Efficacy of Viabahn in the treatment of severe superficial femoral artery lesions: which factors influence long-term patency?

PURPOSE: To evaluate superficial femoral artery (SFA) occlusive disease treatment by means of covered stents. STUDY DESIGN: retrospective. METHOD: From 2000 to 2005, a Hemobahn/Viabahn endoprosthesis was implanted in 102 limbs (95 patients; mean age: 72.1 years, 52-94) for intermittent claudication (group I, n=50 limbs), critical (group II, n=32) or acute ischemia (group III, n=20). Lesions treated were Trans-Atlantic Inter-Society Consensus (TASC) A (n=9) B (n=42), C (n=28) or D (n=23), associated with a good (2 or 3 leg arteries, n=60) or a poor (1 or 0 artery, n=42) runoff. RESULTS: The endograft was placed successfully in all cases, but 3 early deaths (3.2%) (1 in group II and 2 in group III), and 4 acute thromboses (4%) occurred. Primary and secondary actuarial patency rates were 97+/-1.7%, and 99+/-1% at 1 month, 74+/-4.8% & 84+/-4.1% at 1 year,and 71+/-9.5% & 79+/-8.5% at 3 years, after a mean follow-up of 30.2 months (1-60). Long-term primary and secondary patencies were significantly different between TASC Cand TASC D lesions (P<.004 & .001). CONCLUSION: Severity of lesions, rather than preoperative symptoms or runoff, is mainly to be considered before using Hemobahn/Viabahn endoprosthesis in severe SFA occlusive lesions.

Rapid molecular diagnosis of tuberculosis and other mycobacteriosis in smear-negative clinical specimens

Delay in diagnosis of pulmonary and other forms of tuberculosis (TB) can be fatal, particularly in HIV-infected patients. Hence, techniques based on nucleic acid amplification, which are both rapid and of high specificity and sensitivity, are now widely used and recommended for laboratories that diagnose TB. In the present study, diagnostic methods based on mycobacterial DNA amplification were evaluated in comparative trials alongside tradicional bacterial methods, using negative smear samples from patients with clinically-suspected TB (sputum samples from 25 patients with suspected pulmonary TB, urine samples from two patients with suspected renal TB and cerebrospinal fluid samples from one patient with suspected meningeal TB). A specificity of 100% was achieved with DNA amplification methods and tradicional culture/identification methods, in relation to clinical findings and treatment results. For the smear-negative sputa, conventional PCR for M.tuberculosis was positive in 62% of suspected lung TB case, showing the same sensitivity as bacterial identification. Both techniques failed in the detection of extra-pulmonary samples. Nested PCR showed, after species-specific amplification, a sensitivity of 100% for M. avium and 85% for M. tuberculosis. For extra-pulmonary smear-negative samples, only Nested PCR detected M. tuberculosis and all cases were confirmed clinically. Nested PCR, in which two-step amplification reactions are performed, can identify the two most important mycobacteria in human pathology quickly and directly from clinical spicimens

Efficacy of Hemobahn in the treatment of superficial femoral artery lesions in patients with acute or critical ischemia: a comparative study with claudicants.

PURPOSE: To assess the results of covered stents in the treatment of superficial femoral artery (SFA) occlusive disease. METHOD: From July 2000 till June 2003, 32 patients (34 limbs) were scheduled for procedures including Hemobahn deployment in the SFA. Indication for treatment was claudication (group I, N=15 patients and 16 limbs, 31.2% occlusions) or critical and acute ischemia (group II, N=17 patients and 18 limbs, 61.1% occlusions). TASC D SFA lesions were excluded. No limb artery was patent pre-operatively in 19% and 89% of limbs in groups I and II, respectively (p=0.00001). RESULTS: Outflow procedures were performed simultaneously in one limb in group I and 12 in group II (p=0.0003). The technical, hemodynamic and clinical success rates were 100, 100 and 94.1%, respectively. Mean follow-up was 18.1 months. Primary patency rates at 12 months were 81.3+/-10.6% in group I and 88.6+/-9.0% in group II (p=0.547). At 12 months, the secondary patency and limb salvage rates were, respectively, 87.5+/-8.9 and 100% in group I and 87.5+/-8.93 and 94.45+/-6.71% in group II. CONCLUSION: Treatment of SFA occlusive lesions (excluding TASC D lesions) with the Hemobahn covered stent yielded good results for both claudicants with good outflow and patients with critical or acute ischemia with bad outflow, if concomitant outflow-improving procedures were performed.

Comparison between duplex scanning and angiographic findings in the evaluation of functional iliac obstruction in top endurance athletes.

OBJECTIVE: Review of a 10 year-experience, to evaluate the efficacy of pre-operative investigations in the detection of external iliac artery (EIA) endofibrosis in top endurance athletes. DESIGN: Retrospective study. MATERIALS: From September 1995 to March 2004, 13 highly-trained athletes (all men, mean age 32.3 years) underwent surgery for disease involving 14 lower limbs (11 left, one right, one bilateral). METHODS: We compared ultrasound scan (US) and digital subtraction angiography (DSA) data, at rest and at hip flexion with intra-operative findings for all 14 lower limbs. We analyzed the presence of stenosis in the external and common iliac arteries, the presence of psoas muscle arteries and the presence of excessive EIA length. RESULTS: In the affected limbs, before treatment, the mean ankle brachial index (ABI) at rest was 0.98 compared with 0.56 after exercise, p=0.0001. The sensitivities of the US vs DSA examination in the detection of external and common iliac artery stenosis were, respectively, 84.6 and 53.8% vs 53.8 and 12.5%. The muscle psoas artery was detected by DSA with a sensitivity of 57.1 and 100% specificity. For the detection of excessive EIA length, the sensitivity of US was 85.7% with 57.1% specificity. CONCLUSIONS: A fall of ABI after exercise proves the presence of a significant stenosis in symptomatic athletes. Color coded duplex ultrasonography is recommended for non-invasive imaging of suspected endofibrotic stenosis in young athletes, since it detects reliably both stenosis and elongation of iliacal arteries.

Comparison between direct clinical and digital photogrammetric measurements in patients with 22q11 microdeletion.

Thanks to recent advances in imaging and computing technology, photoanthropometry has become an increasingly helpful adjunct to obtain objective clinical evidence of morphologic abnormalities in patients with dysmorphic syndromes. The aim of this study was to evaluate measurements made using a new two-dimensional digital photogrammetry technique by comparison with direct clinical measurements. A total of 14 patients with 22q11 microdeletion were included in this study. There were seven females and seven males between 5 and 38 years of age. Sixteen direct clinical measurements were performed using a graduated anthropometric sliding caliper and angle meter. Photogrammetric measurements were made on digital photographs using a commercially available software package. After calibration to one in situ reference on frontal and profile views, photogrammetric measurements were compared to a total of 14 direct clinical measurements made in the same patients. Findings showed that photogrammetric measurements calibrated to an in situ reference were reliable especially on profile views. No statistical difference was found between 10 of the 14 measurements (P> 0.05) including eight of the nine measurements on profile views and two of the five measurements on frontal views. This study indicates that digital photogrammetry is a useful tool but there is still no reliable standard photographic measurement technique.

Catheter cryoablation of the atrioventricular node in patients with atrial fibrillation: a novel technology for ablation of cardiac arrhythmias.

INTRODUCTION: Recent animal studies demonstrated the feasibility and safety of applying percutaneous catheter cryoablation technology for ablation of arrhythmogenic sites. The studies also showed that reversible "ice mapping" can be performed before creating permanent lesions. We investigated the feasibility and safety of applying this new technology in man. METHODS AND RESULTS: Cryoablation of the AV node (AVN) using a 9-French quadripolar catheter with a 4-mm electrode tip was attempted in 12 patients (mean age 67.8 +/- 11.4 years) with refractory atrial fibrillation. Whereas technical issues prevented adequate tissue contact in two patients, complete AVN block was obtained in the remaining 10 patients after 4.8 +/- 1.9 cryoapplications lasting 5.5 +/- 0.2 minutes resulting in temperatures of -58.1 degrees +/- 5.4 degrees C. In all patients with sinus rhythm at the time of the procedure, cryomapping at warmer temperatures induced reversible AVN block and allowed confirmation of a successful site before definitive ablation. Intracardiac echocardiography was performed in three patients and allowed visualization of the cryocatheter-endocardial contact and cryolesion formation. No major procedural complications were reported. After 6 months of follow-up, 8 of 10 initially successful patients remained in complete block; 1 had partial recovery of AVN conduction manifested by atrial fibrillation with a slow ventricular response, and 1 fully recovered AVN conduction. CONCLUSION: (1) Catheter cryoablation of the AVN can be performed safely in man. (2) Reversible cryomapping is feasible and may offer an advantage over radiofrequency ablation. (3) Cryocatheter-endocardial contact and cryolesion growth can be monitored with intracardiac echocardiography.

Phenotype-genotype correlation in 91 patients with familial Mediterranean fever reveals a high frequency of cutaneomucous features.

OBJECTIVES: To describe the clinical manifestations of familial Mediterranean fever (FMF) in 91 patients from 47 families and provide data from the genetic study. P:atients and methods. We conducted a retrospective chart review of 91 patients (including 83 children aged <15 yr) from 47 families through a questionnaire and a specific database. The genetic analysis included complete screening of known mutations of the MEFV gene on chromosome 16p13.3. A positive diagnosis required at least two mutations, one on each chromosome. RESULTS: Our panel included 52 females and 39 males, with a mean age of 7.27 yr. Of the 47 families, 31 were non-Ashkenazi Jews, 10 were Armenians and six were from other ethnic groups. Clinical features included fever (100%), peritonitis (86%), pleuritis (56%), arthritis (34%) and myalgias (27%). We observed a high rate of cutaneous manifestations (47%); erythema, oedema and recurrent oral ulcers were the most frequent. Phenotype-genotype correlations showed a significant association of M694V homozygosity with earlier age of onset (P: = 0.044), fever >39 degrees C (P: = 0. 002), pleural crisis (P: = 0.0044), splenomegaly (P: = 0.0005) and arthritis (P: = 0.001). Associations with mucocutaneous features were as follows: erysipelas-like erythema (P: = 0.012), oedema (P: = 0.61, not significant) and oral ulcers (P: = 0.45, not significant). CONCLUSION: New phenotype-genotype correlations emerged from our study: homozygosity for the M694V mutation was associated with intensity of fever, splenomegaly and with erysipelas-like erythema. Apart from erysipelas-like erythema, no significant association was found between other cutaneous features and the genotype.

Cryothermal ablation of the slow pathway for the elimination of atrioventricular nodal reentrant tachycardia.

BACKGROUND: We report the first successful slow pathway ablation using a novel catheter-based cryothermal technology for the elimination of atrioventricular nodal reentrant tachycardia (AVNRT). METHODS AND RESULTS: Eighteen patients with typical AVNRT underwent cryoablation. Reversible loss of slow pathway (SP) conduction during cryothermy (ice mapping) was demonstrated in 11 of 12 patients. Because of time constraints, only 2 sites were ice mapped in 1 patient. Seventeen of 18 patients had successful cryoablation of the SP. One patient had successful ice mapping of the SP, but inability to cool beyond -38 degrees C prevented successful cryoablation. A single radiofrequency lesion at this site eliminated SP conduction. No patient has had recurrent AVNRT over 4.9+/-1.7 months of follow-up. During cryoablation, accelerated junctional tachycardia was not seen and was therefore not available to guide lesion delivery. Adherence of the catheter tip during cryothermy (cryoadherence) allowed atrial pacing to test for SP conduction. Cryoablation in the anterior septum produced inadvertent transient PR prolongation consistent with loss of fast pathway conduction in 1 patient and transient (6.5 seconds) 2:1 AV block in another. On rewarming, the PR interval returned to normal, and the AV nodal effective refractory period was unchanged in both. Accelerated junctional tachycardia was seen on rewarming in both but not during cryothermy. CONCLUSIONS: Cryothermal ablation of the SP was achieved in patients with this novel technique. Successful ice mapping of both the SP and fast pathway was demonstrated. The ability to test the functionality of specific ablation sites before production of a permanent lesion may eliminate inadvertent AV block.

Transvenous catheter ice mapping and cryoablation of the atrioventricular node in dogs.

While radiofrequency catheter ablation is very effective, it does not allow for prediction of success prior to full delivery of the energy. We investigated the use of cryoablation using a new catheter on the AV node to determine (1) if a successful site might be identified prior to the ablation itself, and (2) the parameters of cryoablation of the AV node using a new cryocatheter. In eight dogs, the cryoablation catheter was advanced to the AV node to produce transient high degree AV block by lowering the temperature to a minimum of -40 degrees C (ice mapping). Transient high degree AV node block was obtained in seven of eight animals at a mean temperature of -39.9 +/- 11.6 degrees C. No significant pathological modification was found in all animals but one and, in all cases, electrophysiological parameters of the AV node measured before, 20 minutes, 60 minutes, and up to 56 days after cryoapplication were not significantly different. In the 12 other dogs, after ice mapping, cryoablation of the AV node was attempted with a single freeze-thaw cycle in 6 dogs (group I) and a double freeze-thaw cycle in the other 6 dogs (group II). Chronic complete AV block was obtained in only one animal in group I compared to all animals in group II. Ablation of the AV node is effective with a double freeze-thaw cycle using a percutaneous catheter cryoablation system. Ice mapping of the area allows for identification of the targeted site.

Feasibility of cardiac cryoablation using a transvenous steerable electrode catheter.

We investigated the feasibility of using cryogenic technology in an electrode catheter for percutaneous ablation of cardiac tissue. Despite its high success rate, radiofrequency catheter ablation has important limitations especially with regards to the treatment of ventricular arrhythmias associated with a chronic scar. Arrhythmia surgery experience has shown that freezing with a hand held probe can permanently ablate the arrhythmogenic substrate of ventricular tachycardia associated with an old scar. Moreover, cryosurgery also allows for reversible "ice mapping," in which the area likely responsible for the arrhythmia can be evaluated by suppressing its electrophysiologic properties prior to the creation of an irreversible state. A new steerable cryoablation catheter using Halocarbon 502 as a refrigerant was utilized in six dogs. Serial cryoapplications were performed in the right and left ventricles. In two dogs, we attempted reversible ice mapping of the AV node. Pathological evaluation of the lesions was done acutely in all the animals. Forty-two cryoapplications were delivered at a mean temperature of -45 +/- 9.8 degrees C. No lesion was found at pathological evaluation for 16 cryoapplications which did not achieve a temperature of less (colder) than -30 degrees C. The remaining applications resulted in 26 lesions which were hemorrhagic and sharply demarcated from normal myocardium. Histological evaluation revealed contraction band necrosis. Reversible ice mapping of the AV node was successfully achieved in two animals. Cryoablation is feasible using an electrode catheter with multiple electrodes. This technology has the potential to allow for reversible ice mapping to confirm a successful ablation target before definitive ablation.

Is there a future for antiarrhythmic drug therapy?

Drug therapy has traditionally been the mainstay of treatment for both ventricular and supraventricular arrhythmias. However, increasing knowledge about the potentially significant adverse effects of these medications, together with the emergence of new, nonpharmacological approaches to the treatment of arrhythmias, has led some to question the future of antiarrhythmic drug therapy. Antiarrhythmic drugs are quite effective in terminating a variety of arrhythmias, including atrioventricular (AV) node re-entrant and AV tachycardias (particularly calcium antagonists and adenosine), atrial flutter (class III agents) and atrial fibrillation (class IA and IC drugs. The chronic use of antiarrhythmic drugs has been increasingly limited by a fear of adverse effects (especially proarrhythmia) and the availability of highly effective nonpharmacological alternatives (particularly ablation for re-entrant tachycardias involving the AV node and bypass tracts and cardiovertor/defibrillators for malignant ventricular arrhythmias. Atrial fibrillation (AF) continues to be a therapeutic challenge for which there is no safe and curative nonpharmacological therapy. Antiarrhythmic drugs of classes IA, IC and III show efficacy in preventing recurrence of AF but there are concerns about possible pro-arrhythmic complications. In the future, antiarrhythmic agents will continue to be used acutely to terminate a broad range of sustained arrhythmias. Chronic use is likely to depend on the development of safer and/or more effective compounds, as well as on improved ways of predicting which patients are likely to develop pro-arrhythmic reactions. The development of molecular electrophysiology will allow for the identification of agents with selected ion channel blocking profiles which may prove efficacious with a lower risk of complications. Finally, an improved understanding of arrhythmia substrates may permit the identification of therapy that prevents arrhythmias by acting on the underlying substrate, rather than simply trying to modify the electrical end product.

One-to-two atrioventricular conduction causing nonreentrant tachycardia: successful treatment with radiofrequency ablation.

The anatomical substrate for AV nodal reentrant tachycardia (AVNRT) is well known and is due to anterograde conduction through a slow conducting pathway and retrograde conduction using a fast conducting pathway. In this report, we describe a patient with AVNRT who also presented with frequent episodes of paroxysmal nonreentrant tachycardia due to the occurrence of two conducted ventricular beats for each sinus depolarization. Palpitations and arrhythmias were abolished after radiofrequency ablation of the slow pathway.

Mass screening programs for breast cancer in France--average values of assessment criteria.

Breast cancer is the most common cancer in women worldwide. Many studies have been performed worldwide to assess the effectiveness of screening in terms of reduced mortality due to breast cancer. Since the end of 1989, 10 breast cancer mass screening programs using mammography have been carried out in France under the sponsorship of the National Fund for Health Prevention, Education, and Information (FNPEIS) from the National Health Insurance of Salaried Workers (CNAMTS). These 10 campaigns, which are on a district scale, are organized according to variable methods and are assessed using a common procedure. Four groups of criteria are measured in this procedure, which investigates the impact, quality, effectiveness, and costs of screening programs. The average and extreme values of each criterion as calculated from the campaigns are presented in this paper. In order to enlighten the judgment on the French results, a comparison with the international standards in force and with the results of foreign screening programs is proposed.

Use of mammography as a breast cancer screening tool in six districts in France.

Mass screening programs to detect breast cancer are currently under way in many countries. In France, several districts have been running mammographic screening programs since 1989. A survey was conducted in five of these districts and in a sixth district where no screening program was implemented. Using a self-addressed questionnaire mailed to a sample of 1500 women aged over 20 years, the survey was aimed at assessing women's use of mammography as well as their knowledge and perception of mammographic breast cancer screening. According to district, the compliance of the women replying to the questionnaire ranged from 72 to 82%. The proportion of women who had at least one mammography during their life ranged from 41 to 54%, according to district. The percentage of women aged 50 to 69 who had one mammography within 3 years before the survey ranged from 57 to 78% in the experimental districts and was only 48% in the control district. In all districts, women did not know exactly at what age it is recommended to start screening and with what periodicity, but, when invited to do so, they were satisfied with the program and intended to participate again.

[Modalities of reading of detection mammographies of the programme in the Bouches-du-Rhône. Results and costs 1990-1995]. / Modalités de lecture des mammographies de dépistage du programme des Bouches-du-Rhône. Résultats et coûts 1990-1995.

In the Bouches du Rhône breast cancer screening programme, mammograms are read by two separate radiologists of different levels of training. All women with at least one positive reading are recalled for further assessment. During the first round, 3,477 of the 95,967 screenees were recalled by the first reader and 2,321 by the expert reader. The expert increased cancer detection by 15% and 45% of cancers detected by the expert were smaller than 11 mm. The marginal cost of double reading was 21,838 Francs per additional cancer detected. Double reading thus allowed for the detection of cancers of good prognosis which would have gone undetected by a single reader. Its cost seems justified by its impact on the effectiveness of the screening programme.

[Mass screening programs for breast cancer in France. Comparative evaluation]. / Les programmes de dépistage de masse du cancer du sein en France. Evaluation comparative.

OBJECTIVE: The purpose of this work was to comparatively assess the results of mass screening programs for breast cancer implemented in six French departments in 1986, within the scope of the National Fund for Health Prevention, Education and Information of the National Health Insurance Office of Salaried Workers. MATERIAL AND METHODS: The data collected by the screening centres were analyzed by ten assessment teams that were independent from the program promotion staff, all using the same evaluation form. A complementary population study performed in eight French districts then, allowed assessing the frequency of self-referred screening (mammography performed out of program). RESULTS: The rate of participation in screening programs, in relation to the invited population, ranged from 21 to 48%, according to the district (36% in average). This low participation was probably related to the extent of self-referred screening. In fact, 19 to 40% of women, according to the district, had previously had a screening mammographic coverage: rate was around 68% in women aged 50 to 69 years. Positive findings with mammography ranged from 4.5 to 15.8% (10.1% in average), while intervention rates ranged from 0.7 to 1.6% and detection rates from 3.8 to 6.2%. The ratio between benign tumors and cancers ranged from 0.7 to 2.1 according to the district. In order to enlighten the judgement on French results, we propose a comparison with the international standards in force. CONCLUSION: The various experiences with breast cancer screening in France show that this screening is technically feasible on the basis of existing medical structures. However, some criteria are still below the expected values, especially if compared with international standards. This result is probably accounted for by the high rate self-referred screening before age 40 in France. In these conditions, the question is whether extending breast cancer screening programs in France is an appropriate course of action.

Body surface potential distributions during idiopathic ventricular tachycardia.

BACKGROUND: The purpose of this report is to describe the body surface potential maps (BSPMs) during idiopathic ventricular tachycardia (VT) and to determine what differences exist between different idiopathic VT morphologies. METHODS AND RESULTS: We performed BSPMs during VT on 12 consecutive patients (3 women and 9 men; mean age, 42 +/- 13 years) presenting symptomatic idiopathic VT referred to our institution for electrophysiological study. Basal ECG, chest radiograph, and echocardiogram were normal in all patients. Clinical tachycardia showed left bundle branch block pattern (LBBB) in 9 patients, with sustained VT in 5 and nonsustained VT in 4, and right bundle branch block pattern (RBBB) in 3 with sustained VT. We found a unique pattern of BSPMs in each of the 9 patients during idiopathic LBBB VT configuration, whether sustained or nonsustained VT. This pattern appeared at the onset of the QRS and remained stable during the whole QRS complex. The area of minimal potential located in the upper anterior part of the torso was compatible with an origin of VT in the right ventricular outflow tract, as confirmed in 5 patients by successful radiofrequency ablation. We found an evolving pattern with two phases in each of the three RBBB VTs. The electrical axis during the initial part of the QRS could correspond to an endocardial-epicardial vector. The second phase, with a high voltage and area of minimal potential located in the inferior and anterior part of the torso, was compatible with a left ventricular apical origin that was confirmed by epicardial and endocardial mapping during cryosurgery in 1 patient. For all the VTs, the QRS isoarea maps showed the same pattern as the second phase of the QRS. CONCLUSIONS: Two different BSPM patterns were found. All LBBB VTs had the same stable pattern corresponding to an infundibular origin. All RBBB VTs had an evolving pattern that stabilized in the second part of the QRS complex corresponding to an apical origin.

Pace mapping using body surface potential maps to guide catheter ablation of accessory pathways in patients with Wolff-Parkinson-White syndrome.

BACKGROUND. A pace mapping technique using body surface potential maps (BSPMs) was developed to guide the positioning of an ablation catheter at the ventricular insertion point of accessory pathways (AP) in patients with the Wolff-Parkinson-White syndrome (WPW). METHODS AND RESULTS. The study was performed on 30 WPW patients. BSPMs were recorded with 63 leads distributed over the entire torso surface. The catheter used for radiofrequency ablation was first placed in the vicinity of the ventricular preexcitation site predicted by BSPMs recorded during the delta wave. BSPMs were then recorded during pacing with this catheter, the comparison between the preexcited and paced BSPMs indicated whether the pacing site was too anterior or posterior with respect to the preexcitation site, and the catheter was moved accordingly. This process was repeated until the preexcited and paced BSPMs were highly correlated (r > or = 0.8), and ablation then was attempted. It was possible to successfully ablate the AP in 28 patients after an investigation that lasted 54 +/- 44 minutes between the recording of the first paced BSPM and that of the BSPM paced at the successful ablation site. Patients with left free wall pathways needed less investigation time compared with patients with pathways of other locations (46 +/- 9 versus 100 +/- 25 minutes, p = 0.031). The sensitivity of BSPM pace mapping was assessed using pacing with a multipolar catheter, and significant changes were observed on the BSPMs for beats with pacing sites that were only 5 mm apart. CONCLUSIONS, BSPM pace mapping allowed us to achieve a 93% success rate with short investigation durations, provides significant information that cannot be obtained with the standard 12-lead ECG, is a self-correcting procedure that reduces the importance of BSPM alterations due to individual differences in the shape of the torso or heart, and is applicable only to patients with AP showing antegrade conduction.

Epicardial and endocardial mapping of ventricular tachycardia in patients with myocardial infarction. Is the origin of the tachycardia always subendocardially localized?

BACKGROUND: Left ventricular endocardial reentry is the conventional concept underlying surgery for ventricular tachycardia (VT). We assessed the incidences of patterns showing complete reentry circuits at either the subendocardial or subepicardial level and of patterns in which left ventricular endocardial mapping could only in part account for a reentrant mechanism. METHODS AND RESULTS: We retrospectively analyzed epicardial and left ventricular endocardial isochronal maps of 47 VTs induced in 28 patients with chronic myocardial infarction (inferior, 14 patients; anteroseptal, 14 patients). Electrograms were recorded intraoperatively from 128 sites with epicardial sock and transatrial left ventricular endocardial balloon electrode arrays. Given the methodology used in this study, the mapping characteristics of the tachycardias suggested five types of activation patterns: 1) complete (90% or more of VT cycle length) subendocardial reentry circuits in seven VTs (15%) and seven patients (25%), 2) complete subepicardial reentry circuits in four VTs (9%) and four patients (14%), 3) incompletely mapped circuits with a left ventricular endocardial breakthrough preceding the epicardial breakthrough in 25 VTs (53%) and 21 patients (75%), 4) incompletely mapped circuits with a left ventricular epicardial breakthrough preceding the endocardial breakthrough in three VTs (6%) and three patients (11%), and 5) a right ventricular epicardial breakthrough preceding the left ventricular endocardial breakthrough in eight VTs (17%) and seven patients (25%). After surgery, one type 3 VT and three type 5 VTs were reinducible. Thus, left ventricular endocardial reentry substrates (types 1 and 3) accounted for 68% of VTs, but substrates involving subepicardial (types 2 and 4) and deep septal layers (type 5) accounted for 32% of VTs. CONCLUSIONS: In a substantial number of VTs, a substrate localization that is at variance with the conventional concept can be detected by simultaneous epicardial and endocardial mapping and may require modification of the surgical approach conventionally aimed at endocardial layers.