Kai U. Markus

Usefulness of brain natriuretic peptide release as a surrogate marker of the efficacy of long-term cardiac resynchronization therapy in patients with heart failure

1. Smirk FH. R waves interrupting T waves. Br Heart J 1949;11:23–36. 2. Engel TR, Meister SG, Frankl WS. The “R-on-T” phenomenon: an update and critical review. Ann Intern Med 1978;88:221–225. 3. Bluzhas J, Lukshiene D, Shlapikiene B, Ragaishis J. Relation between ventricular arrhythmia and sudden cardiac death in patients with acute myocardial infarction: the predictors of ventricular fibrillation. J Am Coll Cardiol 1986; 8(suppl 1):69A–72A. 4. Fiol Sala M, Marrugat J, Bergada Garcia J, Guindo Soldevila J, Bayes de Luna A. The differential characteristics of early ventricular arrhythmias following a myocardial infarct in patients with and without ventricular fibrillation. Rev Esp Cardiol 1994;47:165–172. 5. Chiladakis JA, Karapanos G, Davlouros P, Aggelopoulos G, Alexopoulos D, Manolis AS. Significance of R-on-T phenomenon in early ventricular tachyarrhythmia susceptibility after acute myocardial infarction in the thrombolytic era. Am J Cardiol 2000;85:289–293. 6. Turitto G, Dini P, Prati PL. The R on T phenomenon during transient myocardial ischemia. Am J Cardiol 1989;63:1520–1522. 7. Ruberman W, Weinblatt E, Goldberg JD, Frank CW, Chaudhary BS, Shapiro S. Ventricular premature complexes and sudden death after myocardial infarction. Circulation 1981;64:297–305. 8. Bigger JT Jr, Weld FM. Analysis of prognostic significance of ventricular arrhythmias after myocardial infarction. Shortcomings of Lown grading system. Br Heart J 1981;45:717–724. 9. Dabrowski A, Kramarz E, Piotrowicz R. Dispersion of QT interval following ventricular premature beats and mortality after myocardial infarction. Cardiology 1999;91:75–80. 10. Grimm W, Walter M, Menz V, Hoffmann J, Maisch B. Circadian variation and onset mechanisms of ventricular tachyarrhythmias in patients with coronary disease versus idiopathic dilated cardiomyopathy. Pacing Clin Electrophysiol 2000;23:1939–1943. 11. Meyerfeldt U, Schirdewan A, Wiedemann M, Schutt H, Zimmerman F, Luft FC, Dietz R. The mode of onset of ventricular tachycardia. A patient-specific phenomenon. Eur Heart J 1997;18:1956–1965. 12. Roelke M, Garan H, McGovern BA, Ruskin JN. Analysis of the initiation of spontaneous monomorphic ventricular tachycardia by stored intracardiac electrograms. J Am Coll Cardiol 1994;23:117–122. 13. Taylor E, Berger R, Hummel JD, Dinerman JL, Kenknight B, Arria AM, Tomaselli G, Calkins H. Analysis of the pattern of initiation of sustained ventricular arrhythmias in patients with implantable defibrillators. J Cardiovasc Electrophysiol 2000;11:719–726.

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.

Multicentre evaluation of a rule-based data filter for home monitoring of implanted cardioverter defibrillators

We developed a rule-based data filter for the automatic interpretation of data transmitted from implantable cardioverter defibrillators (ICDs). The feasibility and user acceptability of the data filter were tested in a multicentre study. Fifteen European centres analysed 10 cases each. The cases represented ICD follow-up findings, e.g. new tachycardia, battery depletion or sensing defects. The mean follow-up period was 68 days (SD 35). A questionnaire was used to collect information regarding the functionality and general concept of automatic data interpretation. A score of five or above (range 1–9) was classified as acceptable. According to the questionnaires, there was a high degree of satisfaction with the general concept of automatic data interpretation (mean 6.7, SD 1.2) and with user guidance (mean 7.1, SD 0.8). Safety (mean 7.0, SD 1.4) and accuracy (mean 6.7, SD 1.4) of the evaluation of device-related and clinical problems were regarded as high. Support in daily routine was considered to be high (mean 7.3, SD 1.1) as the system was easy to understand (mean 7.5, SD 0.9). The results indicated a high user acceptance with easy system handling.

Preserved Parasympathetic Cardiac Innervation after Atrioventricular Node Modification: Evidence from Circle Maps of Respiratory Sinus Arrhythmia

AbstractIntroduction: Respiratory sinus arrhythmia (RSA) and heart rate variability (HRV) are parameters of autonomic cardiac innervation. They decrease with age and after atrioventricular nodal modification (AVNM) suggesting vagal denervation in both situations. We hypothesized, however, that AVNM causes only a transient, functional decline in vagal activity, whereas aging causes permanent vagal denervation. A new method of analyzing RSA phase dynamics based on circle maps (CM) can potentially differentiate between both forms of reduced vagal activity. Methods: In 18 younger and 14 older healthy control subjects 24-hour Holter ECGs were recorded for HRV analysis. Repeated measurements of RSA were acquired during paced breathing (PB). In 16 consecutive patients undergoing AVNM the same measurements were applied before, 1 day and 3 months after the procedure. CM were calculated from consecutive RR intervals and the similarity between different CM quantified by the Kullback information gain (KIG). Results: HRV analysis revealed lower HF bands, LF bands and RSA amplitudes in older vs. younger control subjects. KIG revealed less similarity between younger and older control subjects than within the respective age groups. After AVNM a decrease in HF bands was noted in HRV analysis. Three months after AVNM, HF bands returned to pre-ablation values. CM obtained before and 1 day after AVNM displayed comparable similarity to CM acquired 1 day before and 3 months after ablation. Conclusions: In contrast to conventional HRV parameters, CM of RSA are not altered by ablation in the posteroseptal space but by aging. Thus, this new method appears to differentiate between transient autonomic modification and chronic denervation.