P1658Pharmacological treatment of patients with HFrEF: is it really optimized in case of CRT and/or ICD implantation?

Background

Cardiac resynchronization (CRT) as well as implantable cardiac defibrillator (ICD) in primary prevention should be considered in patients with heart failure and reduced ejection fraction (HFrEF) only when pharmacological treatment has been optimized.

Purpose

we sought to analyze pharmacological treatments according to the presence or not of CRT-P, CRT-D or ICD in real life HFrEF patients by using a multicenter survey.

Methods

the survey (NCT01956539) was carried out between 2015 and 2018 in 32 hospitals and included 2735 patients with HF who gave their consent during consultation or hospitalization. In this study, we analyzed only outpatients with chronic HFrEF treated for more than 6 months.

Results

among 1061 patients studied, 138 had CRT-P or CRT-D and 215 had ICD for primary prevention. The main clinical characteristics were: age 65±13 years, ischemic heart disease in, NYHA classes 1, 2, 3 and 4 in 15%, 52%, 23% and 10% cases respectively, systolic blood pressure 115mmHg [IQR 104–129], heart rate 70bpm [IQR 60–80], eGFR 64ml/min/1.73m2 [IQR 46–83]and LVEF was 30% [IQR 24–34]. The table shows the rate of use of evidence-based drugs and the dose for ACEi/ARB and betablockers, according to the presence of ICD or CRT.

HFrEF CRT-P or D ICD (primary prevention) n=1061 n=138 n=215 Loop diuretics 78.2% 79.7% 74.9% ACEi or ARB 65.2% 75.4% 67.3% Sacubitril/valsartan 5.9% 8.5% 9.5% Betablockers 72.3% 83.9% 76.8% Mineralocorticoid antagonists 45.7% 63.6% 60.2% ACEi/ARB mean % maxi dose 77 81 83 Beta-blockers mean % maxi dose 74 63 79

Conclusion

these results suggest that pharmacological treatment remains poorly optimized in a number of patients with HFrEF who received ICD or CRT

Increased expression of blood muscarinic receptors in patients with reflex syncope

AIMS

Pathophysiology of reflex syncope is not fully understood but a vagal overactivity might be involved in this syncope. Previously, overexpression of muscarinic M2 receptors and acetylcholinesterase was found in particular in the heart and in lymphocytes of rabbits with vagal overactivity as well as in hearts of Sudden Infant Death Syndromes. The aim of this present study was to look at M2 receptor expression in blood of patients with reflex syncope. The second objective was to measure acetylcholinesterase expression in these patients.

METHODS AND RESULTS

136 subjects were enrolled. This monocenter study pooled 45 adults exhibiting recurrent reflex syncope compared with 32 healthy adult volunteers (18-50 years) and 38 children exhibiting reflex syncope requiring hospitalization compared with 21 controls (1-17 years). One blood sample was taken from each subject and blood mRNA expression of M2 receptors was assessed by qRT-PCR. Taking into account the non-symmetric distributions of values in both groups, statistical interferences were assessed using bayesian techniques. A M2 receptor overexpression was observed in adult and pediatric patients compared to controls. The medians [q1;q3] were 0.9 [0.3;1.9] in patients versus 0.2 [0.1;1.0] in controls; the probability that M2 receptor expression was higher in patients than in controls (Pr[patients>controls]) was estimated at 0.99. Acetylcholinesterase expression was also increased 0.7 [0.4;1.6] in patients versus 0.4 [0.2;1.1] in controls; the probability that acetylcholinesterase expression was higher in patients than in controls (Pr[patients>controls]) was estimated at 0.97. Both in adults and children, the expression ratio of M2 receptors over acetylcholinesterase was greater in the patient group compared with the control group.

CONCLUSION

M2 receptor overexpression has been detected in the blood of both, adults and children, exhibiting reflex syncope. As in our experimental model, i.e. rabbits with vagal overactivity, acetylcholinesterase overexpression was associated with M2 receptor overexpression. For the first time, biological abnormalities are identified in vagal syncope in which only clinical signs are, so far, taken into account for differential diagnosis and therapeutic management. Further work will be needed to validate potential biomarkers of risk or severity associated with the cholinergic system.

Comparison of the long-term reproducibility of the walk test and of exercise peak oxygen consumption in patients with preserved exercise capacity

Short-term and long-term reproducibility of the cardiopulmonary (CPX) exercise test have been established. Though short and mid-term reproducibility of the walk test has been ascertained, this was not extensively done for the long-term reproducibility. The aim of the study was to examine the long-term reproducibility of distance walked in an allotted time and to check the stability of the relationship between walked distance and exercise peak VO₂ (pVO₂).

METHODS

Forty six subjects (33 men; 57 ± 14 years), referred for functional capacity assessment, were studied twice by CPX and walking test. On the same day, CPX was performed on a bicycle or a treadmill and walk test in a corridor as required by specific guidelines. We performed a 12-minute walk test and the distance covered in six minutes was systematically taken down. A free time interval of 1.5 hours was observed between the exercise tests. Distance walked in the allotted time and pVO₂ were analysed. Reproducibility was assessed according to Bland and Altman plots and intra-class coefficient correlation (ICC). The relationship between distance ambulated and pVO₂ was analysed by the Spearman coefficient correlation.

RESULTS

The time interval between the two evaluations was 290 ± 10 days. During this meantime, for those subjects having drug treatment, no change was recorded in their regimen. BMI remained stable for the entire studied population (28 ± 5 kg/m²). Minute walked distance was respectively 522 ± 83 and 527 ± 76 m in six minutes, 1033 ± 182 and 1041 ± 153 m in 12 minutes. pVO₂ was 21 ± 7 and 22 ± 7 ml/kg/min (all p = NS). The walk test was reproducible in the long-term, regardless of the modality (6 or 12-minute walk) as shown by the Bland-Altman plots and the high ICC of .89. Spearman's rho coefficient between distance ambulated and pVO₂ was modest and remained stable over time whatever the allotted time: Spearman's r = .54; p = .0011 (1st evaluation) and Spearman's r = .51; p = .0019 (2nd evaluation) between 6-minute distance walked and pVO₂.

CONCLUSIONS

The walking distance in an allotted time seems highly reproducible in the long-term. Its relationship with pVO₂ remains stable over time. It could be of value for repeated assessment of patients' exercise capacity in a first step. Further evaluation in a larger population is needed to confirm our result and its usefulness in clinical practice.

Can we obtain a noninvasive and continuous estimation of cardiac output? Comparison between three noninvasive methods

Cardiac output (CO) is often desirable for assessing the hemodynamic condition of a patient, especially in critically ill cardiac patients. Various noninvasive methods are available for this purpose. Inert gas rebreathing (IGR) and 2D-Doppler echocardiography methods have been validated. Based on the relationship between pulse wave transit time and stroke volume, the VISMO® provides an estimated continuous cardiac output (esCCO) measurement using only an electrocardiogram, pulse oximeter wave, and cuff arterial blood pressure. Doppler echocardiography is being currently used in every day practice in this setting and IGR is a validated method, thus we wanted to assess the agreement between these 3 methods for noninvasive CO calculation and reproducibility of esCCO. Patients followed in our cardiology department received on the same day a CO analysis by esCCO, Doppler echocardiography and IGR. Thirty-four patients were included (16 women, mean age 65 ± 15 years). Bland and Altman plots showed a good agreement between IGR and 2D-Doppler echocardiography (bias = 0.31 L/minute). Though there was also an agreement between esCCO and the other 2, the bias was rather large: 1.18 L/minute with IGR and 1.51 L/min with 2D-Doppler echo. The intraclass correlation coefficient was poor whatever the methods. However, esCCO had a satisfactory reproducibility and accuracy compared rather well with the other 2. This method could be suitable for patient screening and monitoring.

In-hospital complications after invasive strategy for the management of Non STEMI: women fare as well as men

BACKGROUND

To analyze the in-hospital complication rate in women suffering from non-ST elevation myocardial infarction treated with percutaneous coronary intervention (PCI) compared to men.

METHODS

The files of 479 consecutive patients (133 women and 346 men) suffering from a Non STEMI (Non ST-segment elevation myocardial infarction) between the January 1st 2006 and March 21st 2009 were retrospectively analyzed with special attention to every single complication occurring during hospital stay. Data were analyzed using nonparametric tests and are reported as median unless otherwise specified. A p value < .05 was considered significant.

RESULTS

As compared to men, women were significantly older (75.8 vs. 65.2 years; p < .005). All cardiovascular risk factors but tobacco and hypertension were similar between the groups: men were noticeably more often smoker (p < .0001) and women more hypertensive (p < .005). No difference was noticed for pre-hospital cardiovascular drug treatment. However women were slightly more severe at entry (more Killip class IV; p = .0023; higher GRACE score for in-hospital death - p = .008 and CRUSADE score for bleeding - p < .0001). All the patients underwent PCI of the infarct-related artery after 24 or 48 hrs post admission without sex-related difference either for timing of PCI or primary success rate. During hospitalization, 130 complications were recorded. Though the event rate was slightly higher in women (30% vs. 26% - p = NS), no single event was significantly gender related. The logistic regression identified age and CRP concentration as the only predictive variables in the whole group. After splitting for genders, these parameters were still predictive of events in men. In women however, CRP was the only one with a borderline p value.

CONCLUSIONS

Our study does not support any gender difference for in-hospital adverse events in patients treated invasively for an acute coronary syndrome without ST-segment elevation and elevated troponin.

[Myonecrosis and inflammatory response following percutaneous coronary angioplasty. A protective role for betablockers?]

INTRODUCTION

Percutaneous coronary intervention (PCI) is widely used actually for the treatment of coronary disease. Stent implantation in the vessel wall is associated with local healing processes and some myonecrosis. However, little is known about the relationships between systemic inflammatory response, myonecrosis and the patient's and procedural characteristics.

OBJECTIVES

(i) To evaluate the level of C-Reactive Protein (hsCRP) and cardiac troponin I (cTnI) elevation after PCI; (ii) to determine the patient's and procedural factors associated with those elevations.

METHOD

This is a prospective monocentric study carried out in patients hospitalised for elective PCI or for ACS without cTnI elevation. CRP and cTnI were assessed before, after and 24 hours after the procedure.

RESULTS

Thirty-four patients (mean age 64+/-10.9 years; sex ratio 28 males/six females) were included. hsCRP increased in 26 patients (76.4%) and cTnI in 16 patients (47%) after PCI. cTnI elevation did not correlate with inflammatory response. Whereas none of the studied parameters were statistically linked with hsCRP increase, cTnI elevation was significantly associated with AHA-ACC B(2)/C type lesion, the number and the total length of stents implanted, the duration of procedure and treatment by betablockers. Multivariate analysis showed that the independent predictors of cTnI elevation were procedure duration (p=0.032 OR=14.2 CI 95% 7.69-100) and the absence of pretreatment with betablockers (p=0.036, OR=2,6 CI 95% 1.35-35).

CONCLUSION

cTnI elevation following PCI is very frequent and related with the duration of the procedure. Our data suggest a protective role of betablockers in the occurrence of cTnI elevation after PCI. Confirmation of the protective role of betablockers in larger cohort is mandatory.

Role of pre-infarction angina and inflammatory status in the extent of microvascular obstruction detected by MRI in myocardial infarction patients treated by PCI

BACKGROUND/OBJECTIVES

The extent of microvascular obstruction (MVO) during myocardial infarction referred to as the "no-reflow phenomenon", may determine myocardial damage. Our study aimed to investigate the incidence and the influencing factors of MVO in patients with ST-elevation myocardial infarction (STEMI) treated by primary percutaneous intervention (PCI).

PATIENTS, METHODS

Using contrast-enhanced MRI, microvascular obstruction was defined as early hypoenhancement. Contrast defects were scored from 0 (no hypoenhancement) to 3 (strong hypoenhancement). 50 patients (56+/-11 years) with STEMI underwent PCI. Contrast-enhanced MRI (6+/-2 days after STEMI) and biochemical parameters were evaluated.

RESULTS

Microvascular obstruction (score 1 to 3) was observed in 90% of the patients and major microvascular obstruction (score 2-3) in 54%. In univariate analysis, leukocytes and CRP levels were associated with MVO, whereas pre-infarction angina and prior medication by aspirin or calcium channel antagonist appeared protective. Microvascular obstruction intensity positively correlated with baseline inflammation status assessed by C-reactive protein and leukocytes (rho=0.43 and rho=0.44; p=0.003), the peak of CK (rho=0.56; p=0.01) or Troponin I (rho=0.59; p=0.01) and negatively correlated with LVEF (rho=-0.44; p=0.002). Multivariate analysis identified the absence of pre-infarction angina as the only independent predictor for microvascular obstruction (odds ratio, 8.35, 95% confidence interval 1.27-54.71; p=0.027).

CONCLUSION

MRI-detected microvascular obstruction has a high incidence in patients with STEMI treated by primary PCI and determines post-MI LVEF even in patients with post PCI TIMI 3 flow score. Pre-infarction angina appears to be an independent determinant of the extent of MVO detected by MRI.

[Platelet responsiveness to clopidogrel in patients with coronary syndrome. Comparison of platelet aggregation induced by ADP and flow cytometric analysis of intraplatelet VASP phosphorylation]

Although antiplatelet therapy with ASA-clopidogrel reduces the risk of cardiovascular episodes after PCI, a substantial number of events occur during follow-up. Sustained platelet reactivity under dual antiplatelet therapy was recently associated with increased risk of recurrent atherothrombotic events after PCI. Whereas it appears significant to determine clopidogrel responsiveness, the accurate platelet function assay is still under investigation.

OBJECTIVES

(i) to determine the proportion of "low-responders" or "resistants" patients during coronary syndrome (ii) to identify determinants of interindividual variability response to clopidogrel (iii) to compare aggregometry and VASP phosphorylation measured by flow cytometry. Patients were treated by clopidogrel (300 mg loading dose and 75 mg maintenance dose) and ASA (160 mg) (N=27). Additional treatment by GPIIbIIIa antagonists was given to high-risk patients (N=9). Platelet function was monitored by ADP aggregometry (5, 10, 20 microM) and VASP phosphorylation before any treatment by clopidogrel (d0) and at least five days after (d5). The platelet reactivity index (PRI), expressed as percentage, is the difference in VASP fluorescence intensity between resting (+ PGE1) and activated (ADP) platelets. At d5, low responsiveness to clopidogrel was defined by either (i) a PRI > 67.3% corresponding to the mean value -2SD measured in untreated patients (dO) (ii) or an absolute change (delta d0-d5) in aggregation (ADP 10 microM) < to 30%.

RESULTS

PRI, platelet aggregometry to ADP was significantly reduced following clopidogrel treatment (P < 0.01). A wide inter-individual variability to clopidogrel was observed at d5 (PRI from 11 to 83%). Whatever the platelet function used, a large proportion of patients were detected as "low-responders" (37% by VASP, 44% by ADP aggregometry). Absolute change in ADP aggregation was correlated to the variation of PRI (R = 0.559; P = 0.02). Contrary to ADP aggregometry, PRI was not influenced by GPIIbIIIa antagonists or prior administration of ASA. However, the conformity of the two methods to evaluate clopidogrel responsiveness was only 66%. No differences in platelet aggregometry could be observed at d5 between "low" and "good-responders" defined by VASP analysis. At d5, a higher PRI value could be detected in male and patients with history of dyslipemia.

CONCLUSION

During coronary syndrome, impaired platelet responsiveness to clopidogrel was observed in a large proportion of patients whatever the platelet function assay used. VASP analysis was found insensitive to GPIIbIIIa or aspirin administration. Possible mechanisms linking clopidogrel "resistance" measured by VASP assay and enhanced thrombogenicity remain to be characterized. Indeed, clopidogrel "resistance" defined by VASP analysis was not associated with higher platelet aggregation.

[Delays of treatment of acute myocardial infarction with ST elevation admitted to the CCU (coronary care unit) in Alsace]

OBJECTIVE

to determine the time delay from symptom onset to diagnosis and treatment of patients with persistant ST segment elevation myocardial infarction (STEMI).

DESIGN

prospective observational study.

METHOD

patients with symptoms onset < 24 h admitted in all 10 cardiac intensive care units in one French administrative region (Alsace). Data were recorded by doctors on duty soon after hospital admission. Patients with STEMI during hospital stay or as a complication of cardiac interventional procedure were excluded. The Kruskal-Wallis test was used to assess statistical differences between the groups (p value < 0.05).

RESULT

from April to October 2004, 326 patients were admitted for STEMI. Median time between the symptoms onset and the patient's call for medical help was 60 minutes. General practitioners were the first medical contact in 41%. The time from symptoms onset to first medical intervention and from first medical intervention to coronary care unit admission were markedly shorter in patients who had directly called the Emergency Medical Services (group 15-110 patients i.e. 33% of the study population): 44 min vs 75 min otherwise (p=0,003). Median transport time was 60 min. Sixty two percent of the pts were transported by the Emergency Medical Services. The median time from symptoms onset to initiation of reperfusion therapy was 240 min. It was significantly lower in group 15 (170 min vs 286 min - p < 0,001) and for thrombolytic therapy (190 min versus 245 min for primary angioplasty, p=0,007). When thrombolysis (THL) was used, 89% of the pts could be treated during 6 hours of symptoms onset and 44% in 3 hours. For angioplasty only 4% of the pts were treated in the first 90 minutes, 9% in the 2 hours and 30% in the 3 hours of symptoms onset. If the time delay is evaluated from the 1 st medical intervention, call to reperfusion intervention was significatly shorter for THL: 91 versus 157 min, p< 0,003. Angioplasty represented 75% of reperfusion strategy in our area and THL alone only 2,7% and combine therapy 5,4%.

CONCLUSION

our study documents the beneficial effect of a direct call to Emergency Medical Services. Our results also underscore the need for an effort to reduce the time to offer the best appropriate reperfusion techniques in STEMI pts: speed up the admission in the cath-lab, think about pre-hospital thrombolysis followed by coronary angioplasty if necessary.

Prognostic value of C-reactive protein and cardiac troponin I in primary percutaneous interventions for ST-elevation myocardial infarction

BACKGROUND

The rise in cardiac troponin I after ST-elevation myocardial infarction treated by primary percutaneous coronary interventions (PCIs) is predictive of infarct size and left ventricular ejection fraction (LVEF). However, the comparative value of C-reactive protein (CRP) and troponin I for infarct size evaluation and the respective relationships between these biomarkers and mortality have not been investigated.

METHODS

We studied 87 patients who underwent primary PCI for ST-elevation myocardial infarction. Concentrations of troponin I and CRP were measured before and for 72 hours after PCI. Infarct size was measured by the cumulative release of alpha-hydroxybutyrate deshydrogenase during the 72 hours after PCI (QHBDH72) and by delayed radionuclide LVEF (at 4.6 +/- 1.7 weeks).

RESULTS

Concentrations of CRP at peak and at 24, 48 and 72 hours, and of troponin I at 6 and 72 hours, correlated with QHBDH72 and LVEF. In single variable analysis, at a mean follow-up of 42 +/- 8 months, Killip score of 3 to 4, CRP at baseline and at 48 hours, and troponin I at 6 and 72 hours were related to mortality. By multiple variable analysis, Killip score (OR 9.9, CI 1.6-58.8) and troponin I at 72 hours (OR 9.43, CI 2.1-43.5) were the only independent predictors of mortality.

CONCLUSIONS

Plasma concentrations of CRP and troponin I after PCI were related to infarct size and mortality. However, Killip class and troponin I at 72 hours were the only independent predictors of mortality at long-term follow-up.

Diagnostic and prognostic value of circulating D-Dimers in patients with acute aortic dissection

OBJECTIVE

We sought to determine whether assessing D-Dimer might be helpful for the management of acute aortic dissection (AAD).

DESIGN

Single-center retrospective case-control study.

SETTING

University Hospital of Strasbourg France.

PATIENTS

Patients were 94 consecutive patients admitted to our institution with confirmed AAD and in whom D-Dimer test had been performed at presentation. These patients were matched with 94 controls presenting with clinical suspicion of dissection, which was later ruled out.

INTERVENTIONS

Patient characteristics and clinical course were analyzed.

MEASUREMENTS AND MAIN RESULTS

Ninety-three (99%) patients with AAD had elevated D-Dimer (>400 ng/mL) with a median D-Dimer value of 8610 ng/mL (interquartile range, 2982-20,000 ng/mL). Receiver operating characteristic curves analysis showed that D-Dimer, but not C-reactive protein, troponin, lactate dehydrogenase, or leukocyte count, was predictive of a diagnosis of AAD, with a sensitivity and specificity of 99% and 34%, respectively. D-Dimer concentration positively correlated with the anatomical extension of the dissection to the different segments of the aorta (R = .47, p < .0001). A positive relationship was observed between D-Dimer and in-hospital mortality rate among patients with AAD (p = .037). On multivariate analysis, the independent predictors of in-hospital mortality were the presence of pericardial effusion (odds ratio, 6.80; confidence interval, 1.87-27.60), D-Dimer >5200 ng/mL (odds ratio, 5.38; confidence interval, 1.27-30.87), and female gender (odds ratio, 4.96; confidence interval, 1.39-19.95).

CONCLUSIONS

D-Dimers are elevated in patients with AAD and provide valuable diagnostic and prognostic information. In patients with acute chest pain and elevated D-Dimer, a diagnosis of AAD should also be considered. D-Dimer might be a useful complementary tool to the current diagnostic work-up of patients with suspected AAD.

Deletion of MLCK210 induces subtle changes in vascular reactivity but does not affect cardiac function

Myosin light chain kinase (MLCK) plays a key role in the regulation of actomyosin contraction in a large variety of cells. Two isoforms have been described: a short isoform, widely expressed in smooth muscle cells; and a long isoform (MLCK210), mainly localized in the endothelium. This study investigated the consequences on different cardiovascular parameters of MLCK210 gene deletion using MLCK210 knockout mice and of pharmacological inhibition of the kinase using a specific MLCK inhibitor. Deletion of MLCK210 did not affect systolic blood pressure and heart rate or echocardiographic measurements. Electrocardiographic analysis showed neither atrio- nor intraventricular conduction or repolarization defects. Ex vivo responses of aortic rings to vasoconstrictor and vasodilator agonists were not modified in MLCK210 null mice. However, deletion of MLCK210 attenuated shear stress-induced dilation and produced changes in the balance of endothelial-relaxing factors of small mesenteric arteries (SMA). In particular, a reduced flow-mediated NO-dependent dilation was observed. However, it was partially compensated by enhanced indomethacin-sensitive dilation. No significant changes were detected in the endothelium-derived hyperpolarizing component of the vasodilator response. The above effects of MLCK210 gene deletion were confirmed in SMA from wild-type mice by the use of the MLCK enzymatic inhibitor MMZ-10-057. In summary, deletion of MLCK210 was not associated with abnormalities of main in vivo cardiovascular parameters in mice. This study demonstrates a role for MLCK210 in the regulation of flow-dependent dilation in SMA.

Troponin I concentrations following primary percutaneous coronary intervention predict large infarct size and left ventricular dysfunction in patients with ST-segment elevation acute myocardial infarction

The aim of this study was to investigate the ability of troponin I (cTnI) levels to predict myocardial infarction size in patients with ST-segment elevation acute myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). In 87 patients with STEMI undergoing primary PCI, serial plasma concentrations of cTnI and alpha-hydroxybutyrate deshydrogenase (HBDH) were measured before PCI and over the following 72 h. Enzymatic infarct size was estimated by the cumulative release of HBDH during the 72 h following PCI (QHBDH72). Delayed radionuclide left ventricular ejection fraction (LVEF) was measured in 63 patients. While cTnI concentrations at admission did not correlate with QHBDH72 or with LVEF, from the 3rd to the 72nd h following PCI, they did correlated with QHBDH72 (P<0.001; R: 0.76-0.86) and with LVEF (P<0.001; R: -0.42 to -0.50). Receiver-operator characteristic (ROC) curve analysis showed that admission concentrations of cTnI could not predict either a large infarct size (i.e., QHBDH72>10 g-eq l(-1)) or a low LVEF (i.e., LVEF<40%). However, 6 h and up until 72 h after PTCA, cTnI concentrations were predictive of large enzymatic infarct size (sensitivity: 91 and 95%, specificity: 90 and 87%, respectively) and of LVEF under 40% (sensitivity: 75 and 77%, specificity: 90 and 78%, respectively). Thus, our study suggests that in contrast with admission cTnI concentration, cTnI levels following primary PCI represent a reliable tool for predicting large enzymatic infarct size and may help in selecting patients with a high risk of low LVEF at 1 month.

[Value and limitations of coronary artery imaging with the MRI navigator technique. Comparison with coronary angiography results in 37 patients]

The introduction of a non-invasive method of imaging the coronary arteries would be a great advance in daily cardiological practice. The authors report their experience of imaging the coronary arteries with 1 Tesla MRI using the "navigator technique". Twenty-five sections 1.2 mm thick, focused on the proximal left coronary artery, were acquired with a 512 matrix, without injecting contrast during normal respiration with a tolerance on the portion of the right diaphragmatic cupola of 5 mm. Analysis of the coronary segments included in the field of view was performed on native sections after curve reconstruction and on targetedMIP series. A comparison of the results with respect to conventional coronary angiography showed a relatively limited visualisation of the proximal coronary segments because, in addition to the impossibility of carrying out the investigation in 24% of cases (faulty cardiac or respiratory synchronisation, poor signal/noise ratio), only 93% of the left main coronary and 75% of the proximal left anterior descending arteries could be visualised. In the analyzable segments, the diagnostic performances were modest with a global sensitivity of 60.8% and specificity of 91%. With the exception of the left main coronary artery, the sensitivities observed did not make MRI of the coronary arteries a rival to conventional coronary angiography. These limited performances may be explained by the lack of rapidity of the sequences of acquisition compared to the rapid motion of the structures under investigation whose dimensions are 5 to 10 times smaller than their amplitude of excursion. Technical developments are regularly accomplished in this domain, especially 3rd generation sequences in apnoea with injection of contrast media. At present, despite some results reported in the literature, angio-MRI of the coronary arteries cannot be used reliably to guide clinical decisions in coronary artery disease with the exception of some situations like congenital abnormalities of the coronary arteries, non-invasive follow-up of coronary aneurysms or analysis of the left main coronary artery.

[Heart failure and vasopeptidase inhibitors]

The morbidity and mortality of cardiac insufficiency remains such that it justifies the pursuit of finding new drugs and new sensitive techniques to slow or abolish its evolution. Bringing the vasopeptidases, such as omapatrilat, up to date results in a rational process aimed at simultaneously modulating certain interactive humoral systems. They represent drugs which simultaneously inhibit neutral endopeptidase and angiotensin converting enzyme with the effect of potentiating the natiuretic peptide system and bradykinin, and blocking the conversion of angiotensin I and angiotensin II. In the IMPRESS study, omapatrilat has been evaluated in patients with cardiac insufficiency versus lisinopril; there was no significant difference on the principal outcome measure which was exercise tolerance, however it was significantly more effective than lisinopril on the outcome measure combining death and hospital admission for deteriorating cardiac insufficiency. A wider study is underway, the OVERTURE study, which is evaluating omapatrilat versus enalapril on hospital admission and all-cause mortality. The Vanlev dossier has not yet been submitted to the regulatory authorities for obtaining its authorisation to be put on the market.

Myocardial flow reserve parametric map, assessed by first-pass MRI compartmental analysis at the chronic stage of infarction

Regional myocardial flow and flow reserve (MFR) were assessed by compartmental analysis of Gd-enhanced MRI first-pass data in 7 patients with atypical chest pain, and in 15 patients with previous transmural myocardial infarction. The FE product (Flow x Extraction coefficient), derived from the modified Kety equation, was measured in regions corresponding to the Tetrofosmine-SPECT fixed defect and in remote normal regions. The FE product at rest and hyperemic FE product were similar in healed revascularized tissues (70.5 +/- 15.6 and 112.5 +/- 19.5 ml/mn/100 g, respectively) and in normal myocardium (76.2 +/- 18.3 and 142.2 +/- 33.0, respectively). In contrast, the FE index (48.8 +/- 15.2 and 60.7 +/- 18.0, respectively, P < 0.01 versus the two previous groups) and the MFR (1.27 +/- 0.20 vs. 1.91 +/- 0.29 in normal regions) were reduced in healed fibrotic tissues when the infarct-related artery remained occluded. Myocardial flow reserve maps allowed correct identification of regions corresponding to an occluded infarct-related artery.

[Cartography of absolute myocardial perfusion with magnetic resonance imaging. Methods and results]

Ultra-rapid dynamic MRI (one image per heart beat) can follow the progression of the intra-myocardial signal during the first passage of diffusable gadolinium chelates injected as a bolus through a peripheral vein. A quantitative evaluation of myocardial perfusion is possible using a compartmental model of analysis. Absolute myocardial flow can be measured at rest and during hyperaemia induced by dipyridamole. It is possible to associate functional mapping, corresponding to parametric images of the flow indices, to the global evaluation. The ratio between the values obtained during hyperaemia and under basal conditions correspond to the myocardial reserve. The principles, results and limitations of this method are discussed in the light of published results, underlining the advantages of absolute flow measurement and of the differences between the results of MRI and myocardial scintigraphy.

Myocardial bridging as a cause of acute transient left heart dysfunction

The significance of myocardial bridging is still a matter of debate, and although several reports have underlined its pathologic potential, myocardial bridging is often considered to be a benign phenomenon. We present here the case of a 63-year-old woman with a history of acute left heart failure and ECG evidence of ischemia, and whose primary abnormality on extensive workup was myocardial bridging. This case further underlines that myocardial bridging can lead to significant cardiac events.

Neurohormonal profile before and after beta-blockade in patients with neurocardiogenic syncope

Our objective was to evaluate the effects of beta-blockers on the neurohormonal profile, particularly vasopressin (VP) release, in vasovagal syncope and to gain further insight on the pathophysiology of this syndrome. Patients (< or =75 years) with no cardiovascular, neurological disorders, or contraindications to the use of isoproterenol or beta-blockers and being explored for unexplained syncope were included. An 80 degrees HUT was performed under identical conditions. After a 25-min period of passive tilt, isoproterenol was infused at a rate of 1-5 microg/mn if required. Two groups matched for age and sex were considered: a HUT-positive and a HUT-negative group. The HUT-positive group was then given beta-blockers, subsequently reassessed, and divided into two subgroups: alpha beta-blocker nonresponder group and a beta-blocker responder group. Blood samples for assays of norepinephrine (NE), epinephrine (E), and VP were taken at baseline and the end of the procedure. In all, 44 subjects entered the study, 22 in each group. The HUT-positive group exhibited an obvious lesser increase in plasma NE and a clear-cut rise in plasma E and VP compared to the HUT-negative group (P < 0.05). Even though no patient in the HUT-positive group reported recurrent symptoms under treatment, the second HUT could distinguish two subgroups: a beta-blocker nonresponder group (n = 12) whose HUT remained positive and a beta-blocker responder group (n = 10) whose HUT was normalized. The time course of plasma E and VP during the second HUT was similar to that for the HUT-positive and HUT-negative groups. In conclusion, the efficacy of beta-blockers is associated not only with a reduction of the sympathoadrenal stimulation seen in vasovagal syncope but also with a lower release of VP suggesting that low-pressure baroreceptors might be involved in VP release.

Mechanism of Ca2+ release and entry during contraction elicited by norepinephrine in rat resistance arteries

The intracellular Ca2+ stores and the mechanisms of Ca2+ entry produced by norepinephrine (NE) were investigated in small mesenteric resistance arteries of the rat. In Ca2+-free medium, NE (10 microM) elicited a transient increase in both intracellular free Ca2+ concentration ([Ca2+]i) and tension that were both drastically reduced by caffeine and only partially reduced by the two sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) blockers thapsigargin and cyclopiazonic acid, despite the presence of SERCA2a and SERCA2b isoforms in the medial smooth muscle layer of the artery. After depletion of intracellular Ca2+ stores with 10 microM NE, addition of exogenous CaCl2 (2.5 mM) produced large and sustained increases in both [Ca2+]i and contraction of the arteries provided that the agonist was continuously present. In these conditions, the responses to CaCl2 were inhibited by the voltage-dependent Ca2+ entry blocker nitrendipine (1 microM), the putative inhibitor of receptor-operated Ca2+ entry SKF-96365 (30 microM), and NiCl2 (1 mM). The inhibition produced by SKF-96365 and NiCl2 was greater than that of nitrendipine. Also, the responses to CaCl2 were greatly reduced or abolished in the presence of the Na+/Ca2+ exchanger inhibitors 1,3-dimethyl-2-thiourea, 3',4'-dichlorobenzamil, MgCl2, and amiloride or after omission of NaCl in the medium. Also, protein kinase C inhibitors, calphostin C and staurosporine, and tyrosine kinase inhibitors, genistein and tyrphostin 23, both reduced the responses to CaCl2. The inhibitory effect of protein kinase C inhibitor and tyrosine kinase were additive. These results suggest that NE releases Ca2+ from intracellular stores that are caffeine sensitive and partially sensitive to SERCA inhibitors. They indicate that in addition to Ca2+ influx via nitrendipine-sensitive and SKF-96365-sensitive channels, Na+/Ca2+ exchanger participates in the CaCl2-induced contraction produced in NE-exposed vessels. The pathway leading to Ca2+ entry probably involves tyrosine kinase and protein kinase C. All the above mechanisms require ongoing receptor stimulation.

[Prognosis of diastolic cardiac insufficiency]

The natural history and prognosis of diastolic cardiac failure are difficult to determine because of the large differences in the studies which have been performed in this field. The ten studies published to date concerning the prognosis have been performed on hospital populations and, consequently, only the most severe cases have been recruited. Moreover, the threshold values of indices of the ejection phase used to define systolic dysfunction vary from one study to another. A review of these papers provides a rather disconcerting appreciation of the annual mortality rate (from 1.3% to 17.5%). The differences in aetiology, age and threshold values of parameters of systolic function probably explain most of the variability observed. Taking unbiased studies alone in consideration, such as the Framingham study, the mean annual mortality of diastolic cardiac failure between 55 and 71 years, is 3 to 9%, much less than that observed with predominantly systolic dysfunction (15 to 20%). Other prospective studies, adjusting morbidity and mortality to age and other principal prognostic factors, are awaited.

Does the 6-minute walk test predict the prognosis in patients with NYHA class II or III chronic heart failure?

BACKGROUND

We prospectively evaluated the potential of the 6-minute walk test compared with peak VO2 in predicting outcome of patients with New York Heart Association (NYHA) class II or III heart failure.

METHODS AND RESULTS

Patients with a history of heart failure caused by systolic dysfunction were included. The combined final outcome (death or hospitalization for heart failure) was used as the judgment criterion. One hundred twenty-one patients (age 59+/-11 years; left ventricular ejection fraction 29.6%+/-13%) were included and followed for 1.53+/-0.98 years. Patients were separated into two groups according to outcome: group 1 (G1, 74 patients), without events, and group 2 (G2, 47 patients), who reached the combined end point. Peak VO2 was clearly different between G1 and G2 (18.5+/-4 vs. 13.9+/-4 ml/kg/min, p=0.0001) but not the distance walked (448+/-92 vs 410+/-126 m; p=0.084, not significant). Survival analysis showed that unlike peak VO2, the distance covered was barely distinguishable between the groups (p < 0.08). However, receiver operating characteristic curves revealed that the best performances for the 6-minute walk test were obtained for subjects walking < or =300 m. These patients had a worse prognosis than those walking farther (p=0.013). In this subset of patients, there was a significant correlation between distance covered and peak VO2 (r=0.65, p=0.011). Thus it appears that the more severely affected patients have a daily activity level relatively close to their maximal exercise capacity. Nevertheless, the 300 m threshold suggested by this study needs to be validated in an independent population.

CONCLUSIONS

A distance walked in 6 minutes < or =300 m can predict outcome. Moreover, in these cases there is a significant correlation between the 6-minute walk test and peak VO2 demonstrating the potential of this simple procedure as a first-line screening test for this subset of patients.

[MRI semeiology of segmental contraction abnormalities in arrhythmogenic dysplasia of the right ventricle]

The diagnosis of localized arrhythmogenic right ventricular dysplasia may be difficult to ascertain. Aside from electrophysiological arguments, visualization of an abnormal right ventricular contraction pattern is of crucial importance for diagnosis. Cine-MR is almost the only examination method which offers detailed informations on the right ventricular contraction pattern. Nine observations of segmental right ventricular contraction abnormalities assessed by cine-MR are described here: dyskinesia of the distal part of the anterior wall (2), of the inferior wall (2), of the right ventricular outflow tract (2); akinesia of the outflow tract (2) and of the inferior wall (1). Morphological abnormalities of the right ventricle are always associated with contraction abnormalities but seem to be less disease specific. Patients should be more readily referred for a cine-MR examination when the diagnosis of localized right ventricular dysplasia is suspected. Cine-MR sequences related to these observations may be reached via Internet at:http:@alsace.u-strasbg.fr/cardio/coeur.htm.

Diltiazem slow-release and left-ventricular hypertrophy: a volumetric approach of left ventricular mass using magnetic resonance imaging

AIMS

This study was designed to assess the changes in left ventricular mass (LVM) in hypertensive patients with left ventricular hypertrophy under drug therapy with once-daily slow-release diltiazem. Magnetic resonance imaging (MRI) was used for this purpose because of its higher reproducibility than M-mode or two-dimensional echocardiography.

METHODS

Patients suffering from essential hypertension were included if their baseline LVM index (LVMI) was > or = 105 g/m2 in male or > or = 85 g/m2 in female patients, ie, equal or higher to the median values observed in hypertensive patients in our institution. MRI consisted in a true short-axis, electrocardiogram (ECG) gated spin-echo slice acquisition at baseline, after 3 and 6 months of therapy (M0, M3, and M6). Data were stored on magnetic tapes and read subsequently under blind conditions and the control of an external auditor.

RESULTS

Thirty-five patients were included. Of these, 14 patients (40%) were not previously treated. Inter- and intra-observer variability for LVMI measurement were 5.6 +/- 4.3% and 2.1 +/- 3.0%, respectively. Mean baseline LVMI was 110 +/- 16 g/m2 in male and 96 +/- 16 g/m2 in female patients. It decreased by 3.6% at M3 (P = 0.05) and by 6.0% at M6 (P = 0.02). A trend towards a greater LVMI reduction was observed in previously untreated patients.

CONCLUSION

This study confirms that MRI is a reproducible technique for the measurement of LVM. It demonstrates a significant reduction in LVMI as early as the 3rd month of therapy in hypertensive patients treated with once-daily sustained release (SR) diltiazem, although baseline LVMI in the majority of participating patients was only moderately increased.

[Terminal heart failure; therapeutic strategies. Drug therapy in cases of absence of possibility of heart transplantation: dobutamine therapy, aspects of compassion?]

Terminal cardiac failure, despite the gain obtained by angiotensin converting enzyme inhibitors, continues to carry a high annual mortality. Cardiac transplantation, with a 1 year survival of about 80% (a result which is sustained at 5 years), constitutes the treatment of choice for these patients. However, in view of the contraindications to transplantation and the cruel lack of donors organs, many cases of terminal cardiac failure are unable to benefit from transplantation. What are the pharmacological means available for these patients? This is a real therapeutic challenge. The essential objective in the management of these patients with a poor short-term prognosis is the reduction of mortality. However, this aim is not easily attained, at least in the short or medium-term in the present state of our knowledge. Other objectives can therefore by legitimately considered in the management of patients with cardiac failure in the terminal phase: the most important ones are to improve symptomatology and the quality of life. Terminal cardiac failure is a complex syndrome implicating a number of non-cardiac abnormalities. They may not only participate in the symptomatology and high mortality, but also make therapeutic management a delicate operation. Nevertheless, the abnormalities of cardiovascular function remain the cardinal problem. The treatment which we use aims to correct them. The authors propose a review of the possibilities available with reference to data in the medical literature.

Comparison between abnormalities in segmental endocardial motion and abnormalities in segmental wall thickening after anterior myocardial infarction. A cine-magnetic resonance study

In this study, two patterns of regional contract on of the left ventricle have been studied: endocardial motion and wall thickening, in order to check which of these was the most affected after myocardial infarction. The clinical relevance of this comparison was to assess which parameter of the regional contraction abnormality would best depict the severity of the infarction. Long axis cine-magnetic resonance slices were used to assess segmental systolic left ventricular endocardial motion and segmental systolic wall thickening in 39 normal subjects and in 30 patients at the chronic stage of an anterior myocardial infarction. In the group of normal subjects, endocardial motion and wall thickening showed significant regional heterogeneity. Overall endocardial motion was greater than overall wall thickening: 9.5 +/- 2.0 mm vs 7.1 +/- 1.8 mm. P = 4 x 10(-12) (3.1 +/- 1.2 mm vs 2.0 +/- 0.7 mm, P = 9 x 10(-5) after infarction). A significant linear correlation was found between these two parameters. In the infarction group, abnormality scores for endocardial motion and for wall thickening were calculated. These scores were defined as the average values exceeding the mean minus two standard deviations of the normal range for segments corresponding to the antero-septal-apical walls. The abnormality score for endocardial motion greater than the abnormality score for wall thickening: 0.31 +/- 0.12 vs 0.20 +/- 0.07, P = 9 x 10(-4). We conclude that, in clinical practice, endocardial motion is affected to a greater degree by myocardial infarction than is wall thickening and therefore constitutes a more discriminant index in the assessment of post-infarction patients.

[Left ventricular diastolic dysfunction in cardiomyopathies]

Although physiologists have recognised for many years that cardiac performance is based on two functions, systolic and diastolic, it has only been in the last 15 years that clinicians have acknowledged the essentiel role of diastole in the physiopathology of cardiac disease. Many studies have shown that left ventricular diastolic dysfunction resulting from abnormal active relaxation or changes in passive visco-elastic properties of the myocardium modulating its rigidity were responsible for decreased distensibility of the ventricle and an increase in its filling pressures. Therefore, the symptoms of the majority of patients with cardiomyopathy are due, more or less, to diastolic dysfunction. This is particularly the case in hypertrophic cardiomyopathy, most case of which have diastolic dysfunction secondary to an often asymetric distribution of the hypertrophy, to the disorganisation of the myocardiofibres and to interstitial fibrosis. With respect to advanced forms of restrictive cardiomyopathy, as their clinical and haemodynamic characteristics resembling constrictive pericarditis show, they demonstrate caricatural diastolic dysfunction. Finally, although the main abnormality in dilated cardiomyopathies is poor contractility, a decrease in ventricular compliance is constantly observed.

Prognostic factors of chronic heart failure in NYHA class II or III: value of invasive exercise haemodynamic data

Various parameters have been found useful for establishing the prognosis of patients with chronic heart failure, in particular haemodynamic parameters measured at rest. However, few studies deal with the prognostic value of invasive exercise haemodynamic parameters in such patients. Our aim was to test the value of such parameters to assess the prognosis of patients with chronic heart failure in functional class II or III of the New York Heart Association.

METHODS

Between December 1990 and June 1993, 50 patients fulfilled the criteria for inclusion in the study. The average age and ejection fraction of the population were 54 +/- 2 years and 20 +/- 0.5% respectively. All patients were examined clinically; their invasive haemodynamic parameters were measured at rest and during exercise, and their exercise peak VO2, validated by reaching the anaerobic threshold, was determined. They were followed up for 21.2 +/- 1.17 months (ranges 3-26 months). The assessment criteria employed were mortality and the occurrence of major events (heart failure, pulmonary oedema or severe ventricular arrhythmia).

RESULTS

The population consisted of 32 men and 18 women. No gender-related differences were found. Two groups could be distinguished in terms of prognosis: G1: n = 31 living patients with no events, and G2: n = 19 deceased or with major events. G1 and G2 were comparable with regard to age, sex ratio and ejection fraction. Several of the 52 parameters tested were different in the two groups, in particular peak VO2, exercise duration, the workload developed during the cardiopulmonary test and all the invasive exercise haemodynamic parameters except heart rate (P < 0.0001). Haemodynamic parameters at rest had no prognostic value in this series. The ROC curves, the survival curves and the Cox analysis showed that exercise cardiac power output, exercise left ventricular work indices and exercise peak VO2 were the most useful factors for assessing the prognosis of patients with NYHA II or III chronic heart failure. An exercise cardiac power output < 2 watts accurately identified those patients with a short-term poor prognosis, and exercise peak VO2 was almost as accurate. To a lesser extent, the NYHA functional class was also an independent prognostic parameter during multivariate analysis. In conclusion, it appears that invasive haemodynamic parameters are best for determining the prognosis of patients with chronic heart failure. Peak VO2 can, however, be as useful. Moreover this is an easily obtainable non-invasive parameter, which makes it more useful in the evaluation and the follow up of such patients.

[4-year mortality of heart failure with intact systolic function: a retrospective studies]

Heart failure with normal systolic function has been recognised in 30-40% of patients investigated for congestive heart failure. The authors undertook a retrospective study of global and cardiovascular mortality at 4 years in two groups of patients with a history of congestive heart failure documented by equilibrium angioscintigraphy: group I (n = 109) with poor left ventricular systolic function (EF = 26 +/- 9%) and group II (n = 40) with normal systolic function (EF = 58 +/- 8%). The 4 year cardiovascular mortality was less in group II (21.6% vs 49%; p < 0.004) whereas the global mortality was comparable in the two groups. The only discriminating parameters for cardiovascular mortality between the two groups were age of more than 60 years and values of diastolic blood pressure exceeding 90 mmHg which were associated with a higher mortality in the group with normal systolic function. These results indicate a better prognosis in terms of cardiovascular mortality from congestive heart failure in patients with normal systolic function compared with those with poor systolic function.

Determination of free triiodothyronine by six different methods in patients with non-thyroidal illness and in patients treated with amiodarone

We performed a methodological comparison of free triiodothyronine (FT3) estimates in patients with liver cirrhosis and renal failure. Patients were classified in terms of severity of illness on the basis of their total triiodothyronine, total thyroxine and reverse triiodothyronine profiles. FT3 levels, measured in direct dialysis, microchromatography, labelled analogue and two-step immunoextraction assays were significantly (P < 0.01) lower than the control group in all patient categories. However, FT3 measured by a labelled antibody radioimmunoassay was significantly reduced only in the most severely ill sub-group of patients. In a further group of patients on long-term amiodarone therapy for cardiac disease all FT3 methods, with the exception of the labelled antibody radioimmunoassay and an analogue method, yielded significantly (P < 0.01) reduced levels. A significant negative association between FT3 and subject age was demonstrated for all methods except the labelled antibody radioimmunoassay, and a weak but significant negative correlation between log thyrotropin and FT3 was only seen with this assay. Three methods demonstrated a correlation (P < 0.02) with albumin levels in patients with the 'low T3 syndrome'. In this group, albumin had a predictive value (P < or = 0.02) for four out of six assays as determined by stepwise variable selection. Our findings suggest that users of FT3 assays should exercise caution in interpreting results in non-thyroidal illness and amiodarone treated patients, as there are method-related differences in the profiles obtained.

[The timing of cardiac transplantation]

The considerable progress realised over the last 20 years in the domain of cardiac transplantation has had, as a corollary, an ever increasing demand and a cruel shortage of available grafts, responsible for a high mortality of some of the candidates on the waiting list. This situation justifies a review of the objective criteria of eligibility for a more pertinent attribution of donor organs. A review of the recent literature suggests a logical process in the evaluation of candidates. The first step consists of optimisation of medical therapy. This allows classification of patients with respect to the clinical condition obtained, which may be "critical", "unstable" or "stable" and thereby retain the indication for transplantation in the first two groups in the absence of a contra-indication. The timing of the transplantation is more difficult to determine for the 60% or so of patients with a low ejection fraction and who have been stabilised. The measurement of peak VO2 on exercise, which appears to be the most powerful prognostic variable in these patients, with respect to a normal subject of the same age, allows identification of urgent indications for transplantation. Moreover, a 3 monthly follow-up of peak VO2 of patients on the waiting list or deferred also enables reconsideration of their inscription or non-inscription.

Comparison of treadmill and bicycle exercise in patients with chronic heart failure

The general opinion that treadmill exercise elicits circulatory reserve more than bicycle exercise derives from studies conducted in normal subjects or subjects with coronary artery disease. To investigate if this also occurs in patients with chronic heart failure (CHF), 40 patients (mean ejection fraction: 26 +/- 9 percent) with normal pulmonary function underwent in random order both treadmill (Naughton modified protocol, holding on handrails permitted) and bicycle (10 W/min) maximal exercise over a 1-week period. Peak oxygen uptake (19.6 +/- 5.3 vs 17.6 +/- 5.1 ml/min/kg, p < 0.0001), ventilatory threshold (14.4 +/- 4.7 vs 12.0 +/- 3.5 ml/min/kg, p < 0.0001), and minute ventilation (59 +/- 18 vs 55 +/- 15 L/min, p < 0.05) were greater on treadmill than on bicycle. Heart rate, systolic blood pressure, breathing rate, respiratory exchange ratio, perceived exertion scale, and lactate were identical. The coefficient of the correlation between oxygen uptake and time was greater with bicycle than with treadmill (r = 0.97 +/- 0.04 vs 0.90 +/- 0.07, p < 0.001). Thus, treadmill exercise is more suitable for determining peak oxygen uptake in patients with CHF. However, the increase in oxygen uptake is more regular with bicycle exercise.

[Role of the conditions of recording and analysis of the atrial signal on the results of ECG signal averaged P wave]

Several studies have shown that high amplification and averaging of the electrocardiographic P wave may soon enable better identification of people at high risk of paroxysmal atrial fibrillation. The results of this technique are closely dependent on the conditions of recording and analysis of the atrial signal but this factor has not been widely appreciated. The authors, therefore, undertook a study of the reliability of the manual method of measuring P wave duration, the influence of the filters used and the level of background noise on the 3 parameters of analysis: the duration of the P wave (DUR), the root mean square of the amplitude of the terminal 20 milliseconds (RMS20) and the integral under the P curve (IN). The recorder was a Predictor II 5.0 (Corazonix) with a special programme to identify and analyse the P wave in 3 bipolar non-orthogonal leads. DUR was determined manually after amplification and averaging; RMS20 and IN were calculated automatically. In order to assess the reliability of manual determination of the P wave, 48 consecutive patients were studied: two analyses were made with a least a 2 months' interval by entering the data through two filters (unidirectional and FIR). The role of the filters was then studied by passing the preceding 48 recordings to an analysis with three filters: unidirectional, bidirectional and FIR, and comparing the results.(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise peak VO2 determination in chronic heart failure: is it still of value?

The prognostic value of exercise peak VO2 is still controversial. We therefore prospectively studied 75 patients in New York Heart Association functional class II or III with chronic heart failure stabilized by drug treatment. The patients (mean age of 58 +/- 10 years) were submitted to a clinical examination, a radionuclide determination of left ventricular ejection fraction, and a haemodynamic study at rest (right side catheterization); their plasma sodium, plasma creatinine and blood urea nitrogen levels were measured in addition to exercise peak VO2. An exercise peak VO2 threshold value of 14 ml.kg-1.min-1 was used to define two groups: GI (23 patients), with an exercise peak VO2 < or = 14 ml.kg-1.min-1 and G2 (52 patients) with an exercise peak VO2 > 14 m.kg-1.min-1. G1 and G2 were comparable in terms of age, heart rate, left ventricular ejection fraction, cardiac index and mean arterial pressure. Apart from exercise peak VO2, G1 and G2 also showed differences in right and left ventricular filling pressures, plasma sodium, plasma creatinine, blood urea nitrogen levels and exercise duration (all P < 0.01). Moreover the prognosis was worse in G1 than in G2: nine deaths vs 0, and seven major events--major events being defined as pulmonary oedema, hospitalization for heart failure, or severe ventricular arrhythmias--vs three (P < 0.001). A sub-group analysis (deceased patients, living patients with and without major events) was performed. Out of 20 clinical and paraclinical parameters, exercise peak VO2 proved to have the greatest prognostic value.(ABSTRACT TRUNCATED AT 250 WORDS)