Noninvasive Recording of His-Purkinje System (HPS) Activity in Man on Beat-To-Beat Basis

Since 1969 His bundle electrography has been used for diagnosis and for the study of cardiac electrophysiology. This method has employed the catheterization technique and has allowed the continuous recording of electrical activity of the specialized cardiac conduction system in every beat. Such investigation, because of its invasive nature, cannot be considered a routine test; it requires expensive instrumentation, it has physiological and technical limitations that include discomfort, a slight morbidity risk and a rather limited recorded area within the heart. In 1973 a method was developed for a noninvasive recording of the electrical activity within the P-R segment of the electrocardiogram measured from the body surface. This method which employs the signal averaging technique delivers even less medical information than intracardiac measurement. The shortcomings of this averaging method include inability to detect beat-to-beat changes in the true signal. Such a method is not useful in transient arrhythmia detection and a "short acting" drug influence examination. The technical approach to the beat-to-beat noninvasive recording of the HPS activation signal as measured from the body surface has been proposed. Using a specially positioned electrode system, a low noise multiple parallel input amplifier and a computer for sampling, processing and plotting of the measured signal, we have obtained an output curve corresponding to the continuous beat-to-beat HPS activity.     

Adaptive Filtering in Exercise High Resolution ECG as Applied to the Hypertrophic Cardiomyopathy

KEPSKI, R., et al. : Adaptive Filtering in Exercise High Resolution ECG as Applied to the Hypertrophic Cardiomyopathy. The application of adaptive filtering to ECG signals has been investigated for many years. This study shows that the exercise high resolution ECG (HRECG) can also be processed successfully in a similar way. Two groups were included consisting of 20 healthy individuals and 24 patients with hypertrophic cardiomyopathy (HCM) . The HRECG parameters for both groups were similar (  QRSdur: 107 ± 7 vs 114 ± 18 ms NS, LAS: 25 ± 8 vs 22 ± 6 ms NS  ). In the first step, the HRECG signal was acquired at rest to obtain the averaged reference pattern. The next step was associated with peak exercise in which one could calculate short duration averaging (∼ 30 beats) or apply adaptive filtering in which the exercise component (EC) was extracted. Exercise was performed in the supine position on a bicycle ergometer. The load of 50 W was incremented by 50-W steps in 3-minute intervals and the test was ended by fatigue. Signals were recorded in X, Y, and Z bipolar leads with a 20-Hz high pass filter. The short time average QRS duration mostly was abbreviated in normal individuals in contrast to HCM patients in which ventricular activity prolonged with sensitivity, specificity, and negative and positive predictive values: 79%, 65%, 73%, and 72%, respectively. The adaptive recurrent filtration (ARF) after cutoff of the EC at the level of 70 ms (this level is the EC mean value of both groups) showed the following statistics: 63%, 90%, 88%, and 90%. The Student's t-test as applied to the duration of EC allowed a statistically significant difference between normals and HCM patients (  66 ± 4 vs 71 ± 6 ms, P < 0.0052  ) and between HCM patients with and without ventricular tachyarrhythmia and DS (  74 ± 6 vs 69 ± 6 ms, P < 0.046  ).     

Pyramid Electrode Location in a Cardiac Micropotential Study

There are several electrode systems dealing with low noise, body surface, and ECG recordings that have been suggested by various investigators. In the last few years, the most developed system for late potential detection has been related to the uncorrected Frank XYZ leads. However, for His bundle detection many different electrode networks have been used. A pyramid-type electrode system has been used previously for His-Purkinje signal measurement and, with some modifications, for late ventricular activity recordings. This pyramid-type system was used to evaluate 300 adult patients with coronary heart disease (CHD) or cardiomyopathy. In the proposed system, electrodes are located near the myocardium with their configuration consisting of three electrode pairs forming a pyramidal shape. Each electrode can also play the role of the top of the pyramid, with all measurement directions converging to a point. By changing the pyramidal top, signals can be detected in various chosen measurement directions. The pyramid system provides spatial averaging facility, allowing the whole measuring system (consisting of low noise multi-input amplifiers) to detect signals in the range of 1 microVp-p on a beat-to-beat basis. In the majority of cases in hospital environments, however, a number of digital averaging cycles is still necessary. Using this system, late potentials (LP) were found in 29% of the patients without myocardial infarction (MI) and in 86% of cases with remote MI and sustained ventricular tachycardia (VT) and/or ventricular fibrillation (VF). Waveforms suspected to be of His-Purkinje System (HPS) origin were detected in 71% of subjects with normal or prolonged P-R segment.     

Ablation of Severe Drug‐Resistant Tachyarrhythmia During Pregnancy

Ablation of Tachyarrhythmia During Pregnancy. Aims: The goal of this study was to describe mapping and ablation of severe arrhythmias during pregnancy, with minimum or no X‐ray exposure. Treatment of tachyarrhythmia in pregnancy is a clinical problem. Pharmacotherapy entails a risk of adverse effects and is unsuccessful in some patients. Radiofrequency ablation has been performed rarely, because of fetal X‐ray exposure and potential maternal and fetus complications. Group and Method: Mapping and ablation was performed in 9 women (age 24–34 years) at 12–38th week of pregnancy. Three had permanent junctional reciprocating tachycardia, and 2 had incessant atrial tachycardia. Four of them had left ventricular ejection fraction ≤45%. One patient had atrioventricular nodal reciprocating tachycardia requiring cardioversion. Three patients had Wolff‐Parkinson‐White syndrome. Two of them had atrial fibrillation with ventricular rate 300 bpm and 1 had atrioventricular tachycardia 300 bpm. Fetal echocardiography was performed before and after the procedure. Results: Three women had an electroanatomic map and ablation done without X‐ray exposure. The mean fluoroscopy time in the whole group was 42 ± 37 seconds. The mean procedure time was 56 ± 18 minutes. After the procedure, all women and fetuses were in good condition. After a mean period of 43 ± 23 months follow up (FU), all patients were free of arrhythmia without complications related to ablation either in the mothers or children. Conclusion: Ablation can be performed safely with no or minimal radiation exposure during pregnancy. In the setting of malignant, drug‐resistant arrhythmia, ablation may be considered a therapeutic option in selected cases. (J Cardiovasc Electrophysiol, Vol. 21, pp. 877‐882, August 2010)     

Surgery as an Effective Nonpharmacological Mode of Treatment of Atrial Fibrillation Resistant to Standard Therapy

There are two surgical methods for atrial fibrillation (AF) treatment: Maze and corridoring procedures. The first one prevents AF occurrence by performing multiple atriotomies. During the second procedure a corridor between a sino-atrial and the AV node is created together with an electrical isolation of the atria. During 1992 and 1993 seven patients, aged 27–55, mean 43-years-old, with recurrent, resistant to standard therapy AF were referred for surgical treatment to our department. Additional diagnoses include: concealed WPW syndrome in 1 patient, atrial septal defect (ASD) in 3 patients, coronary artery disease in 1 patient. Maze procedure was performed solely in 1 patient, in another together with 2 accessory pathways ablation, in 3 patients with ASD closure and in 1 patient with 2 bypass grafts. In one patient corridoring procedure was performed. Normal sinus rhythm was restored in every patient from 7 to 26 days after the procedure, No surgical complications were noted during the postoperative period. Mechanical function of the atria was documented with echo Doppler 2–6 weeks after the operation. No evidence for AF recurrence was noted within 3–14 months (mean 5 months) of follow-up. The preliminary results of Maze and corridoring procedures are encouraging.     

Enhanced Serum Prolactin Concentration after Metoclopramide Stimulation in Idiopathic Oligozoospermia and Azoospermia

Erhöhte Serum-Prolaktin-Konzentration nach Metoclopramid-Stimulation bei idiopathischer Oligozoospermie und Azoospermie
Ziel der vorliegenden Untersuchung war das Hormonmuster von Männern mit idiopathischer Oligozoospermie und Azoospermie. Es handelt sich um 13 Männer im Alter von 21 – 34 Jahren (3 × Oligozoospermie III, 3 × schwere Oligozoospermie und 7 × Azoospermie). Die Kontrollgruppe bestand aus 11 gesunden Männern mit einer Normozoospermie. Bei allen Männern wurden mittels RIA Bestimmungen von LH, FSH, Prolaktin, Testosteron und DHT (Basalwerte) und Prolaktin nach Stimulation mit Metoclopramid (10 mg i.v.) nach 15, 30 und 60 Min. vorgenommen. Es ergab sich, daß die Männer mit idiopathischer Oligozoospermie und mit Azoospermie signifikant höhere Prolaktinwerte als Reaktion auf die dopaminergische Rezeptorblockade mit Metoclopramid aufwiesen und signifikant niedrigere Konzentrationen für Serum-Testosteron und DHT.     

Relationship between Cycle Length of Typical Atrial Flutter and Double Potential Interval after Achievement of Complete Isthmus Block

Background: There is some disagreement concerning the minimal value of the interval between components of double potentials (DPs interval) that allows distinguishing complete and incomplete block in the cavotricuspid isthmus (CTI). Objectives: To assess clinical utility of the relationship between atrial flutter cycle length (AFL CL) and the DPs interval. Methods: Ablation of the CTI was performed in 87 patients during AFL (245 ± 40 ms). Subsequently, DPs were recorded during proximal coronary sinus pacing at sites close to a gap in the ablation line and after achievement of complete isthmus block. Results: We noted strong correlation between AFL CL and the DPs interval after achievement of isthmus block (r = 0.73). The mean DPs interval was 95.3 ± 18.3 ms (range 60–136 ms) and 123.3 ± 24.3 ms (range 87–211 ms) during incomplete and complete isthmus block, respectively (P < 0.001). When expressed as a percentage of AFL CL, this interval was 35.7 ± 3.5% AFL CL (range 28–40.2%) and 50.4 ± 6.9% AFL CL (range 39–72%) during incomplete and complete isthmus block, respectively (P < 0.001). A cutoff value of 40% of AFL CL identified CTI block with 96.7% sensitivity and 100% specificity. Conclusions: The interval between DPs after achievement of block in the CTI correlates with AFL CL. The DPs interval expressed as a percentage of AFL CL allows better distinguishing between complete and incomplete isthmus block compared to standard method based on milliseconds. The DPs interval below 40% of AFL CL indicates sites close to a gap in the ablation line. (PACE 2010; 33:1518–1527)     

Clinical Validation and Comparison of Alternative Methods for Evaluation of Entrainment Mapping

Introduction: Measuring the postpacing interval (PPI) and correcting for the tachycardia cycle length (TCL) is an important entrainment response (ER). However, it may be impossible to measure PPI due to electrical noise on the mapping catheter. To overcome this problem, 2 alternative methods for the assessment of ER have been proposed: N+1 difference (N+1 DIFF) and PPIR method. PPI-TCL difference (PPI − TCL) correlates very well with ER assessed by new methods, but the agreement with PPI − TCL was established only in relation to PPIR method. Moreover, it is not known which of these methods is superior in the assessment of ER.
Methods: We analyzed 155 episodes of ER in 21 patients with heterogeneous reentrant arrhythmias. ER was estimated by PPI − TCL and by both alternative methods. Agreement between methods was assessed by means of the Bland-Altman test, kappa coefficient (κ), and correlation coefficient (r). Finally, a mathematical comparison of the alternative methods was performed.
Results: The agreement between PPI − TCL and alternative methods was very good. For N+1 DIFF the mean difference was −1.86 ± 7.31 ms; kappa = 0.9; r = 0.98; for PPIR method the mean difference was −1.46 ± 7.65 ms; kapa = 0.92; r = 0.99. Agreement between both alternative methods was also very high: the mean difference of 0.5 ± 6.6 ms; kappa = 0.89; r = 0.99. The analysis of the equations used for calculation of ER by these methods revealed that essentially they were mathematically equivalent.
Conclusion: Each of the alternative methods may be used for evaluation of ER when PPI − TCL cannot be assessed directly. Results obtained by both alternative methods are comparable.     

THE BEHAVIOUR OF SOME INDICES OF CALCIUM-PHOSPHATE METABOLISM IN TURNER'S SYNDROME

The results of calcium and parathormone loading tests in 6 individuals with Turner's syndrome indicate a certain degree of insensitive-ness of the tissues, especially of the kidney, when compared with healthy individuals. A similar insensitiveness expressing itself by a decrease in hydrogen ion excretion was found after ammonium chloride loading. An analysis of the results suggest the existence in this syndrome of insensitiveness of renal tubules to regulatory factors. Osteoporosis and stunting of growth may be connected partly with intestinal calcium loss occurring at puberty, and partly with this insensitiveness to regulatory factors.     

Recurrence of RVOT PVCs with a Marked Shift of Its Exit Point. Gradual Elimination of Arrhythmogenic Focus by Multisite Approach

We present a case of recurrent outflow tract arrhythmia despite repeated ablations. Premature ventricular contractions (PVCs) morphology suggested a right‐sided focus. However, electrograms preceding PVCs were recorded from the right and left outflow tracts, distal coronary sinus, and right sinus of Valsalva. Arrhythmia was eliminated after radiofrequency (RF) applications delivered from different sites. We conclude that, in patients with recurrent outflow tract PVCs, mapping all the sites mentioned above may be necessary to find the earliest activation site and carry out successful ablation. In some patients, RF applications from multiple sites may be necessary to completely eliminate arrhythmia. (PACE 2012; 35:e6–e9)