Biomedical subjects
Publications and source records attributed to P Jaïs.
Although a negative retrograde P wave in lead I during orthodromic reciprocating tachycardia is thought to indicate a left free wall accessory pathway, we describe similar negative P waves in lead I during orthodromic reciprocating tachycardia through anteroseptally situated accessory pathways.
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BACKGROUND: Atrial fibrillation is usually thought to be due to multiple circulating reentrant wavelets. From previous studies, a focal mechanism is considered to be very unlikely. In this report, focal atrial fibrillation is defined on an ECG pattern of atrial fibrillation and later demonstrated to be due to a focal source. METHODS AND RESULTS: Nine patients (five men and four women, age, 38 +/- 7 years) with paroxysmal focal atrial fibrillation are reported here. All were free of structural heart disease and had frequent episodes of atrial fibrillation despite the use of a mean of 4 +/- 2 antiarrhythmic drugs. Atrial fibrillation was associated with runs of irregular atrial tachycardia or monomorphic extrasystoles. The electrophysiological study demonstrated that all the atrial arrhythmias were due to the same focus firing irregularly and exhibiting a consistent and centrifugal pattern of activation. Three foci were found to be located in the right atrium, two near the sinus node and one in the ostium of the coronary sinus. Six others were located in the left atrium at the ostium of the right pulmonary veins (n = 5) and at the ostium of the left superior pulmonary vein (n = 1). All atrial arrhythmias were successfully treated by use of a mean of 4 +/- 4 radiofrequency pulses. CONCLUSIONS: In some patients, the surface ECG pattern of atrial fibrillation is due to a focal rapidly firing source of activity that can be eliminated by discrete radiofrequency energy applications.
Somatostatin and its analogues are now of current use in the management of endocrine gastroentero-pancreatic (GEP) tumours for the purpose of inhibiting hormone hypersecretion, carrying scintigraphy imaging and attempting to slow down tumour growth. Recent molecular studies have revealed the existence of up to five membrane somatostatin receptor subtypes termed SSTR1-5. However, whether or not scintigraphy imaging and tumour characteristics are correlated with specific subtype(s) remains unclear. SSTR1-5 messenger RNA (mRNA) transcripts were investigated in 38 endocrine GEP tumours (32 islet cell tumours, six carcinoid) using reverse transcriptase polymerase chain reaction (RT-PCR), and their distribution was analysed with respect to tumour characteristics and scintigraphy imaging. SSTR2, SSTR5 and SSTR4 were detected in most cases of endocrine GEP tumours (92%, 84%, and 82% respectively), but SSTR1 and SSTR3 were less frequently observed (66% and 50% respectively). No clear-cut correlation was found between tumour characteristics and subtype mRNA distribution. Moreover, no differences in mRNA subtype distribution were found between the 17 tumours detected by scintigraphy and the four tumours not detected by this method. Somatostatin receptor mRNA subtypes are widely expressed in endocrine GEP tumours, but their distribution is not correlated with tumour characteristics or scintigraphy positivity.
Atrial fibrillation, the most common of all sustained cardiac arrhythmias, can be cured using extensive surgical atriotomies. Experimental studies using linear radiofrequency catheter ablation lesions suggest the relative safety and high efficacy of these procedures. However animal models may not be relevant to human pathology because of the small size of atria, different pathophysiologic substrates, and the lack of data pertaining to spontaneous initiation of atrial fibrillation. Preliminary human studies show a higher success rate when linear ablations are performed in the left atrium than in the right atrium and that arrhythmogenic foci play a significant role in atrial fibrillation. However the procedures are prolonged, and it is difficult with current technology to achieve a linear conduction block consistently. The challenge remains to optimize this as yet investigational technique and transform it into a routine procedure.
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Atrioventricular junctional reentrant tachycardia (AVJRT) is the most common form of paroxysmal regular supraventricular tachycardia. In patients with disabling, drug refractory AVJRT, catheter ablation has evolved rapidly from a last-resort treatment in the form of interruption of atrioventricular (AV) conduction to selective modification of AV nodal function as an ideal treatment. This article will focus on the frequently unappreciated electrophysiological activities recordable in man in Koch's triangle during ablation of the so-called slow pathway.
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Cancers from patients with tumor-induced hypercalcemia usually produce a circulating factor that mimics the parathyroid hormone activity, termed parathyroid hormone-related protein. Incidence of tumor-induced hypercalcemia appears to be high in patients with squamous cell carcinoma of the esophagus, and the presence of parathyroid hormone-related protein have been shown in some primary esophageal cancers. In the present study, we have investigated the presence of parathyroid hormone-related protein in a patient with metastasized squamous cell carcinoma of the esophagus complicated with tumor-induced hypercalcemia. Protein was searched by immunohistochemistry, and messenger RNA was investigated by reverse transcriptase-polymerase chain reaction and S1 nuclease assay. Both messenger RNA and protein were detected in hepatic metastases, whereas normal esophageal mucosa and primary cancer did not express detectable protein or messenger RNA using the S1 nuclease assay. Reverse transcriptase-polymerase chain reaction was positive in all these tissues, including normal esophageal mucosa. In conclusion, the present case suggests that tumor-induced hypercalcemia due to esophageal squamous cell carcinoma may be caused by parathyroid hormone-related protein mostly released by liver metastases.
BACKGROUND AND AIMS: Mutations of TP53, a tumor suppressor gene, are found in 60% to 70% of colorectal cancers. These mutations usually induce an overexpression caused by modification of the p53 protein conformation. The aim of this study was to investigate whether stool specimens of patients with colorectal cancer contain increased amounts of p53 protein. METHODS: p53 protein was measured using a sandwich enzyme immunoassay in the stool specimens of 52 patients: 25 with colorectal cancer, 4 with colorectal adenomas and 23 apparently free of gastrointestinal disease. Results were expressed as pg/mg of total protein. The presence of fecal occult-blood was searched using Hemoccult II and Hemolex (an immunochemical assay for human hemoglobin). RESULTS: Median concentrations of stool p53 protein were 16.6 pg/mg (range: 0-591 pg/mg) in patients with colorectal cancers, 39.1 pg/mg (range: 5-72 pg/mg) in patients with adenomas and 5.9 pg/mg (range: 0-65 pg/mg) in control subjects. Resection of colorectal cancers caused a marked decrease of stool p53 protein concentrations. When the cut-off value for stool p53 protein was set at 60 pg/mg of fecal protein (concentrations over the 95th percentile), the positivity of the assay was independent of tumor size and Astler-Coller stage, but weakly associated with rectal location of cancer. The sensitivity of stool p53 protein for colorectal cancer was 44%, and the specificity was 96%. In contrast, the sensitivity of Hemoccult II and Hemolex tests was 48% and 44%, whereas their specificity was 91% and 96%, respectively. CONCLUSION: The detection of p53 protein is achievable in stool, but this assay is not more efficient than fecal occult blood tests for detection of colorectal cancer.
UNLABELLED: Previous experimental data suggest that atrial activity is homogeneously distributed during paroxysmal atrial fibrillation (AFib). Little is known about this in human paroxysmal AFib. METHODS: Twenty-five men and two women (mean age 49 +/- 11 years; five with structural heart disease) with paroxysmal AFib for a mean 5 +/- 6.2 years despite the use of a mean of 3.6 +/- 1.7 antiarrhythmic drugs underwent atrial mapping. The right atrium was divided into four regions: posterior (intercaval), lateral, anterior, and septal. A 14-pole catheter was positioned to assess complex electrical activity defined as the duration of continuous electrical activity or electrograms with FF intervals < 100 ms for 60 seconds (expressed as percentage of time). In addition, the left atrium (divided into three regions: posterior, anterior, and septal) was explored in 12 patients with a multipolar catheter. RESULTS: The complex electrical activity time between all the regions explored was significantly different. In the right atrium, the septal (74% +/- 32%; P = 0.02) and the posterior (63% +/- 32%; P = 0.04) areas were significantly more disorganized than the lateral (22% +/-23%) and anterior (21% +/- 26%) regions. In the left atrium, complex electrical activity was predominant and widely distributed (posterior: 87% +/- 11%; septal: 65% +/- 27%) except in the appendage area (anterior region: 18% +/- 14%). CONCLUSIONS: Quantitative assessment of complex electrical activity in both atria in humans shows heterogeneous temporal and spatial distribution. This may have implications for guiding catheter ablation of AFib.
INTRODUCTION: Atrial fibrillation (AF), the most common arrhythmia, is due to multiple simultaneous wavelets of reentry in the atria. The only available curative treatment is surgical, using atriotomies to compartmentalize the atria. Therefore, we investigated a staged anatomical approach using radiofrequency catheter ablation lines to prevent paroxysmal AF. METHODS AND RESULTS: Forty-five patients with frequent symptomatic drug-refractory episodes of paroxysmal AF were studied. Progressively complex linear lesions were created by sequential applications of radiofrequency current in the right atrium and then in the left atrium if required. The outcome of the procedure was considered a success when the episodes of AF were either eliminated or recurred at a rate of no more than one episode (lasting < 6 hours) in 3 months. Patients who had no more than one episode per month were considered "improved." Right atrial ablation organized local electrical activity and led to stable sinus rhythm during the procedure in 18 (40%) of the 45 patients. However, sustained AF remained inducible in 40 of 45 patients, and the lesions failed to produce evidence of a significant linear conduction block/delay in all but four patients. There were no significant complications except for two transient sinus node dysfunctions. The procedure duration and fluoroscopic time were 248 +/- 79 and 53 +/- 22 min, respectively. Additional sessions were required in 19 patients to treat sustained right atrial flutter or arrhythmias linked to ectopic right or left atrial foci. During a mean follow-up of 11 +/- 4 months, right atrial ablation was successful in 15 (33%) patients, 6 without medication and 9 with a previously ineffective drug. Nine (20%) additional patients were improved. Ten patients with an unsuccessful outcome then underwent linear ablation in the left atrium. The procedure duration and fluoroscopy time were 292 +/- 94 and 66 +/- 24 min. A hemopericardium occurred in one patient. Two patients required reablation to treat ectopic atrial foci. Left atrial ablation terminated AF during the procedure in 8 patients, and sustained AF could not be induced in 5. Subsequent success was achieved in 6 (60%) patients, including 4 without medication, and 1 additional patient was improved. CONCLUSIONS: Successful radiofrequency catheter ablation of drug-refractory daily paroxysmal AF is feasible using linear atrial lesions complemented by focal ablation targeted at arrhythmogenic foci. Ablation only in the right atrium is a safe technique providing limited success, whereas linear lesions in the left atrium significantly increase the incidence of stable restoration of sinus rhythm, the inability to induce sustained AF, and the final success rate. The described technique is promising but must be considered preliminary because significant improvements are required to optimize lesion characteristics and shorten total procedure duration.
INTRODUCTION: The purpose of this study was to evaluate the efficacy and safety of radiofrequency (RF) catheter ablation of common atrial flutter and to determine the optimum target sites in a large series of patients. Three different approaches were used to target the ablation site. The first used a combined anatomic and electrophysiologic approach, whereas the second and the third approaches relied primarily on anatomic guidelines to target the critical area in the atrial flutter reentrant circuit located in the low right atrium. BACKGROUND: Recent studies report the efficacy of RF current application in the low right atrial region to interrupt and prevent recurrences of common atrial flutter using either anatomic or electrophysiologic targets. However, larger groups of patients are required to confirm the efficacy of this technique and to specify the target sites. METHODS AND RESULTS: Two hundred consecutive patients with drug-resistant common atrial flutter were studied. In the first 50 patients, target sites were localized using both anatomic landmarks and electrophysiologic parameters. The anatomic landmarks were area 1 between the tricuspid valve and inferior vena cava orifice; area 2 between the tricuspid valve and coronary sinus ostium; and area 3 between the inferior vena and coronary sinus. The electrophysiologic criterion was to ablate when there was an atrial electrogram occurring during the plateau phase (preceding F wave). The first targeted area was that giving the more stable catheter position. In the following 30 patients, we assessed the effect of RF energy application in a single line to area 1 in the first 10 patients, area 2 in the next 10, and area 3 in the last 10 patients. In the last 120 patients, RF energy was applied only in area 1 using repeated applications. RF energy of 12 to 30 W, or that achieving a temperature of 70 degrees C, was applied for 60 to 90 seconds at each site. The endpoint of the ablation procedure was interruption and noninducibility of common atrial flutter in the first 110 patients and additional isthmal block in 48 of the last 90 patients. Overall, atrial flutter was interrupted and rendered noninducible after a single session in 191 (95%) patients and could not be interrupted in 9 (4.5%) patients. The mean number of RF applications was 12 +/- 8. After a mean follow-up of 24 +/- 9 months, recurrences occurred in 31 (15.5%) patients, 26 of whom underwent a successful second or third session without further recurrences of atrial flutter. Atrial fibrillation not documented before the ablation was detected in 11 patients. On a retrospective analysis of the final successful site in the first group of 50 patients, the location was in area 1 in 39% of patients; area 2 in 36% of patients, and area 3 in 25% of patients. Atrial electrograms recorded at these sites showed a single spike pattern in 46% of patients, and double spike pattern (28%) or fractioned electrogram in 26% patients. When lines of RF lesions were placed at several sites, they produced a success rate of 70%, 40%, and 10% at areas 1, 2, and 3 respectively. In the last series of 120 patients, the procedure was successful in 119 patients: 92% of whom were successfully treated only by a linear lesion between the tricuspid annulus isthmus and the inferior vena cava, and the other 8% by additional applications near the coronary sinus ostium. No complications were observed. CONCLUSIONS: RF catheter ablation of atrial flutter can be done with a high success rate and is safe. The highest success rate is achieved with RF energy applied in the isthmus between the inferior vena cava orifice and the tricuspid valve. However, 15.5% of patients need multiple sessions to achieve success because of recurrence of flutter. Further follow-up is needed to evaluate the long-term effects of this procedure.
Atrioventricular nodal reentrant tachycardias which, for a long time, could only be treated medically, may now benefit from catheter ablation. The rapid retrograde pathway was an effective initial target but carried a risk of complete atrioventricular block of about 10%. Nowadays, most operators deliver the radiofrequency energy (endocavitary cautery) to the slow nodal pathway. Different techniques of guidance (anatomical, electrophysiological, rapid potential, slow potential) are associated with high success rates: 90 to 100%. However, experimental studies suggest that the slow potentials arise from transitional cells within the tachycardia circuit (the anatomical substrate of the slow pathway). There is still a risk of complete atrioventricular block (1 to 5%) which should be clearly explained to patients referred for ablation of this constantly benign arrhythmia.
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Inflammatory pseudotumors (IPT) of the liver are rare benign tumors of unknown origin. Most previously reported cases were initially misdiagnosed and treated surgically; thus, their course under medical treatment remains unclear. We report an additional case of hepatic IPT with a favorable outcome under medical treatment without surgical resection. New imaging and pathologic features of this disease are presented that may facilitate preoperative recognition and appropriate treatment.