Insights into atrial fibrillation.

Atrial fibrillation is the most common clinically relevant heart rhythm disorder and is associated with increased morbidity and mortality. Most important risk factors for atrial fibrillation are high age, arterial hypertension, diabetes mellitus, heart failure and rheumatic heart disease. Chronic atrial fibrillation is classified as paroxysmal, persistent, long-standing persistent and permanent atrial fibrillation. Spontaneous conversion to sinus rhythm is observed in paroxysmal atrial fibrillation, whereas in persistent atrial fibrillation, pharmacological or electrical cardioversion is required in order to restore sinus rhythm. In permanent atrial fibrillation, the arrythmia is accepted by patient and physician and cardioversion is not attempted. Rate control only is thus applied in permanent atrial fibrillation, whereas in paroxysmal and persistent atrial fibrillation, addition rhythm control with anti-arrhythmic drugs and/or ablation is attempted if symptoms persist and age and co-morbidities do not pose contra-indications. Besides rhythm management, oral anticoagulation is the mainstay of therapy for most patients with atrial fibrillation. Risk scores such as the CHA2DS2-VASc score help to identify patients with a high risk of stroke and need for oral anticoagulation. The underuse of vitamin K antagonists in clinical practise is partly due to considerable disadvantages: an increased bleeding risk, a narrow therapeutic window and multiple drug interactions prompting frequent laboratory controls to assess an individual dosage. New oral anticoagulants targeting thrombin (dabigatran) or factor Xa (rivaroxaban, apixaban and edoxaban) may replace warfarin in many patients with atrial fibrillation due to convincing data both on efficacy and safety as well as convenience. However, challenges remain with respect to lack of specific antidotes and high costs.

A dedicated cardioversion unit for the treatment of atrial fibrillation. Reducing costs by optimizing processes.

BACKGROUND: Atrial fibrillation (AF) is the most frequent arrhythmia seen in man. Many patients are admitted to the hospital to undergo transesophageal echocardiography (TEE) for thrombus exclusion and subsequent electrical cardioversion (ECV) under deep sedation to restore sinus rhythm. The present study investigated prospectively how workflow optimization can contribute to reducing time and costs in AF patients scheduled for ECV in an outpatient setting. METHODS: A cardioversion unit (CU) was established and equipped to perform all ECV-associated procedures. Between November 2007 and January 2009, ECV was performed in 115 patients in an outpatient setting. Three different settings were tested for ECV: (1) usual care (n = 19): preparation/follow-up in the outpatient clinic, blood testing in the central hospital laboratory (CHL), TEE in the echocardiography laboratory, and ECV in the intensive care unit; (2) optimized process 1 (n = 41): preparation/follow-up, TEE + ECV during one sedation in the CU, blood testing in the CHL; (3) optimized process 2 (n = 55): preparation/follow-up, TEE + ECV and point of care (POC) blood testing in the CU. All procedure-related costs were listed and classified according to material, human resources, and infrastructure. RESULTS: From setting 1 to 3, there was a significant decrease in procedural time from 480 ± 105 min to 205 ± 85 min (p < 0.001). Likewise, ECV-associated costs could be reduced from 683 ± 104  to 299 ± 63  (p < 0.001). CONCLUSION: Establishing a CU for AF enables a more than 50% reduction in procedural time and costs. A combination of TEE and ECV in one sedation and POC testing in the CU were the major contributors to this time and cost reduction.

Electrical cardioversion of patients with implanted pacemaker or cardioverter-defibrillator: results of a survey of german centers and systematic review of the literature.

AIMS: A relevant number of patients presenting for electrical cardioversion carry a pacemaker (PM) or ICD. Case reports suggest a potential hazard of external cardioversion/defibrillation. The incidence of shock related device complications is unknown. No guidelines or recommendations by international medical societies for a cardioversion protocol of cardiovascular implantable electronic device (CIED) patients exist. We conducted a nationwide survey to gather real-world clinical data on the current clinical approach towards these patients during electrical cardioversion and to estimate the incidence of shock-related complications. METHODS AND RESULTS: Ninety hospitals with > 380 ECV in 2014 were identified from mandatory hospital quality reports and 60 were randomly selected. All centers were provided with a standardized questionnaire on the general proceedings and complications during electrical cardioversion of pacemaker, ICD and CRT patients (CIED patients). Thirty-two centers (53%) participated in the survey. In total, 16,554 ECV were reported (534 ± 314 per center). Biphasic cardioversion with a first shock energy of ≥ 150 J via adhesive patches in antero-posterior orientation was preferred by most centers (78%). Eleven percent (n = 1809) of pts were reported to carry a PM/ICD. The ECV protocol was heterogeneous among centers. Complications associated with electrical cardioversion were reported in 11/1809 patients (0.6%), all were transitory elevations of pacing thresholds. CONCLUSIONS: In this nationwide snapshot survey of cardioversion procedures in Germany, approximately 11% of patients presenting for elective electrical cardioversion were pacemaker or ICD carriers. Cardioversion protocols in these patients are heterogeneous throughout centers and mostly not in accordance with recommendation of the German Cardiac Society. Complications associated with external electrical cardioversion are rare. Controlled trials and large registries are necessary to provide evidence for future recommendations.

The role of intracardiac echocardiography in interventional electrophysiology.

Visualization of the cardiac anatomy becomes more and more important as the complexity of interventions increases. Intracardiac echocardiography (ICE) provides good depiction of cardiac soft tissue structures and has become an important tool in today's cardiology. It has been shown to be valuable during many ablation procedures for supraventricular and ventricular arrhythmias. ICE has been used for monitoring catheter placement, observing catheter-tissue contact and lesion formation as well as titrating ablation energy. The rate of complications could be reduced, outcome of procedures improved and radiation exposure decreased. Even more, new therapy strategies have been evaluated based on ICE and it has also been used in the setting of three- dimensional imaging and image integration.

[Prevalence and severity of pulmonary embolism are dependent on clinical and paraclinical parameters : Analysis of 1,943 consecutive patients with CT pulmonary angiography]. / Prävalenz und Schwere der Lungenarterienembolie in Abhängigkeit von klinischen und paraklinischen Parametern : Analyse von 1943 konsekutiven Patienten mit CT-Pulmonalisangiographie.

BACKGROUND: Patients with pulmonary embolism (PE) have heterogeneous symptoms. Clinical scores and age-adjusted D­dimer should help clinicians to establish the correct diagnosis. METHODS: A cohort of 1,943 consecutive patients with positive D­dimer levels who were referred for CT pulmonary angiography (CTPA) over a period of 5 years to rule PE in or out were retrospectively analyzed. RESULTS: On CTPA n = 362 (19 %) had PE. The prevalence of PE increased stepwise with increasing D­dimer levels (prevalence of PE with 10 percentiles of D­dimers was: 3 %, 4 %, 7 %, 8 %, 8 %, 21 %, 20 %, 27 %, 37 %, 52 %; p < 0.001). D­dimers > 2.0 were significantly associated with PE (OR 7.17 95 % CI 5.27-9.76, p < 0.001). Chest discomfort and tachypnea showed no association with PE. Dyspnoea, pleuritic pain, and general fatigue showed significant associations with age: pleuritic chest pain was more frequent in patients aged < 76 years than in patients aged > 76 years (15 % vs 3 %; p < 0.001) and was highly significantly associated with PE (OR 4.99 95 % CI 2.83-8.81; p < 0.001). General fatigue was more prevalent in patients aged > 76 years (44 % vs 24 %; p < 0.001). PE patients with D­dimers > 6.0 mg/l were hemodynamically more compromised than patients with D­dimers < 6.0 mg/l: tachycardia 32 % vs 20 %, p = 0.015; right ventricular strain on echocardiography: 38 % vs 23 %, p = 0.003; right ventricular strain on ECG: 27 % vs 13 %; p  = 0.001; resuscitation 4 % vs 0 %, p = 0.003; lytic therapy 6 % vs 1 %, p = 0.014. CONCLUSION: The symptoms of PE patients are often vague. Particularly in older patients, fatigue may be the only symptom. The absolute level of D­dimers, particularly > 2.0 mg/l, is a strong predictor of PE. A D­dimer level > 6.0 mg/l is associated with more severe hemodynamic impairment in patients with PE.

Catheter stimulation of cardiac parasympathetic nerves in humans: a novel approach to the cardiac autonomic nervous system.

BACKGROUND: Cardiac parasympathetic nerves run alongside the superior vena cava (SVC) and accumulate particularly epicardially adjacent to the orifice of the coronary sinus (CS). In animals, these nerves can be electrically stimulated inside the SVC or CS, which results in negative chronotropic/dromotropic effects and negative inotropic effects in the atria but not the ventricles. Parasympathetic nerve stimulation (PS) with 20 Hz in the CS, however, also excites the atria, thereby inducing atrial fibrillation. The present study overcomes this limitation by applying high-frequency nerve stimuli within the atrial refractory period. Using this technique, we investigated for the first time whether neurophysiological effects similar to those in animals can be obtained in humans. METHODS AND RESULTS: In 25 patients, parasympathetic nerves were stimulated via a multipolar electrode catheter placed in the SVC (stimulation with 20 Hz; n=14) or CS (pulsed 200-Hz stimuli; n=11). A significant sinus rate decrease and prolongation of the antegrade Wenckebach period was achieved during PS in the SVC. During PS in the CS, a graded-response prolongation of the antegrade Wenckebach interval was observed with increasing PS voltage until third-degree AV block occurred in 8 of 11 patients. The negative chronotropic/dromotropic effects started and terminated immediately after the onset and termination of PS, respectively. Atropine abolished these effects (n=11). CONCLUSIONS: Human parasympathetic efferent nerve stimulation induces reversible negative chronotropic and dromotropic effects. PS may serve as an adjunctive tool for the diagnosis/treatment of supraventricular tachycardias and may be beneficial for ventricular rate slowing during tachycardic atrial fibrillation in patients with congestive heart failure.

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.

Spatial features in body surface potential maps of patients with ventricular tachyarrhythmias with or without coronary artery disease.

Body surface potential maps (BSPM) from patients with coronary artery disease or no structural heart disease were analyzed with respect to their spatial features and QT/QTc dispersion in order to determine whether BSPM allows identification of patients with ventricular fibrillation. QRST integral maps and QT/QTc dispersion were acquired from simultaneous recordings of 62 ECG leads during sinus rhythm in patients with idiopathic ventricular fibrillation (n=13), ventricular fibrillation and coronary artery disease (n=22), coronary artery disease without ventricular fibrillation (n=21) and healthy controls (n=18). The Karhunen-Loeve transformation was applied to reduce the dimensionality of the data matrix of the QRST map to eight coefficients. Linear discriminant analysis allowed discrimination between idiopathic ventricular fibrillation patients and controls with high sensitivity (85%) and specificity (89%). However, discrimination between coronary artery disease patients with or without ventricular fibrillation was poor (68% and 67%, respectively). QTc dispersion calculated from BSPM was longer in idiopathic ventricular fibrillation patients than in controls (99+/-30 ms vs 70+/-14 ms, P=0.009) in contrast to QTc dispersion taken from 12-lead ECG (53+/-21 ms vs. 47+/-12 ms, P=n.s.). No significant difference was noted for coronary artery disease patients with or without ventricular fibrillation. In conclusion, repolarization disturbances detected by BSPM allow identification of ventricular fibrillation patients without structural heart disease. However, our results do not suggest a major impact of QT/QTc dispersion or QRST integral mapping for identification of ventricular fibrillation patients with coronary artery disease.

Technical implementation of an Internet address database with online maintenance module.

The article describes the technical implementation and management of the Internet address database of the center for ZMK (University of Münster, Dental School) Münster, which is integrated in the "ZMK-Web" website. The editorially maintained system guarantees its topicality primarily due to the electronically organized division of work with the aid of an online maintenance module programmed in JavaScript/PHP, as well as a database-related feedback function for the visitor to the website through configuration-independent direct mail windows programmed in JavaScript/PHP.

Piloting a digital event manager in the Intranet of a department of orthodontics.

The present article describes the development and piloting of an Internet-accessible, database-supported event management system at the University of Münster orthodontic clinic. As an important component of the quality management of the clinic, the database centralizes appointments and events and displays these transparently and clearly in the form of a HTML-GUI (= HTML Graphical User Interface) in the local Intranet. The event overviews are also accessible in the global Internet arranged in tabular form with password protection.

Internet-capable publication database system.

Scientific databases are generally accessible to the public via the Internet. Reports of most peer-reviewed (quotable) research is thus available to researchers and others. However, other reports and information of interest to researchers and teachers such as poster presentations at congresses, articles describing techniques and teaching material, and details of vocational and continuing education courses (nonquotable literature) generally do not appear in such databases. This nonquotable literature is often of great use to teachers. A project was therefore initiated at the Münster Dental Clinic which aimed to address the problem by developing a database of all publications and other printed material produced by the staff (faculty). After a systematic search, all such publications (quotable and nonquotable) were entered in the database which is partially accessible via the Internet and fully accessible via the Münster Dental Clinic's Intranet. The complete list can be found in the protected Intranet areas, which can be accessed by all the Dental Clinic's staff members. The database also permits Münster Clinic staff to access the Internet and locate those publications that are on the Internet by year of publication and topic.

[Analysis of QRST integral and QT dispersion by body surface potential mapping in patients with malignant ventricular arrhythmias]. / Analyse von QRST-Integral und QT-Dispersion mittels "Body surface potential mapping" bei Patienten mit malignen ventrikulären Arrhythmien.

In a retrospective analysis in 74 patients with coronary artery disease or no obvious heart disease, the value of "body surface potential mapping" for the identification of repolarization abnormalities was investigated compared to the standard 12-lead ECG. In patients with idiopathic ventricular fibrillation the number of extrema in the QRST integral map was significantly higher than in the control group (3.15+/-0.99 vs. 2.17+/-0.51, p<0.001) and the QT dispersion was also higher (0.10+/-0.03 vs. 0.07+/-0.01, p<0.001), whereas there was no difference between either group in the 12-lead ECG QT dispersion. In patients with coronary artery disease the number of extrema in the QRST integral map and QT dispersion were also higher compared to the control group, but there were no significant differences between patients with or without aborted sudden cardiac death.In conclusion, BSPM identifies repolarization abnormalities not detected by 12-lead ECG, thereby identifying a potential reason for cardiac arrest in patients without overt heart disease. The usefulness of this technique for risk stratification in patients with coronary artery disease remains to be elucidated.

[Cardiogenic shock in a 61 year old female with recurrent panic attacks]. / Kardiogener Schock bei 61-jähriger Patientin mit rezidivierenden Panikattacken.

A 61 year old patient in a severely reduced general condition complaining of epigastric pain was admitted to our emergency room. Because of elevated troponin T and creatine kinase levels and severely reduced left ventricular function as seen in echocardiography as well as negative T-waves in the anterolateral ECG leads we suspected an acute coronary syndrome. The patient underwent coronary angiography after intubation and a coronary artery disease was excluded. The initial therapy included the use of an intraaortic balloon pump, volume and catecholamine administration controlled by a pulmonary artery catheter. Conducting an abdominal ultrasound we detected a mass at the right adrenal gland. The suspected diagnosis of pheochromocytoma was confirmed by elevated catecholamine levels in the urine and a CT scan. After recompensation and subsequent administration of phenoxybenzamine a benign pheochromocytoma was resected. A massive catecholamine secretion due to a pheochromocytoma can lead to a cardiogenic shock and multiple organ failure. In patients with recurrent panic attacks and hypertension a pheochromocytoma should be included in the differential diagnosis.

Evidence of sinoatrial block as a curative mechanism in radiofrequency current ablation of inappropriate sinus tachycardia.

Inappropriate sinus tachycardia is a nonparoxysmal tachycardia characterized by high resting heart rates and a disproportionate response to activity. Sinus node modification with radiofrequency current has been used successfully as treatment for this arrhythmia. However, the electrophysiologic mechanisms leading to successful modification are not yet fully elucidated. We report a case of a patient with drug-resistant inappropriate sinus tachycardia in whom successful treatment of the arrhythmia was achieved by documented sinoatrial exit block induced by radiofrequency current applications.

Effect of biphasic shock duration on defibrillation threshold with different electrode configurations and phase 2 capacitances: prediction by upper-limit-of-vulnerability determination.

BACKGROUND: The defibrillation threshold (DFT) may be affected by biphasic shock duration (BSD), electrode configuration, and capacitance. The upper limit of vulnerability (ULV) may be used to estimate the DFT. For different lead configurations and phase 2 capacitances, we investigated in 18 pigs whether the use of ULV may predict waveforms with lowest DFT. METHODS AND RESULTS: -DFT and ULV were determined by up-down protocols for 10 BSDs. ULVs were measured by T-wave scanning during ventricular pacing (cycle length 500 ms). In protocol 1 (n=6), a pectoral "active can" was combined with an electrode in the superior vena cava as common cathode and a right ventricle electrode as anode (AC+SVC). In protocol 2 and protocol 3 (n=6 each), only the "active can" was used as proximal electrode (AC). Capacitance was 150 microF during both phases in protocol 1 and protocol 3 but 150 microF (phase 1) and 300 microF (phase 2) in protocol 2. ULV and DFT demonstrated a linear correlation in each protocol (r=0.78 to 0.84). Lowest DFTs were found at 10 ms for AC+SVC and at 14 ms for AC (P<0.001). At optimal BSDs, voltage DFTs did not differ significantly between AC (527+/-57 V) and AC+SVC (520+/-70 V). Switching capacitors for phase 2 in a way that reduced leading-edge voltage by 50% while doubling capacity did not change BSD for optimal voltage DFT but increased minimum DFT from 527+/-57 V to 653+/-133 V (P=0.04). CONCLUSIONS: The BSD with lowest DFT is shorter for AC+SVC than for AC. There is no significant difference in voltage DFT between both at optimal BSD. A lower phase 2 capacitance reduces DFTs irrespective of BSD. Because strength-duration curves for DFT and ULV correlate for different BSDs, lead systems, and phase 2 capacitances, ULV determination may allow the prediction of waveforms with lowest DFT.