Stereotactic magnetic resonance imaging-guided radiotherapy for intracardiac metastases: A case report.

Adrenocortical carcinoma is a malignant tumor with a poor prognosis and a frequent metastatic extension. In very rare cases, a cardiac metastatic disease may occur, and surgical resection is essential for its management. MR-guided stereotactic radiotherapy is an attractive radiotherapy modality for the treatment of mobile thoracic tumors, enabling the target to be monitored continuously during irradiation, while the dosimetric plan can be adapted daily if necessary. We report here the case of a patient with intracardiac metastasis secondary to malignant adrenocortical carcinoma, treated with magnetic resonance imaging-guided stereotactic radiotherapy.

Respiratory syncytial virus-associated mortality in a healthy 3-year-old child: a case report.

BACKGROUND: Respiratory syncytial virus (RSV) is the most frequently identified pathogen in children with acute lower respiratory tract infection. Fatal cases have mainly been reported during the first 6 months of life or in the presence of comorbidity. CASE PRESENTATION: A 47-month-old girl was admitted to the pediatric intensive care unit following sudden cardiopulmonary arrest occurring at home. The electrocardiogram showed cardiac asystole, which was refractory to prolonged resuscitation efforts. Postmortem analyses detected RSV by polymerase chain reaction in an abundant, exudative pericardial effusion. Histopathological examination was consistent with viral myoepicarditis, including an inflammatory process affecting cardiac nerves and ganglia. Molecular analysis of sudden unexplained death genes identified a heterozygous mutation in myosin light chain 2, which was also found in two other healthy members of the family. Additional expert interpretation of the cardiac histology confirmed the absence of arrhythmogenic right ventricular dysplasia or hypertrophic cardiomyopathy. CONCLUSIONS: RSV-related sudden death in a normally developing child of this age is exceptional. This case highlights the risk of extrapulmonary manifestations associated with this infection, particularly arrhythmia induced by inflammatory phenomena affecting the cardiac autonomic nervous system. The role of the mutation in this context is uncertain, and it is therefore necessary to continue to assess how this pathogenic variant contributes to unexpected sudden death in childhood.

Outcomes after cryoablation vs. radiofrequency in patients with paroxysmal atrial fibrillation: impact of pulmonary veins anatomy.

AIMS: Pulmonary vein isolation is the mainstay of treatment in catheter ablation of paroxysmal atrial fibrillation (AF). Cryoballoon ablation has been introduced more recently than radiofrequency ablation, the standard technique in most centres. Pulmonary veins frequently display anatomical variants, which may compromise the results of cryoballoon ablation. We aimed to evaluate the mid-term outcomes of cryoballoon ablation in an unselected population with paroxysmal AF from an anatomical viewpoint. METHODS AND RESULTS: Consecutive patients with paroxysmal AF who underwent a first procedure of cryoballoon ablation or radiofrequency were enrolled in this single-centre study. All patients underwent systematic standardized follow-up. Comparisons between radiofrequency and cryoballoon ablation (Arctic Front™ or Arctic Front Advance™) were performed regarding safety and efficacy endpoints, according to pulmonary vein (PV) anatomical variants. A total of 687 patients were enrolled (376 radiofrequency and 311 cryoballoon ablation). Baseline characteristics and distribution of PV anatomical variants were generally similar in the groups. After a mean follow-up of 14 ± 8 months, there was no difference in the incidence of relapse (17.0% cryoballoon ablation vs. 14.1% radiofrequency, P = 0.25). We observed no interaction of PV anatomical variants on mid-term procedural success. CONCLUSION: Our findings suggest that mid-term outcomes of cryoballoon ablation for paroxysmal AF ablation are similar to those of radiofrequency, regardless of PV anatomy. The presence of anatomical variants of PVs should not discourage the referral of patients with paroxysmal AF for cryoballoon ablation.

ACE Inhibitor Delapril Prevents Ca(2+)-Dependent Blunting of IK1 and Ventricular Arrhythmia in Ischemic Heart Disease.

Angiotensin-converting enzyme inhibitors (ACE-I) improve clinical outcome in patients with myocardial infarction (MI) and chronic heart failure. We investigated potential anti-arrhythmic (AA) benefits in a mouse model of ischemic HF. We hypothesized that normalization of diastolic calcium (Ca(2+)) by ACE-I may prevent Ca(2+)-dependent reduction of inward rectifying K(+) current (IK1) and occurrence of arrhythmias after MI. Mice were randomly assigned to three groups: Sham, MI, and MI-D (6 weeks of treatment with ACE-I delapril started 24h after MI). Electrophysiological analyses showed that delapril attenuates MI-induced prolongations of electrocardiogram parameters (QRS complex, QT, QTc intervals) and conduction time from His bundle to ventricular activation. Delapril improved the sympatho-vagal balance (LF/HF) and reduced atrio-ventricular blocks and ventricular arrhythmia. Investigations in cardiomyocytes showed that delapril prevented the decrease of IK1 measured by patch-clamp technique. IK1 reduction was related to intracellular Ca(2+) overload. This reduction was not observed when intracellular free-Ca(2+) was maintained low. Conversely, increasing intracellular free-Ca(2+) in Sham following application of SERCA2a inhibitor thapsigargin reduced IK1. Thapsigargin had no effect in MI animals and abolished the benefits of delapril on IK1 in MI-D mice. Delapril prevented both the prolongation of action potential late repolarization and the depolarization of resting membrane potential, two phenomena known to trigger abnormal electrical activities, promoted by MI. In conclusion, early chronic therapy with delapril after MI prevented Ca(2+)-dependent reduction of IK1. This mechanism may significantly contribute to the antiarrhythmic benefits of ACE-I in patients at risk for sudden cardiac death.

Prevalence, characteristics, and prognosis role of type 1 ST elevation in the peripheral ECG leads in patients with Brugada syndrome.

BACKGROUND: Despite isolated reports of Brugada syndrome (BrS) in the inferior or lateral leads, the prevalence and prognostic value of ST elevation in the peripheral electrocardiographic (ECG) leads in patients with BrS remain poorly known. OBJECTIVE: To study the prevalence, characteristics, and prognostic value of type 1 ST elevation and ST depression in the peripheral ECG leads in a large cohort of patients with BrS. METHODS: ECGs from 323 patients with BrS (age 47 ± 13 years; 257 men) with spontaneous (n = 141) or drug-induced (n = 182) type 1 ECG were retrospectively reviewed. Two hundred twenty-five (70%) patients were asymptomatic, 72 (22%) patients presented with unexplained syncope, and 26 (8%) patients presented with sudden death (12 patients) or appropriated implantable cardioverter-defibrillator therapies (14 patients) at diagnosis or over a mean follow-up of 48 ± 34 months. RESULTS: Thirty (9%) patients presented with type 1 ST elevation in at least 1 peripheral lead (22 patients in the aVR leads, 2 in the inferior leads, 5 in both aVR and inferior leads, and 1 in the aVR and VL leads). Patients with type 1 ST elevation in the peripheral leads more often had mutations in the SCN5A gene, were more often inducible, had slower heart rate, and higher J-wave amplitude in the right precordial leads. Twenty-seven percent (8 of 30) of the patients with type 1 ST elevation in the peripheral leads experimented sudden death/appropriate implantable cardioverter-defibrillator therapy, whereas it occurred in only 6% (18 of 293) of other patients (P < .0001). In multivariate analysis, type 1 ECG in the peripheral leads was independently associated with malignant arrhythmic events (odds ratio 4.58; 95% confidence interval 1.7-12.32; P = .0025). CONCLUSIONS: Type 1 ST elevation in the peripheral ECG leads can be seen in 10% of the patients with BrS and is an independent predictor for a malignant arrhythmic event.

ACE inhibition prevents diastolic Ca2+ overload and loss of myofilament Ca2+ sensitivity after myocardial infarction.

Prevention of adverse cardiac remodeling after myocardial infarction (MI) remains a therapeutic challenge. Angiotensin-converting enzyme inhibitors (ACE-I) are a well-established first-line treatment. ACE-I delay fibrosis, but little is known about their molecular effects on cardiomyocytes. We investigated the effects of the ACE-I delapril on cardiomyocytes in a mouse model of heart failure (HF) after MI. Mice were randomly assigned to three groups: Sham, MI, and MI-D (6 weeks of treatment with a non-hypotensive dose of delapril started 24h after MI). Echocardiography and pressure-volume loops revealed that MI induced hypertrophy and dilation, and altered both contraction and relaxation of the left ventricle. At the cellular level, MI cardiomyocytes exhibited reduced contraction, slowed relaxation, increased diastolic Ca2+ levels, decreased Ca2+-transient amplitude, and diminished Ca2+ sensitivity of myofilaments. In MI-D mice, however, both mortality and cardiac remodeling were decreased when compared to non-treated MI mice. Delapril maintained cardiomyocyte contraction and relaxation, prevented diastolic Ca2+ overload and retained the normal Ca2+ sensitivity of contractile proteins. Delapril maintained SERCA2a activity through normalization of P-PLB/PLB (for both Ser16- PLB and Thr17-PLB) and PLB/SERCA2a ratios in cardiomyocytes, favoring normal reuptake of Ca2+ in the sarcoplasmic reticulum. In addition, delapril prevented defective cTnI function by normalizing the expression of PKC, enhanced in MI mice. In conclusion, early therapy with delapril after MI preserved the normal contraction/relaxation cycle of surviving cardiomyocytes with multiple direct effects on key intracellular mechanisms contributing to preserve cardiac function.

[Are patients undergoing coronary angiography well-informed? Prospective evaluation of the effectiveness of written information]. / Les patients bénéficiant d'une coronarographie sont-ils bien informés ? Évaluation de l'efficacité de l'information écrite. Étude prospective unicentrique.

INTRODUCTION: Prior information in the realization of an invasive intervention is crucial. Indeed, the patient has to know theoretically his disease, diagnostic and therapeutic means, but also the risks of the used technique. The habits of information vary many from one center to another, in spite of the proposition of an information leaflet written by the French Society of Cardiology. Our aim was to evaluate the effectiveness of written information for patients hospitalized for coronary arteriography. METHODS: Among patients hospitalized for realization of a programmed coronarography, a questionnaire was delivered before the information leaflet. The knowledge of the patients was so tested (27 items) before and after the reading of the information sheet (not limited time). The knowledge of the patients concerning coronarography indication, modalities, benefits, possible complications or still later possibilities was informed. RESULTS: Thirty-four patients were included: all knew hospitalization reason, 86% were men, middle-aged 65 (IC 95% 60-70). Thirty-four percent (15-54) had studied in higher education. Ninety-seven percent had had information before. Only 56% (38-74) were informed about the mode of anesthesia, 36% (19-53) duration, 69% (53-86) the injection of iodine, 44% the risk of allergy, 53% the risk of bruise, 15% of the cardiac risks, 21% the renal risks. Seventy-one percent knew the diagnostic benefits, 44% the possible coronary angioplasty, 17% the eventuality of a bypass surgery. The delivery of the information leaflet did not modify the knowledge on most of these items, in particular the modalities and the profits. The risks were known significantly better for the allergy (P=0.019), the bruise (P=0.018), the cardiac risks (0.001). CONCLUSIONS: The population benefiting from a coronarography considers to be enough informed. However, knowledge of the modalities, profits and risks is very low. The delivery of the consensual leaflet does not allow improving the situation, except as far as concerned the complications. Better information is so indispensable, not only to obtain a better support of the patient in the treatment, but also to prevent the forensic implications. The improvement of the information must be multifactorial, but usually used means could be not sufficient.

Routinely-feasible multiple biomarkers score to predict prognosis after revascularized STEMI.

INTRODUCTION: We assessed the long-term prognostic value of an easy-to-do multiple cardiac biomarkers score after a revascularized acute myocardial infarction (MI) in order to evaluate a multimarker approach to risk stratification, based on routine biomarkers. MATERIAL AND METHODS: Blood samples from 138 patients hospitalized with acute myocardial infarction and successfully treated by primary coronary intervention (with TIMI 3 flow) were subsequently tested for creatinin level at admittance and then BNP, hsCRP, troponin I from Day 0 to day 7. The primary endpoint was a clinical evaluation comprising: new hospitalization for cardiac reasons, acute coronary events (acute coronary syndrome), and death. RESULTS: During the median follow-up period of 11.01 months [9.44-12.59], 47 events were recorded. All the following markers were able to predict events: creatinemia on admission (p=0.0057), CRP on day 3 (p, troponin I on day 1 (p<0.001), BNP (p<0.0001) and biological multimarker score (p<0.0001). Clinical events were predicted with a hazard ratio (HR) of respectively 3.30 [2.88-12.30] in BNP Q4 as compared to the three lower quartiles (Q1-3), and 3.15 [2.75-21.00] for the Multimarker approach. The multimarker score was not significantly better than BNP on day 1 alone (p=0.77), troponin on day 1 alone (p=0.43), creatininemia on admission (p=0.19) or CRPhs on day 3 alone (p=0.054). Nevertheless, the Multimarker approach leads to the selection of a smaller, hence more manageable, high-risk population (13% versus 25%). CONCLUSION: Among 138 subjects admitted for acute MI, and all successfully revascularized, a routinely multimarker approach with BNP, hsCRP, creatininemia, troponin I, is feasible. BNP is the most powerful marker, and this multimarker approach renders additional prognostic information helping to identify patients with high-risk to clinical events.

[Atrial fibrillation in 2010: an increasing morbidity and mortality burden]. / La fibrillation atriale en 2010: un poids croissant sur la morbidité et la mortalité cardiovasculaires.

AF, a frequent and banal arrhythmia, is a debilitating and costly disease. The majority of patients with AF are aged 60 to 80 years, but the prevalence is as high as 10% after 80 years and the incidence increases in recent years in an "epidemic" way. AF is responsible for an excess of mortality with an relative risk between 2 and 4 depending of age and sex, especially as cardiovascular risk factors are associated. The morbidity is also important, with cerebral systemic embolism (2-3% per year), heart failure (1 patient for 3), and a total risk of hospitalization from 20 to 30% per year for AF patients with high cardiovascular risks. Whatever be the reasons for hospitalization, cardiovascular or not, in connection with AF or not, these reasons must be well analyzed, so that the risk of occurrence of hospitalization should reflect the efficacy of anti-arrhythmic drugs, or of their complications, or of the comorbidities associated with AF, so common in these older subjects. This morbidity-mortality composite endpoint should now be used in AF randomized trials, as occurring more frequently than mortality (4% per year) or embolic or hemorrhagic usual endpoints. Medico-economic consequences are significant and AF cost is almost 1% of total health spending, with 20% to 30% of the cost for anti-arrhythmic or anti-thrombotic drugs, and 50 to 60% for hospitalizations. Prevention of hospitalizations related to atrial fibrillation may represent a therapeutic target priority on the medico-economic ground.

Can troponin elevation predict worse prognosis in patients with acute pericarditis?

INTRODUCTION: Myopericarditis are common in clinical practice: up to 15% of acute pericarditis have a significant myocardial involvement as assessed by biological markers. This prospective, bicentric study is aimed at describing a myopericarditis population, the clinical and MRI follow-up, and search for prognosis markers. PATIENTS AND METHODS: Between May 2005 and September 2007, 103 patients hospitalised for acute pericarditis were prospectively enrolled. Physical examination, ECG, echocardiography, biological screening and cardiac MRI, in case of myopericarditis defined as acute pericarditis with troponin I elevation, were performed. Between December 2007 and July 2008, patients were contacted for new clinical and MRI evaluation. RESULTS: Among the initial population of 103 patients admitted for acute pericarditis, 14 myopericarditis and 38 pericarditis were included. Compared with pericarditis, the myopericarditis group was associated with the following features: younger age (34.9 years [95% CI 28.3-41.2]; p=0.01), ST-segment elevation (nine patients between 14; p=0.03), higher troponin I (7.3 microg/L [95% CI 4.4-10.2]; p<10(-4)) and lower systemic inflammation (CRP peak 38.1mg/L [95% CI 7-69.2]; p=0.01). In the case of myopericarditis, infectious etiologies were predominant (12 patients among 14; p=0.002) and patients stayed longer in hospital (5.8 days [95% CI 4.7-6.8]; p=0.01). Follow-up showed no difference in terms of functional status (p=0.3) and global complications (p=0.9) between paired myopericarditis and pericarditis. Nevertheless, cardiac mortality was higher for myopericarditis (p=0.04). MRI follow-up showed myocardial sequelae without clinical impact. CONCLUSION: Myopericarditis significantly distinguished from pericarditis. Three years follow-up showed no difference in terms of global complications but a higher cardiac mortality for myopericarditis. MRI myocardial lesions did not develop into symptomatic sequelae.

[C-reactive protein (CRP) after revascularized STEMI: is CRP a prognostic factor?]. / Intérêt de la C-reactive protein (CRP) dans l'évaluation pronostique de l'infarctus du myocarde revascularisé

PURPOSE: During myocardial infarction (MI), numerous biomarkers increase, such as troponin (necrosis), BNP, and high sensibility C-reactive protein (hsCRP) (inflammation). The objectives of the study were to study kinetics of hsCRP after a revascularized MI, and correlations between hsCRP and clinical outcomes or biological markers, and prognostic value of CRP. PATIENTS AND METHODS: Fifty-two patients were admitted for STEMI (ST segment Elevation MI). Primary coronarography interventions (PCI) were performed for urgent reperfusion. Patients were included only in case of success (TIMI 3). Clinical examination was completed by a biological follow-up of BNP, troponin-I (before and after PCI, days 1, 2, 3, 6) and hsCRP (days 0, 1, 2, 3, 6). Clinical outcomes follow-up was performed during hospitalization, on the first month, and the sixth month. RESULTS: hsCRP increases during the first days (peak on day 3: 46.1mg/L), and decreases between the third and the seventh day. Clinical outcomes were correlated with CRP: door-to-balloon time, age, creatinin level on admission. During follow-up, there were clinical events in 13/49 (26%) of the patients. Among them, hsCRP on day 2 was higher (p < 0.0001), compared to other patients. Compared to other biological markers, hsCRP was correlated with BNP on days 2 and 3 (p = 0.008). CONCLUSION: hsCRP increases after revascularized STEMI, in accordance to the infarct size, in the first days. hsCRP is correlated with cardiovascular pronostic biomarkers. hsCRP could play an active role, and could be used as a pronostic biomarker after revascularized STEMI, which are usually considered as a low-risk population.

Long-term follow-up of biventricular pacing using a totally endocardial approach in patients with end-stage cardiac failure.

BACKGROUND: Besides standard left ventricular (LV) stimulation via the coronary sinus, a transseptal approach allows left ventricular endocardial stimulation. We report our long-term observations with biventricular stimulation, using a strictly endocardial system for patients presenting with severe congestive heart failure. METHODS: Six patients with nonischemic cardiomyopathy (mean age = 60 +/- 9.6 years, women) in New York Heart Association (NYHA) functional class III (n = 5) or IV, despite optimal drug therapy, and a mean LV ejection fraction of 24 +/- 3%, underwent implantation of biventricular stimulation systems between April 1998 and March 1999. All presented with left bundle branch block and an increased LV end-diastolic diameter (mean = 66 +/- 5 mm). In all patients, a bipolar pacing lead was implanted in the lateral LV wall using a direct transseptal approach. After implantation, all patients received oral anticoagulation. RESULTS: QRS duration decreased from 184 +/- 22 ms to 108 +/- 11 ms. NYHA functional class decreased to II in all patients within 1 month. Over a 85 +/- 5 month follow-up, two patients underwent cardiac transplantation, 2 and 4 years after device implantation, respectively; two patients died of end-stage heart failure 4 years after system implantation; and two patients were alive in functional class II. One patient, who experienced syncope due to fast ventricular, underwent implantation of an ICD. One transient ischemic attack occurred in a patient whose anticoagulation was temporarily interrupted. CONCLUSIONS: Long-term endocardial biventricular stimulation via a transseptal approach was safe and effective in this small population. This approach needs to be further compared with conventional epicardial pacing via the coronary sinus.

[Intra-cardiac lymphoma with right heart failure: a therapeutic emergency in two patients]. / Lymphome intracardiaque avec insuffisance cardiaque droite: à propos de deux cas.

We report the cases of two patients admitted to the Emergency Department with a clinical picture of right heart failure. An emergency echocardiograph suggested an intra-cardiac tumor which turned out to be a primary intra-cardiac lymphoma in one case, and a diffuse lymphoma principally localised in the heart in the other. Echocardiographic, CT and MRI investigations clarified the sites, as well as anatomical relations and extensions. Histology confirmed the diagnosis, and allowed classification of the lymphoma in order to decide on treatment. A PET scan performed in one patient illustrated the response to treatment. The respective significance of each of these investigations is discussed, in addition to the management. While transthoracic echocardiography remains the key element in the acute management, MRI and PET scans are being used more and more often for determining the character of these lesions, as well as for assisting with therapeutic decisions and for follow-up.

[Surgery of ventricular tachycardia in post-infarction left ventricular aneurysm]. / Chirurgie des tachycardies ventriculaires sur anévrismes ventriculaires gauches post-infarctus.

The treatment of post-infarction ventricular tachycardias with antiarrhythmic drug therapy, implantable automatic defibrillators, radiofrequency ablation, also includes different surgical procedures such as endocardial resection of the infarct scar, encircling endocardial ventriculotomy and endocardial cryoablation or thermoexclusion by laser. These procedures may be extensive or limited, guided or not by preoperative mapping. The aim of this review of the literature is to update our knowledge of these different surgical techniques and to define their indications.

[Characterization of premature ventricular contraction initiating ventricular fibrillation]. / Caractéristiques morphologiques des extrasystoles ventriculaires initiatrices des fibrillations ventriculaires.

UNLABELLED: The aim of this study is to characterize the electrocardiographic features of premature ventricular contractions (PVC) from different anatomical region that trigger ventricular fibrillation (VF). METHODS AND RESULTS: 36 consecutives patients (20 males, 42+/-14 yrs) undergoing VF ablation from 7 centres were studied (22 with idiopathic VF, 4 associated with a long QT syndrome, 3 with Brugada syndrome, 4 with ischaemic cardiomyopathy and 3 associated with other substrate). Mapping of these PVC showed 2 different origins, which were then confirmed by ablation: right ventricular outflow tract (RVOT) (22%) and peripheral Purkinje network (81%). One patient had PVC from both origins (Brugada). RVOT PVC were frequent but had triggered only 5+/-5 episodes of VF for 26+/-33 months. Purkinje PVC were more likely to be present during electrical storm with 18+/-28 episodes of VF for 33+/-45 months. Right Purkinje PVC have a left bundle branch block with superior axis morphology whereas left Purkinje ones have a right bundle branch block. The axis of activation showed variation from inferior to superior depending on the area of origin from the Purkinje network and the exit site to the myocardium. However Purkinje PVC were characterized by short QRS duration (126+/-18 vs 145+/-13ms for RVOT PVC; p=0.05). In addition the coupling interval was significantly shorter compared to RVOT PVC (292+/-45 vs 358+/-37ms respectively; p=0.005). CONCLUSION: PVC initiating VF demonstrate specific electrocardiographic features that facilitate determination of their origin. Ablation of these typical PVC is feasible in order to reduce ICD shock.

Implante de desfibrilador: a propósito de um limiar de desfibrilação elevado / Defibrillator implant: aiming at a high defibrillator threshold

Este artigo tem por finalidade orientar a conduta nos casos de pacientes com taquicardia ventricular sustentada e disfunção grave, encaminhados para implante de desfibrilador, situação cada vez mais frequente. Discute-se a possibilidade de utilizar alternativas cirúrgicas para solucionar situações em que os limiares de desfibrilação permanecem altos durante os testes realizados no momento do implante

[Ventricular tachycardia due to branch to branch re-entry]. / Tachycardies ventriculaires par rentrée de branche a branche.

Ventricular tachycardia due to branch to branch re-entry constitutes a rare clinical entity. This circuit is remarkable by the fact that it is made up of the branches or hemi-branches of the bundle of His bifurcation. They occur under specific conditions, with a combination of left ventricular dilatation and atrioventricular or intraventricular conduction defects. They are also very often found in Steinert's disease. A positive diagnosis can sometimes be difficult and relies on a variety of factors. Recording of the His potential shows His activity preceding each ventriculogram, and variations in spontaneous cycles between 2 ventriculograms preceded by variations between the 2 His potentials. Atrial capture without modification of the QRS is possible, but fusion excludes the diagnosis. Drug therapy is only slightly effective, and the best treatment is ablation of the right branch of the bundle of His, which stops the tachycardia definitively.

Mapping and ablation of ventricular fibrillation.

Sudden cardiac death frequently results from ventricular fibrillation (VF). While VF is frequently the eventual mode of death in patients with abnormal ventricular substrates, it has also been described in patients with structurally normally hearts. Until recently, the management of patients who have survived sudden cardiac death has focused on treating the consequences by implantation of a defibrillator. However, such therapy remains restricted in many countries, is associated with a prohibitive cost to the community, and may be a cause of significant morbidity in patients with frequent episodes or storms of arrhythmia. Evidence emerging from the study of fibrillation both in the atria and the ventricle suggests an important role for triggers arising from the Purkinje network or the right ventricular outflow tract in the initiation of VF. Initial experience in patients with idiopathic VF and even those with VF associated with abnormal repolarization syndromes (LQT or Brugada syndrome) or myocardial infarction suggests that long term suppression of recurrent VF may be feasible by the elimination of these triggers. With the development of new mapping and ablation technologies, and greater physician experience, catheter ablation of VF, with the ultimate aim of curing such patients at risks of sudden cardiac death, may not be an unrealistic goal in the future.

[The electrocardiogram of atrioventricular blocks]. / Electrocardiogramme des blocs auriculo-ventriculaires.

Atrioventricular block (AVB) is defined as delay or absence of transmission of one or more atrial excitations to the ventricle. Physiological functional block protects the ventricle against very rapid atrial rhythms. Organic blocks may be transient, due to an acute regressive condition, or chronic, in which case they fall into two groups--permanent blocks or paroxysmal and generally rate-dependant blocks. The blocks are classified in three categories according to whether the atrial activation is delayed, conducted intermittently or not at all. The site of AVB may be determined by His bundle recordings but it may also be deduced from the surface ECG recording. Fundamental studies have questioned the reality of Rosenbaum's phase 3 and 4 blocks and suggest abnormalities of excitability in pathological zones.