Fibrillation atriale (de la physiopathologie aux traitements actuels)

La fibrillation atriale (FA) est le trouble du rythme cardiaque le plus fréquent et dont la prévalence est en constante augmentation. Les extrasystoles déclenchant cette arythmie naissent le plus souvent des veines pulmonaires. Ainsi l ablation des veines pulmonaires est devenue un traitement important de cette arythmie, surtout quand elle est paroxystique. Cependant le maintien de la FA est assuré par du substrat atrial pathologique.Le traitement endocavitaire de ce substrat comprend essentiellement l ablation de potentielsfragmentés enregistrés en FA.Nous avons démontré que ces potentiels fragmentés existent aussi en rythme sinusal etqu une partie de ces potentiels pouvait être générée par une activation vagale myocardiquelocale.Par ailleurs cette ablation de FA présente de nombresuses complications dont certaines sont potentiellement graves comme par exemple la tamponnade.Nous avons montré que la ponction transseptale nécessaire pour réaliser cette intervention pouvait être effectuée de manière sure en utilisant un monitorage du septum interatrial parechocardiographie endovasculaire utilisée par voie oesophagienne, diminuant ainsi le risque de tamponnade.Nous avons aussi montré que la présence d une récidive d arythmie précoce (21 mois et une amplitude de l onde fibrillatoire < 0.07 mV étaient des facteurs importants d échec d ablation de FA persistante.Pas de résumé anglaisPARIS-EST-Université (770839901) / SudocPARIS12-Bib. électronique (940280011) / SudocSudocFranceF

Development of a human model for the study of effects of hypoxia, exercise, and sildenafil on cardiac and vascular function in chronic heart failure

Background: Pulmonary hypertension is associated with poor outcome in patients with chronic heart failure (CHF) and may be a therapeutic target. Our aims were to develop a noninvasive model for studying pulmonary vasoreactivity in CHF and characterize sildenafil's acute cardiovascular effects. Methods and Results: In a crossover study, 18 patients with CHF participated 4 times [sildenafil (2 × 20 mg)/or placebo (double-blind) while breathing air or 15% oxygen] at rest and during exercise. Oxygen saturation (SaO2) and systemic vascular resistance were recorded. Left and right ventricular (RV) function and transtricuspid systolic pressure gradient (RVTG) were measured echocardiographically. At rest, hypoxia caused SaO2 (P = 0.001) to fall and RVTG to rise (5 ± 4 mm Hg; P = 0.001). Sildenafil reduced SaO2 (−1 ± 2%; P = 0.043), systemic vascular resistance (−87 ± 156 dyn·s−1·cm−2; P = 0.034), and RVTG (−2 ± 5 mm Hg; P = 0.05). Exercise caused cardiac output (2.1 ± 1.8 L/min; P &lt; 0.001) and RVTG (19 ± 11 mm Hg; P &lt; 0.0001) to rise. The reduction in RVTG with sildenafil was not attenuated by hypoxia. The rise in RVTG with exercise was not substantially reduced by sildenafil. Conclusions: Sildenafil reduces SaO2 at rest while breathing air, this was not exacerbated by hypoxia, suggesting increased ventilation–perfusion mismatching due to pulmonary vasodilation in poorly ventilated lung regions. Sildenafil reduces RVTG at rest and prevents increases caused by hypoxia but not by exercise. This study shows the usefulness of this model to evaluate new therapeutics in pulmonary hypertension

038 Major bleeding still predicts death with a radial invasive strategy in NSTE-ACS: an analysis from theABOARD Study

AimWe sought to determine the incidence and type of major bleeding in moderate-to-high risk acute coronary syndromes (ACS) treated with intense antiplatelet therapy and systematic invasive strategy using predominantly the radial approach. We also examined whether these bleedings has an impact on mortality after multivariable adjustment.MethodsIn the multicenter randomized ABOARD study, 352 patients with acute coronary syndromes without ST-segment elevation were randomized for a “primary PCI” strategy or a strategy of intervention deferred to the next working day. No difference was observed in clinical outcomes between the two groups. Major bleeding complications (STEEPLE definitions) were correlated to 1 month mortality.ResultsPatients were treated by intense antiplatelet therapy: with a mean 660mg (±268) loading of clopidogrel and 111mg (±40) maintenance dose while 99% of the PCI patients receive abciximab the radial approach was predominant (84%).During the first 30 days major bleeding complications occurred in 19 patients (5.4%) with transfusion in 16 patients (4.5%). Occurrence of major bleeding did not differ between immediate and delayed intervention. The most frequent overt bleeding complications were from the gastrointestinal tract. The composite of GI bleeding and occult bleeding (loss of Hb of >3g/dL) represented n = 11 (57.9%) of all major bleeding complications. Major bleeding was associated with a significantly higher peak of creatinine during hospitalization 170.16 μmol/L ± 169.34 vs. 97.05 μmol/L ± 56.96 (p = 0.005) and a higher mortality rate 26.3% vs. 0.6%. After adjustment for all baseline characteristics, major bleeding was independently associated with an impressive increased hazard of death during the first 30 days (Odd ratio 75.7; 95% CI, 11.3 to 505.3; p<0.0001).ConclusionIn a population of radial catheterization for NSTEACS, GI bleeding is the most frequent bleeding complication. Despite the reduction of access site bleeding, major bleeding still remains a major independent predictor of mortality

Etude du systeme neurohormonal dans l'insuffisance cardiaque humaine. Implications cliniques

SIGLEINIST T 77410 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Rapid cooling of the heart with total liquid ventilation prevents transmural myocardial infarction following prolonged ischemia in rabbits.

International audienceSTUDY AIM: Total liquid ventilation (TLV) with cooled perfluorocarbons has been demonstrated to induce an ultrafast cardioprotective cooling in rabbits. However, it remains unknown whether this technically challenging strategy would be actually more potent than a conventional external cooling after a prolonged ischemia inducing transmural myocardial infarction. METHODS: Anesthetized rabbits were randomly submitted to 60min of coronary artery occlusion (CAO) under normothermic conditions (Control group, n=7) or with cooling started at the 5th min of CAO (target left atrial temperature: 32 degrees C). Cooling procedures were either external cooling using cold blankets (EC group, n=7) or ultrafast cooling initiated by 20min of TLV (TLV group, n=6). An additional group underwent a similar ultrafast cooling protocol started at the 20th min of CAO (TLV(delayed) group, n=6). After reperfusion, all hypothermic animals were rewarmed and infarct size was assessed after 4h. RESULTS: In the EC group, the target temperature was reached only at 60min of CAO whereas this time-interval was dramatically reduced to 15 and 25min of CAO in TLV and TLV(delayed), respectively. Infarct sizes were significantly reduced in TLV and TLV(delayed) but not in EC groups as compared to Control (45+/-18%, 58+/-5%, 78+/-10% and 82+/-7% of the risk zone, respectively). Similar significant differences were observed for the sizes of the no-reflow zones (15+/-9%, 23+/-8%, 49+/-11% and 58+/-13% of the risk zone, respectively). CONCLUSION: Cooling induced by TLV afforded a potent cardioprotection and prevented transmural infarction following prolonged and severe ischemia, even when started later than a surface cooling in rabbits

Does the physical examination still have a role in patients with suspected heart failure?

AIMS: The prognostic value of signs of congestion in patients suspected of having chronic heart failure (CHF) is unknown. Our objectives were to define their prevalence and specificity in diagnosing CHF and to determine their prognostic value in patients in a community heart failure clinic. METHODS AND RESULTS: Analysis of referrals to a community clinic for patients with CHF symptoms. Systolic CHF (S-HF) was defined as left ventricular ejection fraction (LVEF) &lt;/=45%, heart failure with normal ejection fraction (HeFNEF) as LVEF &gt; 45%, and amino-terminal pro-brain natriuretic peptide &gt;50 pmol L(-1); other subjects were defined as not having CHF. Signs of congestion were as follows: no signs; right heart congestion (RHC: oedema, jugular venous distension); left heart congestion (LHC: lung crackles); or both (R + LHC). Of 1881 patients referred, 707 did not have CHF, 853 had S-HF, and 321 had HeFNEF. The median inter-quartile range (IQR) age was 72 years (64-78), 40% were women, and LVEF was 47% (35-59). Overall, 417 patients had RHC of whom 49% had S-HF and 21% HeFNEF. Eighty-five patients had LHC of whom 43% had S-HF and 20% had HeFNEF. One hundred and seventy-two patients had R + LHC of whom 71% had S-HF and 16% had HeFNEF. During a median (IQR) follow-up of 64(44-76) months, 40% of the entire patient cohort died. The combination of R + LHC signs was an independent marker of an adverse prognosis (chi(2)-log-rank test = 186.1, P&lt; 0.0001). CONCLUSION: Clinical signs of congestion are independent predictors of prognosis in ambulatory patients with suspected CH

Left ventricular flow propagation during early filling is related to wall relaxation: A color M-mode Doppler analysis

AbstractObjectives. This study was designed to evaluate the relation between the velocity of flow propagation and left ventricular relaxation by using color M-mode Doppler echocardiography to analyze flow propagation in the left ventricle.Background. Noninvasive attempts to identify alterations in left ventricular relaxation have been hampered because both the relaxation rate and left atrial filling pressure are the determinants of peak early velocity and filling rate.Methods. Color M-mode velocity data were transferred to a microcomputer and compared with conventional pulsed Doppler data to assess the ability of color M-mode echocardiography to analyze velocity field properties. The velocity of flow propagation was measured as the slope of the flow wave front during early filling in normal subjects (n = 29) and in patients with disease that alters relaxation (dilated cardiomyopathy [n = 31], ischemic cardiomyopathy [n = 8], hypertrophic cardiomyopathy [n = 5], systemic hypertension [n = 22] and aortic valve disease [n = 25]). In nine patients with end-stage dilated cardiomyopathy, echocardiographic and left heart catheterization data were obtained at baseline and during intracoronary dobutamine infusion.Results. Color M-mode and pulsed Doppler echocardiographic data were highly correlated (n = 217, r = 0.94, p < 0.0001, velocity range 0.2 to 1.5 m/s). The velocity of flow propagation was lower in patients than in normal subjects (0.46 ± 0.15 vs. 0.84 ± 0.11 m/s, p < 0.0001). The decrease was significant in all disease forms with or without left ventricular dilation. The velocity of flow propagation was related to peak early velocity in normal subjects (p < 0.001) but not in patients. It varied inversely with the isovolumetric relaxation time constant during dobutamine infusion and the two variables were highly correlated (p < 0.0001).Conclusions. The velocity of flow propagation during early filling seems to be highly dependent on the left ventricular relaxation rate and could be an important tool in studying diastolic function