Biomedical subjects
Pierre-Vladimir Ennezat
Publications and source records attributed to Pierre-Vladimir Ennezat.
Momentarily stuck in the foramen ovale.
An 80-year-old woman was admitted for a diagnosis of severe pulmonary embolism. A large serpentine thrombus stuck in a patent foramen ovale (PFO) completely resolved without the patient experiencing any manifestation. The right renal artery was the final destination. Thromboaspiration was unsuccessful. Three months later, the patient was diagnosed with a malignant melanoma and metastatic dissemination.
Endocardial radiofrequency ablation during mitral valve surgery: effect on cardiac rhythm, atrial size, and function.
BACKGROUND: Restoration of sinus rhythm is thought to lead to a reduction in left atrial size and to recovery of atrial contraction. We aimed to investigate changes in atrial size and function in patients undergoing radiofrequency ablation for atrial fibrillation during mitral valve surgery. METHODS: In a prospective study, 70 patients (64 +/- 10 years) with mitral valve disease and atrial fibrillation underwent mitral surgery and left atrial endocardial radiofrequency ablation. Evaluation was achieved before surgery, at 7 days, 5 months, and 22 months after surgery. Maximal right and left atrial areas, left atrial diameter, and volume were measured. Atrial filling fraction (ventricular filling related to atrial contraction to total ventricular filling ratio) was used as an index of atrial contraction. RESULTS: At the end of follow-up (22 +/- 10 months) most patients (91%) were in sinus rhythm. Actuarial freedom from atrial fibrillation recurrence was 62.5% after 2 years. Atrial size decreased, with a significant improvement in right (36 +/- 15 vs 10 +/- 20% preoperatively, p < 0.0001) and left (25 +/- 12 vs 7 +/- 14%, p < 0.0001) atrial filling fraction. Despite similar preoperative atrial size, at the end of follow-up atrial fibrillation recurrence was associated with a higher left atrial volume than in patients free of recurrence (41 +/- 14 vs 32 +/- 9 mL/m2, p = 0.004). Independent predictors of atrial fibrillation recurrence were previous mitral procedure (p = 0.029), left ventricular ejection fraction (p = 0.033), and mitral rheumatic lesion (p = 0.034). CONCLUSIONS: Left atrial radiofrequency ablation for atrial fibrillation during mitral surgery is an effective procedure restoring sinus rhythm. Right and left atrial size was significantly reduced, with a recovery in atrial contraction.
Chordal cutting technique through aortotomy: a new approach to treat chronic ischemic mitral regurgitation.
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The "clover technique" as a new approach for correction of postendocarditic severe tricuspid valve regurgitation.
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Comparative value of Doppler echocardiography and B-type natriuretic peptide assay in the etiologic diagnosis of acute dyspnea.
OBJECTIVES: We compared the accuracy of B-type natriuretic peptide (BNP) assay with Doppler echocardiography for the diagnosis of decompensated congestive left-heart failure (CHF) in patients with acute dyspnea. BACKGROUND: Both BNP and Doppler echocardiography have been described as relevant diagnostic tests for heart failure. METHODS: One hundred sixty-three consecutive patients with severe dyspnea underwent BNP assay and Doppler echocardiogram on admission. The accuracy of the two methods for etiologic diagnosis was compared on the basis of the final diagnoses established by physicians who were blinded to the BNP and Doppler findings. RESULTS: The final etiologic diagnosis was CHF in 115 patients. Twenty-four patients (15%) were misdiagnosed at admission. The BNP concentration was 1,022 +/- 742 pg/ml in the CHF subgroup and 187 +/- 158 pg/ml in the other patients (p < 0.01). A BNP cutoff of 300 pg/ml correctly classified 88% of the patients (odds ratio [OR] 85 [19 to 376], p < 0.0001), but a high negative predictive value (90%) was only obtained when the cutoff was lowered to 80 pg/ml. The etiologic value of BNP was low in patients with values between 80 and 300 pg/ml (OR 1.85 [0.4 to 7.8], p = 0.4) and also in patients who were studied very soon after onset of acute dyspnea. Among the 138 patients with assessable Doppler findings, a "restrictive" mitral inflow pattern had a diagnostic accuracy for CHF of 91% (OR 482 [77 to 3,011], p < 0.0001), regardless of the BNP level. CONCLUSIONS: Bedside BNP measurement and Doppler echocardiography are both useful for establishing the cause of acute dyspnea. However, Doppler analysis of the mitral inflow pattern was more accurate, particularly in patients with intermediate BNP levels or "flash" pulmonary edema.
Role of creatine kinase in cardiac excitation-contraction coupling: studies in creatine kinase-deficient mice.
To understand the role of creatine kinase (CK) in cardiac excitation-contraction coupling, CK-deficient mice (CK-/-) were studied in vitro and in vivo. In skinned fibers, the kinetics of caffeine-induced release of Ca2+ was markedly slowed in CK-/- mice with a partial restoration when glycolytic substrates were added. These abnormalities were almost compensated for at the cellular level: the responses of Ca2+ transient and cell shortening to an increased pacing rate from 1 Hz to 4 Hz were normal with a normal post-rest potentiation of shortening. However, the post-rest potentiation of the Ca2+ transient was absent and the cellular contractile response to isoprenaline was decreased in CK-/- mice. In vivo, echocardiographically determined cardiac function was normal at rest but the response to isoprenaline was blunted in CK-/- mice. Previously described compensatory pathways (glycolytic pathway and closer sarcoplasmic reticulum-mitochondria interactions) allow a quasi-normal SR function in isolated cells and a normal basal in vivo ventricular function, but are not sufficient to cope with a large and rapid increase in energy demand produced by beta-adrenergic stimulation. This shows the specific role of CK in excitation-contraction coupling in cardiac muscle that cannot be compensated for by other pathways.
Different effects of mibefradil and amlodipine on coronary vessels and during beta-adrenergic stimulation in conscious dogs.
Coronary effects of Ca -channel blockers mibefradil and amlodipine were compared in conscious dogs. Ten dogs were instrumented for measurement of aortic and left ventricular pressures, circumflex coronary blood flow velocity (CBFv), and coronary diameter (CD). A permanent catheter was implanted in the circumflex coronary artery. At doses having no systemic effects (7.5-150 micro g/kg), mibefradil and amlodipine increased CBFv and CD dose dependently. At the same dose, mibefradil increased less CBFv than amlodipine. However, for a similar increase in CBFv induced by amlodipine, mibefradil increased CD more. BAY K8644, an L-type Ca -channel agonist, prevented the CBFv and CD responses to amlodipine, but minimally affected the coronary responses to mibefradil. Intracoronary isoproterenol (6 ng/kg) increased LV dP/dt max, CBFv, and CD. Amlodipine markedly altered these responses, while mibefradil did not affect LV inotropic response and slightly altered CBFv response to isoproterenol. Thus, in conscious dogs, both mibefradil and amlodipine exert coronary vasodilation, with different patterns on coronary conductance and resistance vessels and during beta-adrenergic stimulation. These differences could be related to their actions on different Ca channels.
[What is the place of beta-adrenergic blockade therapy in coronary syndromes in the modern management era?].
This paper shows the eventual benefits of treatment with beta-blockers in post-myocardial infarction. An overview of main clinical trials that have been conducted to test this therapeutic in acute coronary syndrome. In patients presenting with acute myocardial infarction, the early use of intravenous beta-blockers had shown a modest and non significant reduction in mortality. Substantial reductions in mortality and reinfarction have been demonstrated when beta-blockers have been used soon after an acute myocardial infarction and continued long-term. However, these benefits were observed in randomised clinical trials conducted in the 1970s and 1980s, prior to the widespread use of reperfusion therapies and antiplatelet agents. It appears obvious that the long-term use of beta-blockers may be questionable after any acute coronary syndrome especially if complete reperfusion has been achieved and left ventricular function is preserved.
[Is there a role for calcium antagonists when beta-adrenergic blockade therapy is contraindicated in post-myocardial infarction?].
The purpose of this paper is to examine the eventual benefits of treatment with calcium channel blockers in post-myocardial infarction, through an overview of main placebo-controlled trials that have been conducted to test this therapeutic in acute coronary syndromes. It appears obvious that the vast majority of these trials was conducted in the pre-reperfusion era and failed to demonstrate a reduction in mortality. To conclude, the superiority of a therapy with calcium antagonists over a placebo in the management of post-myocardial infarction remains unknown. In contrast, adverse effects associated with the prescription of calcium antagonists are well known.