[Stereotactic body radiation therapy for hepatocellular carcinoma: Results from a retrospective multicentre study]

PURPOSE

The purpose of this paper was to describe local control, overall survival, progression-free survival and toxicity of CyberKnife^®-based stereotactic body radiation therapy of hepatocellular carcinoma.

MATERIAL AND METHODS

Records of all the patients treated for hepatocellular carcinoma at the Eugene-Marquis cancer centre, Rennes and the Bretonneau hospital, Tours (France), between November 2010 and December 2016, were reviewed. Radiation therapy was performed as a salvage treatment, while awaiting liver transplantation or if no other treatment was possible.

RESULTS

One hundred and thirty-six patients were consecutively included in the study. The median follow-up was 13months. Median total dose prescribed, fractionation and overall treatment time were respectively 45Gy, three fractions and 5 days. Overall survival, progression-free survival and local control rates at 1year and 2years were 79.8 % and 63.5 %, 61.3 % and 39.4 %; 94.5 % and 91 %. Two grade 3 acute toxicity events and two grade 4 late toxicity events corresponding to a duodenal ulcer have been reported. Seven patients underwent classic radiation-induced hepatitis and 13 patients showed non-classical radiation-induced hepatitis. Barcelona Clinic Liver Cancer stage, World Health Organisation grade and planning target volume were correlated with overall survival in univariate Cox analysis.

CONCLUSION

Stereotactic body radiation therapy is effective and well-tolerated for inoperable hepatocellular carcinoma or as a bridge to liver transplantation. Toxicity is mainly related to cirrhotic background and requires a selection of patients and strict dose constraints.

Reirradiation of gliomas under stereotactic conditions: Prognostic factors for survival without relapse or side effects, a retrospective study at Tours regional university hospital (France)

PURPOSE

To search for factors correlated with relapse-free survival following stereotactic reirradiation in patients with recurrent glioma following radiochemotherapy and evaluate tolerance to this treatment.

PATIENTS AND METHODS

Initial radiotherapy was given according to the protocol of Stupp and al. Reirradiation was performed using the CyberKnife^® system. Patients could have had surgical resection initially and at the time of recurrence. We analysed 13 patients treated between July 2010 and September 2014. The median age was 55 years. The doses delivered ranged from 20 to 36Gy, in one to ten fractions.

RESULTS

Median survival after stereotactic radiotherapy was 14 months. Survival without relapse was 3.7 months. Factors significantly influencing duration of relapse-free survival were: age (P=0.04), total dose (P=0.02), dose per fraction (P=0.04) and number of fractions (P=0.01). We found no correlation between gross tumour volume, clinical target volume, grade of tumour or prescription isodose and relapse-free survival following radiochemotherapy. Three patients developed radionecrosis.

CONCLUSION

Reirradiation under stereotactic conditions is well tolerated. A dose of more than 30Gy delivered in 5 or more fractions seems to prolong relapse-free survival.

White matter atlas of the human spinal cord with estimation of partial volume effect

Template-based analysis has proven to be an efficient, objective and reproducible way of extracting relevant information from multi-parametric MRI data. Using common atlases, it is possible to quantify MRI metrics within specific regions without the need for manual segmentation. This method is therefore free from user-bias and amenable to group studies. While template-based analysis is common procedure for the brain, there is currently no atlas of the white matter (WM) spinal pathways. The goals of this study were: (i) to create an atlas of the white matter tracts compatible with the MNI-Poly-AMU template and (ii) to propose methods to quantify metrics within the atlas that account for partial volume effect. The WM atlas was generated by: (i) digitalizing an existing WM atlas from a well-known source (Gray's Anatomy), (ii) registering this atlas to the MNI-Poly-AMU template at the corresponding slice (C4 vertebral level), (iii) propagating the atlas throughout all slices of the template (C1 to T6) using regularized diffeomorphic transformations and (iv) computing partial volume values for each voxel and each tract. Several approaches were implemented and validated to quantify metrics within the atlas, including weighted-average and Gaussian mixture models. Proof-of-concept application was done in five subjects for quantifying magnetization transfer ratio (MTR) in each tract of the atlas. The resulting WM atlas showed consistent topological organization and smooth transitions along the rostro-caudal axis. The median MTR across tracts was 26.2. Significant differences were detected across tracts, vertebral levels and subjects, but not across laterality (right-left). Among the different tested approaches to extract metrics, the maximum a posteriori showed highest performance with respect to noise, inter-tract variability, tract size and partial volume effect. This new WM atlas of the human spinal cord overcomes the biases associated with manual delineation and partial volume effect. Combined with multi-parametric data, the atlas can be applied to study demyelination and degeneration in diseases such as multiple sclerosis and will facilitate the conduction of longitudinal and multi-center studies.

[Management of gliomas]

Gliomas are the most frequent primary brain tumors. Their care is difficult because of the proximity of organs at risk. The treatment of glioblastoma includes surgery followed by chemoradiation with the protocol of Stupp et al. The addition of bevacizumab allows an increase in progression-free survival by 4 months but it does not improve overall survival. This treatment is reserved for clinical trials. Intensity modulation radiotherapy may be useful to reduce the neurocognitive late effects in different types of gliomas. In elderly patients an accelerated radiotherapy 40 Gy in 15 fractions allows a similar survival to standard radiotherapy. O(6)-methylguanine-DNA methyltransferase (MGMT) status may help to choose between chemotherapy and radiotherapy. There is no standard for the treatment of recurrent gliomas. Re-irradiation in stereotactic conditions allows a median survival of 8 to 12.4 months. Anaplastic gliomas with 1p19q mutation have a greater sensibility to chemotherapy by procarbazine, lomustine and vincristine. Chemoradiotherapy in these patients has become the standard treatment. Many studies are underway testing targeted therapies, their place in the therapeutic management and new radiotherapy techniques.

Impact of free on-site vaccine and/or healthcare workers training on hepatitis B vaccination acceptability in high-risk subjects: a pre-post cluster randomized study

Despite recommendations for adults at high-risk of hepatitis B virus (HBV) infection, HBV vaccine uptake remains low in this population. A pre-post randomized cluster study was conducted to evaluate the impact of on-site free HBV vaccine availability and/or healthcare worker training on HBV vaccination acceptability in high-risk adults consulting in 12 free and anonymous HIV and hepatitis B/C testing centres (FATC). The FATC were randomly allocated into three groups receiving a different intervention: training on HBV epidemiology, risk factors and vaccination (Group A), free vaccination in the FATC (Group B), both interventions (Group C). The main outcomes were the increase in HBV vaccination acceptability (receipt of at least one dose of vaccine) and vaccine coverage (receipt of at least two doses of vaccine) after intervention. Respectively, 872 and 809 HBV-seronegative adults at high-risk for HBV infection were included in the pre- and post-intervention assessments. HBV vaccination acceptability increased from 14.0% to 75.6% (p <0.001) in Group B and from 17.1% to 85.8% (p <0.001) in Group C and HBV vaccine coverage increased from 9.4% to 48.8% (p <0.001) in Group B and from 11.2% to 41.0% (p <0.001) in Group C. The association of training and free on-site vaccine availability was more effective than free on-site vaccine availability alone to increase vaccination acceptability (ratio 1.14; from 1.02 to 1.26; p 0.017). No effect of training alone was observed. These results support the policy of making HBV vaccine available in health structures attended by high-risk individuals. Updating healthcare workers' knowledge on HBV virus and its prevention brings an additional benefit to vaccination acceptability.

Inducible ventricular arrhythmias and patency of infarct-related artery in survivors of acute myocardial infarction

BACKGROUND

Patency of infarct-related artery in patients who suffered an acute myocardial infarction (AMI) has been shown to be associated with improved survival. Ventricular tachyarrhythmias induced by programmed electrical stimulation may be predictive of arrhythmic events and sudden death.

HYPOTHESIS

The study was undertaken to assess the possible effect of a patent infarct-related coronary artery on induced ventricular tachyarrhythmias during programmed ventricular stimulation in survivors of AMI.

METHODS

In this prospective study, programmed electrical stimulation was performed before hospital discharge (14 +/- 2 days) in 79 patients who survived an AMI. Patients were subdivided into two groups: Group I with patent infarct-related coronary artery (n = 64) and Group 2 with occluded infarct-related artery (n = 15) at coronary angiography performed at 14 +/- 2 days. These two groups were comparable in terms of mean left ventricular ejection fraction, location of infarct-related artery, number of diseased vessels, peak creatine kinase value, and infarct location.

RESULTS

Ventricular arrhythmias were induced in 21 patients ( 32.6%) of Group I and 4 patients (26.6%) of Group 2. This difference was not statistically significant.

CONCLUSION

This study suggests that ventricular arrhythmias induced by programmed ventricular stimulation in survivors of AMI did not differ whether the infarct-related artery was patent or occluded. Other factors may play a role in electrical instability as assessed by programmed ventricular stimulation.

Late lethal hepatitis B virus reactivation after rituximab treatment of low-grade cutaneous B-cell lymphoma

The chimeric anti-CD20 monoclonal antibody, rituximab, is a promising treatment for cutaneous B-cell lymphomas. Classically used in combination with a multiagent-chemotherapy regimen, it can sometimes give excellent results alone. Because of its selective action on B lymphocytes, it is considered a moderate immunosuppressant in terms of infection. We describe a woman with relapsed cutaneous follicular centre B-cell lymphoma and secondary lymph-node involvement treated with rituximab alone, which induced a complete remission. One year later, she experienced a fatal hepatitis B virus (HBV) reactivation. Several such HBV reactivations were reported after combined rituximab and multiagent chemotherapy for B-cell lymphomas. This is the first case of HBV reactivation occurring during the year following rituximab monotherapy in the absence of any other immunosuppressive factor.

[Remodelling in atrial fibrillation]

It is well known that atrial fibrillation (AF) tends to become permanent with time as illustrated by the fact that it becomes more difficult to maintain sinus rhythm when AF has been present for a long time. Atrial remodelling plays a part in this process and has been studied in experimental models. Atrial remodelling is defined as all the phenomena occurring during AF contributing to its maintenance. The persistence of AF induced by stimulation in the animal depends on the duration and the repetition of the atrial stimulation and it would appear that "AF induces AF". The tendency for AF to persist is associated with a shortening of the effective atrial refractory period with loss of its adaptation to the heart rate. The determining factor of both electrical and structural remodelling is the rapidity of the atrial rhythm of the AF itself. These phenomena lead to a type L calcium cellular overload as shown by its prevention or attenuation by the administration of verapamil, a calcium antagonist. Electrical remodelling is accompanied by a structural remodelling in the experimental model of persistent AF over several weeks. Samples from the two atria examined by electronic microscopy show mitochondrial changes, an accumulation of glycogen, a deficit in myofibrils, a redistribution of the nuclear chromatim and a reduction of sarcoplasmic reticulum with changes in protein structure. This structural remodelling is a reaction of adaptation similar to that observed in hibernating myocardium during ischaemia and aims to prolong cellular viability by decreasing atrial contractility. Another aspect of structural remodelling is the activation of fibroblasts with formation of fibrosis with resulting heterogeneity of the conduction tissue. There is also an increase in converting enzyme and angiotensin II concentrations. Irbesartan, an angiotensin II antagonist, reduced fibroblast growth. This has clinical applications as shown by the reduction in the recurrences of AF after cardioversion when given in association with amiodarone. Persistent AF leads to left atrial dilatation with abnormal atrial contractility. Further studies are necessary to determine the effect of atrial remodelling which might also act on the foci responsible for inducing the AF. Better understanding of atrial remodelling will contribute to the use of new pharmacological agents to prevent AF.

[A multicentre trial of the diagnostic value and cost of electrocardiography in symptoms suggesting arrhythmia with a new event recorder with transtelephonic transmission]

Events recorders are used for electrocardiographic documentation of symptoms of arrhythmia too sporadic and short lasting to be recorded by 24 hour Holter monitoring. However, there are no French studies comparing the value and cost of event recorders with conventional diagnostic methods. Recently, a new telediagnostic device has become available in France leading to an assessment of the technique. The aim of this study was to determine the value of this event recorder and the cost of diagnostic ECG in the assessment of presumed arrhythmic symptoms such as palpitations or rare tachycardia (<3 episodes per week) of short duration, compared with conventional techniques. Fifty-eight patients with these criteria were randomised, 30 to Survcard (Group I) and 28 to conventional diagnostic methods (Group II). The patients were comparable with respect to age, sex distribution, type of symptoms and associated cardiac disease. The ECG diagnosis of the symptoms was established in 20 cases (66.6%) of patients in Group I in 17 +/- 16 days, and in 14 cases (50.0%) of Group II in 23 +/- 28 days. The difference between the two groups was not statistically significant. The cost of a positive diagnosis for Group I (Survcard) varied from 0 to 228.47 Euro with an average of 71.22 +/- 117.02 Euro. The cost of positive diagnosis in Group II varied from 76.80 to 2340.41 Euro with an average of 480.39 +/- 797.41 Euro. In conclusion, this study showed that the percentage of patients with a positive diagnosis was comparable in the two groups but that the cost was 6 times higher in the group investigated by conventional methods than in the Survcard group because of more costly medical intervention.

[Cardioversion by external electric shock for atrial fibrillation: does patient age affect immediate results?]

The restoration of sinus rhythm by external electric shock in patients with persistent atrial fibrillation is a well established treatment. However, in current practice this treatment is generally indicated less in the elderly subject although this attitude is not factual. The objective of this work was to evaluate the immediate results of cardioversion by external electric shock, comparing the success rates in four age groups: under 60 years, between 60 and 69 years, between 70 and 79 years, and over 80 years. This study was performed on 182 consecutive patients aged from 25 to 89 years: 35 patients aged less than 60 years, 52 patients aged from 60 to 69 years, 65 patients aged from 70 to 79 years, and 30 patients aged 80 years or over. The success rates were 91.4% before 60 years, 90.4% between 60 and 69 years, 90.8% between 70 and 79 years, and 83.3% after 80 years. There was no significant difference between the success rates in the four age groups (p = 0.68). Among the other factors analysed, only the duration of atrial fibrillation and the body mass index significantly influenced the results of external electric shock in this series. This work suggests that age does not significantly influence the immediate results of external electric shock. According to these data it does not appear justified to contra-indicate cardioversion by external electric shock on the sole criterion of age.

Catheter ablation using very high frequency current: effects on the atrioventricular junction and ventricular myocardium in sheep

BACKGROUND

Radiofrequency ablation is currently used in the treatment of various cardiac arrhythmias. However, this technique is limited by impedance rise, leading to coagulum formation and desiccation of tissue. We developed a new generator, providing very high frequency (27 MHz) current, which is in the intermediate range between radiofrequency and microwave energy. The aim of this study was to evaluate the results for catheter ablation of the atrioventricular junction and characteristics of the lesions obtained at ventricular sites.

METHODS AND RESULTS

The generator was coupled to a specially designed 7-French coaxial catheter. The study included experiments performed on 10 sheep (Wt. 31- 42 kg). In seven sheep, the catheter was introduced into the femoral vein and advanced across the tricuspid annulus to record the largest possible His electrogram. VHF current was applied for 25 s, with increasing energies. The energy needed to obtain complete atrioventricular (AV) block ranged from 60 to 100 Watts. Six animals were observed for 6 to 21 days. Complete AV block was found to be persistent. In those seven sheep in whom AV junction was ablated and in three additional sheep, the ablation catheter was positioned toward the right ventricular apex using the same approach and into the left ventricle via the femoral artery, and 20 to 90 Watts energy was delivered in order to assess the size of the induced lesions. Side effects included ventricular tachycardia degenerating into ventricular fibrillation in six cases, but the same effect was observed in this animal model with radiofrequency energy. No cardiac perforation was noted. No thrombus was observed at the catheter tip. The size of the lesion ranged from 3 to 45 mm in width and 1 to 15 mm in depth.

CONCLUSIONS

Catheter ablation using VHF current is feasible and appears effective in producing stable AV block when applied at the AV junction and results in substantial myocardial lesions. Further studies are needed to define its clinical interest and side effects.

Influence of residual myocardial ischaemia on induced ventricular arrhythmias following a first acute myocardial infarction

OBJECTIVES

The purpose of this study was to assess the possible effect of residual myocardial ischaemia on induced ventricular arrhythmia during programmed ventricular stimulation in survivors of a first acute myocardial infarction.

BACKGROUND

Most deaths after hospital discharge for acute myocardial infarction are sudden and presumably arrhythmic. Sudden cardiac death results from a dynamic interaction of structural abnormalities and transient triggering factors. The role of myocardial ischaemia as a trigger for ventricular arrhythmias remains unclear. We hypothesized that residual myocardial ischaemia after a first acute myocardial infarction is a potent trigger for sustained ventricular tachyarrhythmias, particularly in the presence of an abnormal myocardium.

METHODS AND RESULTS

In this prospective study, programmed electrical stimulation, coronary angiography and dipyridamole-thallium-201 scintigraphy single-photon emission computed tomography were performed in 90 consecutive survivors of a first acute myocardial infarction. Patients, divided in two groups - group 1 with induced ventricular tachyarrhythmia (n=24) and group 2 without induced ventricular tachyarrhythmia (n=66) - were compared regarding residual myocardial ischaemia. The two groups were comparable in terms of mean left ventricular ejection fraction, infarct size and location, gender ratio, peak creatine kinase value, and extent of coronary disease. Residual myocardial ischaemia was detected in 32 patients: 15 (42.5%) belonged to group 1 and 17 (25.7%) to group 2. There was a statistically significant difference between the two groups regarding the presence and the extent of residual myocardial ischaemia (P<0.05).

CONCLUSION

Residual myocardial ischaemia, revealed by dipyridamole-thallium-201 scintigraphy following a first acute myocardial infarction, might contribute to electrical instability evaluated by programmed ventricular stimulation.

External cardioversion of atrial fibrillation: comparison of biphasic vs monophasic waveform shocks

AIMS

It is well established in transthoracic ventricular defibrillation that biphasic truncated waveform shocks are associated with superior defibrillation efficacy when compared with damped sine wave monophasic waveform shocks. The aim of this study was to explore whether biphasic waveform shocks were superior to monophasic waveform shocks for external cardioversion of atrial fibrillation (AF).

METHODS AND RESULTS

Fifty-seven patients in whom cardioversion of AF was indicated were randomized in this prospective study, to transthoracic cardioversion with either monophasic damped sine waveform shocks or biphasic impedance compensating waveform shocks. In the group randomized to monophasic waveform shocks (27 patients), a first shock of 150 J was delivered, followed (if necessary) by a 360 J shock. In the biphasic waveform group (30 patients), the first shock had an energy of 150 J and (if necessary) a second 150 J was delivered. All shocks were delivered in the anterolateral chest pad position. Sinus rhythm was restored in 16 patients (51%) with the first monophasic shock and in 27 patients (86%) with the first biphasic shock. The difference was statistically significant (P=0.02). After the second shock, sinus rhythm was obtained in a total of 24 patients (88%) with monophasic shocks and in 28 patients (93%) with biphasic shocks. No complication was observed in either group and cardiac enzymes (CK, CKmb, troponin I, myoglobin) did not show any significant changes.

CONCLUSION

This study suggests that at the same energy level of 150 J, biphasic impedance compensating waveform shocks are superior to monophasic damped sine waveform shocks cardioversion of atrial fibrillation.

Ventricular tachycardia with QRS configuration similar to that in sinus rhythm and a myocardial origin: differential diagnosis with bundle branch reentry

INTRODUCTION

Tachycardia with a QRS configuration which resembles that in sinus rhythm is usually thought to be supraventricular. Ventricular tachycardia, with a similar QRS configuration to that in sinus rhythm on the 12-lead ECG, can occur. The mechanisms of this form of ventricular tachycardia have not been previously reported.

METHODS AND RESULTS

The mechanism of ventricular tachycardia was defined during electrophysiological study in five patients. During sinus rhythm, all patients had a wide QRS complex (>0.12 s) on the 12-lead ECG. The morphology remained grossly unchanged during spontaneous, symptomatic tachycardia. Four of the five patients had coronary artery disease and left ventricular dysfunction. The remaining patient had idiopathic dilated cardiomyopathy. The relationship between the His bundle, deflection, the right bundle branch and the QRS complex was evaluated during tachycardia. Atrial and ventricular pacing, and ventricular activation mapping were performed during tachycardia to define the tachycardia mechanism. The tachycardia induced at electrophysiological testing, which was similar to the clinical tachycardia, was proven to be ventricular tachycardia in each patient. The morphology of ventricular tachycardia was right bundle branch block in two patients and left bundle branch block in three patients. The median tachycardia cycle length was 300 ms (range: 260-480 ms). His bundle activation occurred in a 1:1 relationship with ventricular activation during tachycardia in all patients at least intermittently. The tachycardias were thought initially to be bundle branch reentry tachycardia. With further intervention and continued observation, it became clear that His bundle activation was passive and was not required for the tachycardia to sustain. During tachycardia, His bundle activation appeared to precede the local ventricular activation. Instead, the His bundle was activated slowly from the previous ventricular beat causing a long ventricular-His (VH) interval. This was shown by: (1) activation patterns, (2) response to pacing, (3) intermittent VH dissociation, and (4) termination of ventricular tachycardia.

CONCLUSION

A unique form of ventricular tachycardia is described. The QRS complex morphology on the 12-lead ECG during tachycardia was grossly similar to that during sinus rhythm. The His bundle activation was passive and occurred with a long activation time from the ventricle to the His bundle. Although it mimics usual bundle branch reentry, this form of ventricular tachycardia appears to be due to a different mechanism in which the His bundle is not obligatory for the continuation of the reentrant phenomenon.

Effects of digoxin on chemoreflex in patients with chronic heart failure

The effects of digitalis on the baroreflexes in human chronic heart failure have been well studied. Similarly, since it has been recently shown that chemoregulation remains generally effective during cardiac failure, the goal of this study was to evaluate the effects of a chronic administration of digoxin on the chemoreflexes. Hemodynamic and blood gas parameters were assessed in 7 patients with chronic congestive heart failure before and after chronic administration for 10 days of digoxin therapy (0.25 mg daily). In both situations measurements were performed 1/ in baseline conditions at room air and, 2/ after inhalation of pure O2 for 30 min, in order to inhibit the activation of the chemoreflexes. At room air, acute O2 inhalation resulted in a significant decrease in heart rate and cardiac output. After digoxin therapy, comparatively to pre-treatment values, cardiac output, stroke volume and PaO2 were significantly higher while heart rate, systemic resistance and pulmonary wedge pressure were lower. Furthermore, acute O2 inhalation did not modify heart rate or any hemodynamic variables. These results suggest that after digoxin therapy chemoreflex was no more activated in these patients. This effect may be related to the sympatho-inhibitory and to the positive inotropic effects of digoxin: improving hemodynamic and blood gas parameters may result in the inactivation of the reflex.

Pharmacologic management of atrial fibrillation: current therapeutic strategies

BACKGROUND

Atrial fibrillation (AF), the most common form of sustained arrhythmia, is associated with a frightening risk of embolic complications, tachycardia-related ventricular dysfunction, and often disabling symptoms. Pharmacologic therapy is the treatment used most commonly to restore and maintain sinus rhythm, to prevent recurrences, or to control ventricular response rate.

METHODS

This article reviews published data on pharmacologic treatment and discusses alternative systems to classify AF and to choose appropriate pharmacologic therapy.

RESULTS

AF is either paroxysmal or chronic. Attacks of paroxysmal AF can differ in duration, frequency, and functional tolerance. In the new classification system described, 3 clinical aspects of paroxysmal AF are distinguished on the basis of their implications for therapy. Chronic AF usually occurs in association with clinical conditions that cause atrial distention. The risk of chronic AF is significantly increased by the presence of congestive heart failure or rheumatic heart disease. Mortality rate is greater among patients with chronic AF regardless of the presence of coexisting cardiac disease. The various options available for the treatment of chronic AF include restoration of sinus rhythm or control of ventricular rate. Cardioversion may be accomplished with pharmacologic or electrical treatment. For patients in whom cardioversion is not indicated or who have not responded to this therapy, antiarrhythmic agents used to control ventricular response rate include nondihydropyridine calcium antagonists, digoxin, or beta-blockers. For patients who are successfully cardioverted, sodium channel blockers or potassium channel blockers such as sotalol, amiodarone, or a pure class III agent such as dofetilide, a selective potassium channel blocker, may be used to prevent recurrent AF to maintain normal sinus rhythm.

CONCLUSIONS

The ultimate choice of the antiarrhythmic drug will depend on the presence or absence of structural heart disease. An additional concern with chronic AF is the risk of arterial embolization resulting from atrial stasis and the formation of thrombi. In patients with chronic AF the risk of embolic stroke is increased 6-fold. Therefore anticoagulant therapy should be considered in patients at high risk for embolization. Selection of the appropriate treatment should be based on the concepts recently developed by the Sicilian Gambit Group (based on the specific channels blocked by the antiarrhythmic agent) and on clinical experience gained over the years with antiarrhythmic agents. For example, termination of AF is best accomplished with either a sodium channel blocker (class I agent) or a potassium channel blocker (class III agent). In contrast, ventricular response rate is readily controlled by a beta-blocker (propranolol) or a calcium channel blocker (verapamil). Alternatively, antiarrhythmic drug therapy may be chosen based on the Vaughan-Williams classification, which identifies the cellular electrophysiologic effects of the drug.

[Acute intracranial hypertension and anicteric cholestasis revealing Whipple's disease without digestive involvement]

Whipple's disease is a rare infectious disease with potential central nervous system manifestations and a poor prognosis. We report the case of a young woman who presented with acute intracranial hypertension associated with cholestasis which revealed Whipple's disease without digestive involvement. The diagnosis was supported by the presence of PAS-diastase positive hepatic granulomas. A long course of antibiotics resulted in complete remission of the disease without relapse. An acute neurologic syndrome associated with cholestasis should suggest Whipple's disease.

Spontaneous episodes of atrial fibrillation after implantation of the Metrix Atrioverter: observations on treated and nontreated episodes. Metrix Investigators

OBJECTIVES

We sought to evaluate the number and duration of device-treated and self-terminating, nontreated episodes of atrial fibrillation (AF) after implantation of the Metrix Atrioverter.

BACKGROUND

A recent study has shown that the Atrioverter can rapidly restore sinus rhythm in patients with AF; however, the effect of the device on the clinical course of the arrhythmia in these patients is unknown.

METHODS

The Atrioverter was implanted in 51 patients with symptomatic, recurrent, drug-refractory AF. The device was programmed to periodically monitor the cardiac rhythm. Defibrillation of AF episodes was performed under physician observation.

RESULTS

During a mean follow-up of 260 +/- 144 days, 1,161 episodes of AF were observed during valid monitoring periods in 45 of 51 patients. Forty-one patients experienced 231 episodes for which they sought defibrillation therapy. The average duration of the treated episodes during valid monitoring periods (190 of 231 episodes in 39 of 41 patients) was significantly longer than that of the nontreated episodes (38 +/- 44 vs. 10 +/- 8 h; p < 0.05). The time between episodes requiring Atrioverter therapy increased, and the risk of having an episode requiring treatment decreased. No changes were observed in the number and duration of the short-lasting, nontreated episodes as time since implantation of the device increased.

CONCLUSIONS

In patients with symptomatic, recurrent, drug-refractory AF, the frequency of long-lasting episodes, which were treated under observation with repeated defibrillation using the Atrioverter, decreased. The number and duration of short-lasting, nontreated episodes did not change during the 20-month study period. The effect of ambulatory use of the device on the recurrence of short-lasting episodes needs to be evaluated.

Specific up-regulation of mitochondrial F0F1-ATPase activity after short episodes of atrial fibrillation in sheep

INTRODUCTION

Ventricular fibrillation induced by either digitalis intoxication or electrical stimulation is reported to alter myocardial energy by impairing the sarcolemmal Na,K-ATPase or the receptor for digitalis and the mitochondrial ATPase synthase or F0F1-ATPase. However, little is known about these membrane functions during atrial fibrillation (AF).

METHODS AND RESULTS

We analyzed the effects of electrically induced AF on biochemical activities of atrial F0F1-ATPase and Na,K-ATPase in sheep. A group of six sheep was subjected to direct short electrical stimulation of the right atrium to induce AF. Sham-operated sheep served as a control group. Microsomal and mitochondrial membranes of atrial muscle were isolated and tested for enzymatic activity. All paced sheep developed multiple episodes of sustained AF, with a mean total duration of 110 minutes over a 2-hour period. Data showed that short-term pacing-induced AF significantly activated membrane F0F1-ATPase activity (P < 0.05) without changes in cytochrome-c oxidase activity, Na,K-ATPase activity, ouabain sensitivity, and alpha1-subunit expression.

CONCLUSION

Specific activation of F0F1-ATPase activity is an early molecular consequence of sustained AF in sheep.

Inhibition of Na,K-ATPase by external electrical cardioversion in a sheep model of atrial fibrillation

INTRODUCTION

Electrical external cardioversion commonly used to treat atrial fibrillation (AF) is associated with myocardial membrane damage and disturbances in ionic homeostasis (hemodynamically unstable). The present study was designed to investigate whether alterations in ionic homeostasis observed were due in part to changes in the myocardial activity of Na,K-ATPase.

METHODS AND RESULTS

AF was induced by pacing in ten anesthetized sheep divided into two groups. Group I (n = 4) received a single external countershock of 360 J after three episodes of AF lasting 10 minutes. Group II (n = 6) served as controls. Activity, responsiveness to ouabain, and membrane expression of catalytic alpha and beta subunits of Na,K-ATPase in sarcolemmal myocardial membrane fractions were investigated. Membrane fluidity and fatty acid composition, and plasma levels of atrial natriuretic factor (ANF) also were measured. One shock after episodes of AF significantly decreased ventricular Na,K-ATPase activity up to 50% (P < 0.001) without modification of atrial activity at the membrane level. Sites with low affinity to ouabain showed a fivefold lower affinity for ouabain in the cardioversion group than in the control group (IC50 = 7.9 micromol/L vs 40 micromol/L ouabain, P < 0.05). Plasma levels of ANF were significantly increased in the cardioversion group compared with the control group. These changes were independent of membrane modulation in terms of expression of Na,K-ATPase, membrane fluidity, and fatty acid composition.

CONCLUSION

This study suggests that left ventricular perturbation of ionic homeostasis subsequent to transthoracic cardioversion could result from inactivation of Na,K-ATPase activity.

Plasma beta-endorphin and adenosine concentration in pulmonary hypertension

To determine whether beta-endorphin plays a role in the regulation of pulmonary vascular tone in patients with pulmonary hypertension, we investigated the relations between hemodynamics and beta-endorphin and adenosine concentrations in 3 clinical situations: (1) normal hemodynamics (7 subjects, mean pulmonary artery [PA] pressure 18.5 +/- 1 mm Hg); (2) moderate pulmonary hypertension secondary to chronic obstructive pulmonary disease (COPD) (8 patients, mean PA pressure 31 +/- 3 mm Hg); and (3) severe primary pulmonary hypertension (PPH) (8 patients, mean PA pressure 70 +/-5 mm Hg). Plasma beta-endorphin and adenosine were measured in a distal PA and in the femoral artery in room air and during oxygen inhalation. Beta-endorphin levels were similar in the pulmonary and systemic circulations. No difference was observed between patients with COPD and PPH, but relative to controls, both had significantly higher beta-endorphin levels. Pulmonary adenosine was significantly lower in patients with pulmonary hypertension than in controls (-60% in COPD [p <0.005] and -70% in PPH [p <0.001]). Pure oxygen administration significantly decreased adenosine and beta-endorphin levels, much more so in patients with COPD and PPH. We found a negative correlation between beta-endorphin and adenosine concentrations (r = -0.751, p <0.001): the higher the adenosine, the lower the beta-endorphin level. These observations suggest that because adenosine release by pulmonary vascular endothelium is reduced in pulmonary hypertension, the resulting worsened hypoperfusion and tissue oxygenation may cause increased beta-endorphin release.

Classification system of atrial fibrillation

A number of publications and clinical trials on the management of atrial fibrillation (AF) deal with this arrhythmia as if it represents a single entity. As a result, advances made in recent years have not affected the way AF patients are treated in general practice except, perhaps, for the use of warfarin in anticoagulation. Therefore, there is a need for a classification system and for uniformity in the nomenclature used. The two terms currently used to describe AF, paroxysmal and chronic, require a time frame. It is proposed that if an AF episode lasts longer than 7 days, the condition should be considered chronic. For the first symptomatic, non-self-terminating episode that is fewer than 7 days long, the term recent onset AF may be used, or recent discovery if the AF is asymptomatic or if the duration cannot be determined. Attacks of paroxysmal AF may differ in their duration, frequency, and functional tolerance. In the classification system described, three clinical aspects of paroxysmal AF were isolated in such a way as to have implications for therapy. This classification system was found to be useful for characterizing different subsets of patients with AF.

Dietary fish oil promotes positive inotropy of ouabain in the rat heart

We tested the hypothesis that a fish oil (FO) diet promotes positive inotropy of ouabain without increased toxicity. For 2 mo, two groups of adult male rats were fed 1) a regular food diet supplemented with dietary long-chain polyunsaturated fatty acid from FO or 2) a regular food diet (control). The responsiveness to ouabain was evaluated for the two groups in Langendorff-perfused hearts, by (31)P nuclear magnetic resonance spectroscopy, and on purified membrane-bound Na-K-ATPase. The maximum positive inotropy achieved with ouabain was nearly two times higher in the FO than in the control group and was not associated with significant changes in energetics. Alteration of function and energetic metabolism and inhibition of Na-K-ATPase in response to 3 x 10(-4) M ouabain were delayed in the FO group. This study demonstrates that dietary FO, by a cardiac membrane incorporation of n-3 polyunsaturated fatty acid, promotes positive inotropy of ouabain without toxicity and changes in cardiac metabolism.

[Implantable ventricular defibrillator. Systematic induction of ventricular arrhythmia is not useful except for implantation]

Checking the efficacy of a defibrillator after its implantation is current practice. This control usually entails induction of ventricular fibrillation (VF). The aim of this study was to assess the utility of this practice in patients with an endovascular system of electrodes. Implantation was acquired when a margin of security of 10 days or more had been obtained. During the postoperative test, the choice of energy was that which reduced VF at implantation. Of the 84 patients included in this study, 59 were implanted with an endovascular electrode system alone and the other 25 patients had endovascular electrodes associated with a subcutaneous patch electrode. The average time from implantation to the postoperative test was 31 +/- 12 days. Arrhythmia sensing was normal and reduction by the defibrillator was observed in all patients. The average energy of the electric shocks was not significantly different to that observed at implantation (18.6 +/- 3.6 J and 19.3 +/- 4.7 J). Fifty patients had antiarrhythmic drugs (amiodarone = 43) at implantation, and 32 at the time of the postoperative test (amiodarone = 17). This study showed that the postoperative test with induction of VF was normal in all patients. Therefore, the authors propose that follow-up should consist of consultation including interrogation of the defibrillator and a chest X-ray to check the position of the electrodes. If one of these tests is abnormal or if the perioperative threshold of defibrillation does not provide an adequate margin of safety, induction of a ventricular arrhythmia is necessary to check the function of the system.

Treatment of hepatitis C patients with normal aminotransferases levels

An important subset of patients with chronic hepatitis C have normal ALT levels despite having detectable HCV RNA in serum. These patients are typically identified after donating blood and being found positive for antibody to HCV (anti-HCV). A strict definition of this patient population is needed, which should include the presence of anti-HCV, detectable HCV RNA by PCR and persistently normal ALT levels. These patients are usually asymptomatic, but on liver biopsy almost all have histologic evidence of chronic hepatitis. The histologic findings generally are mild, and cirrhosis is rare. The long-term outcome of this group of patients with chronic HCV infection is not known, but the prognosis is probably good. In small, uncontrolled trials of IFN-alpha in patients with normal ALT levels, end-of-treatment virologic responses occurred in 42% of patients, and sustained responses 6 to 12 months afterwards in 13% of patients. These rates of response are not very different from those reported in patients with elevated ALT levels. Importantly, in most studies, serum ALT levels became elevated during IFN therapy in approximately one half of patients, and levels remained elevated in some of these patients after therapy. These findings suggest that IFN-alpha therapy is not usually beneficial and may be harmful in chronic hepatitis C patients with normal ALT levels. Combination therapy with IFN and ribavirin has not been evaluated in this group of patients.

[Changes in homeostasis during surgical liver resection]

OBJECTIVES

To assess changes in haemostasis during liver resection and to discuss the indications for antifibrinolytic therapy.

STUDY DESIGN

Open prospective study.

PATIENTS

The study included 39 consecutive non-cirrhotic patients presenting for liver resection under portal triad clamping.

METHOD

General anaesthesia was obtained with thiopentone, fentanyl, vecuronium and isoflurane. Transfusion scheme was standardized. Aprotinin (5,000 kIU.kg-1 BW) was administered in case of unexplained bleeding in the operative field. Coagulation pattern was assessed by routine tests and thrombelastrography before surgery, before portal triad clamping, 5 min after reperfusion and at completion of surgery. Patients requiring aprotinin intraoperatively were compared to others.

RESULTS

In 32 patients no significant bleeding occurred. Their coagulation pattern was moderately changed and remained within the normal range. In seven patients severe bleeding occurred which was treated with aprotinin. Their coagulation tests were significantly modified, especially after reperfusion, associating an increase in aPTT, TT, FDP, DDim, r + k and a decreased platelet count.

CONCLUSION

These changes were more in favour of a dilution coagulopathy or a DIC than hyperfibrinolysis. Therefore substitutive therapy with coagulation factors should be preferred to an antifibrinolytic agent. A systematic administration of the latter for liver resection in non-cirrhotic patients is debatable, considering the allergic risk (reoperation for cancer recurrence), thrombosis facilitation (pedicle clamping) and high cost.

Relationship of plasminogen activator inhibitor-1 levels following thrombolytic therapy with rt-PA as compared to streptokinase and patency of infarct related coronary artery

BACKGROUND

Type 1 plasminogen activator inhibitor (PAI-1) is considered to be risk factor for acute myocardial infarction (AMI). A rebound of circulating PAI-1 has been reported after rt-PA administration. We investigated the relationships between PAI-1 levels before and after thrombolytic therapy with streptokinase (SK) as compared to rt-PA and the patency of infarct-related arteries.

METHODS AND RESULTS

Fifty five consecutive patients with acute MI were randomized to streptokinase or rt-PA. The plasma PAI-1 levels were studied before and serially within 24 h after thrombolytic administration. Vessel patency was assessed by an angiogram at 5+/-1days. The PAI-1 levels increased significantly with both rt-PA and SK as shown by the levels obtained from a control group of 10 patients treated with coronary angioplasty alone. However, the area under the PAI-1 curve was significantly higher with SK than with rt-PA (p<0.01) and the plasma PAI-1 levels peaked later with SK than with rt-PA (18 h versus 3 h respectively). Conversely to PAI-1 levels on admission, the PAI-1 levels after thrombolysis were related to vessel patency. Plasma PAI-1 levels 6 and 18 h after SK therapy and the area under the PAI-1 curve were significantly higher in patients with occluded arteries (p<0.002, p<0.04 and p<0.05 respectively). The same tendency was observed in the t-PA group without reaching significance.

CONCLUSIONS

This study showed that the PAI-1 level increase is more pronounced after SK treatment than after t-PA treatment. There is a relationship between increased PAI-1 levels after thrombolytic therapy and poor patency. Therapeutic approaches aimed at quenching PAI-1 activity after thrombolysis might be of interest to improve the efficacy of thrombolytic therapy for acute myocardial infarction.

Internal low-energy cardioversion: a therapeutic option for restoring sinus rhythm in chronic atrial fibrillation after failure of external cardioversion

AIMS

Conventional external cardioversion remains the technique of choice for restoration of sinus rhythm in patients with chronic atrial fibrillation (AF). Recent reports have suggested that internal low-energy cardioversion is efficient and safe in terminating AF in patients with failed external cardioversion.

METHODS AND RESULTS

In 20 of 118 consecutive patients with spontaneous chronic AF (>7/days), who underwent low-energy cardioversion, one or more attempts at restoring sinus rhythm with external cardioversion had failed. Low-energy internal cardioversion was performed under light sedation. Shocks were delivered (using an external custom defibrillator) between two nonapolar catheters positioned in the right atrium (cathode) and in the coronary sinus (anode). Heart disease was present in 12 and absent in eight patients ('lone' atrial fibrillation). Atrial fibrillation was established for a period ranging from 12 days to 53 months. Low-energy internal cardioversion restored sinus rhythm in 15 of the 20 patients (75%) with a mean energy of 4.5+/-1.2 J, a mean conversion voltage of 355+/-53 V and a mean impedance of 63+/-8 ohms. No complications were observed. With a mean follow-up of 6+/-7 months, 11 patients (73%) were in stable sinus rhythm.

CONCLUSIONS

This study provides evidence in support of low-energy internal cardioversion as a valuable therapeutic option in patients in whom conventional external cardioversion failed. This technique is safe and does not require general anaesthesia.

Characterization of different subsets of atrial fibrillation in general practice in France: the ALFA study. The College of French Cardiologists

BACKGROUND

The clinical presentation and causes of atrial fibrillation (AF) in the 1990s may differ from AF seen 2 to 3 decades ago. It was the objective of this prospective study to characterize various clinical presentations and underlying conditions of patients with AF observed in general practice in France.

METHODS AND RESULTS

The study population comprised 756 patients (19 to 95 years of age) with electrocardiographically documented AF subdivided into paroxysmal (<7 days), chronic (last episode >1 month) and recent onset AF(persistent >7 days and<1 month). Symptoms were present in 670 patients (88.6%). The relative prevalences of paroxysmal, chronic, and recent onset AF were 22.1%, 51.4%, and 26.4%, respectively. Cardiac disorders, present in 534 patients (70.6%), included hypertension (39.4%), coronary artery disease (16.6%), and myocardial diseases (15.3%) as the most common. Rheumatic valvular disease represented a common cause in women (25. 0%) but not in men (8.0%). The paroxysmal group differed by a high percentage of palpitations (79.0%) and a low percentage of underlying heart disease (53.9%). With a mean follow-up of 8.6+/-3.7 months, 28 patients (3.7%) died, including 6 fatal cerebrovascular accidents. Among the 728 patients who survived, congestive heart failure occurred in 30 patients (4.1%), and embolic complications occurred in 13 patients (1.8%). In the paroxysmal AF group, 13 patients (8.0%) developed chronic AF and 51 (31.3%) had AF recurrences. At the time of follow-up, 53 patients (14.3%) from the chronic AF group and 108 patients (55.7%) from the recent onset AF group were in sinus rhythm.

CONCLUSIONS

This large-scale study establishes the current demographic profile of out-of-hospital patients with AF and highlights some of the changes that have occurred in the past decades, including a particular shift in cardiac causes toward nonrheumatic AF. This study also demonstrates significant differences between various subsets of AF.

[Hereditary resistance to vitamin K antagonists. Apropos of a case]

Resistance to vitamin K antagonists is a rare phenomenon. In general, it is the result of poor patient compliance, malabsorption, a diet rich in vitamin K, or the use of enzyme inducers. Occasionally, the diagnosis of resistance is made when plasma levels are high. The authors report a case of hereditary resistance to vitamin K antagonists in a 43 year old man admitted for atrial fibrillation. The precise prevalence of this anomaly is unknown. However, the existence should be known to clinicians who often use this important family of drugs.

[Heart perforation following transvenous implantation of a cardiac pacemaker]

OBJECTIVES

We studied the incidence, clinical signs and severity of heart perforations occurring after transvenous pacemaker implantation.

PATIENTS AND METHODS

A series of 16 consecutive cases of heart perforation observed in one cardiac pacing unit from 1989 to 1998 were reviewed.

RESULTS

Heart perforation occurred after implantation in 9 cases; the verall incidence for all lead implantation was 0.57%. The ventricle was perforated in 6 cases, the atrium in 1, and an undetermined site in 2 cases. Active fixation was involved in 5 cases, passive fixation in 4. A bipolar lead was used in 7 cases and a unipolar lead in 2. Heart perforation occurred after prior external stimulation in 7 cases, including one case with tamponnade requiring emergency pericardial drainage after implantation. Repositioning the lead in the ventricle was sufficient in 6 cases and a thoracotomy for an atrial wound was performed in 1 case. Difficulties in right ventricular catheterism due to kyphoscoliosis in elderly subjects was found to be a risk factor.

CONCLUSION

Heart perforation following transvenous pacemaker implantation is an exceptional complication with currently used material. Tamponnade is extremely rare. Besides verifying the mechanical performance of the leads, prevention requires a rigorous protocol for catheterism and wall fixation.

Cholesterol and omega-3 fatty acids inhibit Na, K-ATPase activity in human endothelial cells

We have investigated the effects of cholesterol and omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexenoic acid (DHA) on Na, K-ATPase activity in human endothelial cells (HUVEC). Cultured HUVEC were incubated for 18 h with pure egg phosphatidylcholine (PC), or cholesterol-enriched liposomes (4 mg PC/ml). EPA and DHA alpha-tocopherol-acetate were emulsified with PC and incubated with HUVEC (10 mM). Na, K-ATPase and 5'-nucleotidase activities were determined using the coupled assay method on microsomal fractions obtained from cultured cells using non treated cells as control. Cholesterol enrichment significantly reduced both Na, K-ATPase and 5'-nucleotidase activities by a similar level (- 40%), whereas pure phospholipid liposomes inhibited this activity only by 22%. The dose-response curves of Na, K-ATPase activity were all biphasic assuming the presence of two independent sites exhibiting different affinities for ouabain of nM and microM respectively. The cholesterol induced inhibitory effect was greater for low affinity sites (-54%) as compared to that of the high affinity sites (-24%) whereas omega-3 fatty acids reduced the activity of both sites by 22%. Short term effects of EPA and DHA on Na, K-ATPase activity were determined by incubating microsomal fractions from untreated cells with various concentrations of free fatty acids (from 1 to 200 microM) for 20 min. Both EPA and DHA significantly reduced Na, K-ATPase activity but inhibition by EPA seems to be more effective than DHA. These results suggest that cholesterol and omega-3 fatty acids reduce Na, K-ATPase activity in HUVEC.

Epidemiology and classification of atrial fibrillation

Atrial fibrillation (AF) is a common clinical problem, particularly in the elderly and in patients with organic heart disease. AF generally is classified into paroxysmal and chronic forms. Chronic AF can be the end result of paroxysmal AF in about 30% of patients. Paroxysmal AF can be defined as attacks of arrhythmia lasting < 7 days separated by prolonged periods of sinus rhythm. Chronic AF is AF established for > 7 days. Therefore, the differentiation of paroxysmal from chronic or established AF is based on the history of recurrent episodes and the duration of the current episode of AF. The first episode of persistent AF or the first discovery of AF often is referred to as recent onset AF. Most epidemiologic studies highly underestimate the incidence of paroxysmal and/or asymptomatic AF. The prevalence of AF varies with the age group and patient population studied. AF is found in 3% to 5% of the population > 60 years of age. AF is associated with organic heart disease in 70% to 80% of patients. Of the patients admitted to our Cardiology Division during 1 year, 15% of hospitalized patients had a documented history of AF. The risk of an individual patient developing AF often is difficult to assess, but increasing age and the presence of valvular heart disease and congestive heart failure increase the risk of AF. Other important predictive and causative factors of AF include hypertension, diabetes in women, left ventricular hypertrophy in both sexes, and coronary artery disease, mainly in older patients and patients with left ventricular dysfunction. Other causes of AF include coronary artery disease, hypertrophic cardiomyopathy and dilated cardiomyopathy, chronic obstructive pulmonary disease, pericarditis, and congenital heart disease such as left atrial myxoma and atrial septal. AF can occur in the absence of detectable organic heart disease, so-called "lone AF," in about 30% of cases. The term "idiopathic AF" implies the absence of any detectable etiology including hyperthyroidism, overt sinus node dysfunction, and overt or concealed preexcitation. Stroke is the most important factor of mortality and morbidity associated with AF. These epidemiologic data are essential for designing appropriate therapeutic treatment of this common arrhythmia.