V-013 ETEP - STEP BY STEP

Minimally invasive approaches are increasingly being used for the correction of abdominal wall hernias. Although laparoscopy presents as a greater technical challenge compared to classical techniques, once the learning curve is overcome, the advantages are multiple: less postoperative pain, shorter hospital stay, faster return to daily/professional activities and lower rate of surgical site infection.

The authors present the case of a 55yo women with a history of type 2 diabetes mellitus and peripheral venous insufficiency. No history of previous surgeries. The patient was referred to an appointment in the Ambulatory Surgery Centre for evaluation of a primary midline hernia. Symptoms were worsening in the last 6 months. No previous episodes of complications. Preoperative evaluation included an abdominopelvic computed tomography, which revealed a hernia sac containing only fatty tissue (no intestinal loops present) and a 19 mm hernial neck with a supra-umbilical median location. No other abdominal wall defects were evident.

The patient was proposed for a laparoscopic approach - extended totally extraperitoneal (eTEP) in ambulatory setting. The surgery and post-operative period (9 months) to date went without intercurrences.

The present video aims to demonstrate the main steps of the surgical technique applied in a tertiary centre with years of experience in laparoscopic abdominal wall surgery.

With this paper the authors pretend to demonstrate that laparoscopy may become the gold-standard in abdominal wall hernia correction as soon as the know-how and respective learning curve are aquired. Until then, these cases should continue to be referred to specialized tertiary centres.

Outcomes and predictors of clinical response after upgrade to resynchronization therapy

Funding Acknowledgements

Type of funding sources: None.

BACKGROUND

 Upgrade to  resynchronization therapy (CRT) is common practice in Europe. However, patient selection remains a challenge. Data regarding predictors of response to upgrade is currently lacking.

AIM

To identify predictors of clinical response after upgrade to CRT.

METHODS

Single-center retrospective study of consecutive patients submitted to upgrade to CRT (2007-2018). Patients underwent clinical and echocardiographic (echo) evaluation at baseline, 6-months and 1-year. Major adverse cardiac events (MACE) included hospitalization for heart failure (HF) or all-cause mortality. Clinical response was defined as New York Heart Association (NYHA) class improvement without MACE in the 1st year of follow-up (FU). Left ventricle end-systolic volume reduction of >15% designated echo response. Multivariate logistic regression was performed to identify predictors of clinical response to CRT.

RESULTS

Fifty-six patients submitted to upgrade to CRT (80.4% male, mean age 70.0 ± 9.6 years) were included; 43 patients (78.2%) previously had a pacemaker and 12 (21.8%) had a defibrillator device.  Most patients had non-ischemic HF (67.9%), with a mean baseline left ventricle (LV) ejection fraction of 27.9 ± 6.4%. Indications for upgrade were mainly pacemaker dependency or pacing-induced LV dysfunction (76.6%) and de novo left bundle branch block (23.4%).

Thirty-one (59.3%) patients were clinical responders. MACE occurred in 37.5% of patients; 28.6% were hospitalized for HF and 13% died during the 1st year of FU. Clinical responders had a lower rate of atrial fibrillation (AF) (46.9% vs. 53.1%, p=.025) and a higher rate of pacemaker rythm prior to upgrade (80.6% vs 47.6%, p=.013). Among responders, the previous device was more frequently a pacemaker (87.5% vs 61.9%, p=.029), and the new device a CRT-P (81.2% vs 54.5%, p=.035). HF etiology did not differ between responders and non-responders.

Multivariate analysis identified absence of AF (odds ratio [OR] 4.4, 95% confidence interval [CI] 1.1-17.6, p=.037), CRT-P (OR 5.7, 95% CI 1.3-25.8, p=.022) and quadripolar lead implant (OR 3.8, 95% CI 1.3-25.8, p=.024) as predictors of clinical response in upgraded patients.

CONCLUSIONS

In this cohort, absence of AF, implantation of CRT-P and use of a quadripolar lead predicted clinical response to upgrade to CRT. Larger studies are warranted to tailor selection of patients for upgrade procedures.

Superresponse to cardiac resynchronization therapy: clinical outcomes and predictors

Funding Acknowledgements

Type of funding sources: None.

BACKGROUND

Resynchronization therapy (CRT) reduces morbidity and mortality in selected patients with heart failure with reduced ejection fraction (HFrEF). Patients that experience significant reverse remodelling and left ventricular (LV) ejection fraction (LVEF) improvement have been called "superresponders".

AIM

To describe a cohort of superresponders and identify predictors of superresponse to CRT.

METHODS

Single-center retrospective study of consecutive patients submitted to CRT implantation (2007-2018). Patients underwent echocardiographic (echo) assessment at baseline, 6-months and 1-year. Superresponse was defined as LVEF≥50% during the 1st year of follow-up (FU). Major adverse cardiac events (MACE) included heart failure hospitalization or all-cause mortality. Multivariate logistic regression was performed to identify predictors of superresponse. Survival analysis with Kaplan-Meier method and Log-rank test was performed to compare outcomes between superresponders and non-superresponders.

RESULTS

295 CRT patients (70.5% male, mean age 67 ± 11 years) were included. Fifty-nine (21.4%) patients were superresponders. Superresponders were more often female (42.4% vs 25.8%, p=.021), tended to be older (69.6 vs 66.7 years, p=.054) and had lower rates of coronary disease (17.2% vs 32.9%, p=.032), atrial fibrillation (20.3% vs 38.0%, p=.018), valve disease (13.6% vs 30.0%, p=.018) and chronic kidney disease (6.9% vs 26.0%, p=.003). Superresponders had higher rates of non-ischemic HF (88.1% vs 69.1%, p=.006) and were more often implanted with CRT-P (69.5% vs 37.8%, p<.001). HFrEF medication did not differ between groups.

Superresponders had lower baseline LV end-systolic volumes (115.5 vs 166.2 ml, p<.001) and N-terminal pro B-type natriuretic peptide (NT-proBNP) values (1232.6 vs 5252 pg/ml, p<.001). Baseline QRS duration did not differ (171.7 vs 171.3 ms, p=.883). During a median FU of 3 ± 5 years, there were no differences in terms of ventricular arrythmias (5.3% vs 6.8%, p=.913) or appropriate defibrillator therapies (1.8% vs 6.8%, p=.147) between groups. In addition to LVEF improvement (53.7% vs 35.3%, p<.001), superresponders also showed higher tricuspid annular plane systolic excursion values (22.1 vs 19.8 mm, p=.004) during FU. MACE occurred less frequently (Log-rank test, p=.003) and all-cause mortality (Log-rank test, p < 0.001) was lower in superresponders.

Multivariate analysis identified female gender (odds ratio [OR] 5.7, 95% confidence interval [CI] 1.03-31.73, p=.045), older age (OR 1.1, 95% CI 1.02-1.24, p=.017) and lower baseline NT-proBNP (OR 0.9, 95% CI 0.99-1.00, p=.011) as independent predictors of superresponse to CRT.

CONCLUSION

In superresponders, in addition to a significant improvement in LVEF, we observed an improvement in right ventricular function. As expected, MACE and all-cause mortality were lower. Female gender, older age and lower baseline NT-proBNP predicted super-response to CRT.

Comparison of de novo and upgrade to resynchronization therapy: a propensity-score matched analysis

Background

Upgrade to resynchronization therapy (CRT) from conventional pacemaker (P) or defibrillator (D) is common practice in Europe. However, guidelines (GL) are discordant: Pacing GL give a class I recommendation, while Heart Failure (HF) GL provide a class IIb indication. Previous studies suggested worse outcomes in upgraded patients (pts).

Aim

To compare response rate and clinical outcomes in a cohort of pts receiving de novo or upgrade to CRT.

Methods

Single-center retrospective study of consecutive pts submitted to CRT implantation (2007–2017). Major adverse cardiac events (MACE) included HF hospitalization (HHF) or all-cause mortality. Clinical response was defined as New York Heart Association class improvement without MACE in the first year of follow-up (FU). Left ventricle end-systolic volume reduction of >15% denoted echocardiographic (echo) response. Survival analysis with Kaplan-Meier method and Log-rank test was performed. Propensity-score matching (PSM) analysis was made to adjust for possible confounder variables.

Results

230 CRT recipients (70.9% male, mean age 67±11 years, 71.5% non-ischemic cardiomyopathy, 39.6% CRT-P) were included, of whom 46 (20%) underwent an upgrade. Upgraded pts were older (69.8 vs 65.9 years, p=0.015), with higher rates of permanent atrial fibrillation (37.0% vs 12.7%, p=0.001), moderate to severe valve disease (45.7% vs 22.3%, p=0.002), chronic kidney disease (37.0% vs 17.2%, p=0.005) and treatment with mineralocorticoid receptor antagonists (79.1% vs 52.0%, p=0.002). They were more likely to receive CRT-P (65.2% vs 33.2%, p<0.001) and CRT-D were more often implanted for secondary prevention (60.0% vs 17.9%, p=0.001). No differences emerged in procedural complications, clinical (74.4% vs 71.4%, p=0.712) or echo (66.7% vs 69.7%, p=0.822) response rates.

During a median FU of 3±4 years, all-cause mortality was similar among groups (Log Rank test, p=0.522, unadjusted hazard ratio [HR] 1.25, confidence interval [CI] 95% 0.62–2.49, p=0.534). There was a statistical tendency for higher MACE rate in the upgrade group (Log Rank test, p=0.064, HR 1.66, CI 95% 0.95–2,91, p=0.076). No differences were found in lead dislodgement (10.9% vs 7.1%, p=0.368) or endocarditis (2.2% vs 4.3%, p=0.692) rates.

PSM analysis identified 88 matched pairs (46 upgrade/42 de novo pts). In this cohort, all-cause mortality (Log Rank test, p=0.77, HR 0.89, CI 95% 0.39–2.03, p=0.78) and MACE (Log Rank test, p=0.36, HR 1.38, CI 95% 0.68–2.81, p=0.37) were comparable between groups [graph no. 1].

Conclusion

Upgrade to CRT was similar to de novo implantation in terms of complications and clinical and echo response, in this cohort. The risk for MACE and mortality was also comparable.

Graph 1

Funding Acknowledgement

Type of funding source: None

Frequency of specific CD8+ T cells for a promiscuous epitope derived from Trypanosoma cruzi KMP-11 protein in chagasic patients

The K1 peptide is a CD8(+)T cell HLA-A*0201-restricted epitope derived from the Trypanosoma cruzi KMP-11 protein. We have previously shown that this peptide induces IFN-gamma secretion by CD8(+)T cells. The aim of this study was to characterize the frequency of K1-specific CD8(+)T cells in chagasic patients. Nineteen HLA-A2(+)individuals were selected from 50 T. cruzi infected patients using flow cytometry and SSP-PCR assays. Twelve HLA-A*0201(+)noninfected donors were included as controls. Peripheral blood mononuclear cells were stained with HLA-A2-K1 tetramer, showing that 15 of 19 infected patients have K1-specific CD8(+)T cells (0.09-0.34% frequency) without differences in disease stages or severity. Of note, five of these responders were A*0205, A*0222, A*0226, A*0259 and A*0287 after molecular typing. Thus, a phenotypic and functional comparison of K1-specific CD8(+)T cells from non-HLA-A*0201 and HLA-A*0201(+)infected patients was performed. The results showed that both non-HLA-A*0201 and HLA-A*0201(+)individuals have a predominant effector memory CD8(+)T cell phenotype (CCR7-, CD62L-). Moreover, CD8(+)T cells from non-HLA-A*0201 and HLA-A*0201(+)individuals expressed IL-2, IFN-gamma and perforin without any differences. These findings support that K1 peptide is a promiscuous epitope presented by HLA-A2 supertype molecules and is highly recognized by chagasic patients.

Catheter ablation of ventricular tachycardia in Chagasic Cardiomyopathy

There is a limited experience with catheter ablation for treatment of ventricular tachycardia (VT) in Chagasic cardiomyopathy. A 30-year-old woman experienced episodes of palpitations and syncope due to attacks of VT. A diagnosis of Chagas disease was established on a biological basis. Two-dimensional echo and contrast ventriculography showed an apical aneurysm with thrombus. Surgery was indicated to resect the aneurysm and ablate the VT. Ventricular tachycardia recurred 1 month later despite therapy, including amiodarone. Two clinical frequent and well-tolerated tachycardias were identified. The site of origin was located in the right ventricular apex and in the apical-lateral wall of the left ventricle, respectively. Catheter ablation was performed at two sites with DC shocks (total energy 600 J) after unsuccessful radiofrequency ablation. Holter recordings performed during the post-operative period showed only infrequent extrasystoles. After follow-up of 24 months the patient remains asymptomatic. Drug-refractory VT in Chagasic cardiomyopathy can be ablated by medium-energy DC shocks after failure of radiofrequency ablation.

Immunological and structural characterization of an epitope from the Trypanosoma cruzi KMP-11 protein

The K1 peptide is an HLA-A*0201-restricted cytotoxic epitope derived from the Trypanosoma cruzi KMP-11 protein, this being the etiological agent of Chagas' disease. This work describes the K1 peptide's secondary structure and its recognition by sera from chagasic patients. Circular dichroism and NMR spectroscopy analysis revealed that the K1 peptide adopts an alpha-helical conformation. Fifty-six percent of individuals had anti-K1 and 86% anti-KMP-11 antibodies by ELISA in the chronic Chagas' group and 28 and 68% in the indeterminate Chagas' group, respectively. By contrast, no reactivity was observed in sera from healthy individuals and tuberculosis patients. Antibody response subclass specificity to the K1 peptide was IgG1 and IgG3. Taken together these results support the idea that the K1 peptide acts as a B-cell-inducer epitope during Chagas' disease.

Evaluation of IFN-gamma production by CD8 T lymphocytes in response to the K1 peptide from KMP-11 protein in patients infected with Trypanosoma cruzi

The cellular response mediated by MHC class I restricted CD8+ T cells has been shown to be crucial in the control of Chagas disease. The K1 peptide derived from T. cruzi KMP-11 protein has a high binding affinity to the HLA-A*0201 molecule. Nevertheless, it is not known whether this peptide is processed and displayed as an MHC class I epitope during natural infection by T. cruzi. The aim of this study was to evaluate, by ELISPOT assay, the ability of K1 peptide to activate CD8+ T lymphocytes to produce IFN-gamma. Therefore, CD8+ T lymphocytes from 22 HLA-A*0201+ individuals, 12 chronic chagasic patients and 10 uninfected controls, were analysed. The results revealed that two of the chagasic patients had IFN-gamma-secreting CD8+ T cells that were able to respond to K1 peptide with a relative frequency of 110 and 230 per million CD8+ T cells. In contrast, none of HLA-A*0201+ uninfected controls responded to K1 peptide. Responses to HLA-A*0201 restricted peptide from the influenza matrix protein were found in six chagasic patients and four uninfected controls with an average frequency of 175 and 111 cells per million CD8+ T cells, respectively. Moreover, a flow cytometric assay for degranulation showed that chagasic responders had K1-specific cytotoxic CD8+ T cells. It is shown here for the first time that the K1 peptide is efficiently processed, presented and recognized by CD8+ T lymphocytes during the natural course of Chagas disease.

[Permanent AV junction (Coumel type) reciprocal tachycardia]

Permanent auriculo-ventricular junctional reciprocating tachycardia is a special form of tachycardia usually incessant, secondary to an slow retrograde conduction pathway.

OBJECTIVE

To establish the clinical, electrophysiological characteristics and therapy results in patients with this diagnosis.

METHOD

Descriptive study.

RESULTS

Nine patients with average age 28.1 +/- 19.2 years, six women. Seven patients presented with dyspnea or palpitations. The left ventricular ejection fraction before treatment was 43.3 +/- 19.5%. The electrocardiographic findings were: heart rate of 139.2 +/- 16.7 bpm, QRS 78.9 +/- 16.2 ms and RP'/P'R relation of 1.8 +/- 0.5. The location of the accessory pathways was: right postero-septal in seven (77.7%), left lateral in one (11.15%) and left postero-lateral in one (11.15%). Radiofrequency ablation was performed in eight patients with an 87.5% success rate, two cases were taken to surgery with successful treatment, one of them after percutaneous ablation failure. Those with systolic left ventricular dysfunction recover their function in the follow-up. Any case has recurred.

CONCLUSIONS

In our center, permanent auriculo-ventricular junctional reciprocating tachycardia is an infrequent arrhythmia, predominantly in women and associated with reversible left ventricular dysfunction. Right postero-septal was the most frequent localization of the pathway. Radiofrequency ablation was performed successfully in 87.5% of cases.

[Neurocardiogenic syncope in children]

Between december of 1994 and june 1997, 90 children and adolescents were referred to the Shaio Clinic Foundation for evaluation of recurrent unexplained syncope. Head-up tilt testing was positive in 45 (50%), 23 male, with a mean age of 12.7 years (range 5-17 years). The response during Head-up tilt testing was predominantly vasodepressor (57%), followed by mixed in 24% and cardioinhibitory in the remaining 17%. The majority of patients had a positive response during pharmacological phase with isoproterenol infusion at a mean time of 17 +/- 8 minutes. Head-up tilt is a safe diagnostic test and defines the cause of unexplained syncope in up to 50% of children and young adults with recurrent syncope. The management was based on education, control of risk factors and psychological and/or physical rehabilitation. In the 15.2 months follow up we observed complete remission or a significant reduction of symptoms in 95% of the cases. Only 5% of the patients persisted or had worsening of their symptoms.

Multiple hemopoietic defects and lymphoid hyperplasia in mice lacking the transcriptional activation domain of the c-Rel protein

The c-rel protooncogene encodes a member of the Rel/nuclear factor (NF)-kappaB family of transcriptional factors. To assess the role of the transcriptional activation domain of c-Rel in vivo, we generated mice expressing a truncated c-Rel (Deltac-Rel) that lacks the COOH-terminal region, but retains a functional Rel homology domain. Mice with an homozygous mutation in the c-rel region encoding the COOH terminus of c-Rel (c-relDeltaCT/DeltaCT) display marked defects in proliferative and immune functions. c-relDeltaCT/DeltaCT animals present histopathological alterations of hemopoietic tissues, such as an enlarged spleen due to lymphoid hyperplasia, extramedullary hematopoiesis, and bone marrow hypoplasia. In older c-relDeltaCT/DeltaCT mice, lymphoid hyperplasia was also detected in lymph nodes, liver, lung, and stomach. These animals present a more severe phenotype than mice lacking the entire c-Rel protein. Thus, in c-relDeltaCT/DeltaCT mice, the lack of c-Rel activity is less efficiently compensated by other NF-kappaB proteins.

IFN-gamma is a potent inducer of Ig secretion by sort-purified murine B cells activated through the mIg, but not the CD40, signaling pathway

IFN-gamma has been shown to either stimulate or inhibit Ig secretion. No studies have yet addressed the basis for these seemingly conflicting properties nor whether IFN-gamma acted directly at the level of the B cell to mediate its effects. Thus, we studied the ability of IFN-gamma to regulate Ig secretion in sort-purified, resting murine B cells that were >99% Ig+, activated either through membrane Ig using unconjugated or dextran-conjugated anti-IgD antibodies (alphadelta-dex) or through CD40 using soluble or membrane CD40 ligand (CD40L). B cells activated with alphadelta-dex proliferated but do not secrete Ig, even in the presence of IL-1 + IL-2. We demonstrate that IFN-gamma only when added subsequent to B cell stimulation with alphadelta-dex, but not unconjugated anti-IfD antibody, plus IL-1 + IL-2 induces up to 100-fold enhancements in Ig secretion and in the numbers of Ig-secreting cells. The predominant Ig isotype secreted is IgM, with IgG3 and IgG2a comprising the majority of non-IgM antibody. IFN-gamma must act in concert with IL-2 for stimulation of Ig secretion. Further, IFN-gamma synergizes with IL-3 + granulocyte-macrophage colony stimulating factor for induction of Ig synthesis. IFN-gamma also enhances IgA syntheses by transforming growth factor-beta-induced membrane IgA+ cells. By contrast, 125IIFN-gamma fails to stimulate Ig secretion in B cells activated with CD40L in the presence or absence of IL-1 + IL-2 or IL-4. However, the combination of CD40L and alphabeta-dex is strongly synergistic for IFN-gamma-induced Ig secretion. Thus, these data establish that IFN-gamma can act directly on the B cell to induce Ig synthesis without the participation of any other cell and demonstrates that the mode of activation of the B cell plays an important role in directing the action of IFN-gamma.

Concomitant mitral valve or atrial septal defect surgery and the modified Cox-maze procedure

Atrial fibrillation (AF) is generally associated with rheumatic valve disease and atrial septal defects (ASD) in young adults. Surgical correction of both disorders fails to convert to sinus rhythm or prevent further episodes of paroxysmal or chronic AF in most patients. The role and efficacy of combining mitral valve surgery or ASD correction with AF surgery in this setting has not been widely addressed and remains to be established. The present study prospectively assessed the recovery of sinus rhythm, functional status, and atrial function in 21 patients (mean age 42 +/- 9.2 years) who underwent a modified Cox-maze procedure concomitant with mitral valve or ASD surgery at our institution between March 1993 and February 1995. Seventeen (81%) had chronic AF, and 4 (19%) had paroxysmal AF, with a mean AF duration of 3.5 +/- 3.6 years (range 0.6 to 15.3). Concomitant surgery was performed in 9 patients (42.9%) with mitral stenosis, 5 (23.8%) with mitral regurgitation, 1 (4.8%) with mitral and aortic regurgitation, and 3 (14.3%) with ASD. Eighteen patients (86%) were in New York Heart Association class II to IV before operation. Doppler echocardiography was performed in all patients before surgery, and 1 week, and 3 and 6 months after surgery in patients maintaining sinus rhythm. One patient with severe mitral stenosis and depressed ventricular function died in the immediate postoperative period. Sinus rhythm was restored in the immediate postoperative period in 7 patients (35%), and in another 10 patients (50%) before discharge (mean 5.8 +/- 2 days). Overall, sinus rhythm was restored before discharge in 17 patients (85%); 3 (15%) patients required antiarrhythmic therapy. Doppler echocardiography performed 3 months after surgery documented atrial contractility (A and E waves) in 12 patients (71%). After a mean follow-up period of 8 months (range 3 to 23), 18 (90%) remained in sinus rhythm. Sinus rhythm was successfully restored and maintained in most patients with drug refractory AF undergoing a concomitant Cox-maze procedure with mitral valve or ASD surgery improving atrial function and New York Heart Association class.

[Fulguration of extrasystolic ventricular focus]

A case is presented of symptomatic premature ventricular contractions refractory to drug therapy with right bundle branch block QRS morphology and left axis deviation in a 68-year-old female without structural heart disease. Endocardial mapping localized the extrasystolic focus at meso-inferoapical region of the left ventricular septum suggesting an origin from the Purkinje network of the left posterior fascicle. Catheter ablation with direct-current energy abolished extrasystolic complexes, without complications. The patient remained asymptomatic over a follow-up of 3 months.

Time- and frequency-domain analyses of the signal-averaged ECG in patients with arrhythmogenic right ventricular dysplasia

BACKGROUND

Arrhythmogenic right ventricular dysplasia (ARVD) is characterized by recurrent ventricular tachycardia of right ventricular origin and a cardiomyopathy with hypokinetic areas involving the free wall of the right ventricle. Subjects have a risk of sudden cardiac death, particularly during sports and strenuous exercise. Routine clinical examinations may be normal, but fragmented or delayed electrograms are usually recorded in the right ventricle of these patients. However, the frequency with which late potentials are detected by conventional time-domain analysis of the signal-averaged ECG (SAECG) is not high. This study evaluated the usefulness of the frequency-domain analysis of the SAECG in addition to the conventional time-domain analysis for a screening test to detect patients with ARVD.

METHODS AND RESULTS

SAECG was recorded by using a bipolar X, Y, and Z lead system in 28 patients with ARVD (mean age, 38 +/- 13 years) and 35 age-matched normal subjects (mean age, 35 +/- 11 years). The conventional time-domain analysis of the SAECG was performed at two different high-pass filter settings, 25 and 40 Hz, and the low-pass cutoff frequency was fixed at 250 Hz. The fast-Fourier transform analysis of SAECG was performed using a Blackman-Harris window. Area ratio 1 (area of 20 to 50 Hz)/(area of 0 to 20 Hz) and area ratio 2 (area of 40 to 100 Hz)/(area of 0 to 40 Hz) were calculated. In the conventional time-domain analysis, 20 (71%) and 18 (64%) patients had positive criteria at filter settings of 25 and 40 Hz, respectively. In the frequency-domain analysis, 18 (64%) and 20 (71%) patients had abnormal values in area ratios 1 and 2, respectively. Combining the time- and frequency-domain analyses, all patients were judged positive, with a sensitivity of 100% and a specificity of 94%.

CONCLUSIONS

Each result of the time- and frequency-domain analyses revealed that both methods had equivalent value. Combining the two domain analyses improved the sensitivity without reducing the specificity. These findings suggest that combining the time- and frequency-domain analyses of the SAECG may be useful as a screening test to detect patients with ARVD.

[Radiofrequency ablation in ventricular tachycardia: initial experience and evaluation of its limitations]

The purpose of this paper is to report our initial experience with radiofrequency catheter ablation in 21 patients with ventricular tachycardia of different etiologies and to evaluate the causes which play a role in its limitation. The results show a low rate of effectiveness: total clinical success of 43%. Nevertheless there was a high success rate in a specific subsets of patients. The results depends on several factors: the electrophysiologic mechanisms and substrates of the tachycardia, the criteria to localize the critical area perpetuating the arrhythmia and the biophysical aspects of radiofrequency energy. Its usefulness is manifested in ventricular tachycardia with structurally normal heart and it has a limited success in cases with organic heart disease. Improvement of technical aspects and better understanding of the mechanisms of the tachycardia and characteristics of the target site will enhance the results of radiofrequency catheter ablation in ventricular tachycardia.

[Arrhythmogenic right ventricular dysplasia. A new clinical entity]

Arrhythmogenic right ventricular dysplasia has been identified in 1977. It affects the right ventricle and its etiology is unknown. It has been recently included in the group of cardiomyopathies since it affects mainly the right ventricular muscle. It is found in young adults, frequently sportsmen who have a nearly normal cardiac physical examination. Ventricular arrhythmias could lead to palpitations, syncopes or even sudden death. This accident could be the first presenting sign of the disease. Two physiopathogenic mechanisms have been considered: heredo-familial origin or the result of a burned out myocarditis which could be the result of an abnormal immunological response. Its treatment mainly involves antiarrhythmic drugs. In the resistant cases ablative techniques, implantable defibrillator or surgery and even cardiac transplantation could be considered. Correctly treated, ARVD has a good prognosis. More extensive studies are necessary both on the clinical as well as the basic science standpoints.

Cystic fibrosis

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