Daniel Grandmougin

Systemic Infection Related to Endocarditis on Pacemaker Leads Clinical Presentation and Management

BACKGROUND Endocarditis related to pacemaker (PM)-lead infection is a rare but serious complication of permanent transvenous pacing. To determine in which situations the diagnosis should be evoked and to determine optimal management, we reviewed our experience with endocarditis related to PM-lead infection. METHODS AND RESULTS Fifty-two patients were admitted for endocarditis related to PM-lead infection. The presentation was acute in 14 patients, with onset of symptoms in the first 6 weeks after the last procedure on the implant site, and chronic in 38 patients. Fever occurred in 86.5%. Clinical and/or radiological evidences of pulmonary involvement were observed in 38.4%. Pulmonary scintigraphy disclosed pulmonary infarcts in 31.2%. Local complications were found in 51.9%. Elevated C-reactive protein was found in 96.2%. A germ was isolated in 88.4% of patients and was a Staphylococcus in 93.5%. Transthoracic echocardiography demonstrated vegetations in only 23% of patients, whereas transesophageal echocardiography disclosed abnormal appearances on the PM lead in 94%. We systematically tried to ablate all the material. Two techniques were used: percutaneous ablation or surgical removal during extracorporeal circulation. All patients were treated with antibiotics after removal of the infected material. Two patients died before lead removal and 2 after surgical removal; the predischarge mortality was 7.6%, and the overall mortality was 26.9% after a follow-up of 20.1+/-13 months. CONCLUSIONS The diagnosis of endocarditis related to PM-lead infection should be suspected in the presence of fever, complications, or pulmonary lesions after PM insertion. Transesophageal echocardiography should be performed to look for vegetations. Staphylococci are involved in the majority of these infections. The endocardial system must be entirely removed and appropriate antibiotic therapy pursued for 6 weeks.

Total orthotopic heart transplantation for primary cardiac rhabdomyosarcoma: factors influencing long-term survival

BACKGROUND Primary cardiac sarcomas are uncommon and rare, with an unequal distribution in the population. A dismal prognosis is usually admitted that is related to a high propensity to develop distant metastasis with survival rarely exceeding 2 years. We report a case of a patient with a primary cardiac rhabdomyosarcoma characterized by an exceptional long-term survival after surgical treatment by a total orthotopic heart transplantation. From this limited experience, we reviewed factors that may influence survival to optimize therapeutic strategy. METHODS A 33-year-old man was found to have a 10-cm primary cardiac rhabdomyosarcoma located in the right atrium and extending to the atrioventricular groove; therefore, resection was not possible. Since no metastases were detected, the patient was scheduled for urgent cardiac transplantation, which was performed after adjuvant radiotherapy. RESULTS Postoperative outcome was uneventful and the patient is still alive, with regular follow-up, at 102 months. CONCLUSIONS In a case of primary rhabdomyosarcoma, heart transplantation, despite immunosuppressive therapy, can provide long-term survival and can be considered for selected patients after rigorous analysis of predictors of survival.

Paroxysmal postural dyspnea related to a left atrial ball thrombus

We report herein an uncommon clinical observation of a 82-year-old woman with paroxysmal postural dyspnea related to a giant ball-thrombus located in the left atrium and partly protruding through the mitral orifice. No mitral stenosis was otherwise disclosed. The patient had a previous medical history of chronic atrial fibrillation without any anticoagulant therapy. The atrial mass was easily removed and the postoperative course was uneventful. Disclosure of such a free-floating ball-thrombus in the left atrial cavity requires prompt surgical treatment because of high risks of acute hemodynamic decompensation due to obstruction of the left ventricular inflow or, more rarely, systemic embolic events.

Factors affecting epicardial dispersion of repolarization: a mapping study in the isolated porcine heart

OBJECTIVE Non-uniform drug-induced prolongation of repolarization predominating in the midmyocardial (M) cell layers has been shown to be responsible for perpetuation of reentry, giving rise to torsade de pointes. However, the absence of M cells in immature animals, especially the pig, suggests other possible underlying mechanisms. We sought to examine, in this species, the effects of predisposing factors to torsade de pointes on the dispersion of epicardial repolarization and their contribution to arrhythmogenesis. METHODS Computerized mapping of repolarization and activation was conducted on the epicardial surface in 29 Langendorff-perfused hearts of eight-week-old pigs. Activation-recovery intervals were measured simultaneously from 128 unipolar electrograms. RESULTS Baseline iso-interval maps were dipolar (41%) or multipolar (59%). Dispersion of repolarization was reverse frequency-dependent but was unaffected by lowering [K+]o. DL-Sotalol (0.1 mmol/l) reinforced local gradients and thus increased epicardial dispersion, whereas intramural recordings did not demonstrate any predominant effect in midmyocardial layers. Phenylephrine (1 mumol/l) notably augmented DL-sotalol effects. After [Mg++]o lowering, although dispersion was not significantly increased, DL-sotalol was associated with the spontaneous occurrence of polymorphic ventricular tachycardia in seven out of nine experiments. When maps of repolarization of escape beats were compared with activation maps of first arrhythmic beats, an arc of functional dissociation was observed in the vicinity of a steep gradient of repolarization in two out of nine tachycardias. CONCLUSION Epicardial dispersion of repolarization is increased by slow rates, DL-sotalol and phenylephrine but is not the only requirement for initiation of polymorphic ventricular tachycardia. In combination with other factors, it helps continuation of the arrhythmia in this model.

Ventricular tachycardia originating from the posteroseptal process of the left ventricle with inferior wall healed myocardial infarction

Ventricular tachycardia (VT) substrates may form in preferential locations and similar electrocardiographic patterns may be observed when ventricular activation starts from a particular site. We examined the role of the posterior inferior process of the left ventricle in the mechanism of VT occurring after inferior wall myocardial infarction. We reviewed isochronal maps of 40 VTs obtained at surgery in 13 patients, with a 128-electrode system using epicardial sock and endocardial balloon electrode arrays. Based on the epicardial to left endocardial relation we observed 7 tachycardias in 7 patients with onset of activation over the crux of the heart. This activation mimicked excitation through a posteroseptal accessory pathway. Endocardial activation maps showed breakthroughs occurring 6 to 40 ms later and did not give evidence in favor of macroreentry. In all but 1 VT, left-axis deviation was present (-30 to -75 degrees) with a positive concordance from leads V2 to V6 (QRS wave patterns were variable in V1). These tachycardias, which were clinical in 3 of 7 cases, were interpreted as arising from the posterior inferior process of the left ventricle and successfully ablated by left septal and epicardial cryolesions. In another patient, this concept was further validated by percutaneous radiofrequency ablation of a tachycardia with the previously described morphology. In conclusion, VT may originate from the posteroseptal process of the left ventricle with inferior wall healed myocardial infarction. Because these tachycardias can be successfully eliminated, their characteristic morphologies may provide clinical markers for the identification of patient candidates to surgical or nonsurgical ablative therapy.

Clarithromycin reduces Isus and Ito currents in human atrial myocytes with minor repercussions on action potential duration.

The macrolide antibacterial agent clarithromycin has been shown to cause QT interval prolongation on the electrocardiogram. In rabbit heart preparations clarithromycin (concentration dependently) lengthened the action potential duration and blocked the delayed rectifier current. The aim of the present study was to investigate the clarithromycin effects: (i) on the Ca2+ L‐type and the main K+ repolarizing currents on human atrial myocytes, using whole‐cell patch clamp recordings and (ii) on action potentials recorded from human atrial and ventricular myocardium using conventional microelectrodes. It has been found that (i) 10–30 μm clarithromycin reduced the sustained current Isus significantly and that a 100 μm concentration was needed to cause a significant reduction in the transient outward current Ito, whereas clarithomycin did not affect the calcium current and (ii) clarithromycin (10–100 μm) prolonged the action potential duration in atrial preparations but did not alter the different parameters of the ventricular action potential. It is concluded that clarithromycin exerts direct cardiac electrophysiological effects that may contribute to pro‐arrythmic potential.

Aortic root replacement with a pulmonary autograft in young adults: medium-term results in 70 patients

BACKGROUND Pulmonary autograft aortic valve replacement has been introduced in our institution in selected adult patients in light of the known disadvantages and limitations of conventional prosthetic valves. METHODS We prospectively evaluated the use of the pulmonary autograft in a series of 70 young adults (31.2+/-8.7 years, range 16 to 49 years) operated on from March 1992 to April 1997 with aortic root replacement only. RESULTS There were no in-hospital deaths and two noncardiac-related late deaths during follow-up of up to 62 months (mean 33 months). Thromboembolic complications were not observed. One patient required reoperation for infective endocarditis 4.3 years after surgery. Discharge echo-Doppler studies showed normal autograft and allograft valve function. Serial echo-Doppler studies showed no significant progression of aortic insufficiency and no dilatation of the autograft. A severe stenosis of the pulmonary allograft developed in 1 patient. CONCLUSION Aortic root replacement with a pulmonary autograft, although more complex than conventional prosthetic valve replacement, is a safe, effective, and reproducible procedure in properly selected adult patients. Long-term results remain to be evaluated.

Identification of ventricular tachycardia of epicardial origin from unipolar potentials obtained at the endocardial surface: Is it feasible?

LACROIX, D., et al.: Identification of Ventricular Tachycardia of Epicardial Origin from Unipolar Potentials Obtained at the Endocardial Surface: Is It Feasible? VT late after myocardial infarction usually originates from the endocardial surface; subepicardial substrates are also possible. The identification of these atypical locations with endocardial mapping remains unresolved even with new mapping technologies. This study compared isopotential maps, signal morphology, and activation patterns around left endocardial breakthroughs recorded in VTs originating from the subepicardium or subendocardium after remote myocardial infarction. These results were extracted from a database of 111 tachycardias obtained at surgery in 34 patients. Mapping was performed with a 128‐unipolar electrode system using an epicardial mesh and a left ventricular endocardial balloon. Subepicardial (n = 7) and subendocardial VTs (n = 10) were defined as complete superficial reentry and/or as tachycardias with a ≥ 25‐ms delay between the earliest activity and the breakthrough of activation on the opposite surface. A positive potential distribution covering the area of initial endocardial activity was observed in a single subepicardial VT but in none of the subendocardial ones (P = NS). R waves were observed on the earliest endocardial unipolar signals in two subepicardial VTs and five subendocardial VTs (P = NS). The area covered by the first 5‐ms or 10‐ ms isochrone at the endocardial level was larger in subepicardial VTs than in subendocardial VTs but the difference was not significant. In conclusion, despite a wider endocardial area of early activity in VTs of subepicardial origin, no reliable criteria can be proposed to identify these tachycardias from mapping data restricted to the endocardial surface. This is probably due to highly nonuniform anisotropic propagation around the scarred tissue.

Failure of Marfan anatomic criteria to predict risk of aortic dissection in Turner syndrome: necessity of specific adjusted risk thresholds†

Patients with Turner syndrome are prompt to develop spontaneous acute aortic dissection following insidious aortic dilatation, with abnormal cardiovascular anatomy and consequently require specific guidelines for regular surveillance since they represent a subset of high-risk young patients. We report a rare and uncommon case of spontaneous acute aortic dissection in a 48-year old female patient with Turner syndrome who was not apparently eligible for a prophylactic surgery. A CT scan showed a Stanford type A aortic dissection and was urgently referred for surgical management. We operated on the patient under deep hypothermia (18°C) and circulatory arrest with a retrograde cerebroplegia as the primary entry tear was located in the arch. The postoperative course was uneventful and the patient was discharged at the eighth postoperative day. Following description of this case, special attention was paid to determine predisposing risk factors for aortic dissection to be specifically adjusted to TS patients.

Chronic amiodarone effects on epicardial conduction and repolarization in the isolated porcine heart.

Amiodarone is a potent antiarrhythmic agent with complex chronic effects, notably on repolarization and conduction, that are not fully understood. Its low arrhythmogenic potential has been related to a lack of increase in repolarizution dispersion. Since its effects are not documented in pigs we conducted a mapping study of activation and repolarization in isolated perfused porcine hearts. Amio20 female pigs (n = 7) received amiodarone 20 mg/kg per day over 4 weeks while Amio 5O female pigs (n = 7) received 50 mg/kg per day over 4 weeks. Concentrations of the drug encompassed values found in clinical studies. Then, activation patterns and activation‐to‐recovery intervals (ARI) were mapped epicardially from 128 unipolar electrograms in isolated perfused hearts in corroboration of epicardial action potential recordings. Mean ARI was longer in Amio20 experiments compared to the seven control hearts (325 ±11 ms vs 288 ± 5 m.s at 1,000 ms), whereas ARI dispersion was not different, being comprised between 7 and 11 ms and generating smooth gradients. In Amio5O experiments, mean ARI was further prolonged (390 ±10 ms at 1,500 ms) with an exaggerated reverse rate dependence concomitant with a depressant effect on the plateau of the action potential. Again, ARI dispersion did not differ from controls. Finally, the drug depressed the maximal rate of depolarization (Vmax) and slowed conduction in a rate dependent and concentration dependent fashion. In conclusion, chronic amiodarone induces Class I and Class HI antiarrhythmic effects in ventricular porcine epicardium that are concentration dependent but does not affect dispersion of repolarization. This may partly explain its low arrhythmogenic potential.