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Biomedical subjects

J C Deharo

Publications and source records attributed to J C Deharo.

At least 19 recordsLinked to original sources
PubMed2003

[The best of arrhythmias in 2002].

In the era of evidence based medicine the year 2002 will be remembered principally for having brought the results of two large trials in areas of daily preoccupation for rhythmologists: those of atrial fibrillation and of prevention of rhythmic sudden death. The Atrial Fibrillation Following Investigation of Rhythm Management (AFFIRM) study compared strategies for controlling frequency and rhythm in atrial fibrillation for subjects aged over 65 years or having at least one risk factor for cerebral vascular accident. In an unexpected fashion, although in accordance with other recent results, the two strategies are equivalent in terms of mortality. It also underlined the necessity of continuing anticoagulation with an INR > 2. even when it is proposed to maintain the rhythm. In the matter of primary prevention of sudden coronary death, the Multicenter Automatic Defibrillator Implantation Trial II (MADIT II) had the originality of evaluating patients with no other risk factor than a severe alteration in left ventricular ejection fraction (30% Pounds). This "simple" selection of patients at risk allowed a mortality reduction of 30% to be demonstrated by the placement of a ventricular defibrillator, in addition to that brought about by optimal conventional treatment. In the chapter on syncope, the Framingham study delivers information in terms of incidence and long term prognosis, in a non selected population. Even if these results are difficult to compare with those recent studies using notably the inclination test, they remind us of the poor prognosis of cardiac origin syncope and the absence of excess mortality in patients affected by vagal syncope. The significance of these very wide series does not preclude drawing the greatest attention to the work by the Bordeaux team who have been able to provide evidence, in 27 patients with relapsing idiopathic ventricular fibrillation, of the initiator role of extra-systoles originating from the distal Purkinje network. A medium term cure was obtainable by ablation of these extra-systoles. This work of course allows the prospect of application to other types of malign ventricular arrhythmias.

Anticoagulants↗
PubMed2002

The effects of antimalarial drugs on ventricular repolarization.

Cardiotoxicity has become a major concern during treatment with antimalarial drugs. Lengthening of the QTc and severe cardiac arrhythmia have been observed, particularly after treatment with halofantrine for chloroquine-resistant Plasmodium falciparum malaria. The purpose of this prospective study was to evaluate whether antimalarial agents alter dispersion of the QTc and ventricular repolarization dynamicity. Sixty patients with uncomplicated falciparum malaria were randomly allocated in four groups of 15 patients and treated with quinine, mefloquine, artemether, or halofantrine at recommended doses. Patients in treatment groups were compared with a group including 15 healthy controls with no history of malaria and/or febrile illness within the last month. QTc dispersion was measured on surface electrocardiograms. Repolarization dynamicity was analyzed from Holter recordings, which allow automatic beat-to-beat measurement of QT and RR intervals. Plasma drug concentration was determined by reversed-phase high-performance liquid chromatography. No change in QTc dispersion was observed after treatment with quinine, mefloquine, or artemether. Treatment with halofantrine was followed by a significant increase in QTc dispersion at 9 hours (P < 0.0001) and 24 hours (P < 0.01). Assessment of QT heart rate variability by QT/RR nychtohemeral regression slope demonstrated no significant difference between the artemether (mean +/- SEM = 0.170 +/- 0.048), mefloquine (0.145 +/- 0.044), and the control groups (0.172 +/- 0.039). A significant decrease in the Q-eT/RR slope was observed in the quinine group compared with the control and artemether groups (0.135 +/- 0.057; P < 0.04). With halofantrine, a significant increase in the QT/RR regression slope (0.289 +/- 0.118) was observed (P < 0.0002). QTc interval, QT dispersion, and QT regression slope were significantly correlated with halofantrine and quinine plasma concentration. Mefloquine and artemether did not alter ventricular repolarization. Quinine induced a significant decrease in QT/RR slope of the same order of magnitude as those previously observed with quinidine. Both QTc dispersion and QT/RR slope were significantly modified by halofantrine. These repolarization changes were related to a class-III antiarrhythmic drug effect and may explain the occurrence of ventricular arrhythmia and/or sudden deaths reported after halofantrine intake.

Adult↗
PubMed2000

Continuous monitoring of an endocardial index of myocardial contractility during head-up tilt test.

BACKGROUND: Previous studies suggest that vigorous myocardial contractions stimulate ventricular mechanoreceptors and lead to vasovagal syncope. We studied an endocardial index of myocardial contractility during the head-up tilt test in vasovagal patients and control patients, and we evaluated the effect of negative inotropic drugs on myocardial contractility and tilt test outcome. METHODS AND RESULTS: We investigated 19 patients with recurrent vasovagal syncope and positive tilt test (group 1) and 11 patients with no syncope and negative tilt test (group 2). Myocardial contractility was continuously measured during a tilt test (60 degrees ) through a microaccelerometer incorporated in the tip of a right ventricular electrode to sense left ventricular contractility. Patients in groups 1 and 2 were evaluated during an unmedicated tilt test, and patients in group 1 were reevaluated during a tilt test with infusion of esmolol (n = 10) or disopyramide (n = 9). During the unmedicated test, patients in group 1 exhibited a significant increase in myocardial contractility immediately on postural change (P <.05), unlike patients in group 2. Patients in group 1 also had a further increase in myocardial contractility before the end of tilt (P <.01). With drug administration, the changes in supine myocardial contractility were nonsignificant and were not related with the outcome of the tilt test (P <.05). CONCLUSIONS: An increase in myocardial contractility is detected by the sensor during the tilt test. The changes induced by the drugs on supine myocardial contractility are minor and not related with the outcome of the head-up tilt test.

Adrenergic beta-Antagonists↗
PubMed2000

His-Purkinje system reentry as a proarrhythmic effect of flecainide.

We report a case of tachycardia due to reentry within the His-Purkinje system (HPS) occurring after introduction of flecainide. The patient presented with a mild mitral regurgitation and normal left ventricular function. He had incomplete left bundle branch block with left-axis deviation. At the electrophysiology study, a prolonged HV interval was observed at baseline, and the tachycardia could be reproduced after ajmaline infusion. Six months after interruption of flecainide, the patient remains free of arrhythmia recurrence. The authors emphasize that proarrhythmic effects of flecainide may include reentry within the HPS in patients with underlying HPS disease.

Administration, Oral↗
PubMed2000

Near fatal electrical storm in a patient equipped with an implantable cardioverter defibrillator for Brugada syndrome.

A patient with Brugada syndrome experienced incessant ventricular fibrillation 7 years after implantation of an ICD. General anesthesia, fast ventricular pacing, bretylium, and atenolol infusion were ineffective; amiodarone infusion was started. After 190 defibrillation shocks over 36 hours, the electrical storm stopped. A multiorgan failure occurred as a complication of the electrical storm and necessitated prolonged reanimation. Thorough cardiac evaluation revealed no structural abnormality and the patient, now on chronic oral amiodarone therapy, remains free of arrhythmia 1 year after the event.

Adult↗
PubMed2000

[The best of cardiac pacing in 1999].

Since the first clinical application to man forty years ago, for the treatment of bradycardia, cardiac pacing has been the object of continuous technological innovation in parallel with those in electronics and computerisation. However, independently of these expected advances, there has been a surprising widening of the field of application of pacing into those of haemodynamics and rhythmology. The recent publication of the long-term results of the Pacing in Cardiomyopathy (PIC) study confirmed the sustained decrease of intraventricular pressure gradient, of NYHA functional stage and improved quality of life of patients with hypertrophic obstructive cardiomyopathy paced in the DDD mode. The investigators also underlined the placebo effect of the pacemaker. The decrease in risk of sudden death and the reduction in ventricular remodelling have not been demonstrated yet. More recently, biventricular pacing has been proposed for the treatment of dilated cardiomyopathy and a French study showed a long-term improvement in NYHA stage and effort capacity. Several prospective randomised trials are under way to validate this indication. Acute haemodynamic evaluations have confirmed the efficacy of biventricular stimulation but also underline the value of left ventricular pacing alone. The effects on mortality, the selection of patients and the optimal configuration of pacing remain to be defined. In the field of prevention of atrial arrhythmias, the results of the multicenter SYNBIAPACE study, investigating biatrial pacing in patients with interatrial conduction defects, only showed a tendency to an increase in the delay before recurrence of atrial fibrillation. The value of the memory functions of pacemakers and the algorithms of prevention of atrial arrhythmias are still under investigation. Haemodynamic transducers have been introduced in some recent pacemakers to assess myocardial contractility and have applications in the evaluation of different pacing modes and in the optimisation of the atrioventricular interval. Their value in the treatment of neurocardiogenic syncope is under evaluation. In conclusion, it is not overoptimistic to imagine that, in the near future, the cardiac pacemaker will be part of a "control and treatment system" well over the limits of treating patients with bradycardia.

Cardiac Pacing, Artificial↗
PubMed2000

[Left bundle branch block. Electrocardiographic and prognostic aspects].

The concept of left bundle branch block (LBBB) was recognised at the beginning of the 20th century but confusion, due to the extrapolation data from animal experimentation, persisted for many years between the electrocardiographic appearances of LBBB and right bundle branch block (RBBB). The typical appearances of LBBB are now well known and consist of: 1) increased duration of the QRS complex > 0.12 seconds; 2) a wide, exclusive R wave with a plateau or notched summit in the left precordial leads and usually in D1 and aVL; 3) an important delay in the intrinsecoid deflection in the left precordial leads (0.08 to 0.12 seconds after the onset of QRS); 4) an axis of repolarisation opposite that of the QRS complex with so-called "secondary" abnormalities. The authors emphasise that some electrocardiographic variants carry a poor prognosis, in particular those with major QRS axis deviation to the left or, much less commonly, to the right. The diagnosis of left ventricular hypertrophy is possible in cases of LBBB by using the criteria of QRS amplitude in the left precordial leads. On the other hand, the diagnosis of myocardial infarction is more difficult, the criteria being very specific but having a sensitivity < 50%. The deleterious effects of LBBB on the haemodynamics are well known but their study has become a new firld of research since the introduction of bi-ventricular pacing for the treatment of cardiac failure. In dilated cardiomyopathy, LBBB increases the duration of functional mitral regurgitation and decreases left ventricular filling times. The prognostic implications of LBBB have been the object of many studies: the reports in the literature indicate a large increase in mortality when LBBB develops in patients over 44 years of age. The progression to complete atrioventricular block is common only when the HV interval exceeds 100 ms. In other cases, the prophylactic implantation of a cardiac pacemaker does not improve the prognosis which depends on the severity of the underlying cardiac disease.

Bundle-Branch Block↗
PubMed2000

[Hospital management of atrial fibrillation. Epidemiologic data and therapeutic strategy. Report of 100 consecutive patients].

Despite recent large scale trials, the management of atrial fibrillation remains very variable. The authors report the results of a prospective study of the management of atrial fibrillation in their department. One hundred consecutive patients admitted for atrial fibrillation were included in the study. The epidemiological and clinical data and the results of the therapeutic strategy were recorded prospectively. Three embolic complications occurred before hospital admission. The hospital stay was marked by spontaneous reduction of atrial fibrillation in 14 cases in the 6 hours following admission. The therapeutic strategy was the following: 40 arrhythmias were respected (well tolerated, > 1 year or with a left atrium 60 mm). Oral amiodarone (30 mg/Kg and 15 mg/Kg the next day) was given to 22 patients. Only 9 patients (41%) were converted (average delay of 12 hours). Four patients received intravenous amiodarone, reducing two arrhythmias. Twenty patients were treated by external electrical cardioversion of first intent and 14 after failure of pharmacological reduction. All of these procedures, early (after 48 hours anticoagulation and transoesophageal echocardiography), or late (after 1 month of anticoagulation), restored sinus rhythm without complications, especially embolic. This register showed a relatively low efficacy of oral amiodarone in the reduction of atrial fibrillation and underlines the efficacy and safety of external electrical cardioversion, even when performed early.

Administration, Oral↗
PubMed2000

[Pacemaker syndromes].

The pacemaker syndrome refers to symptoms and signs in pacemaker patients caused by inadequate timing of atrial and ventricular contractions. The lack of normal atrioventricular synchrony may result in decreased cardiac output and increased in atrial pressure which elicits a systemic hypotensive reflex response. These hemodynamic disturbances mostly occur in the presence of retrograde VA conduction is present. The incidence of pacemaker syndrome is uncertain, and varies from 7% to 20% of all ventricular paced patients. Neurologic symptoms or symptoms suggesting low cardiac output or congestive heart failure are indicative of the pacemaker syndrome. These symptoms may vary from mild to severe, they are nonspecific and very common among cardiac patients with or without pacemaker. In many patients they are not even noted until AV synchrony is restored. The pacemaker syndrome is not restricted to the VVI stimulation mode. It can be seen, though rarely, in atrial and even dual-chamber pacing (VDD, DDI, DDD). In these cases it is usually occasional and may be due to inappropriate programming or selection of the pacing mode.

Heart Diseases↗
PubMed1999

Quality of life in patients with complete heart block and paroxysmal atrial tachyarrhythmias: a comparison of permanent DDIR versus DDDR pacing with mode switch to DDIR.

A prospective double-blind randomized crossover study was done in 15 patients with complete heart block and intermittent ATs. The pacemaker was randomly programmed to dual chamber inhibited rate responsive pacing (DDIR) and to DDDR with mode switch, for 1 month each. An event recorder was given to the patients and after each period, a QOL questionnaire was obtained. Based on telemetric data, all but two patients had AT during follow-up. The duration and frequency of these episodes were not related to mode settings. AV synchrony was better preserved in DDDR (P < 0.05). Most symptom-related event recordings during DDIR showed loss of AV synchrony; DDDR with mode switch caused symptoms due to tracking of ST. Overall the QOL score was not different between the modes. Fewer somatic complaints were noted during DDDR pacing than during baseline. DDIR stimulation showed no difference. Twelve patients preferred the period of DDDR pacing; one experienced severe symptoms during DDIR. In conclusion, patients with paroxysmal AT, DDDR with mode switch, and DDIR had no influence on the occurrence, nor on the duration of AT episodes. AV synchrony was better preserved in DDDR, which was also associated with fewer somatic complaints compared to the baseline. In DDDR, symptoms were observed when ST was tracked. QOL was comparable, although more patients preferred DDDR.

Adult↗
PubMed1998

Right- and left-sided interatrial septal aneurysm mimicking atrial tumor and stroke.

We report the cases of two patients with cerebral embolization and interatrial septal aneurysm. Transesophageal echocardiography required for stroke showed right-sided interatrial septal aneurysm in the first patient and left-sided interatrial septal aneurysm in the second. In the two patients, interatrial septal aneurysm was mimicking atrial cystic tumor or abscess. Significant internal carotid artery stenosis was found in the first patient and aortic arch atheroma with mobile components but no patent foramen ovale in the second patient. In the two patients, interatrial septal aneurysm appears to be only an incidental finding and not the true cause of stroke. Furthermore, we discuss the differential diagnoses of atrial masses.

Aged↗
PubMed1998

Giant interatrial septal aneurysm mimicking a right atrial tumor.

We report the case of a patient with a giant interatrial septum aneurysm who was admitted to our hospital for analysis of palpitations. Transthoracic echocardiography was not contributive and cardiac magnetic resonance imaging demonstrated a small interatrial septal aneurysm. In our study, only transesophageal echocardiography provided the correct diagnosis, showing a giant interatrial septal aneurysm protruding far away into the right atrium and mimicking a right atrial cystic tumor.

Diagnosis, Differential↗
PubMed1998

Treatment of malignant primary vasodepressive neurocardiogenic syncope with a rate responsive pacemaker driven by heart contractility.

In a 41-year-old man suffering from frequent syncope, the tilt test reproducibly induced a primary vasodepressive neurocardiogenic syncope. Pharmacotherapy either failed to prevent the syncope induced at the tilt test or was poorly tolerated. In the minutes preceding the syncope, a dramatic increase in heart contractility was sensed by a microaccelerometer located at the tip of a right ventricular pacing electrode. When the tilt test was repeated with the pacemaker programmed in the DDDR mode, high rate dual chamber pacing occurred during the tilt phase and prevented the syncope. Three months after implantation, the patient remains totally symptom free.

Adult↗
PubMed1998

A sensor-based evaluation of heart contractility in patients with head-up tilt-induced syncope.

Studies using the head-up tilt test (HUT) suggest that a reflex increase in sympathetic activity resulting in vigorous myocardial contractions precedes neurally-mediated syncope (NMS). The aim of this study was to evaluate heart contractility changes during positive HUT. Ten patients with recurrent NMS and positive HUT were investigated. Before HUT we temporarily placed a standard right ventricular pacing electrode incorporating in its tip a recently developed microaccelerometer (Sorin Biomedica, Italy) that measures the peak endocardial acceleration (PEA) during the isovolumetric phase as an index of heart contractility. PEA potential amplitude, heart rate and mean blood pressure were continuously studied during HUT. Syncope occurred 16.7 +/- 10.3 min after 60 degrees tilt, either at baseline (8 patients) or after sublingual nitrate administration (2 patients). PEA value was stable at 0.62 +/- 0.34 (1G = 9.8 m/sec2) during the supine phase. It slightly increased to 0.72 +/- 0.44 G (p = NS) during the first minutes of 60 degrees tilt and then remained unchanged until a further increase of 71 +/- 79% (range 10 to 266%) as compared to tilt value (p = 0.004) at 2.8 +/- 2.4 min (range 0.25 to 6.5 min) before the syncope in 9 patients. The latter increase was not observed in the patient with dilated cardiomyopathy. In conclusion, a significant increase in heart contractility was observed in 9 patients in the minutes preceding HUT-induced NMS. These changes might be used for driving a rate adaptive pacemaker when cardiac pacing is indicated to prevent NMS.

Electrodes, Implanted↗
PubMed1998

Multisite pacing as a supplemental treatment of congestive heart failure: preliminary results of the Medtronic Inc. InSync Study.

This report describes the initial results of the "InSync" study, a European and Canadian multicenter trial that examines the safety and efficacy of a multisite pacemaker (Medtronic InSync) and of left ventricular pacing leads (Medtronic 2187 and 2188) implanted via a cardiac vein as a supplemental treatment of refractory congestive heart failure. Over a 10-month period, the system was implanted successfully in 68 of the 81 (84%) patients who had been enrolled in the study. The 68 patients were, on average, 66 +/- 10 years old, had a mean left ventricular ejection fraction (LVEF) = 21% +/- 9%, and 63% were in NYHA functional Class III and 37% were in Class IV. No system implant related complication occurred. During follow-up, 7 of 10 patients who exited the study had died, 4 suddenly. There was a clinical benefit among surviving patients, which was corroborated by a significant improvement in NYHA functional class and in the Minnesota Living with Heart Failure Quality of Life Questionnaire Score (MLS) and by a longer distance covered during a 6-minute walk test. This clinical improvement was associated with a significant narrowing of the paced QRS complex during biventricular pacing, a significant decrease in the interventricular mechanical delay, and a trend towards an increase in the duration of ventricular filling. These encouraging preliminary results confirm the feasibility and reliability of this new multisite pacing system in the management of dilated cardiomyopathy and support the continuation of further evaluations of this complementary treatment of refractory congestive heart failure.

Aged↗