptional case of a patient with four accessory pathways with anterograde conduction and a fasciculo-ventricular fiber in whom we performed a radiofrequency ablation. A 20 year old healthy male patient was seen at the emergency room after suffering syncope. The electrocardiogram showed atrial fibrillation with wide QRS complex suggestive of preexcitation. The electrophysiologic study demonstrated the presence of four atrio-ventricular accessory pathways with antegrade conduction (left lateral, right posteroseptal, right midseptal and right posterolateral). After ablation of the fourth accessory pathway, the electrocardiogram showed a persistent delta wave with a short HV interval. Atrial stimulation demonstrated decremental conduction, progressive lengthening of the AH interval and no modification in the HV interval nor in the preexcitation pattern, suggestive of the presence of a fasciculo-ventricular fiber. This exceptional case report is demonstrative of the complexity of the Wolff-Parkinson-White syndrome, and the feasibility and efficacy of radiofrequency catheter ablation in a single procedure.

Adult↗
PubMed1998

[Sudden death in hypertrophic myocardiopathy].

Hypertrophic cardiomyopathy is the most common cause of sudden death in young individuals who are otherwise healthy. Risk of sudden death is highest in patients who are between 14 and 35 years old. Several mechanisms are involved in sudden death: ventricular arrhythmias, supraventricular arrhythmias leading to cardiac collapse, bradycardias and severe ischemia. Many studies have analyzed how to identify high risk patients. The factors that best identify high risk patients are: previous history of sudden death or syncope, induction in adults of sustained ventricular arrhythmias, the presence of non-sustained ventricular tachycardia in symptomatic patients, the presence of ischemia associated with hypotension in children, the presence of mutations in the beta-myosin heavy chain together with a family history of sudden death and a poor left ventricular ejection fraction. Risk stratification should be done on an individualized basis. In those patients in whom a high risk for sudden arrhythmic death is suspected, the only current effective treatment is the implantable defibrillator.

Adolescent↗
PubMed1998

Hypertrophic cardiomyopathy: role of the implantable cardioverter-defibrillator.

OBJECTIVES: We report the occurrence of cardiac events during long-term follow-up in patients with hypertrophic cardiomyopathy (HCM) after cardioverter-defibrillator implantation. BACKGROUND: The identification of patients at high risk for sudden death and the prevention of recurrence of sudden death in HCM represents a difficult problem. METHODS: We retrospectively analyzed the occurrence of cardiac events during follow-up of 13 patients with HCM who received an implantable cardioverter-defibrillator (ICD) because of aborted sudden death (n = 10) or sustained ventricular tachycardia (n = 3) (group I). Findings were compared with those in 215 patients with an ICD and other structural heart disease or idiopathic ventricular fibrillation (group II). RESULTS: After a mean (+/-SD) follow-up period of 26+/-18 months, 2 of 13 patients in group I received appropriate shocks. The calculated cumulative incidence of shocks was 21% in group I and 66% in group II after 40 months (p < 0.05). We observed a low incidence of recurrence of ventricular tachycardia/fibrillation during follow-up in patients with HCM. No deaths occurred. CONCLUSIONS: Our data suggest that ventricular tachyarrhythmias may not always be the primary mechanism of syncope and sudden death in patients with HCM. The ICD seems to have a less important impact on prognosis in patients with HCM than in patients with other etiologies of aborted sudden death.

Adult↗
PubMed1998

Radiofrequency ablation of anteroseptal, para-Hisian, and mid-septal accessory pathways using a simplified femoral approach.

Feasibility of RF ablation using a simplified two-catheter technique from a femoral approach was studied in 97 consecutive patients with a manifest or concealed accessory pathway located at the anteroseptal, mid-septal, and para-Hisian areas. RF was applied at the site with the shortest V-delta interval or the earliest retrograde atrial activation during orthodromic tachycardia or right ventricular pacing. Ablation was initially successful in 88 of 97 patients (91%). Success rate was 94% (16/17) for anteroseptal, 94% (39/43) for para-Hisian, and 89% (33/37) for mid-septal accessory pathways, without differences between manifest and concealed pathways for any of the locations. Mean number of RF pulses was 8 +/- 5 for anteroseptal, 6 +/- 6 for mid-septal, and 12 +/- 13 for para-Hisian accessory pathways. Two patients (2%) required implantation of a permanent pacemaker for complete AV block. At a mean follow-up of 27 +/- 14 months, four patients with previous manifest preexcitation experienced resumption of intermittent preexcitation, but only one required a second successful procedure for recurrence of palpitations. RF ablation can be used effectively and without impairment of normal AV conduction in the majority of patients with anteroseptal, para-Hisian, and mid-septal accessory pathways using a simplified two-catheter technique from a femoral approach.

Adult↗
PubMed1998

Long-term follow-up in patients with the permanent form of junctional reciprocating tachycardia treated with radiofrequency ablation.

This study sought to determine the long-term follow-up, safety, and efficacy of radiofrequency catheter ablation of patients with the permanent form of junctional reciprocating tachycardia (PJRT). We assessed the reversibility of tachycardia induced LV dysfunction and we detailed the location and electrophysiological characteristics of these retrograde atrioventricular decremental pathways. PJRT is an infrequent form of reciprocating tachycardia, commonly incessant, and usually drug refractory. The ECG hallmarks include an RP interval > PR with inverted P waves in leads II, III, a VF, and V3-V6. During tachycardia, retrograde VA conduction occurs over an accessory pathway with slow and decremental conduction properties, located predominantly in the posteroseptal zone. It is known that long-lasting and incessant tachycardia may result in tachycardia induced severe ventricular dysfunction. We included 36 patients (13 men, 23 women, mean +/- SD, aged 44 +/- 22 years) with the diagnosis of PJRT. Seven patients had tachycardia induced left ventricular dysfunction. Radiofrequency energy was delivered at the site of earliest retrograde atrial activation during ventricular pacing or during reciprocating tachycardia. All patients were followed at the outpatient clinic and serial echocardiograms were performed in those who presented with depressed LV function. Radiofrequency ablation was performed in 36 decremental accessory pathways. Earliest retrograde atrial activation was right posteroseptal in 32 patients (88%), right mid-septal in 2 (6%), right posterolateral in 1 (3%), and left anterolateral in 1 (3%). Thirty-five accessory pathways were successfully ablated with a mean of 5 +/- 3 applications. A mid-septal accessory pathway could not be ablated. After a mean follow-up of 21 +/- 16 months (range 1-64) 34 patients are asymptomatic. There were recurrences in 8 patients after the initial successful ablation (mean of 1.2 months), 5 were ablated in a second ablation procedure, 2 patients required a third procedure, and 1 patient required four ablation sessions. All patients with LV dysfunction experienced a remarkable improvement after ablation. Mean preablation LV ejection fraction in patients with tachycardiomyopathy was 28% +/- 6% and rose to 51% +/- 16% after ablation (P < 0.02). Our study supports the concept that radiofrequency catheter ablation is a safe and effective treatment for patients with PJRT. Radiofrequency ablation should be the treatment of choice in these patients because this arrhythmia is usually drug refractory. The majority of accessory pathways are located in the posteroseptal zone. Cessation of the arrhythmia after successful ablation results in recovery of LV dysfunction.

Adolescent↗
PubMed1998

Enhanced detection criteria in implantable defibrillators.

INTRODUCTION: Enhanced detection criteria in third-generation implantable defibrillators have been implemented to avoid inappropriate therapy of fast supraventricular arrhythmias. We prospectively analyzed the use of these criteria in patients with an implantable defibrillator with electrogram storing capability. METHODS AND RESULTS: In 82 consecutive patients with a Guidant-CPI implantable defibrillator, sudden onset > 9% and stability < 40 msec were systematically programmed in zone 1 of therapy together with a sustained rate duration security mechanism. All detected tachycardia episodes were analyzed. The study population consisted of 59 patients who had at least one episode of tachycardia detected in zone 1 during follow-up. The tachycardia rate in zone 1 never exceeded 210 beats/min. Twenty patients had no episodes during follow-up, and three patients had episodes detected exclusively in zone 2 of therapy. Supraventricular arrhythmias were detected frequently in the ventricular tachycardia zone (193 of 690 tachycardia episodes in 23 of 59 patients). Use of sudden onset was very effective in detecting sinus tachycardias (65 of 67 episodes), and stability was very useful in detecting atrial fibrillation (31 of 32 episodes). However, sensitivity in detecting ventricular tachycardia was only 90% (451 of 497 episodes). Application of the sustained rate duration criterion allowed appropriate treatment of all ventricular tachycardia episodes, increasing sensitivity to 100%; however, specificity in appropriate nontreatment of supraventricular decreased from 96% to 83%. Subsequent analysis of different algorithms applied to our data showed that sudden onset > 9% and stability < 40 msec was the algorithm with the best specificity and sensitivity. CONCLUSION: Programming sudden onset and stability detection criteria with a sustained rate duration safety net for triggering tachycardia therapy results in appropriate device management in most patients with supraventricular and slow (< 210 beats/min) ventricular tachycardias.

Algorithms↗
PubMed1998

Neck pounding during sinus rhythm: a new clinical manifestation of dual atrioventricular nodal pathways.

OBJECTIVE: To determine the clinical and electrophysiological characteristics of patients with paroxysmal palpitations and neck pounding during sinus rhythm. METHODS: Clinical, electrocardiographic, and electrophysiological characteristics of six patients with paroxysmal palpitations and neck pounding during sinus rhythm were studied in basal conditions and when symptomatic. Response to treatment was observed. RESULTS: Baseline ECGs were normal (four patients) or had first degree atrioventricular block with intermittent PR shortening. During symptoms, narrow QRS rhythms were seen without visible P waves (three patients) or with P waves partially hidden in the QRS complex (three patients). Dual atrioventricular nodal pathways were found in all five patients who had electrophysiological studies. In these patients the slow pathway conduction time was long enough (mean (SD), 425 (121) ms) for ventricular activation after slow pathway conduction during sinus rhythm to coincide with the next atrial depolarisation, causing neck pounding during exercise (four patients) or at rest (two patients). Tachycardia was not induced in any patient. Medical treatment aggravated symptoms in three patients. A pacemaker was successfully used in two. CONCLUSIONS: Neck pounding during sinus rhythm is a clinical manifestation of dual atrioventricular nodal pathways. Medical treatment may aggravate symptoms but a pacemaker may offer definitive relief.

Adult↗
PubMed1997

Identification of a genetic locus for familial atrial fibrillation.

BACKGROUND: Atrial fibrillation, the most common sustained cardiac-rhythm disturbance, affects over 2 million Americans and accounts for one third of all strokes in patients over 65 years of age. The molecular basis for atrial fibrillation is unknown, and palliative therapy is used to control the ventricular rate and prevent systemic emboli. We identified a family of 26 members of whom 10 had atrial fibrillation which segregated as an autosomal dominant disease. We subsequently identified two additional families in which the disease was linked to the same locus. METHODS: We screened the human genome with 300 polymorphic dinucleotide-repeat markers using an unconventional strategy of pooling the DNA samples into two groups (affected and unaffected), which reduced the sample size by approximately 90 percent, before performing linkage analysis to map the locus. This made it possible to identify potential loci within a few weeks. RESULTS: The lod scores for markers D10S569 and D10S607, located at 10q22-q24, were 3.60 in Family 1. The disease locus in Families 2 and 3 was also linked to the same markers, with lod scores of 6.02 and 5.35 for markers D10S569 and D10S607, respectively, when data on all three families were combined. Haplotype analysis of the three families showed that the locus was between D10S1694 and D10S1786, an interval of 11.3 centimorgans. CONCLUSIONS: Identification of the gene for familial atrial fibrillation will help to elucidate the molecular basis of the disease and provide insights into acquired forms. The strategy of pooling DNA samples for analysis is more time and cost effective than conventional screening and should accelerate the process of gene mapping in the future.

Adult↗
PubMed1997

Atrial fibrillation induced by atrioventricular nodal reentrant tachycardia.

In 4 patients with recurrent episodes of paroxysmal atrial fibrillation as the only documented arrhythmia, electrophysiologic study showed that atrial fibrillation originated after a very fast transition from atrioventricular nodal reentrant tachycardia. Recognition of atrioventricular nodal reentrant tachycardia as the triggering factor for atrial fibrillation has important therapeutic consequences.

Adult↗
PubMed1997

[Radiofrequency ablation of occult left accessory pathways without catheterization of the coronary sinus].

BACKGROUND: Radiofrequency catheter ablation of concealed left-sided accessory pathways conventionally implies the introduction of several catheters for the assessment of electrophysiological properties as well as for the localization of the accessory pathways. PATIENTS AND METHODS: Feasibility of radiofrequency ablation using a simplified two-catheter technique without coronary sinus catheterization was prospectively studied in 95 consecutive patients with a single concealed left free-wall accessory pathway. A 6F quadripolar catheter was introduced into the right atrium/right ventricle and tachycardia was induced by electrical stimulation. The presence of a concealed left-sided accessory pathway was suggested electrocardiographically (negative P wave in I and/or aVL during orthodromic tachycardia) or by earlier atrial activation in the pulmonary artery compared to the right atrium. Mapping of the mitral annulus and ablation were performed during orthodromic tachycardia or ventricular pacing using a 7F steerable catheter. Radiofrequency energy was applied at sites with the shortest VA interval. The procedure was considered effective if tachycardia could not be induced and if VA dissociation or exclusive nodal VA conduction were observed. RESULTS: The procedure was initially successful in 93 out of 95 patients (98%). Mean number of applications were 3.2 +/- 2. Mean fluoroscopy time and total procedure duration were 14 +/- 9 and 108 +/- 33 minutes respectively. At a mean follow-up of 21 +/- 13 months, 2 patients required a second session because of tachycardia recurrence. CONCLUSIONS: Radiofrequency catheter ablation of concealed left-sided accessory pathways can be safely, effectively and rapidly performed using a two-catheter technique without coronary sinus catheterization.

Adult↗
PubMed1997

[Arrhythmogenic dysplasia of the right ventricle].

Arrhythmogenic right ventricular dysplasia is a disease of the cardiac muscle of unknown etiology. Landmarks of this disease are the presence of muscular atrophy and replacement of ventricular myocardium by adipous and fibroadipous tissue. This disease was originally described by Fontaine et al in 1977 during surgical ablation of drug refractory ventricular tachycardias in patients without evident structural heart disease. During surgery anomalies in contractility of the right ventricle and the presence of adipous tissue were documented. Some years later, Markus et al reported the first clinical series of patients with arrhythmogenic right ventricular dysplasia. Since then, this disease has been widely recognized and must be considered in the differential diagnosis of all patients with ventricular arrhythmias originating in the right ventricle.

Arrhythmias, Cardiac↗
PubMed1997

[Familial auricular fibrillation].

INTRODUCTION AND OBJECTIVE: We present two families with atrial fibrillation in 20 of 50 members, during three generations, with known cardiac rhythms, in order to communicate their infrequent existence and the most relevant clinical facts. METHOD: Clinical situation, evolution, ECG and ECHO findings, treatments and complications related with the disease are investigated. RESULTS: The presence of atrial fibrillation in 20 members is demonstrated, although one of them was on sinus rhythm at the time of the study; 3 patients had left ventricular enlargement on the ECHO study; the clinical situation was good in all patients except two who died because of complications related to the arrythmia and a third patient that had a brain stroke. The patients received different treatments because they where controlled by different physicians; the possible lethal proarrythmic effect in such cases must be taken into account. CONCLUSION: Familiar atrial fibrillation is a very infrequent arrythmia, usually well tolerated, that follows a dominant autosomic hereditary pattern. The use of antiagregants is advised because of the risk of embolism, or the use of anticoagulants in the presence of associated risk factors. Electric cardioversion has been show not be useful. The possible proarrythmic effect of some antiarrythmic agents, used in the control of cardiac frequency, must be taken into account.

Adolescent↗
PubMed1997

Hemodynamic deterioration following radiofrequency ablation of the atrioventricular conduction system.

Radiofrequency ablation of the atrioventricular conduction system (ACS) has become an established therapy for patients with drug refractory atrial fibrillation. We observed eight patients with hemodynamic deterioration after radiofrequency ablation of the atrioventricular conduction system. As we found hemodynamic deterioration related to worsening mitral regurgitation, we compared the clinical history, electrophysiological, and echocardiographic data from the patients with hemodynamic deterioration and worsening mitral regurgitation (group 1) to those without hemodynamic deterioration and stable mitral regurgitation after the procedure (group 2). Eight out of 108 patients (7.4%) undergoing ablation of the ACS deteriorated hemodynamically with acute pulmonary edema in three and congestive heart failure in five patients occurring at a mean of 3 and 8 weeks, respectively, after the procedure. Three of these patients were referred for mitral valve surgery. Two patients underwent ablation using a left-sided approach. A right-sided approach was used in five patients. In one patient, a left- and right-sided approach was used. Compared to group 2 patients, group 1 patients had significantly higher left ventricular end-diastolic diameters (64 +/- 6 mm vs 56 +/- 9 mm) at baseline despite similar fractional shortening (32% +/- 11% vs 34% +/- 13%), left ventricular end-systolic diameters (43 +/- 9 mm vs 36 +/- 7 mm) and degree of mitral regurgitation (1.4 +/- 1.1 vs 1.4 +/- 0.7) on echocardiographic analysis. Thus, hemodynamic deterioration together with progression of mitral regurgitation is a potential complication of ablation of the ACS (up to 7.4%). Patients with high left ventricular end-diastolic diameters and moderate mitral regurgitation at baseline seem prone to this complication.

Adult↗
PubMed1997

Ventricular fibrillation and sudden death after radiofrequency catheter ablation of the atrioventricular junction.

Two hundred thirty-five patients underwent RF catheter ablation of AV conduction for symptomatic drug refractory AF (84%), atrial flutter (9%), and atrial tachycardia (7%). In the first 100 patients, postablation pacing was not prospectively set at any specific rate and was always < or = 70 beats/min. In the next 135 patients, postablation pacing was prospectively set at 90 beats/min for 1-3 months. Six of the first 100 patients (6%) had VF or sudden death after the RF procedure and none (0%) of the next 135 patients did (P < 0.05). One of the six patients had recurrent VF 4 days after the ablation. Five patients were successfully resuscitated and one patient died. There were no statistically significant differences between patients with and without (aborted) sudden death or between the first 100 and the next 135 patients with respect to age, sex, underlying heart disease, EF, number of RF applications, or left-or right-sided approach of the procedure. VF mostly occurred during episodes of slow ventricular escape rhythms or during slow ventricular pacing. We conclude that malignant ventricular arrhythmias and sudden death are possible complications of RF ablation of the AV function. The mechanism of these complications could have a bradycardia dependent nature and it seems that the occurrence of malignant arrhythmias can be prevented by temporarily pacing the heart at relatively fast rates immediately after ablation.

Aged↗
PubMed1997

Radiofrequency ablation of concealed left free-wall accessory pathways without coronary sinus catheterization: results in 100 consecutive patients.

INTRODUCTION: Feasibility of radiofrequency (RF) ablation using a two-catheter technique without coronary sinus catheterization was studied in 100 consecutive patients with a single concealed left free-wall accessory pathway. METHODS AND RESULTS: Tachycardia was induced by electrical stimulation in the right atrium/right ventricle, and the presence of a concealed left free-wall accessory pathway was suggested electrocardiographically (negative P wave in leads I and/or aVL during orthodromic tachycardia) or by earlier atrial activation in the pulmonary artery compared to the high right atrium. Mapping of the mitral annulus was performed during right ventricular pacing or orthodromic tachycardia, and RF energy was applied at the site with the earliest retrograde atrial activation. Ablation was considered effective if tachycardia could not be induced, and if VA dissociation or exclusive retrograde nodal conduction was observed. Ablation was initially successful in 98 of 100 patients. Mean number of radiofrequency pulses were 3.2 +/- 2. Mean fluoroscopy time and total procedure time was 14 +/- 9 and 107 +/- 32 minutes, respectively. There were no complications related to the procedure. At a mean follow-up of 22 +/- 13 months, two patients experienced tachycardia recurrence and required a second procedure, which was successful. CONCLUSIONS: Our results suggest that RF catheter ablation of concealed left free-wall accessory pathways can be safely, effectively, and rapidly performed using a simplified two-catheter technique with no need for coronary sinus catheterization.

Adult↗
PubMed1997

Further characterization of the syndrome of right bundle branch block, ST segment elevation, and sudden cardiac death.

We recently described a syndrome characterized by an ECG pattern of right bundle branch block and persistent ST segment elevation in leads V1 to V3 in patients suffering from aborted sudden cardiac death and not having demonstrable structural heart disease. We present new observations on this syndrome, especially those related to asymptomatic and intermittent forms. Forty-seven patients with the described ECG pattern were identified; 32 were symptomatic with syncope and sudden death aborted by cardiopulmonary resuscitation. Eleven patients received pharmacologic therapy, mainly amiodarone and/or beta-blocking agents, and 21 patients received an implantable defibrillator with or without pharmacologic therapy. Three of the 11 patients on pharmacologic therapy died suddenly during follow-up, while 9 of 21 patients with an implantable defibrillator used the device during follow-up. The remaining 15 patients were asymptomatic when first seen. Three patients died suddenly after 6 years, 3 months, and 2 months of follow-up without treatment. Another patient received an implantable defibrillator after syncope and had subsequent episodes of ventricular fibrillation terminated by the defibrillator. The other 11 patients remain asymptomatic without (6) or with (5) treatment with beta blockers. In 14 of the 47 patients, the ECG normalized momentarily during follow-up but later became abnormal again. During transient normalization of the ECG, administration of ajmaline or procainamide unmasked the described ECG pattern in six patients who received the drug. Long-term follow-up of survivors failed to show progression to any form of right or left ventricular cardiomyopathy.

Adolescent↗
PubMed1997

[Right bundle-branch block, the elevation of the ST segment in V1 to V3 and sudden death: the diagnostic and therapeutic approach].

In 1992, Brugada and Brugada described the "syndrome of right bundle branch block, persistent ST segment elevation and sudden death". This clinical and electrocardiographic entity, which occurs in patients with a structurally normal heart, has drawn the attention of many investigators. Nowadays, the occurrence of sudden death in otherwise asymptomatic patients with a typical ECG, and the transient normalization of the ECG in symptomatic patients, support the existence of asymptomatic and intermittent forms of this disease. The knowledge of these new forms and the modulation of the ECG pattern by administration of antiarrhythmic and autonomic drugs suggest that a functional abnormality of the electrical activity of the heart is responsible for this syndrome. The role of "M cells" in ventricular repolarization and in the occurrence of polymorphic ventricular arrhythmia suggests that these cells are the substrate for that electrical abnormality. Further studies are required to determine the appropriate therapeutic strategy for these patients. Until new information is available, the implantable cardioverter defibrillator is indicated in all symptomatic patients.

Bundle-Branch Block↗