Markus Zarse

Association of echocardiographic atrial size and atrial fibrosis in a sequential model of congestive heart failure and atrial fibrillation

BACKGROUNDnCardioversion (CV) success of atrial fibrillation (AF) inversely correlates to the size of the left atrium (LA). Atrial fibrillation and its most important risk factor, congestive heart failure (CHF), both induce atrial structural enlargement and fibrosis. To investigate the effect of AF and CHF on atrial dilatation and fibrosis, and to estimate whether echocardiographically determined atrial size may be used as a marker for atrial fibrosis.nnnMETHODSnIn six dogs, pacemakers were implanted followed by HIS bundle ablation. After 4 weeks of rapid ventricular stimulation (185 bpm) for CHF induction, additional rapid atrial stimulation (500 bpm) was maintained for 7 weeks to induce AF. Serial determinations of echocardiographic atrial size were performed. Seven dogs with sinus rhythm served as histological controls. Postmortem tissue was obtained to determine the degree and composition of atrial fibrosis.nnnRESULTSnWhile the ejection fraction of the AF/CHF dogs decreased significantly from 57+/-5% to 19+/-7% (P<.01), an increased degree of atrial fibrosis was found (right atrium [RA], 4.9+/-2.0% to 19.9+/-5.4%; LA, 4.4+/-1.6% to 22.2+/-3.2%; P<.01), accompanied by a significant increase of atrial volumes (LA: 21+/-4 to 44+/-4 mm3; P<.01; RA: 10+/-3 to 18+/-6 mm3; P<.05) and LA diameters (34+/-4 to 43+/-2 mm, P<.05). Atrial fibrosis and size significantly correlated.nnnCONCLUSIONSnAtrial fibrillation/CHF leads to a significant atrial fibrosis and dilation. The increased echocardiographic size correlates to the degree of atrial fibrosis and may be used as clinical marker for atrial fibrosis. The fibrosis accompanying atrial dilatation may also explain why LA size, as determined by echocardiography, is a strong predictor of CV success.

Chronic Augmentation of the Parasympathetic Tone to the Atrioventricular Node:A Nonthoracotomy Neurostimulation Technique for Ventricular Rate Control During Atrial Fibrillation

Long‐Term Cardiac Neurostimulation. Introduction: The right inferior ganglionated plexus (RIGP) selectively innervates the atrioventricular node. Temporary electrical stimulation of this plexus reduces the ventricular rate during atrial fibrillation (AF). We sought to assess the feasibility of chronic parasympathetic stimulation for ventricular rate control during AF with a nonthoracotomy intracardiac neurostimulation approach.

Dilatation of the pulmonary veins in atrial fibrillation: a transesophageal echocardiographic evaluation.

Ectopic beats originating from sleeves of atrial tissue within the pulmonary veins (PVs) can induce and sustain paroxysmal atrial fibrillation (AF). Left atrial stretch and dilatation favors the development of atrial ectopy and AF. Similarly, PV dilatation, if present, might trigger PV ectopy in patients with AF. This study was designed to evaluate whether PV dilatation is present in patients with nonfocal AF and whether the PV diameter correlates to the left atrial diameter (LAD). The diameters of the right superior (RSPV) and left superior PV (LSPV) were measured at the ostium and at a depth of 1 cm in 170 patients (AF, n = 75 ; sinus rhythm [SR], n = 95) using transesophageal echocardiography. The LAD was determined by transthoracic echocardiography. The diameters of the PVs were significantly larger in patients with AF than in patients with SR (LSPVostium: AF 13.6 ± 3.5 mm vs SR 10.6 ± 2.7 mm, P < 0.001 ; LSVP1cm: AF 12.5 ± 2.9 mm vs SR 10.2 ± 2.5 mm, P < 0.001 ; RSPVostium, AF 13.9 ± 3.5 mm vs SR 11.7 ± 2.9 mm, P < 0.001 ; RSVP1cm: AF 12.8 ± 2.8 mm vs SR 10.6 ± 2.6 mm, P < 0.05). Similarly, LAD was larger in patients with AF (44.7 ± 7.7 mm) as compared to patients with SR (38.8 ± 6.8 mm, P < 0.001). Neither for the SR nor the AF group did the PV size correlate to the LAD. AF is associated with a significant enlargement of the RSPV, LSPV, and LAD. There is no correlation between LAD and PV diameters. This raises the question whether PV dilatation in patients with AF is a cause or a consequence of AF and whether it may contribute to the development and perpetuation of AF. (PACE 2003; 26:1371–1378)

Telephonic transmission of 12-lead electrocardiograms during acute myocardial infarction:

To test the feasibility of a small and simple system for telephonic transmission of 12-lead electrocardiograms (ECGs), 70 patients with acute coronary syndrome admitted to the cardiac care unit (CCU) were included in a feasibility study. The transmission system consisted of a belt with multiple electrodes, which was positioned around the chest. The ECG signal was sent to a call centre via a standard telephone line. In parallel, a standard 12-lead ECG was recorded on site. In a retrospective analysis, each lead of the transmitted ECG was compared with the on-site 12-lead ECG with regard to ST-segment changes and final diagnosis. In all 37 patients with acute ST-elevation myocardial infarction, the diagnosis was correctly established on the basis of telephone-transmitted ECGs. In 96% of limb and 88% of chest leads, ST elevations which were visible in standard ECGs were correctly displayed on telephonically transmitted ECGs. In the remaining 33 patients no false-positive diagnosis was made using transtelephonic ECG analysis. A control group of 31 patients without apparent heart disease showed high concordance between standard ECGs and telephonically transmitted ECGs. Telephonically transmitted 12-lead ECGs interpreted by a hospital-based internist/cardiologist might allow a rapid and accurate diagnosis of ST-elevation myocardial infarction and may increase diagnostic safety for the emergency staff during prehospital decision making and treatment of acute myocardial infarction.

Prevalence, clinical correlates and treatment of permanent atrial fibrillation among the elderly: insights from the first prospective population-based study in rural Greece.

To investigate the prevalence of permanent atrial fibrillation (AF), its clinical associated conditions and treatment status in the elderly population in rural Greece. 720 people (46.1% males) older than 65xa0years (mean age: 72.5xa0±xa05.7xa0years) living in four villages in rural Greece were screened with an electrocardiogram (response rate: 90.5%) for the presence of permanent AF. They underwent a physical examination, including blood pressure (BP) measurement, and body mass index (BMI) calculation, in addition to an interview about their medical history, physical activity, smoking habits, alcohol consumption and medication use. Subjects with AF for whom anticoagulants were contraindicated were identified and stroke risk stratification was performed using the CHADS2 algorithm. The prevalence of permanent AF was 5% (6.6% among men and 3.6% among women) and it increased with age. In the entire population, ECG evidence of myocardial ischaemia and ventricular premature beats were independently associated with the presence of permanent AF (OR 5.266; 95% CI 2.22–12.49, Pxa0=xa00.0001 and OR 2.61; 95% CI 1.059–6.432, Pxa0=xa00.037, respectively), while female sex was independently associated with the absence of the AF (OR 0.327; CI 0.147–0.729, Pxa0=xa00.006). From those patients who were eligible for anticoagulation, 40.6% were treated with anticoagulants, 34.3% were given antiplatelets therapy and the rest received no antithrombotic treatment. This is the first prospective study demonstrating the prevalence, clinical correlates and treatment status of permanent AF in Greece. These results confirm the high prevalence of permanent AF among the elderly and underscore the issue regarding anticoagulants underutilization.

Targeting of cardiac autonomic plexus for modulation of intracardiac neural tone

AIMSnVentricular rate control is considered as an initial choice of therapy in many patients with atrial fibrillation (AF). We could previously show that electrostimulation of the right inferior ganglionated plexus (RIGP), which supplies the AV node, instantly decreases ventricular rate during AF. This study describes the development of a technique to reliably implant a chronic lead inside the RIGP.nnnMETHODS AND RESULTSnIn nine mongrel dogs with AF, the RIGP was identified by neuromapping with probatory high-frequency stimulation (20 Hz) over steerable electrode catheters until a significant ventricular rate slowing was achieved. Then an active fixation, permanent pacemaker lead was fixed closed to the mapping catheter left in place as anatomical marker. Initially (n = 4) available guiding catheters and steerable lead stylets were employed to navigate and anchor the lead, which resulted in repetitive screw-in attempts. Therefore, a guiding catheter was developed, which allowed angiography, lead advancement through its lumen, and probatory neurostimulation over its tip. This tool allowed lead delivery within 40 min (n = 5). Neurostimulation via the permanent lead elicited negative dromotropic effects with stimulation frequency, voltage, and impulse duration as determinants of stimulation efficacy.nnnCONCLUSIONnActive fixation of a permanent pacing lead inside the RIGP is feasible without thoracotomy. Thereby, ventricular rate control during AF can be achieved with stimulus voltages applied for myocardial electrostimulation.

Patient-tailored implantable cardioverter defibrillator testing using the upper limit of vulnerability: the TULIP protocol

AIMSnWe evaluated the feasibility of the TULIP (Threshold test using Upper Limit during ImPlantation) protocol, which was designed to provide a confirmed, low defibrillation energy value during implantable cardioverter defibrillator (ICD) implantation with only two induced ventricular fibrillation (VF) episodes.nnnMETHODS AND RESULTSnNinety-eight patients (62 +/- 12 years, 86 male) from 13 clinical centres underwent an active can ICD implantation. A single coupling interval derived from electrocardiogram lead II during ventricular pacing was used for VF induction shocks at 13, 11, 9, and 6 J in a step-down manner until the upper limit of VF induction (ULVI) was determined. If ULVI >or=9 J, a defibrillation energy of ULVI + 4 J was tested. For ULVI <9 J, the defibrillation test energy was 9 J. In 79/98 patients (80.6%), two induced VF episodes were sufficient to obtain confirmed defibrillation energy of 11.1 +/- 3.3 J. The mean strength of the successful VF induction shock was 6.8 +/- 4.3 J, the coupling interval was 303 +/- 35 ms, and the number of delivered induction shocks until the first VF induction was 3.9 +/- 1.6.nnnCONCLUSIONnTULIP is a safe and simple device testing procedure allowing the determination of confirmed, low defibrillation energy in most patients with two VF episodes induced at a single coupling interval.

Morphology and function of the intrinsic cardiac nervous system

ZusammenfassungBisher konnte das vegetative kardiale Nervensystem im Wesentlichen nur durch medikamentöse Katecholamingabe, β-Rezeptoren-Blockade oder Atropingabe therapeutisch beeinflusst werden. Das intrinsische kardiale Nervensystem stellt ein neuronales Netzwerk dar, das eine dynamische Anpassung der Herzfunktion an verschiedene physiologische und pathophysiologische Einflüsse ermöglicht. Inzwischen gelingen eine Identifizierung und Lokalisierung dieser Nervenfasern mittels perkutaner Katheterstimulation. Dies ermöglicht die gezielte Stimulation parasympathischer Nervenfasern, die Sinus- oder AV-Knoten innnervieren, wodurch z. B. die atrioventrikuläre Überleitung bei tachykardem Vorhofflimmern gebremst werden kann. Eine Stimulation sympathischer linksventrikulärer Nervenfasern erhöht selektiv die kardiale Inotropie. Auch eine Stimulation parasympathischer Neurone mittels chronischer Verweilelektroden gelingt inzwischen. Darüber hinaus kann durch die gezielte Ausschaltung vegetativer Nerven mittels Katheterverödung Einfluss auf das atriale Substrat von Vorhofflimmern genommen werden.Die perkutane elektrische Stimulation und Ablation kardialer vegetativer Nervenfasern bieten daher die Möglichkeit, dynamisch in die Regulation von kardialer Kontraktion, Perfusion und Erregungsausbreitung einzugreifen.AbstractAccess to the intrinsic cardiac autonomic nervous system can now be achieved via percutaneous catheter stimulation techniques. Thereby, cardiac functions like atrioventricular nodal conduction, sinus cycle length and ventricular inotropy can be dynamically regulated. The present article provides examples of this new technique in acute and chronic models but also first human applications.

Morphologie und Funktion des intrinsischen kardialen Nervensystems

ZusammenfassungBisher konnte das vegetative kardiale Nervensystem im Wesentlichen nur durch medikamentöse Katecholamingabe, β-Rezeptoren-Blockade oder Atropingabe therapeutisch beeinflusst werden. Das intrinsische kardiale Nervensystem stellt ein neuronales Netzwerk dar, das eine dynamische Anpassung der Herzfunktion an verschiedene physiologische und pathophysiologische Einflüsse ermöglicht. Inzwischen gelingen eine Identifizierung und Lokalisierung dieser Nervenfasern mittels perkutaner Katheterstimulation. Dies ermöglicht die gezielte Stimulation parasympathischer Nervenfasern, die Sinus- oder AV-Knoten innnervieren, wodurch z. B. die atrioventrikuläre Überleitung bei tachykardem Vorhofflimmern gebremst werden kann. Eine Stimulation sympathischer linksventrikulärer Nervenfasern erhöht selektiv die kardiale Inotropie. Auch eine Stimulation parasympathischer Neurone mittels chronischer Verweilelektroden gelingt inzwischen. Darüber hinaus kann durch die gezielte Ausschaltung vegetativer Nerven mittels Katheterverödung Einfluss auf das atriale Substrat von Vorhofflimmern genommen werden.Die perkutane elektrische Stimulation und Ablation kardialer vegetativer Nervenfasern bieten daher die Möglichkeit, dynamisch in die Regulation von kardialer Kontraktion, Perfusion und Erregungsausbreitung einzugreifen.AbstractAccess to the intrinsic cardiac autonomic nervous system can now be achieved via percutaneous catheter stimulation techniques. Thereby, cardiac functions like atrioventricular nodal conduction, sinus cycle length and ventricular inotropy can be dynamically regulated. The present article provides examples of this new technique in acute and chronic models but also first human applications.

Patients with atrial fibrillation complicated by coronary artery disease. Is a single value of sensitive cardiac troponin I on admission enough

BackgroundAtrial fibrillation (AF) is the most common arrhythmia in the general population. Cardiac troponin I (cTnI) can be elevated in patients with AF without coexisting coronary artery disease (CAD). The aim of this study was to characterize the diagnostic accuracy and clinical usefulness of a cTnI assay for the diagnosis of CAD in patients with AF.MethodsPatients with AF undergoing coronary angiography were included in the study. The workflow chart encompassed measuring of cTnI in all patients at admission and after 6xa0h.ResultsPatients with CAD were older (73.8u2009±u20097.6 vs. 65.3u2009±u200912.9xa0years) than patients without CAD; for all other characteristics, no significant differences were observed. Of the patients, 39 had CAD [12 patients one-vessel disease (VD), 14 patients 2-VD, 13 patients 3-VD] and 16 patients had acute myocardial infarction and were undergoing percutaneous coronary intervention. There was no significant difference in cTnI concentrations between patients without and with CAD at admission (0.02 vs. 0.03xa0ng/ml, respectively); however, a difference was noted after 6xa0h (0.03 vs. 0.06xa0ng/ml, respectively).ConclusionAF patients both without and with CAD showed similar cTnI concentrations at admission. A second validation of cTnI is mandatory for all patients.ZusammenfassungHintergrundVorhofflimmern (VHF) stellt die häufigste Arrhythmie in der Gesamtbevölkerung dar. Bei Patienten mit VHF kann eine Erhöhung des Troponinxa0I (TNI) ohne eine gleichzeitig vorhandene koronare Herzkrankheit (KHK) auftreten. Das Ziel dieser Studie ist die Charakterisierung der diagnostischen Genauigkeit und des klinischen Nutzens von TNI zur Diagnose einer KHK bei Patienten mit VHF.StudiendesignEingeschlossen wurden Patienten mit VHF, bei denen eine Koronarangiographie durchgeführt wurde. Bei allen Patienten erfolgte bei der Aufnahme und nach 6xa0h eine TNI-Kontrolle.ErgebnisseDie Patienten mit einer KHK waren älter (73,8u2009±u20097,6 vs. 65,3u2009±u200912,9 Jahre), während sich für alle anderen Charakteristika keine signifikanten Unterschiede fanden. Neununddreißig Patienten hatten eine KHK (12 Patienten: 1-Gefäß-KHK, 14 Patienten: 2-Gefäß-KHK, 13 Patienten: 3-Gefäß-KHK). Sechszehn Patienten hatten einen akuten Myokardinfarkt und wurden einer perkutanen Intervention unterzogen. Das TNI zeigte bei Patienten mit und ohne vorliegende KHK keinen signifikanten Unterschied bei der Aufnahme (0,02 vs. 0,03xa0ng/ml), jedoch nach 6xa0h (0,03 vs. 0,06xa0ng/ml).SchlussfolgerungPatienten mit und ohne vorliegende KHK zeigten bei der Aufnahme ähnliche Konzentrationen von TNI, so dass eine zweite Kontrolle notwendig ist.