Differential Effect of Targeted Temperature Management Between 32 °C and 36 °C Following Cardiac Arrest According to Initial Severity of Illness: Insights From Two International Data Sets

BACKGROUND

Recent guidelines have emphasized actively avoiding fever to improve outcomes in patients who are comatose following resuscitation from cardiac arrest (ie, out-of-hospital cardiac arrest). However, whether targeted temperature management between 32 °C and 36 °C (TTM32-36) can improve neurologic outcome in some patients remains debated.

RESEARCH QUESTION

Is there an association between the use of TTM32-36 and outcome according to severity assessed at ICU admission using a previously derived risk score?

STUDY DESIGN AND METHODS

Data prospectively collected in the Sudden Death Expertise Center (SDEC) registry (France) between May 2011 and December 2017 and in the Resuscitation Outcomes Consortium Continuous Chest Compressions (ROC-CCC) trial (United States and Canada) between June 2011 and May 2015 were used for this study. Severity at ICU admission was assessed through a modified version of the Cardiac Arrest Hospital Prognosis (mCAHP) score, divided into tertiles of severity. The study explored associations between TTM32-36 and favorable neurologic status at hospital discharge by using multiple logistic regression as well as in tertiles of severity for each data set.

RESULTS

A total of 2,723 patients were analyzed in the SDEC data set and 4,202 patients in the ROC-CCC data set. A favorable neurologic status at hospital discharge occurred in 728 (27%) patients in the French data set and in 1,239 (29%) patients in the North American data set. Among the French data set, TTM32-36 was independently associated with better neurologic outcome in the tertile of patients with low (adjusted OR, 1.63; 95% CI, 1.15-2.30; P = .006) and high (adjusted OR, 1.94; 95% CI, 1.06-3.54; P = .030) severity according to mCAHP at ICU admission. Similar results were observed in the North American data set (adjusted ORs of 1.36 [95% CI, 1.05-1.75; P = .020] and 2.42 [95% CI, 1.38-4.24; P = .002], respectively). No association was observed between TTM32-36 and outcome in the moderate groups of the two data sets.

INTERPRETATION

TTM32-36 was significantly associated with a better outcome in patients with low and high severity at ICU admission assessed according to the mCAHP score. Further studies are needed to evaluate individualized temperature control following out-of-hospital cardiac arrest.

New approach for hair keratin characterization: use of the confocal Raman spectroscopy to assess the effect of a thermal stress on human hair fiber

OBJECTIVE

The objective of our research was to investigate the heat-protecting effect of a product ex vivo and in vivo on human hair fibers.

METHODS

A preparatory study was carried out in order to determine an optimal threshold of thermal stress. For this, the structure of cross-sections of the hair fiber was observed by optical microscopy. Then, Scanning Electron Microscopy (SEM) and Confocal Raman Spectroscopy (CRS) were applied to analyze ex vivo and in vivo morphological and molecular damage in hair structure after heat stress. Finally, in vivo tests were used to collect consumer perception.

RESULTS

The preparatory study enabled us to determine an optimal stress threshold of 10 heating cycle for SEM and 5 heating cycle for CRS. Based on spectral hierarchical classification using Ward's clustering algorithm, the ex vivo Raman results show that the spectral signature of the hair treated and heated is very close to the negative control. This shows that the product preserves the keratin structure after thermal stress. These results were also confirmed by an in vivo Raman analysis performed on hair samples from 5 donors. In concordance with Raman results, SEM show that treated hair present lesser "bubbles" and "crackling" on the hair surface. Finally, the in vivo studies proved that hair was more protected from the heat.

CONCLUSION

The authors concluded that the product shows protective properties with respect to morphological and molecular heat damage. We also demonstrate that the product promotes the α-helix keratin conformation and preserves the S-S disulfide bands.

Epidemiology and impact of frailty in patients with atrial fibrillation in Europe

BACKGROUND

Frailty is a medical syndrome characterised by reduced physiological reserve and increased vulnerability to stressors. Data regarding the relationship between frailty and atrial fibrillation (AF) are still inconsistent.

OBJECTIVES

We aim to perform a comprehensive evaluation of frailty in a large European cohort of AF patients.

METHODS

A 40-item frailty index (FI) was built according to the accumulation of deficits model in the AF patients enrolled in the ESC-EHRA EORP-AF General Long-Term Registry. Association of baseline characteristics, clinical management, quality of life, healthcare resources use and risk of outcomes with frailty was examined.

RESULTS

Among 10,177 patients [mean age (standard deviation) 69.0 (11.4) years, 4,103 (40.3%) females], 6,066 (59.6%) were pre-frail and 2,172 (21.3%) were frail, whereas only 1,939 (19.1%) were considered robust. Baseline thromboembolic and bleeding risks were independently associated with increasing FI. Frail patients with AF were less likely to be treated with oral anticoagulants (OACs) (odds ratio 0.70, 95% confidence interval 0.55-0.89), especially with non-vitamin K antagonist OACs and managed with a rhythm control strategy, compared with robust patients. Increasing frailty was associated with a higher risk for all outcomes examined, with a non-linear exponential relationship. The use of OAC was associated with a lower risk of outcomes, except in patients with very/extremely high frailty.

CONCLUSIONS

In this large cohort of AF patients, there was a high burden of frailty, influencing clinical management and risk of adverse outcomes. The clinical benefit of OAC is maintained in patients with high frailty, but not in very high/extremely frail ones.

Compared prognostic impact of incident atrial fibrillation versus history of atrial fibrillation in patients with AMI: the FAST-MI programme

Background

History of atrial fibrillation (HxAF) and new onset atrial fibrillation (NOAF) at acute stage of MI are associated with poorer survival. Whether both entities carry an increased risk of stroke is uncertain.

Using data from the FAST-MI 2010 and 2015 registries, we analysed the associations between HxAF and NOAF and risk of 3-year death, nonfatal stroke or combined death or stroke.

Methods

The FAST-MI registries are nationwide French cohorts consecutively including AMI patients admitted over a 1-month period every 5 years. Baseline characteristics, acute management and medications at discharge are collected. Among 9460 patients with STEMI or NSTEMI, 610 (6.4%) had HxAF, and 626 (6.6%) developed NOAF.

Main characteristics

Table 1 Overall, NOAF was associated with larger and more severe AMIs.

Results

In hospital survivors, 3-year death was 8.6% in patients without AF, 23.2% in those with NOAF and 29.2% in those with HxAF. 3-year Kaplan-Meier rates of non-fatal stroke were 1.1%, 0.3% and 3.6%, respectively (Figure).

Compared with no AF, NOAF was not associated with non-fatal stroke (Cox HR, 95% CI: 0.17, 0.02–1.21), while HxAF was (HR, 95% CI 2.04, 1.13–3.66, P=0.017). Risk of death or stroke was increased for both NOAF (HR, 95% CI 1.35, 1.10–1.65, P=0.004) and HxAF (HR 95% CI, 1.37, 1.14–1.65, P=0.001). Risk of all-cause death at 3 years was increased for NOAF (HR, 95% CI 1.32, 1.09–1.60) and HxAF (HR, 95% CI 1.30, 1.09–1.55). The results were concordant in patients not receiving oral anticoagulants at discharge.

Conclusion

Both NOAF and HxAF are associated with increased risk of death at 3 years after AMI. NOAF, however, is not associated with an increased risk of non-fatal stroke.

Figure 1. Non-fatal stroke

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): Pharma companies

Joint Position Paper of the Working Group of Pacing and Electrophysiology of the French Society of Cardiology (SFC) and the Société française d'imagerie cardiaque et vasculaire diagnostique et interventionnelle (SFICV) on magnetic resonance imaging in patients with cardiac electronic implantable devices

Magnetic resonance imaging (MRI) has become the reference imaging for the management of a large number of diseases. The number of MR examinations increases every year, simultaneously with the number of patients receiving a cardiac electronic implantable device (CEID). A CEID was considered an absolute contraindication for MRI for years. The progressive replacement of conventional pacemakers and defibrillators by MR-conditional CEIDs and recent data on the safety of MRI in patients with "MR-nonconditional" CEIDs have progressively increased the demand for MRI in patients with a CEID. However, some risks are associated with MRI in CEID carriers, even with "MR-conditional" devices because these devices are not "MR-safe". A specific programing of the device in "MR-mode" and monitoring patients during MRI remain mandatory for all patients with a CEID. A standardized patient workflow based on an institutional protocol should be established in each institution performing such examinations. This joint position paper of the Working Group of Pacing and Electrophysiology of the French Society of Cardiology and the Société française d'imagerie cardiaque et vasculaire diagnostique et interventionnelle (SFICV) describes the effect and risks associated with MRI in CEID carriers. We propose recommendations for patient workflow and monitoring and CEID programming in MR-conditional, "MR-conditional nonguaranteed" and MR-nonconditional devices.

P1021Low incidence of atrial tachycardia following ablation of low voltage areas in sinus rhythm for persistent atrial fibrillation

.  Background: Dedicated ablation strategies for persistent atrial fibrillation (AF) have shown a limited success rate with frequent atrial tachycardia (AT) occurrence. Recent studies suggest that atrial arrhythmogenic sites are related to tissular heterogeneities and increased fibrosis can be identified as reduced bipolar voltage areas.

. Purpose: Targeting low voltage areas (LVA) in addition to PVI may represent an efficient strategy for the ablation of persistent AF, and may limit the risk of AT recurrence.

. Methods: We prospectively included consecutive patients with symptomatic persistent AF. The ablation strategy consisted of the following steps: circumferential pulmonary vein isolation (CPVI), Sinus rhythm restoration by electrical cardioversion, voltage map performed in sinus rhythm. Complementary RFA was guided by low voltage areas (0.2-0.4 mV). Success was defined as freedom from AF/ atrial flutter or atrial arrhythmia at 12 months or more.

. Results:  101 patients (mean age: 62.5 +/- 10.4 years, men 73%) were included with persistent AF or long standing AF (7%). Procedure time was: 154 ± 25 min and fluoroscopy time: 184 ± 90 sec. Time of RFA was 44.7 +/- 12 min. Mean LA volume was 182 +/- 38 mL. LVA were found in 50 patients (49.5%). The distribution of these areas was:  30 anterior wall 29.7%), 21 septum (20.7%), 19 roof (18.8%), 5 inferior (4.9%), 11 left appendage (10.8%), 6 posterior (5.9%), 3 mitral isthmus (3%). RF ablation was realized for all LVA and homogenisation was attempt. After a single procedure at a mean FU of 12 months, 72.3% of patients were free of symptomatic AF. 27 patients had recurrence of atrial AF: 7 permanent, 15 persistent and 5 paroxysmal AF. Predictive factors of recurrence of AF were: long standing persistent AF, large left atrial volume (> 205 mL), shorts AF cycle length (< 168 ms) and reduce LEVF (< 45%). Atrial tachycardia occurred in 5 patients (4,9%). Mechanisms of AT were: typical cavo-tricuspid flutter in one patient, peri-mitral flutter in 2 patients, and atrial focal tachycardia (close to pulmonary veins) in 2 patients.

. Conclusion: These results suggest that PVI with complementary RF ablation guided on low voltage areas is an efficient strategy for symptomatic persistent AF, and reduce the recurrence of AT following this ablation strategy.

The mechanism of action of zopiclone

The mechanism of action of the cyclopyrrolone hypnotic drug zopiclone involves allosteric modulation of the GABAAreceptor. Zopiclone displaces the binding of [3H]-flunitrazepam with an affinity of 28 nM, and enhances the binding of the channel blocker [35S]-TBPS. The binding of zopiclone, unlike that of hypnotic benzodiazepines, is not facilitated by GABA. Zopiclone does not distinguish between GABAA receptors containing different α-subunits (BZ1and BZ2phenotype). Studies with protein-modifying agents (egdiethylpyrocarbonate) and photoaffinity labelling suggest that cyclopyrrolones bind to a domain on the GABAA receptor different from the benzodiazepine binding domain. The consequence of this interaction with the GABAAreceptor is to potentiate responses to GABA, as can be demonstrated by electrophysiological methods. Subchronic treatment of mice with high doses of zopiclone does not produce the changes in sensitivity of the GABAAreceptor that are observed with hypnotic benzodiazepines.

Implementation of a classification strategy of Raman data collected in different clinical conditions: application to the diagnosis of chronic lymphocytic leukemia

The literature is rich in proof of concept studies demonstrating the potential of Raman spectroscopy for disease diagnosis. However, few studies are conducted in a clinical context to demonstrate its applicability in current clinical practice and workflow. Indeed, this translational research remains far from the patient's bedside for several reasons. First, samples are often cultured cell lines. Second, they are prepared on non-standard substrates for clinical routine. Third, a unique supervised classification model is usually constructed using inadequate cross-validation strategy. Finally, the implemented models maximize classification accuracy without taking into account the clinician's needs. In this paper, we address these issues through a diagnosis problem in real clinical conditions, i.e., the diagnosis of chronic lymphocytic leukemia from fresh unstained blood smears spread on glass slides. From Raman data acquired in different experimental conditions, a repeated double cross-validation strategy was combined with different cross-validation approaches, a consensus label strategy and adaptive thresholds able to adapt to the clinician's needs. Combined with validation at the patient level, classification results were improved compared to traditional strategies.

Extracorporeal cardiopulmonary resuscitation in out-of-hospital cardiac arrest: a registry study

Aims

Out-of-hospital cardiac arrest (OHCA) without return of spontaneous circulation (ROSC) despite conventional resuscitation is common and has poor outcomes. Adding extracorporeal membrane oxygenation (ECMO) to cardiopulmonary resuscitation (extracorporeal-CPR) is increasingly used in an attempt to improve outcomes.

Methods and results

We analysed a prospective registry of 13 191 OHCAs in the Paris region from May 2011 to January 2018. We compared survival at hospital discharge with and without extracorporeal-CPR and identified factors associated with survival in patients given extracorporeal-CPR. Survival was 8% in 525 patients given extracorporeal-CPR and 9% in 12 666 patients given conventional-CPR (P = 0.91). By adjusted multivariate analysis, extracorporeal-CPR was not associated with hospital survival [odds ratio (OR), 1.3; 95% confidence interval (95% CI), 0.8–2.1; P = 0.24]. By conditional logistic regression with matching on a propensity score (including age, sex, occurrence at home, bystander CPR, initial rhythm, collapse-to-CPR time, duration of resuscitation, and ROSC), similar results were found (OR, 0.8; 95% CI, 0.5–1.3; P = 0.41). In the extracorporeal-CPR group, factors associated with hospital survival were initial shockable rhythm (OR, 3.9; 95% CI, 1.5–10.3; P = 0.005), transient ROSC before ECMO (OR, 2.3; 95% CI, 1.1–4.7; P = 0.03), and prehospital ECMO implantation (OR, 2.9; 95% CI, 1.5–5.9; P = 0.002).

Conclusions

In a population-based registry, 4% of OHCAs were treated with extracorporeal-CPR, which was not associated with increased hospital survival. Early ECMO implantation may improve outcomes. The initial rhythm and ROSC may help select patients for extracorporeal-CPR.

P999Major adverse events with percutaneous left atrial appendage closure in patients with atrial fibrillation in real life setting

Methods

We analysed data from all AF patients treated with Watchman or Amplatzer LAA closure according to European guidelines in 8 French cardiology departments. Antithrombotic management was decided for each patient on an individual basis. A Cox regression model was used for multivariable analysis of major adverse events. Yearly rate of ischemic stroke during follow-up was calculated and compared to that expected for a same risk score population. Yearly rate of bleeding was extrapolated from that reported with the HASBLED score.

Results

A total of 469 consecutive AF patients (299 males, 74.9±8.9 years old, mean CHA2DS2-VASc score 4.5±1.4, HASBLED score 3.7±1.0) received LAA closure from March 2012 to January 2017. There were 272 Watchman devices (58%) and 197 ACP devices (42%) implanted. At discharge, 36% received a single anti platelet therapy (APT), 23% received dual APT, 29% received OAC and no APT, 5% received OAC plus APT and 8% received no antithrombotic therapy. Mean follow up was 11.4 months (median 7, interquartile 3–22 months) during which 70 major adverse events (19 ischemic strokes, 18 major haemorrhages and 33 deaths) were recorded in 69 patients. The annual rate of ischemic stroke was 3.96%, which translates into a 13% relative risk reduction (95% CI −59 to 52%) as compared with the calculated stroke rate for similar CHA2DS2-VASc score after adjustment for exposure to APT and OAC. The annual rate of major bleeding in the study was 3.75%, which corresponds to a 48% relative risk reduction (95% CI 9 to 70%) as compared with the rate that would have been expected based on a comparable HAS-BLED score. Yearly rate of mortality was 7.4% (2.5 to 3 fold higher than in previous randomized trials) and the rate of non-cardiovascular death was 82%. None of the baseline characteristics was predictive of major adverse events, neither in univariate nor in multivariable analysis, which highlights the difficulty in identifying a risk of unfavourable outcome with simple tools.

Conclusions

AF patients treated with LAA closure may have a lower risk of stroke and bleeding events compared to their theoretical risk. However, our findings indicate that a high rate of major adverse events is observed in these patients during follow-up. This questions the suggested cost-effectiveness of the procedure (with models based on previous trials) for a real-life perspective. A better identification of patients with a relevant benefit of LAA closure is needed among those with long-term anticoagulation contraindication, both for an optimal management of each patient on an individual basis and for a global perspective with limited healthcare resources.

Conformation changes in human hair keratin observed using confocal Raman spectroscopy after active ingredient application

OBJECTIVE

In hair care cosmetic products' evaluation, one commonly used method is to evaluate the hair appearance as a gold standard in order to determine the effect of an active ingredient on the final state of the hair via visual appreciation. Although other techniques have been proposed for a direct analysis of the hair fibres, they give only surface or structural information, without any accurate molecular information. A different approach based on confocal Raman spectroscopy has been proposed for tracking in situ the molecular change in the keratin directly in the human hair fibres. It presents a high molecular specificity to detect chemical interactions between molecules and can provide molecular information at various depths at the cortex and cuticle levels.

METHODS

To evaluate the potential of confocal Raman spectroscopy in testing the efficiency of cosmetic ingredients on keratin structure, we undertook a pilot study on the effectiveness of a smoothing shampoo on natural human hair, by analysing α-helix and β-sheet spectral markers in the Amide I band and spectral markers specific to the cystin sulfur content.

RESULTS

We confirmed that an active proved to be effective on a gold standard decreases α-helix keratin conformation and promotes β-sheet keratin conformation in the hair fibres. We also showed that treatment with the effective active decreases the intensity of covalent disulfide (S-S at 510 cm-1 ) cross-linking bands of cysteine. These data confirm that the effective active also acts on the tertiary structure of keratin.

CONCLUSION

From these experiments, we concluded that the effective active has a smoothing effect on the human hair fibres by acting on α-helix and β-sheet keratin conformation and on the tertiary structure of keratin. Based on these results, confocal Raman spectroscopy can be considered a powerful technique for investigating the influence of hair cosmetic ingredients on keratin structure in human hair fibres. Moreover, this analytical technique has the advantage of being non-destructive and label free; in addition, it does not require sample extraction or purification and it can be applied routinely in cosmetic laboratories.

Human skin penetration of hyaluronic acid of different molecular weights as probed by Raman spectroscopy

BACKGROUND

Topical delivery of molecules into the human skin is one of the main issues in dermatology and cosmetology. Several techniques were developed to study molecules penetration into the human skin. Although widely accepted, the conventional methods such as Franz diffusion cells are unable to provide the accurate localization of actives in the skin layers. A different approach based on Raman spectroscopy has been proposed to follow-up the permeation of actives. It presents a high molecular specificity to distinguish exogenous molecules from skin constituents.

METHODS

Raman micro-imaging was applied to monitor the skin penetration of hyaluronic acids (HA) of different molecular weights. The first step, was the spectral characterization of these HA. After, we have determined spectral features of HA by which they can be detected in the skin. In the second part, transverse skin sections were realized and spectral images were recorded.

RESULTS

Our results show a difference of skin permeation of the three HA. Indeed, HA with low molecular weight (20-300 kDa) passes through the stratum corneum in contrast of the impermeability of high molecular weight HA (1000-1400 kDa).

CONCLUSION

Raman spectroscopy represents an analytical, non-destructive, and dynamic method to evaluate the permeation of actives in the skin layers.

Contribution of Raman spectroscopy in nephrology: a candidate technique to detect hydroxyethyl starch of third generation in osmotic renal lesions

Raman spectroscopy, a candidate tool for detection of HES, a volume expander administrated after hemodynamic instability, in the kidney.

[Atrial fibrillation and heart failure: a dangerous criminal conspiracy]

Atrial fibrillation (AF) and heart failure (HF) often coexist. Both associated with an altered prognosis, their coexistence is associated with a higher mortality. This dangerous criminal conspiracy is explained by common risk factors but also by a strong causative relationship. AF can be the cause of HF, especially by leading to a tachycardia-induced cardiomyopathy, either isolated or associated to an underlying heart disease. HF is a common cause of AF. It remains to be determined whether AF is an independent mortality risk factor or a simple marker of advanced HF, perhaps because available therapeutic tools are not enough successful to prevent AF.

Histopathological characterization of primary cutaneous melanoma using infrared microimaging: a proof-of-concept study

BACKGROUND

The diagnosis of malignant melanoma is based upon the histological evaluation of the lesion. As such, the morphological interpretation relies on the expertise of a dermatopathologist. Infrared microimaging is emerging as a new powerful tool to investigate tissue biochemistry. Infrared spectra probe the biochemical constitution of the sample and are real tissue-specific spectroscopic fingerprints.

OBJECTIVES

To assess the potential of infrared microimaging to aid in the analysis of tissue sections from primary cutaneous melanomas.

METHODS

Ten samples of melanoma sections from the main histological subtypes were investigated using infrared microimaging combined with multivariate statistical analyses.

RESULTS

This methodology yielded highly contrasted colour-coded images that permitted to highlight tissue architecture without any staining. It was possible to discriminate tumour areas from normal epidermis automatically, and intratumoral heterogeneity as revealed by our approach was correlated with the aggressiveness of the tumour.

CONCLUSIONS

This proof-of-concept study shows that infrared microimaging could help in the diagnosis of primary cutaneous melanoma.

Confocal Raman microspectroscopy on excised human skin: uncertainties in depth profiling and mathematical correction applied to dermatological drug permeation

Confocal Raman microspectroscopy represents the advantage of giving structural and conformational information on samples without any destructive treatment. Recently, several studies were achieved to study the skin hydration, endogenous and exogenous molecules repartition in the skin using the confocal feature of this technique. Meanwhile, when working through a material boundary with a different refractive index, the main limitation remains the spatial precision, especially the distortion in the depth and the depth resolution. Recently, several authors described mathematical models to correct the depth and the resolution values. In this study, we combined theoretical approaches, proposed by different authors with experimental measurements to try to find out the most appropriate approach for correction. We then applied the corrections on in-depth profiles tracking the penetration of Metronidazole, a drug produced by Galderma for rosacea treatment, through excised human skin.

Changes in adsorption and permeability of mitoxantrone on plasma membrane of BCRP/MXR resistant cells

A selective analysis of adsorbed mitoxantrone (MTX) was performed by surface-enhanced Raman scattering (SERS) at the range of cellular membrane. Disruption of the membrane fluidity was carried out to appraise changes in membrane adsorption of MTX and drug uptake in sensitive (HCT-116 S) and resistant BCRP/MXR (HCT-116 R) cells. Based on spectral MTX modifications, micro-SERS spectroscopy discriminated clearly drug adsorption phenomena on plasma membrane from drug in solution. A 3-fold higher SERS intensity of MTX for HCT-116 R was observed concluding to a higher drug adsorption on resistant membrane. The increase of membrane fluidity with benzyl alcohol (BA) or chloroform (CF) resulted in a 3-fold decrease of MTX adsorption on HCT-116 R, exclusively. BA and CF improved intracellular accumulation of MTX (e.g., 823 and 191 pmol MTX/10(6) HCT-116 R incubated with or without BA). At 4 degrees C, drug accumulation measurements showed a decrease of MTX permeability in resistant membrane (42 pmol MTX/10(6) cells), restored with fluidizers (e.g., 342 pmol MTX/10(6) cells with BA). Fluorescence confocal microscopy involved an exclusive MTX emission around the plasma membrane of resistant cells whereas fluidizers increased the intracellular uptake of MTX in both cell lines at the same time with less drug emission around the plasma membrane. Changes of the membrane structure of resistant cells should modify both drug adsorption and membrane permeation.

[The choice of pacing sites: should we change our practice?]

For the past 45 years the sites used for elective pacing have been the apex of the right ventricle and the right atrium. Although the initial objective of pacing was the "simple" correction of a conduction disorder, a more recent evolution has been to achieve a favourable haemodynamic effect, considering left ventricular filling and synchronisation of ventricular contraction as essential. Demonstration of the benefit in terms of survival brought about by pacing in atrioventricular block has not required large trials. However, it is possible that this improvement in morbidity and mortality is in part offset by the altered haemodynamics due to pacing at the right ventricular apex. At the atrial level, the prevention of AF is the holy grail of atrial pacing, but is far from being attained, perhaps because the physiopathological bases are not clear and have not really been demonstrated, casting doubt on the final objective. The choice of pacing site is essential in this context, as much in the atrium as in the ventricle. The current problem regarding this choice is the same as for all medical treatment, where the risk/benefit ratio is evaluated: if the usual sites are potentially deleterious, is it possible to continue using them or is it necessary to change implantation practices, and what level of proof is needed?

[Predictive criteria of early recurrence of atrial arrhythmia after reduction by electrical cardioversion]

The management of atrial arrhythmias aims not only to restore sinus rhythm but also to maintain it. Ten to thirty per cent of patients have early recurrence of atrial arrhythmias, the treatment of which remains empiric. The aim of this study was to define factors predictive of early recurrence of atrial arrhythmias and the consequences on the length of hospital stay. A series of 131 patients who underwent reduction of atrial arrhythmias by electrical cardioversion was studied retrospectively. A recurrence within 24 hours was observed in 12.2% of the patients. These recurrences significantly increased the length of hospital stay (6.8+/-6.3 versus 3.6+/-3.8 days, p=0.005). This study confirms two previously reported results with respect to more long-term recurrences. In the "early recurrence" group, the duration of the atrial arrhythmia was longer (p=0.003) and there were fewer treatments with amiodarone (p=0.03). In addition, original results were obtained. In the "early recurrence" group, the patients were more often treated with furosemide (p=0.02), class Ic antiarrhythmics (p=0.007) or anaesthetised with thiopental (p=0.002) than patients without early recurrences. Experimental data explain these results. However, they require confirmation by a prospective randomised trial.

[Electrophysiologic remodeling and drug treatment of atrial fibrillation]

Since 1995, a number of studies have established and detailed the mechanisms of electrical and structural atrial remodeling induced by atrial fibrillation. Atrial remodeling involves many cellular components, from ionic channels to connexins. The determination of these mechanisms may help to define a new therapeutic targets of atrial fibrillation, a frequent arrhythmia that remains difficult to treat. Atrial remodeling prevention may lead to limit the evolution of the arrhythmia (early recurrences after reduction, AF secondary to atrial tachycardia, permanent AF, decrease in atrial contractility, sinus dysfunction). Except amiodarone, the usual antiarrhythmic drugs have no effect on atrial remodeling. Calcium channel inhibitors prevent early remodeling but have no effect on prolonged remodeling. Digoxin increases remodeling. Angiotensin II receptor inhibitors have been shown to prevent early AF recurrence after reduction and are very promising in such a direction. Other methods such as the one of antioxidant therapy seem to be promising and could define soon a new antiarrhythmic therapeutic class, the antiremodeling drugs.

[External electrical cardioversion of atrial arrhythmia: predictive criteria of success]

AIM

Supraventricular arrhythmia is a major public health problem because of its prevalence and clinical consequences. The first step of the treatment usually consists in restoring sinusal rhythm. The aim of this study is to evaluate results and predictive factors of success of electrical cardioversion.

METHODS

We studied a series of 143 consecutive electric cardioversion preformed in 131 French patients.

RESULTS

The rate of successful direct current cardioversion was 91.2%. Negative predictive factors are the height body mass index and the age of arrhythmia. Atrial flutter is a predictive factor of success. These results agree with published results. Our study highlights the interest of some nonantiarrhythmic drugs received by the patient during the period before the direct current cardioversion. Thus, a spironolactone treatment appears to be a new predictive factor of the success of electrical cardioversion (success in patients treated with spironolactone: 100% vs 89% without, P = 0.04).

CONCLUSIONS

Our results agree with usual predictive factors of the success of cardioversion. Nevertheless, a new approach is that of the positive effect of spironolactone on cardioversion. A prospective randomized study is necessary to confirm this result.

[Arrhythmic cardiomyopathy]

Arrhythmic cardiomyopathy (ACM) is a clinical entity which can be reproduced in experimental models and which corresponds to all myocardial changes induced by chronic tachycardia. It may affect the atria and/or ventricles and, in this case, occur with all types of arrhythmia. Arrhythmia complicating a cardiomyopathy is the differential diagnosis of ventricular ACM. Nevertheless, the potential deleterious haemodynamic changes of any chronic arrhythmia may aggravate pre-existing ventricular dysfunction and, therefore, should always be considered. The development of ACM is usually progressive and depends on the heart rate, but there may also be a myocardial predisposition in certain cases. ACM is an association of haemodynamic, electrophysiological, metabolic and histological changes. Regression, which is the rule, starts in the first days following control of the ventricular rhythm but continues clinically over several months. The physiopathological mechanisms of ACM are multiple and include essentially abnormal cellular calcium concentrations. The treatment is optimally the restoration and maintenance of sinus rhythm, or at least control of the ventricular rate. Because of its curative effects, selective radiofrequency ablation of the arrhythmogenic substrate is the treatment of choice when this is localised. In chronic atrial fibrillation, when sinus rhythm cannot be maintained, the control of the ventricular response at rest and on exercise depends on pharmacological treatment, and, when ineffective, on radiofrequency modification of atrioventricular conduction with optimisation of the pacing mode.

[Electrophysiological remodeling induced by atrial fibrillation. An experimental curiosity or major factor in atrial fibrillation in man?]

Atrial fibrillation usually progresses from a paroxysmal to a permanent arrhythmia, even in the absence of underlying cardiac disease. The treatment is more difficult when the arrhythmia is chronic. This progression may be explained by the aggravation of underlying cardiac disease with time. Another explanation is that the arrhythmia induces functional and structural changes of the atrial tissues (remodelling) which promote the perpetuation of the arrhythmia and which make treatment less effective. Although the electrophysiological changes predisposing to atrial fibrillation have been known for over 15 years, it was only in 1995 that experimental studies showed the presence of atrial electrophysiological remodelling induced by the arrhythmia. This process of long term adaptation of the atrial myocytes to the tachycardia comprises marked changes of the parameters which sustain the arrhythmia: changes in refractory period (decreased duration, inadaptation to the heart rate, increased dispersion), reduced conduction speed and sinus dysfunction. Atrial remodelling also affects the contractile function by the structural changes. The calcium currents play a major role in its development. This mechanism has not yet been completely defined in the clinical setting and its importance in sustaining the arrhythmia has not been clearly evaluated. Atrial fibrillation remains one of the most difficult arrhythmias to treat. A better understanding of cellular mechanisms of remodelling could open up new therapeutic approaches to limit the natural history of the arrhythmia with progression to chronicity and structural changes responsible for the degradation of atrial contractility.

Temporal and geographical trends in indications for implantation of cardiac defibrillators in Europe 1993-1998. Medtronic ICD System Investigators

Despite the demonstrated efficacy of implantable cardioverter defibrillators (ICDs) in reducing sudden and total mortality in selected populations, their implantation rates vary greatly between countries. The aim of our study was to analyze temporal and geographical trends in ICD implantations in countries with similar health related expenditure in Western Europe. A total of 2,257 patients from ten European evaluation studies of Medtronic defibrillators and defibrillation electrodes, conducted between 1993 and 1998, representing 12 countries, was included in this analysis. Rates of implantation and clinical characteristics were compared between countries and years of implantation. Rates of implantation differed greatly between Western European countries and did not correlate with indices of health related expenditure (i.e., number of patients per physician and number of patients per hospital bed). However, there was a strong and statistically significant negative correlation between the use of amiodarone and the rates of implantation (r = -0.66, P = 0.02). Temporal trends showed a significant increase in the age of the patients receiving an ICD between 1993 and 1998 (57 +/- 14 vs 61 +/- 12 years, mean +/- SD, P < 0.001). There was also a temporal trend towards an increased incidence of coronary artery disease and a significant decrease in the incidence of cardiomyopathy. There was a temporal increase in implantations in patients with a history of ventricular tachycardia. Despite a general scientific agreement that ICDs are a first line treatment for patients at high risk of sudden cardiac death, their acceptance remains low in several developed countries. This low acceptance may not be entirely related to budget constraint but may also be related to their perceived efficacy by physicians and health authorities.

[Heart rate and mortality: review of the literature]

A great number of studies focussed on a wide variety of subjects have been concerned with the subject of morbi-mortality and the effect of heart rate. These studies show that there is a connection between high heart rate and arterial hypertension, and a significant coronary, cardiovascular, non-cardiovascular and overall mortality risk. Two explanations are possible for this. The increase in heart rate together with associated sympathetic hyperactivity can be considered a cardiovascular risk factor: or it could be viewed as an independent risk factor, associated with an increase in mechanical constraints.

Blood pressure response to the first 36 hours of heart failure therapy with perindopril versus captopril. French General Hospitals National College of Cardiologists

An open randomized hospital study conducted in 169 centers in France compared the blood pressure response to the first 36 h of treatment with perindopril (PER), 2 mg once daily, with that to captopril (CAP), 6.25 mg t.i.d., in 725 patients (mean age, 70 years; men, 67%) with echocardiographic left ventricular systolic dysfunction (fractional shortening, < or = 28%) due to ischemia (56.7%) or hypertension (34.5%) and a systolic blood pressure (SBP) > or = 120 mm Hg. Each dose of CAP induced a sharp and rapid decrease in blood pressure (maximum, 1.5-2 h); with PER, the decrease was gradual (maximum, 6 h) and variation was less marked. However, at 36 h, the decrease in blood pressure versus baseline was similar on both treatments. Over the 36-h period, there were 22 (3%) dropouts due to marked orthostatic hypotension (SBP, <90 mm Hg), and they were fewer with PER than with CAP: 16 cases in the CAP group versus six in the PER group (p = 0.036). At 36 h, heart rate was lower with CAP than with PER: 75.2 versus 77.5 beats/min, respectively (p = 0.039). As initial therapy for stabilized left ventricular systolic dysfunction, the first dose of PER (2 mg) induced a significantly smaller decrease in blood pressure than the first dose of CAP (6.25 mg); dropouts due to orthostatic hypotension were also significantly fewer with PER than with CAP.

[A randomized double-blind trial comparing cibenzoline and disopyramide in the prevention of recurrences of atrial tachyarrhythmia]

The aim of this multicenter, randomised, double-blind trial was to compare the efficacy and tolerance of oral disopyramide (D: 250 mg slow release twice daily) compared with cibenzoline (C: 130 mg twice daily) in the prevention of recurrences of atrial arrhythmias over a 6 month period. Sixty patients (mean age: 62 +/- 14 years; 37 men, 23 women; cardiac disease in 60% of cases) were randomised to two groups: C (N = 31) and D (N = 29). The commonest arrhythmia was atrial fibrillation (83%). The arrhythmia was recent (< 3 months) in 41% of patients and present for more than one year in 38% of patients. Sixteen patients of Group C (52%) and 11 of Group D (38%) had recurrences after an average of 79 +/- 58 days for Group C and 58 +/- 40 days for Group D (p = NS). The probability of absence of recurrence at 6 months was 36 +/- 11% in Group C and 55 +/- 10% in Group D (p = NS). Four patients in Group C (13%) and 13 patients in Group D (45%) had at least one unwanted side-effect (p = 0.009). Treatment was stopped because of side-effects in 2 patients in group C (6%) and 6 patients in Group D (21%). These results show that cibenzoline has a comparable efficacy for the prevention of recurrence of atrial tachyarrhythmia and is significantly better tolerated than disopyramide. This differences is mainly related to the marked anticholinergic effects of disopyramide.

[Management of arrhythmias in patients with heart failure]

Cardiac failure is a common cause of arrhythmia. Many factors predispose to the genesis of arrhythmias in these patients. A number of non-invasive methods allow stratification of the risk of arrhythmia in cardiac failure. Approximately half the deaths of these patients are due to arrhythmia. Unfortunately, most of the investigations for risk evaluation have a high negative predictive value but a lower positive predictive value. The treatment of supraventricular arrhythmias, mainly atrial fibrillation, is complex in cardiac failure. Class I antiarrhythmics are contraindicated. The only remaining options are Class II, especially Sotalol, and Class III drugs, especially Amiodarone. In some cases, non-pharmacological methods such as ablation, pacing or an implantable atrial defibrillator must be considered. The treatment of ventricular arrhythmias is also difficult. In this indication, Class I antiarrhythmic agents must also be avoided. Non-sustained ventricular tachycardia may be treated by betablockers or amiodarone. The use of an implantable defibrillator is increasingly recommended after the results of several controlled large scale trials. The indication is obvious in patients resuscitated from sudden death and these devices are also beneficial in sustained ventricular tachycardia in patients with cardiac failure. Many studies are currently under way to determine the value of this therapeutic modality in indications now considered to be "prophylactic".

Effects of a selective A1-adenosine receptor agonist on heart rate and heart rate variability during permanent atrial fibrillation

BACKGROUND

Mean heart rate and irregularity of the rate, i.e., heart rate variability (HRV), are two aspects of heart rate during atrial fibrillation (AF). An important goal of AF therapy is to control mean heart rate during exercise; the determinants of HRV during AF remain poorly known although its prognostic value has been established.

OBJECTIVES

To investigate the effects of a stable, long-acting, selective A1-adenosine receptor agonist, SDZ WAG994, on heart rate during exercise and on HRV.

METHODS

In a multicenter, double-blind, randomized, placebo-controlled, parallel group study, patients with permanent AF performed a symptom-limited exercise test and underwent 24-hour ECG monitoring on day 1 during treatment with placebo, and on day 2 during treatment with either placebo or 2 mg SDZWAG994 orally. Changes in mean heart rate during exercise and changes in HRV indices between day 1 and day 2 were compared between the two groups.

RESULTS

Thirty-two patients (64 +/- 8 years; 81% male; 25% in NYHA Class II; 38% with no structural heart disease) were included in the study. During active treatments, heart rate remained unchanged at rest and increased significantly during exercise. A significant daytime increase in short-term HRV indices (DpNN50 = 4.5% P = 0.01; DrMSSD = 6% P = 0.03; DSDNN Index = 6% P = 0.02) occurred during active treatment.

CONCLUSIONS

Selective A1-adenosine receptor agonism with SDZ/WAG994 limits the increase in mean heart rate during exercise in patients with AF. In addition, this agonist selectively increases short-term HRV indices, suggesting that pNN50, rMSSD, and SDNN reflect vagal influences during AF.

[Auricular vulnerability: what information can be obtained from the study of auricular vulnerability? How to perform this study?]

The factors involved in atrial vulnerability are the presence of intra-atrial conduction disorders and abnormalities of refractory periods which are short, dispersed and poorly adapted to heart rate. All these factors are arrthythmogenic. The main value of the study of atrial vulnerability consists of investigation of unexplained ischaemic cerebrovascular accidents in young subjects. In practice, atrial vulnerability can be measured in the context of a classical endocavitary electrophysiological investigation. The stimulation and recording parameters must be standardized. Latent atrial vulnerability can be considered to be present when at least one of the following elements are found: significant inducibility, very short and poorly adapted effective refractory periods, decreased latent atrial vulnerability index.

Electrophysiological effects of vasoactive intestinal peptide in rabbit atrium: a modulation of acetylcholine activity

Vasoactive Intestinal Peptide (VIP) is a 28-amino acid peptide partially co-secreted with acetylcholine (Ach) in the atrial tissue. We studied the electrophysiological effects of VIP and Ach in rabbit isolated right atrium by the microelectrode technique. After a 10-min superfusion with VIP, action potential duration at 90% of repolarization (APD90) was lengthened by 23% (P = 0.01) at the concentration of 10(-8) M (n = 10), by 22% (P = 0.004) at 10(-7) M (n = 10) and by 33% (P = 0.03) at 2 x 10(-7) M (n = 5). To explain this APD90 lengthening, we performed 10 other experiments with VIP 10(-7) M, including five preparations pretreated with verapamil (10(-6) M) for 20 min. In the five preparations not pretreated, APD90 was increased by 27% (P = 0.04) after 10 min but remained unchanged in those previously exposed to verapamil, suggesting that VIP is a calcium current activator. Ach (1.4 x 10(-5) M) was superfused in five other experiments and we observed a 31% decrease in APD90 (P= 0.04) at 10 min. After washout, we simultaneously perfused, on the same preparations, Ach (same concentration) and VIP (10(-7) M) for 10 min. The decrease in APD90 (19%) was no longer significant. VIP (2 x 10(-7) M) lengthened cellular effective refractory periods (ERP) by 26% (P = 0.04) after 10 min (n = 5), whereas Ach (1.4 x 10(-5) M) decreased ERP by 33% (P = 0.04) at 10 min (n = 5). In conclusion, VIP lengthens atrial APD90, which may be the result of calcium current activation. In addition, VIP could modulate Ach activity in limiting APD90 shortening in the presence of Ach and because of its opposite effect on atrial ERP. Therefore, VIP could be involved in the control of vagal atrial arrhythmias.