[Ablation of atrial fibrillation: new technologies and challenges]

In industrialized countries, the number of atrial fibrillation (AF) catheter ablation procedures regularly increases every year, but these interventions are still time consuming and complex, especially for chronic AF. The stakes in the future are twofold : to reduce the duration of each ablation procedure and to increase the success rate for the more difficult AF ablation cases (i.e. : chronic AF), but with the lowest possible complications rate. Some technological improvements may contribute to reach these goals. Intracardiac 3D mapping and navigation systems as well as robotic-assisted catheter manipulation are available and these technologies are regularly upgraded. These systems are helpful both in catheter manoeuvring and repositioning as well as in the understanding of arrhythmia circuits and the definition ablation targets. In addition, these systems are equipped with software specially designed for automatic electrogram analysis to identify myocardial areas which may play a role in the maintenance of chronic AF. Cardiac imaging, such as MRI, may also help identifying arrhythmogenic areas in patients with chronic AF, with subsequent MRI 3D images integrated into a 3D mapping / navigation system. Several companies have invested on the research and development of ablation catheters aiming both at the reduction of procedure time as well as the improvement of the quality of the created lesions, especially with 'smart'catheters which can appreciate wall contact quality. Whatever the type of catheter shape or type of energy used, technological improvement is needed before the expected efficacy is reached.

[Silent atrial fibrillation]

Asymptomatic atrial fibrillation (AF) is common, may adversely affect quality of life, and above all can be as serious as symptomatic AF. The prevalence of AF reported in epidemiological studies is significantly underestimated, as asymptomatic AF is often not known about. The efficacy of pharmacological or non-pharmacological treatment is often overestimated if the only aim considered is symptomatic recurrences. Like symptomatic AF, asymptomatic AF justifies anticoagulation, depending on the risk of embolism. Estimating the risk of embolism only from symptomatic episodes may result in unjustified discontinuation of antithrombotic treatment. Finally, frequent asymptomatic episodes may worsen atrial or even ventricular remodelling and result in tachycardia-induced cardiomyopathy.

[Correlation between atrial function and functional capacity in highly trained subjects]

AIM

The aim of the study is to show the relationship existing between tissular Doppler imaging (TDI) parameters and functional capacity in highly trained subjects.

METHODS AND PATIENTS

We therefore studied 46 patients including 22 untrained and 24 trained subjects. Each subject had pulsed TDI recording of systolic (S) and diastolic (E and A) longitudinal myocardial velocities in the basal portion of the RV free wall (RV), the septum (sep) and the LV free wall (LV) from apical 4C view. Athletes underwent the same day a cardiopulmonary test during which we measured peak V(O)2 (ml/kg/min) and anaerobic threshold (AT, ml/kg/min) and calculated VE/V(CO)2 slope. We studied differences between echocardiographic parameters in the two groups using Student test. Coefficients of correlations were calculated using the Spearman method.

RESULTS

Differences between two groups concerned Tei index of right (RV) and left ventricle (LV), telediastolic diameter of LV, and A waves on each wall. In athletes RV, sep and LV S waves did not correlate with V(O)2, AT or VE/V(CO)2 RV, sep and LV A waves correlated significantly and negatively with V(O)2, RV and sep A waves negatively with AT, and sep and LV A waves positively with VE/V(CO)2.

CONCLUSION

In athletes, atrial function shows a negative relationship with cardiopulmonary exercise parameters: the lower the proportion of LV filling due to atrial contraction, the better the level of functional capacity. This is probably due to myocardial structure, which allows more efficient early filling in hypertrophic athlete's heart.

[Quantification of right ventricular function by 2D speckle imaging and three dimensional echography. Comparison with MRI]

PURPOSE

The echocardiographic assessment of right ventricular (RV) function requires many different parameters. We studied and compared with magnetic resonance imaging (MRI) two markers of RV function derived from new imaging tools: 2D speckle imaging (2DSI) and three dimensional echography.

METHODS AND RESULTS

Thirty-two patients (19 with RV ejection fraction [RVEF]< or =45%) underwent both complete echocardiography--including standard parameters of RV function (fractional area change [FAC], Tei index, systolic velocity of tricuspid annulus by DTI), 3D full-volume acquisition on RV--and MRI for the evaluation of RV volumes and RVEF. 2DSI was applied to high frame rate cine loops centred on the RV free wall with measurement of peak systolic strain (%) in the basal, median and apical segments of this wall. Strain, especially in RV median and apical segments, is reduced in patients with RVEF less or equal to 45% (median strain: -16.39+/-5.27 vs. -24.74+/-8.00 [p=0.002]; apical strain -13.01+/-6.84 vs. 22.53+/-11.32 [p=0.03]) with a very good correlation with RVEF (r=-0.717, p=0.0001) but also with the usual echographic parameters of RV function, (FAC: r=0.019; Tei: r=0.01; peak systolic velocity: r=0.002). The 3D RVEF is also but poorly correlated with MRI RVEF, (r=0.447, p=0.017). Furthermore, 3D significantly underestimated RV volumes. By multivariate analysis, apical strain (p=0.004) and FAC (p=0.029) were predictive of a decreased RVEF.

CONCLUSION

Apical strain as measured from 2DSI seems a promising parameter in the estimation of RV function. 3D estimation of RVEF is more disappointing because of an important underestimation of RV volumes.

[Long-term clinical benefits of using active stents in diabetic patients: two year follow-up of a consecutive series of 122 patients]

The objective of our study is to evaluate the long-term results of coronary angioplasty using active stents in a population of diabetic patients. This is a single-centre study on a consecutive series of 122 diabetic patients (40% of them insulin dependent) who between January 2003 and June 2004 underwent angioplasty with implantation of an active stent (sirolimus Cypher(R) or paclitaxel Taxus(R)) for one or more de novo coronary lesions. The mean age was 66 +/- 10 years and a total of 171 coronary segments were treated. The lesions treated were complex (type B2 + C) in 69% of the cases, with a mean stent length of 21 +/- 15 mm and a mean stent diameter of 2.7 +/- 0.3 mm. Follow-up at two years for 119 patients (3 lost to follow-up) revealed a mortality rate of 4.2%, and a myocardial infarction rate of 7.5%. The rates for revascularisation of the target lesion and the target vessel were 11.4% and 17.8% respectively, with a rate of major cardiac events of 22.5%. During this period, 25.2% of the patients underwent revascularisation of at least one vessel. This study confirms the benefits of using active stents for revascularisation of the target lesion in diabetic patients. However, it serves as a reminder that the progression of coronary atheroma is global, and that the prognosis for these patients depends essentially upon managing risk factors, and particularly on controlling their diabetes.

Left ventricular systolic dysfunction is an independent predictor of homocysteine in angiographically documented patients with or without coronary artery lesions

BACKGROUND

Elevated plasma homocysteine is a risk factor for coronary artery disease (CAD) and thromboembolic disorders that seems also to be associated with chronic heart failure.

OBJECTIVE

To evaluate the association between homocysteine and left ventricular dysfunction and to assess whether it is independent of CAD.

PATIENTS AND METHODS

A prospective study evaluated this relationship in 709 patients referred for diagnostic coronary angiography, including 515 CAD and 194 patients without evidence of coronary artery lesions.

RESULTS

The homocysteine level was significantly higher in the 187 patients with a left ventricular ejection fraction (LVEF) dysfunction < 40% (P < 0.0001) than in those without ventricular dysfunction. LVEF, NYHA functional class II or III and CAD, stable angina and hypertension were clinical characteristics that influenced total homocysteine level in univariate analysis. Homocysteine was significantly associated with LVEF and N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) in univariate regression (r = -0.267, 95% CI -0.33 to -0.19, P < 0.0001, and r = 0.381, 95% CI 0.28-0.47, P < 0.0001, respectively) and in multiple regression (P = 0.0022 and P = 0.0001, respectively). Other determinants were creatinine and vitamin B(12), but not folate. LVEF was a predictor of homocysteine > 15 micromol L(-1) in the whole population (P for trend < or = 0.0001) and in patients without documented CAD (P for trend = 0.0058).

CONCLUSION

Our results showed an association of homocysteine with left ventricular systolic dysfunction and NT-pro-BNP that existed independently of documented CAD. Whether this association reflects a causative factor or a consequence of CHF and influences the prognosis of the disease remains an open question.

[Mycotic coronary aneurysm with Escherichia coli sepsis: a case report]

We report the case of a patient who was admitted for acute coronary syndrom associated with fever originating from urinary tract. Coronary arteriography revealed a huge coronary aneurysm which ruptured a short time after diagnosis. After surgery, it was proven to be mycotic aneurysm related to Escherichia Coli sepsis.

[Prevalence of sudden cardiac death during sports activities]

Sudden death during sport is a rare and unexpected event. It essentially affects young males, and a cardiomyopathy that had not been diagnosed during medical examinations is present in the majority of cases. In young subjects, there is generally hypertrophic cardiomyopathy or arhythmogenic right ventricular dysplasia. This is revealed during sporting activity, and sudden death is often the first symptom of the disease. Competitive sport increases the relative risk of sudden death to 2.5 compared to the risk in a non-sporting subject. The prevalence of sudden death during competitive sport is poorly understood. From the rare studies available, it could be estimated at 2.3/100,000 athletes per year. In Europe, it essentially occurs during football matches. However, the prevalence of sudden death during so-called 'recreational' sports is not precisely known. It could be much higher because these activities involve a larger number of people, and take place without supervision and usually without a medical examination beforehand. The participants are older, and coronary pathology is usually implicated.

[Contribution of EKG-gated multislice CT in the diagnosis of arrhythmogenic right ventricle dysplasia: report of two selected cases]

Arrhythmogenic cardiomyopathy of the right ventricle is characterized by replacement of right myocardial cells by fibro-fatty tissue and arrhythmias. The authors present two cases where EKG gated multislice CT was valuable. In one case, comprehensive evaluation of extensive ventricular dysplasia complicated by intraventricular thrombus was achieved whereas accurate evaluation of the ventricular wall process was possible in another case.

[Acute or sub-acute thrombosis of steel stents]

The use of coronary endoprostheses has greatly contributed to the improvement in the results of coronary angioplasty. Nevertheless, the risk of stent thrombosis remains a major preoccupation. We studied a retrospective series of 2997 patients who had undergone coronary angioplasty between 1999 and 2003. 36 patients (1.2%) had an acute or sub-acute stent thrombosis, occurring in two thirds of cases in the first 4 days with particularly serious clinical consequences: 5 deaths (13.8%) and 27 myocardial infarctions (75%). A comparison between the 2 groups of patients with thrombosis (n = 36) and without thrombosis (n = 2961) using multivariate analysis determined predictive factors for thrombosis: systolic LV dysfunction < 40% (p < 0.0001 OR 3.8 [2-7.3]), angioplasty for lesions on the anterior interventricular artery (p < 0.0001 OR 2.7 [1.4-5]), angioplasty performed in the acute phase of MI (p < 0.05 OR 13.9 [6.7-29.2]), B2-type complex lesions (p < 0.01 OR 2.5 [1.3-5]), residual dissection at the dilated site (p < 0.02 OR 5.1 [1.4-18.2]). More than ever, acute thrombosis remains a topical subject. This study emphasises the incidence of steel stent thrombosis; the clinical consequences and the predictive factors for early occlusion.

[AFFIRM: what we have learned ... and pending issues]

During these last years, several therapeutic strategies trials have been performed in atrial fibrillation: the goal was to compare the rhythm control strategy (restoration and maintenance of sinus rhythm) to the rate control strategy (slowing of heart rate in atrial fibrillation). The most important of these different trials is the AFFIRM study. The main conclusion of this trial is that rate control can be chosen in first intention and not only in case of failure of the rhythm control strategy. These results can not be applied to 2 categories of patients: on one hand patients with heart failure and on the other hand young patients without cardiopathy in whom the strategy of rhythm control and sinus rhythm maintenance, mainly by class I antiarrhythmic drugs, remains the better choice.

[Mortality prognostic factors of cardiogenic shock complicating an acute myocardial infarction and treated by percutaneous coronary intervention]

OBJECTIVE

To determine the in-hospital prognosis and late outcome of cardiogenic shock complicating acute myocardial infarction treated by early (< 24 hours) percutaneous coronary intervention (PCI).

METHODS

Retrospective monocentric study of a consecutive cohort of patients undergoing early PCI (< 24 heures) for cardiogenic shock complicating acute myocardial infarction from 1994 to 2004.

RESULTS

The cohort included 175 patients (mean age = 65 +/- 14 years, 68% male). A successful PCI was obtained in 69% of patients. The in-hospital mortality was 43%. Independent risk factors associated with an increased mortality were: absence of TIMI three flow (P < 0.0001), absence of smoking (P < 0.009) and the need for mechanical ventilation (P < 0.002). Nor stent use or anti GP IIb/IIa infusions were predictors of a better outcome. At hospital discharge, mean left ventricular ejection fraction (LVEF) was 38 +/- 12%. Kaplan-Meier estimate of survival was 63% for in-hospital survivors (maximum follow-up = 9 years). Independent predictors of an impaired long-term outcome were: a LVEF < 0.3 (P < 0.028) and 3-vessel disease on coronary angiography (P < 0.004).

CONCLUSION

In-hospital mortality of patients suffering cardiogenic shock complicating acute myocardial infarction and treated by PCI remains high despite PCI improvement. The long-term survival appears, however, to be better than that of patients with coronary artery disease and low LVEF.

[Prevalence of Brugada syndrome among 35,309 inhabitants of Lorraine screened at a preventive medicine centre]

Brugada syndrome is a recently identified cause of sudden death. Its primary prevention remains controversial, and epidemiology poorly defined.

PATIENT POPULATION AND METHODS

Electrocardiograms (ECG) of 35,309 individuals (mean age = 37.2 years, 47% men) recorded over a 1-year period were reviewed and classified as (1) typical, (2) suspicious, and (3) negative. Subjects whose ECG was suspicious were offered a provocative test with flecainide, 2 mg/kg, i.v., and individuals whose ECG was typical were advised to undergo programmed ventricular stimulation (PVS).

RESULTS

In 14 men and 6 women between the ages of 24 and 77 years (mean =47.5), ECGs were typical (n=6) or suspicious (n=14). Among 6 subjects with typical ECGs, 3 underwent PVS, which was positive in 1, who received an implantable cardioverter defibrillator (ICD). Among 14 subjects whose ECGs were suspicious, 5 declined further investigations and 5 developed typical ECG characteristics of Brugada syndrome after flecainide administration. PVS was negative in 4 subjects who consented to the procedure. Overall, among 35,309 individuals screened, 11 had ECG findings consistent with Brugada syndrome and, over a follow-up of 30 months, all had remained free of adverse cardiac event.

CONCLUSIONS

we estimated a prevalence of Brugada syndrome of 0.3% in Lorraine. A single patient received an ICD for inducible ventricular tachyarrhythmia during PVS, representing a potential 30 per million asymptomatic adult rate of ICD implantation for this indication.

[Imaging of the coronary arteries with multi-channel CT: a pictorial assay]

Advances in cardiac imaging with multidetector row CT allow new applications in the diagnosis of cardiac pathology. The purpose of this article is to illustrate the normal anatomy and main anatomical variants of the coronary arteries that can be detected with multi-channel CT. The images presented here were obtained using 4-channel and 16-channel multi-detector row CT units. Post-processing of CT imaging data was performed using: VRT, MPVR, and 2D curved MPR. Because of continuing technical advances, the use of CT imaging in the evaluation of cardiac disorders is likely to increase.

[The electrocardiogram in ventricular tachycardias]

The electrocardiogram, as much as the clinical examination, is a basic tool for the cardiologist. Technological advances have led to a certain lack of interest in learning to read the electrocardiogram, for which close analysis can allow precise diagnosis, notably in the field of cardiac rhythm disorders. This article concerns the electrocardiogram in ventricular tachycardias with two themes: differential diagnosis of wide QRS complex tachycardias and recognition of the site of origin of a ventricular tachycardia. "Fine" analysis of the electrocardiogram is not an intellectual "game". Actually, careful analysis of the 12 lead ECG allows exact and rapid diagnosis in a large majority of cases, distinguishing a ventricular tachycardia from a supraventricular tachycardia with conduction defect; the appropriate management can be selected without delay. At the same time, close reading of the electrocardiogram also allows the site of origin of a ventricular tachycardia to be recognised. Combining this information with elements of the patient's record can allow the arrhythmia to be related to a known pathology or to prompt a targeted aetiological investigation.

[New systems of mapping and navigation in electrophysiology]

The indications of radiofrequency ablation of arrhythmias have considerably increased since the introduction of the technique in the early 1990s. Interventional rhythmologists now treat arrhythmias which are more and more complex by their mechanism. This requires accurate representation of the ablation catheter position and the integration of spatial and temporal data to identify the arrhythmogenic substrate. The systems of mapping and navigation developed over the last ten years are important tools for interventional rhythmologists. They are very useful for the identification of complex arrhythmogenic substrates which require "individualised" ablations in specific cases. The aim of this article is to review different systems of mapping, and/or navigation currently on the market and their principal characteristics without entering into the details of their use in interventional electrophysiology.

Correlation between electrogram morphology and standard criteria to validate bidirectional cavotricuspid block in common atrial flutter ablation

AIM

Assessment of a bidirectional conduction block within the cavotricuspid isthmus (CTI) is critical during radiofrequency (RF) atrial flutter (AF) ablation. We investigated the use of bipolar atrial electrogram (BAE) morphology as an additional criterion identifying CTI block and tested it against two recognized criteria: differential pacing and reversal of the right atrial depolarization sequence during coronary sinus (CS) pacing.

METHODS AND RESULTS

An RF ablation procedure was performed during 600 ms CS pacing in 100 consecutive patients with a common AF. BAE recorded along the CTI were continuously monitored. CTI conduction block was achieved by RF ablation in all patients and a clear change in BAE polarity in the Electrogram recorded by the dipoles located on the CTI and immediately lateral to the intended line of block (RS to QR pattern) associated with a confirmed CTI conduction block was observed in all cases. BAE morphology changes predicted bidirectional CTI conduction blocks with a 100% positive and a 100% negative predictive value. At a mean follow-up of 33 +/- 11 months, there was a 5% AF recurrence rate.

CONCLUSIONS

Our study suggests that morphological changes in BAE recorded at sites lateral and adjacent to the target line of block may be used as a unique and robust criterion to validate CTI conduction block during AF ablation procedure.

[Relevance of in vitro studies for the immunity of cardiac implants in an electromagnetic field environment]]

The object of this article is to show the contribution of the vitro experimental approach, based on the basic rules of electromagnetic compatibility (EMC), as a complementary tool to the clinical studies. Results can be obtained by a experimental approach in vitro with electromagnetic phantoms associated to a bench of "standard" test to allow a possible comparison between various studies. After describing the protocol developed for the cardiac implants (pacemakers and defibrillators), examples of partial results are presented by way of illustration.

Safety of a controlled-release flecainide acetate formulation in the prevention of paroxysmal atrial fibrillation in outpatients

OBJECTIVES

The cardiac safety of a once-a-day 200 mg controlled-release formulation of flecainide acetate in the prevention of paroxysmal atrial fibrillation (PAF) was assessed in outpatients.

MATERIAL AND METHODS

The drug was administered for 24 weeks to 227 patients diagnosed with recurrent Paf episodes. Cardiac safety was assessed primarily by the maximum change from baseline in QRS duration. Changes in left ventricular function at echocardiography, incidence of proarrhythmic effects determined from ECG and Holter recordings and cardiovascular adverse events were also taken into account to assess cardiac safety. Efficacy was documented by actuarial methods.

RESULTS

Mean maximum QRS increase from baseline was 11.4% (n = 181); QRS increase was < 15% in 71.8% of the patients and > or = 25% in 18.8%. Only 4 patients had maximum QRS value > 100 ms under treatment. Left ventricular ejection fraction remained within +/- 20% of baseline for 90% of the patients, increased above 20% for 8.6% and decrease below 30% for 1.4% (n = 139). Bradycardia (13.2%; n = 129) and ventricular extrasystoles (10.6%; n = 104) were the most frequently identified proarrhythmic effects. Atrio-ventricular block (4.0%), supra-ventricular tachycardia (2.2%), bundle branch block (1.8%) and atrial fibrillation (1.3%) were the most frequent drug-related cardiac adverse events. Estimated treatment success rate was 74% (95% CI: [68%; 80%]) and the incidence of Paf episodes decreased from baseline 28.6% to 11.0% (P < 0.0001).

CONCLUSIONS

We provided evidence for a good cardiac safety profile of the controlled-release formulation of flecainide acetate and confirmed the effectiveness of the drug in the prevention of PAF recurrences.

[Characteristics and causes of death in 283 patients with implanted defibrillators]

The implantable automatic defibrillator has proved its superiority over pharmacological treatments for preventing mortality by serious ventricular arrhythmia. We studied the cause of death in a population of 283 consecutive patients implanted between February 1988 and December 2000 (age at implantation: 58 +/- 14.7 years; extremes: 15-78 years, 45 females, ejection fraction: 0.39 +/- 0.15) and followed up over a median of 25 months (extremes = 1 day-163 months).

RESULTS

At the end of follow up, 55 patients had died (average age: 62.7 +/- 12.6 years, extremes: 15-79 years, 7 females). All except 2 had a cardiopathy: ischaemic cardiopathy (n = 38, 36 IDDM), dilated cardiomyopathy (n = 14), arrhythmogenic dysplasia of the right ventricle (n = 1). The median interval between implantation and death was 35 months (extremes = 1 day-137 months). The causes of death were the following: cardiac insufficiency (n = 24), refractory arrhythmias (n = 13), other cardiac causes (n = 8), extra-cardiac pathologies (n = 10). The deceased patients had presented an average of 86.6 +/- 23.4 ventricular arrhythmias (extremes = 0-1309) but 18 of them (33%) did not present any during follow up.

CONCLUSIONS

Cardiac insufficiency is the prime cause of death in refractory arrhythmias; on patient in 4 dies from ventricular arrhythmia, despite the defibrillator and one deceased patient in 3 had no arrhythmia during follow up.

[Treatment with lepirudin in heparin-induced thrombocytopenia. A case report]

We report the case of a 71 old woman presenting a bilateral massive pulmonary embolism with intraventricular right thrombus complicating heparin induced thrombocytopenia (HIT) persistent after one month of conventional anticoagulant processing. We underline the effectiveness of lepirudin (Refludan) in the curative processing of pulmonary embolism allowing here to avoid a complex surgical thromboembolectomy. We evoke the place of this molecule in the curative therapeutic strategy of HIT with thrombotic phenomena.

Antithrombotic therapy is associated with better survival in patients with severe heart failure and left ventricular systolic dysfunction (EPICAL study)

BACKGROUND

In patients with congestive heart failure (CHF), clinical trials have demonstrated the benefit of a number of drugs on morbidity and mortality. Nevertheless so far, there is no published controlled study of long-term antithrombotic therapy in patients with CHF. The aim of this work was to identify the relationship between cardiovascular drug use, especially antithrombotic therapy, and survival of CHF patients in current clinical practice, using an observational, population-based database.

METHODS

The EPICAL study (Epidémiologie de l'Insuffisance Cardiaque Avancée en Lorraine) has identified prospectively all patients with severe CHF in the community of Lorraine. Inclusion criteria were age 20-80 years in 1994, at least one hospitalisation for cardiac decompensation, NYHA III/IV HF, ventricular ejection fraction < or =30% or cardiothoracic index > or =60% and arterial hypotension or peripheral and/or pulmonary oedema. A total of 417 consecutive patients surviving at hospital discharge were included in the database. The average follow-up period was 5 years. Univariate Cox models were used to test the relationship of baseline biological and clinical factors to survival. Cardiovascular drug prescriptions were tested in a multivariate Cox model adjusted by other known predictive factors.

RESULTS

Duration of disease >1 year, renal failure, serum sodium > or =138 mmol/l, old age, serious comorbidity, previous decompensation, high doses of furosemide and vasodilators use were independently associated with poor prognosis at 1 and 5 years. Oral anticoagulants, aspirin, lipid lowering drugs and beta-blockers use were associated with better survival. There was no interaction between aspirin and angiotensin converting enzyme inhibitor use on survival.

CONCLUSION

Antithrombotic therapy was associated with a better long-term survival in our study population of severe CHF. These results together with other previously published circumstantial evidence urge for a prospective, controlled and randomised trial specifically designed to evaluate optimal oral anticoagulants and aspirin in patients with congestive heart failure.