Search

N-acetylcysteine (NAC) may be best known for its role in the treatment for acetaminophen toxicity, but it’s well-documented antioxidant, antiplatelet, and vasodilatory effects have prompted multiple studies of its potential use in the treatment of several cardiac disease. The most prominent clinical application of NAC related to the cardiovascular diseases has been in the prevention of contrast-induced nephrotoxicity after coronary angiography/intervention (discussed in the chapter on applications of NAC in renal disease), but studies of its role as an adjunct to nitrate therapy and in the treatment of hypertension and acute myocardial infarction are significant and provocative. NAC has been studied for its potential protective effects after cardiac surgery regarding its potentially protective effects against acute postoperative renal failure and myocardial injury and in reducing postoperative atrial fibrillation. Studies of NAC use in hypertension and as an adjunct to nitrates for angina have focused on its ability to improve nitric oxide metabolism by potentiating its vasodilatory effects and limiting nitrate tolerance. Studies of its use in other cardiac conditions focus on its antioxidant effects, ability to be a free radical scavenger, and anti-inflammatory effects. Despite multiple individual studies showing positive results, NAC has yet to be established as a therapeutic agent for any of these cardiac conditions. Some of the issues limiting its widespread application are the variation in trial design and dosing schedules as well as failure of larger studies and meta-analysis to confirm its clinical utility. The limited benefits of NAC use that have been demonstrated in cardiac conditions need to be weighed against the potential for side effects and cost. Nevertheless, recent trials of its potential role in limiting infarct size and improving diastolic dysfunction hold promise and warrant further study. We believe that further well-designed larger controlled trials are needed to establish whether there is a clinical role for NAC therapy.

Background: Identifying the timing and morphology of an ectopic P wave from the surface electrogram can aid in the diagnosis and localization of atrial arrhythmias. Given the relatively short coupling interval of atrial ectopic beats, the P wave is often obscured by the larger amplitude QRS-T wave complex. A method to uncover such “buried” P waves using a standard 12-lead surface ECG would be clinically useful and could potentially be a noninvasive guide to catheter ablation of focal atrial tachycardia. Methods: We developed an automated computerized program (BARD DUO LAB SYSTEM™) designed to subtract the QRS-T wave complex from the surface electrogram and uncover a previously obscured P wave. The purpose of the present study was to validate this program. The surface ECG from 21 patients undergoing atrial pacing during electrophysiologic study (group I) and 10 patients with atrial tachycardia (group II) were analyzed and the derived P-wave morphology assessed using correlation waveform analysis (CWA) and visual grading by three reviewers. Results: The algorithm successfully uncovered the P wave in each surface ECG. For the 21 patients in group I, average CWA comparing the derived P wave with the previous paced P wave was 83%. Average CWA for group II was 82%. Visual grading of the match between derived P waves and paced P waves revealed a 21/21 match in group I patients and a 12/12 match in 9/10 of group II patients. Conclusions: An ectopic atrial P wave obscured by a coincident QRS-T wave complex can be accurately uncovered using this new algorithm. Addition of this technique to existing methods may improve the diagnosis of atrial arrhythmias and aid in the localization and ablation of ectopic atrial foci.

We report the percutaneous transcatheter closure of a patent foramen ovale using an Amplatzer septal occluder in a rare patient with carcinoid heart disease involving both the right and left heart who presented with severe hypoxemia secondary to intra-atrial shunting. We believe this is the first report of this technique being utilized in a patient with carcinoid heart disease and it may represent an alternative to surgical closure in these patients at high risk for surgical complications.

In this study the single-dose and steady-state pharmacokinetics of unchanged triflusal and its metabolite 2-hydroxy-4-trifluoromethylbenzoic acid (HTB) were studied in 12 elderly subjects treated with a single oral administration of 300 mg triflusal and repeated oral administrations of 300 mg triflusal b.i.d. for 13 days. After a single administration, unchanged triflusal is promptly absorbed (t(max) 0.75 h, C(max) 3.83mgr;g/mL) and rapidly depleted from the systemic circulation. Its concentration was measurable only up to 1 to 4 h after administration. The apparent terminal half-life was 0.85 h. HTB proves to be quickly generated from triflusal (t(max) 2.00 h, C(max) 39.88mgr;g/mL) and slowly eliminated from the body (t = 54.6 h). With the dose regimen proposed, unchanged triflusal does not accumulate in the body. Conversely, HTB plasma concentration builds up progressively toward steady-state levels of approximately 102mgr;g/mL after 4 to 5 d of treatment. No substantial change in peak time, elimination rate constant and half-life evaluated after single-dose treatment was observed on multiple-dose regimen for unchanged triflusal and its metabolite HTB. Therefore, our findings do not indicate a time-dependent pharmacokinetics for triflusal. There were no changes in blood pressure, heart rate or laboratory safety date, i.e., biochemical or hematological profiles.

MARENCO, J.P., et al.: Use of the AutoCapture Pacing System with Implantable Defibrillator Leads.Introduction: Previous studies using various bipolar pacemaker leads have shown that the AutoCapture (AC) Pacing System is able to verify ventricular capture and regulate pacing output, increasing patient safety with respect to unexpected threshold changes and potentially prolonging device longevity. An increasing number of patients with implantable cardioverter defibrillators (ICDs) require ventricular pacing that contributes to a shortening of longevity of these systems. This prospective study tested the compatibility of the AC system with bipolar ICD leads. Methods: The AC algorithm was evaluated prior to ICD testing in 30 ICD recipients. A single coil, active fixation, true bipolar ventricular lead was implanted in 21 patients, and a dual coil, passive fixation, integrated bipolar ventricular lead was implanted in 9 patients. A ventricular evoked response sensitivity test and an AC threshold test were performed using a pacemaker with the ventricular AC algorithm. Results: AC was recommended in 22/30 (73.3%) of implants, including 20/21 (95.2%) with the single coil and 2/9 (22.2%) with the dual coil lead. Mean polarization was lower (1.23 ± 0.95 mVvs3.70 ± 2.33 mV, P = 0.013) while the mean evoked response was higher (18.04 ± 8.29 mVvs10.13 ± 4.22 mV, P = 0.002) with the single coil leads. Conclusion: Automatic threshold tracking using the AC is compatible with ICD leads. Leads with lower polarization and greater evoked response are more likely to result in recommendation of AC use. Use of this system offers the potential for increasing ICD generator longevity and improving patient safety in response to late unexpected threshold increases. (PACE 2003; 26[Pt. II]:471–473)

Objectif Evaluer l’influence d’un stage d’entrainement intensif a la plongee sous-marine en bouteille sur la pression arterielle centrale et la distensibilite aortique. Methodes La pression arterielle aortique et carotide a ete obtenue par une methode non invasive de mesure de courbes de pression arterielle enregistrees a l’aide d’une technique de tonometrie au niveau radiale et carotide chez des plongeurs militaires (n = 34). La pression arterielle brachiale est obtenue par methode oscillometrique (Colin BP8800MS) et les pressions arterielles systolique et diastolique sont considerees pour le calcul de la pression arterielle moyenne obtenue au niveau de l’artere radiale par tonometrie. La vitesse de propagation de l’onde de pouls carotido-femorale a ete obtenue avec l’appareil complior (©). Les enregistrements ont ete realises chez chaque plongeur avant et apres un stage de plongee intensive d’une duree de 15 semaines (60 plongees entre 15 et 60 metres associees a une course a pied intensive quotidienne). Resultats les plongeurs (voir les caracteristiques dans le tableau) ont une pression arterielle brachiale qui n’est pas influencee par le stage intensif de plongee, de meme que les pressions arterielles evaluees au niveau aortique et carotide (voir tableau). De meme aucune influence du stage de plongee n’a ete note concernant l’amplification de la pression arterielle, la vitesse de propagation de l’onde de pouls et l’index d’augmentation. Seule la frequence est modifiee (60.3 +/- 1.61 vs 56.5 +/- 1.28 Batt/min ; p = 0.013 entre avant et apres le stage). Conclusion Nos premiers resultats indiquent que la pratique de la plongee sous-marine de facon intensive durant 15 semaines n’a pas d’influence sur la pression arterielle brachiale, centrale, et la vitesse de propagation de l’onde de pouls, malgre une baisse de la frequence cardiaque Download : Download full-size image .

ARDS developed in association with tumor lysis syndrome (TLS) in a patient with non-Hodgkin's lymphoma. Although a number of life-threatening complications have been noted to occur following TLS, this appears to be the first report of ARDS developing in association with TLS.

Objectives To evaluate central (carotid) artery blood pressure (BP) in endurance athletes. Methods Derived ascending aortic pressure and direct carotid pressure waveforms were recorded using radial and carotid tonometry at rest in 30 endurance athletes and 30 sedentary controls, all males matched for age, height, brachial systolic BP (SBP) and diastolic BP. Results Whereas brachial BP was similar in the two groups, carotid SBP and pulse pressure (PP) were higher in endurance athletes than in controls irrespective of age (123.1±2.17 vs. 110.2±1.29 mmHg, and 50.9±1.95 vs. 34.1±1.01 mmHg, respectively; p

Context Sudden cardiac death is a major public health problem in the United States, and improving survival after out-of-hospital cardiac arrest has been the subject of intense study. Early defibrillation has been shown to be critical to improving survival. Use of automated external defibrillators (AEDs) has become an important component of emergency medical systems, and recent advances in AED technology have allowed expansion of AED use to nontraditional first responders and the lay public. Objectives To examine advancements in AED technology, review the impact of AEDs on time to defibrillation and survival, and explore the future role of AEDs in the effort to improve survival following sudden cardiac arrest. Data sources MEDLINE was searched for articles from 1966 through December 2000 (Medical Subject Headings: electric countershock, heart arrest, resuscitation, emergency medical services; keywords: automatic external defibrillator, automated external defibrillator, public access defibrillation). Reference lists of relevant articles, news releases, and product information from manufacturers were also reviewed. Study selection Initial MEDLINE search produced 4816 articles, from which 101 articles were selected for referencing based on having been published in a peer-reviewed journal and on relevance to the subject of the manuscript as determined by all 5 authors. Data extraction All studies were critically reviewed for relevance, accuracy, and quality of data and study design by all authors. Data synthesis Recent advances in AED technology and design have resulted in marked simplification of AED operation, improvements in accuracy and effectiveness, and reductions in cost. Use of AEDs by first responders and laypersons has reduced time to defibrillation and improved survival from sudden cardiac arrest in several communities. Initial studies of the cost-effectiveness of AED use in comparison with other commonly used treatments are favorable. Conclusion The AED represents an efficient method of delivering defibrillation to persons experiencing out-of-hospital cardiac arrest and its use by both traditional and nontraditional first responders appears to be safe and effective. The rapidly expanding role of AEDs in traditional emergency medical systems is supported by the literature, and initial studies of public access to defibrillation offer hope that further improvements in survival after sudden cardiac death can be achieved.