Effects of different atrial pacing modes evaluated by intracardiac signal-averaged ECG

Background: Analysis of high gain, signal-averaged (SA) ECG is an accepted method evaluating abnormalities of atrial repolarization - the presence of late potentials (ALP) - predictive for atrial arrhythmias. Recently it has been proven that the location of atrial leads has an influence on atrial activation and modifies the risk of atrial arrhythmias. The aim of our study was to estimate the effect of different modes of atrial pacing on signal-averaged P waves recorded from external (conventional) and from intra-atrial leads. Methods: Recordings were performed in 24 patients during biatrial (BiA) pacing system implantation. A surface SA-ECG was obtained from orthogonal leads, and intra-atrial signals were recorded and averaged separately from the right and left atrium during sinus rhythm (SR) and atrial pacing from the right atrial appendage, coronary sinus or both (BiA pacing). We analyzed standard SA-ECG parameters (P/A wave duration, RMS20 and LAS5) and the presence of atrial late potentials (ALP-Pdur > 125 ms and RMS20 < 2.40 mV). Results and conclusions: Right atrial appendage pacing prolongs the duration of atrial potential in external and intracardiac leads and decreases its homogeneity in comparison to SR. RAA pacing increases the occurrence of ALP both in external and internal SA-ECG. Coronary sinus pacing does not deteriorate atrial activation in comparison to SR. Biatrial pacing shortens atrial potential, increases its homogeneity and eliminates atrial late potential criteria in most of patients in comparison to SR. It can be observed both in external and intra-atrial leads and confirms the beneficial effects of BiA pacing on atrial excitation, explaining its antiarrhythmic effect. Evaluation of signal-averaged intra-atrial electrograms supplies more data about local conduction disturbances with micro-voltage oscillations during final part of atrial excitation (low RMS20 and prolonged LAS5) than conventional techniques and seems to be a valuable tool for the evaluation of new resynchronizing atrial pacing modes. (Cardiol J 2008; 15: 129-142

Coronary sinus pacing: Its influence on external and intraatrial signal-averaged P wave time domain parameters

Background: The coronary sinus (CS) was, for 10 years, the standard place for permanent atrial pacing, and the antiarrhythmic properties of CS pacing were described by Moss in the early 70&#8217;s. These observations were confirmed during EP studies, although currently permanent CS pacing is infrequently applied. Signal averaged (SA) P wave analysis has established values for the examination of EP properties of atrial myocardium. The aim of our study was to estimate the effect of CS pacing on the signal-averaged P wave recorded from external and intraatrial leads. Methods: Recordings were performed in 24 patients during biatrial pacing system implantation. A surface SA-ECG was obtained from orthogonal leads, and intraatrial signals were recorded and processed separately from the right and left atrium at SR and CS pacing. We analyzed standard SA-ECG parameters (P/A wave duration, RMS20 and LAS5) and the presence of atrial late potentials (ALP-Pdur > 125 ms and RMS20 < 2.40 mV). Results and conclusions: Coronary sinus pacing favourably modifies SA P wave parameters of the left atrium; it significantly shortens Pdur, distinctly increases RMS20, decreases LAS5 and eliminates ALP in most patients in comparison to SR. It indicates beneficial effects of CS pacing on left atrial excitation and may explain its antiarrhythmic effect. Coronary sinus pacing does not deteriorate right atrium activation; it even slightly increases RMS20 and shortens the duration of LAS5 in RA in comparison to SR. Our findings suggest that CS is still an attractive site for permanent atrial pacing in patients with atrial arrhythmias and atrial conduction disturbances. (Cardiol J 2007; 14: 470-481

Electrophysiological effects of single site RAA pacing evaluated by means of high-gain SA-ECG recorded from intra-atrial leads

Background: Conventional right atrial appendage pacing (RAAp) eliminates the electrophysiological consequences of bradycardia only, leading to suppression of the rhythm-dependent arrhythmias but in some patients RAAp may increase AF recurrences or even promote it in patients without AF history. Relatively rare incidence of AF in patients implanted with single lead VDD pacing system may indicate RAAp influence. Atrial conduction disturbances (ACD) are the known substrate of re-entrant atrial arrhythmias and their detection is important for the selection of proper therapy. Time-domain analysis of P-wave in signal-averaged ECG (SA-ECG) recorded from chest leads is an accepted method evaluating inhomogeneity of atrial excitation, predictive for atrial arrhythmias. The aim of our study was to estimate the effect of RAAp on SA-ECG recorded from conventional external and from intraatrial leads. Methods: Recordings were performed in 24 patients during biatrial pacing system implantation. A surface SA-ECG was obtained from orthogonal leads and intraatrial signals were recorded and averaged separately from the right and left atrium at SR and RAAp (LA pacing was temporary switched). We analyzed standard SA-ECG parameters (P/A wave duration, RMS20 and LAS5) and the presence of atrial late potentials (ALP-Pdur > 125 ms and RMS20 < 2.40 &#181;V). Results and conclusions: RAAp significantly prolongs all parameters reflecting atrial activation (P ECG, TAAT, SA-ECG Pdur, SA-IEGM Adur in RA and LA) by 20 to 30 ms in comparison to SR. RAAp decreases RMS20 and prolongs LAS5 values both in external and intraatrial leads, which reflects increased micro-oscillations in the final portion of atrial potential. The lower RMS20 and higher LAS5 values in RA compared to LA suggest less homogenous depolarization in right atrium. This may suggest that atrial activation extinguishes more homogenously in LA. A different explanation may be that the observed sluggish ending of RA signal may be the result of a far-field sensing from the LA. The strong correlations between RAA paced P wave, TAAT, SA-ECG Pdur, SA-IEGM RA and LA Adur confirm that those parameters reproduce mostly the velocity of conduction within the atria. Our findings indicates significant aggravation of ACD (mainly in RAA) and suggests that the search is needed for another RA lead location for permanent single site and biatrial pacing. (Cardiol J 2007; 14: 372-383

Electrophysiological effects of biatrial pacing evaluated by means of signal-averaged P wave time-domain parameters. The significance of persistent atrial late potentials in right atrium during biatrial pacing

Background: Atrial conduction disturbances are a known substrate of re-entrant atrial arrhythmia, and their detection is important for the selection of proper therapy. Time-domain analysis of P-wave in signal-averaged ECG (SA-ECG) recorded from chest leads is an accepted method evaluating inhomogeneity of atrial excitation, predictive for atrial arrhythmias. Biatrial (BiA) pacing created a new therapeutic option for patients with atrial arrhythmias. The aim of our study was to estimate the effect of BiA pacing on SA-ECG recorded from conventional external and from intraatrial leads. Methods: Recordings were performed on 24 patients during BiA pacing system implantation. A surface SA-ECG was obtained from orthogonal leads, and intraatrial signals were recorded and averaged separately from the right and left atria at sinus rhythm and BiA pacing. We analyzed standard SA-ECG parameters (P/A wave duration, RMS20 and LAS5) and the presence of atrial late potentials (ALP-Pdur > 125 ms and RMS20 < 2.40 mV). Results and conclusions: BiA pacing favorably modifies SA-ECG parameters in the right and left atrium. BiA pacing significantly shortens P duration, significantly increases RMS20 and reduces atrial late potentials (ALP) occurrence in most patients in comparison to sinus rhythm both atria. ALP are still present in 46% of patients in spite of effective BiA pacing, which can be observed mainly in the right atrium and is connected with increased risk of atrial fibrillation recurrence. This phenomenon suggests a limited effect of RAA-based BiA pacing on the synchrony of atrial activation, and a search is needed for another right atrial lead location for permanent BiA pacing. (Cardiol J 2008; 15: 26-38

Analysis of high gain signal-averaged P/A wave time domain parameters recorded from external leads (SA-ECG) and internal electrograms (SA-IEGM) recorded from three right- and left-intraatrial leads

Background: Time-domain analysis of the P-wave in signal-averaged ECG (SA-ECG) recorded from chest leads is an accepted method for evaluating the inhomogeneity of atrial excitation, predictive for atrial arrhythmias. The aim of the study was to determine the value of the SA-ECG technique for intraatrial signal processing. Additional aims were to evaluate the correlation between SA-ECG parameters (external and intraatrial) and the frequency of atrial fibrillation recurrences, ongoing antiarrhythmic therapy and LA diameter. Methods: Recordings were performed in 24 pts during biatrial pacing system implantation. A surface SA-ECG was obtained from orthogonal leads, and intraatrial signals were recorded and averaged separately from the right and left atrium. We analyzed standard SA-ECG parameters (P/A wave duration, RMS20 and LAS5) and the presence of atrial late potentials (ALP-Pdur > 125 ms and RMS20 < 2.40 mV). Results and conclusions: Intraatrial SA-ECG provides accurate data for ALP analysis, mostly due to its improved signal quality and QRS discrimination. P-duration and RMS20 seem to be parameters with good correlation between external and internal SAECG. Intraatrial SAECG offers a valuable tool to evaluate abnormalities of the final part of atrial excitation. There are no straight associations between SA-ECG parameters and arrhythmic burden, ongoing antiarrhythmic therapy and LA diameter. (Cardiol J 2007; 14: 287-300

Pacemaker lead extraction and recapture of venous access: Technical problems arising from extensive venous obstruction

We report the case of the extraction of 18 year-old leads in a patient with a DDD pacemaker, and chronic obstruction of the left subclavian and innominate veins coexisting with extensive stenoses in the upper caval vein. After removal of pacing leads, angiographic guidewires were introduced via the Byrd dilatators and new pacing leads introduced with the use of long sheaths originally dedicated for transvenous left ventricular leads implantation. With this case, we discuss the problems arising during reimplantation of pacing leads in patients with chronic venous occlusion. (Cardiol J 2012; 19, 5: 513-517

Contrast-induced nephropathy in clinical practice

Nefropatia indukowana kontrastem (CIN) stanowi coraz częściej występujące powikłanie zabiegów z wykorzystaniem środka cieniującego, zwłaszcza wśród osób obciążonych chorobami układu sercowo-naczyniowego. Nefropatia indukowana kontrastem jest czynnikiem istotnie zwiększającym zarówno chorobowość, jak i śmiertelność w tej grupie chorych. Niewyjaśniony do końca patomechanizm rozwoju CIN uniemożliwia skuteczne leczenie tego powikłania, dlatego tak istotna staje się profilaktyka. Jak na razie tylko nawodnienie pozostaje złotym standardem w zapobieganiu CIN, pozostawiając na dalszym planie stosowanie N-acetylocysteiny, wodorowęglanu sodu czy statyn jako metod o niepewnej skuteczności. W niniejszej pracy starano się przedstawić metody zapobiegania CIN zarówno z punktu widzenia lecznictwa zamkniętego, jak i postępowania w warunkach ambulatoryjnych, uwzględniając różny stopień ryzyka rozwoju tego powikłania.Contrast-induced nephropathy (CIN) becomes more frequent complication of contrast administration, especially among patients with cardiovascular diseases. CIN significantly increases both morbidity and mortality in this group of patients. Unexplained pathomechanism of CIN preclude effective treatment of this complication, hence it becomes prevention so important. So far, only the hydration remains the gold standard for the prevention of CIN abandon use of N-acetylcysteine, sodium bicarbonate, or statins as methods as uncertain efficacy. In this paper we have tried to provide a method of preventing CIN both in inpatient as well as out patient procedure taking into account different degrees of risk of developing this complication

Electocardiographic abnormalities in hemodialysis patients

Choroby układu sercowo-naczyniowego stanowią najczęstszą przyczynę zgonu pacjentów hemodializowanych. Zwiększona wolemia i zaburzenia elektrolitemii obecne u pacjentów leczonych nerkozastępczo zwiększają ryzyko wystąpienia groźnych zaburzeń rytmu oraz nagłej śmierci sercowej. Badanie elektrokardiograficzne (EKG) stanowi powszechnie dostępny test pozwalający określić nie tylko rodzaj arytmii i ocenić zaburzenia związane z depolaryzacją i repolaryzacją miokardium, ale również rozpoznać obecność przerostu jam serca. Przedstawiona praca to próba przybliżenia danych dotyczących zmian zachodzących w EKG w czasie zabiegu hemodializy oraz w trakcie przewlekłego leczenia nerkozastępczego.Cardiovascular disease is the leading cause of mortality among hemodialysis patients. Fluid overload, dyselectrolitemia increase the risk of malignant arrhythmia and sudden cardiac death in hemodialysis group. Electrocardiography (ECG) is the most widely used test to assess type of arrhythmia, myocardium depolarization and repolarization disturbances as well as cardiac hypertrophy. This review summarized database of ECG disturbances during chronic hemodialysis and over hemodialysis session itself

Acute left main coronary artery occlusion following inadvertent delivery of radiofrequency energy during ventricular tachycardia ablation successfully treated by rescue angioplasty with stenting: A two-year follow-up

Radiofrequency catheter ablation (RFCA) is a treatment mode in patients with recurrent, symptomatic, ventricular arrhythmias. A rare but potentially life-threatening complication of RFCA includes injury to the coronary arteries, which leads to acute occlusion and myocardial infarction. In the few reported cases, the most frequently affected vessel has been the left main coronary artery. We present the case of a 28 year-old female. During the RFCA procedure, an acute occlusion of the left main coronary artery occurred, which was treated successfully with emergency angioplasty