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ECG Pattern (ecg + pattern)
Selected AbstractsBrugada-Type ECG Pattern and Extreme QRS Complex Widening with Propafenone OverdoseJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2006CAN HASDEMIR M.D. [source] Unusual ECG Pattern of Right Atrial Appendage Atrial Tachycardia in One Patient with Right PneumonectomyPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 5 2010KAZUYOSHI SUENARI M.D. The right atrial appendage atrial tachycardia (RAA AT) has been previously reported as a rare site in focal AT. We report a patient with a history of a right pneumonectomy who underwent catheter ablation of the AT originating from the RAA. This RAA AT showed unusual P-wave morphology compared with previous reports. We describe the RAA AT following right pneumonectomy using a NavX system (St. Jude Medical, St. Paul, MN, USA). (PACE 2010; e46,e48) [source] Electrocardiogram Differentiation of Benign Early Repolarization Versus Acute Myocardial Infarction by Emergency Physicians and CardiologistsACADEMIC EMERGENCY MEDICINE, Issue 9 2006Samuel D. Turnipseed MD Abstract Objectives: ST-segment elevation (STE) related to benign early repolarization (BER), a common normal variant, can be difficult to distinguish from acute myocardial infarction (AMI). The authors compared the electrocardiogram (ECG) interpretations of these two entities by emergency physicians (EPs) and cardiologists. Methods: Twenty-five cases (13 BER, 12 AMI) of patients presenting to the emergency department with chest pain were identified. Criteria for BER required four of the following: 1) widespread STE (precordial greater than limb leads), 2) J-point elevation, 3) concavity of initial up-sloping portion of ST segment, 4) notching or irregular contour of J point, and 5) prominent, concordant T waves. Additional BER criteria were 1) stable ECG pattern, 2) negative cardiac injury markers, and 3) normal cardiac stress test or angiography. AMI criteria were 1) regional STE, 2) positive cardiac injury markers, and 3) identification of culprit coronary artery by angiography in less than eight hours of presentation. The 25 ECGs were distributed to 12 EPs and 12 cardiologists (four in academic medicine, four in community practice, and four in community academics [health maintenance organization] in each physician group). The physicians were informed of the patients' age, gender, and race, and they then interpreted the ECGs as BER or AMI. Undercalls (AMI misdiagnosed as BER) and overcalls (BER misdiagnosed as AMI) were calculated for each physician group. Results: Cardiologists correctly interpreted 90% of ECGs, and EPs correctly interpreted 81% of ECGs. The proportion of undercalls (missed AMI/total AMI) was 2.8% for cardiologists (95% confidence interval [CI] = 0.09% to 5.5%) compared with 9.7% for EPs (95% CI = 4.8% to 14.6%) (p = 0.02). The proportion of overcalls (missed BER/total BER) was 17.3% for cardiologists (95% CI = 11.4% to 23.3%) versus 27.6% for EPs (95% CI = 20.6% to 34.6%) (p = 0.03). The mean number of years in practice was 19.8 for cardiologists (95% CI = 19 to 20.5) and 11 years for EPs (95% CI = 10.5 to 12.0) (p < 0.001). Conclusions: Although correct interpretation was high in both groups, cardiologists, who had significantly more years of practice, had fewer misinterpretations than EPs in distinguishing BER from AMI electrocardiographically. [source] Focal Origin of Atrial Tachycardia in Dogs with Rapid Ventricular Pacing-Induced Heart FailureJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 10 2003GUILHERME FENELON M.D. Introduction: Dogs with rapid ventricular pacing-induced congestive heart failure (CHF) have inducible atrial tachycardia (AT), with a mechanism consistent with delayed afterdepolarization-mediated triggered activity. We assessed the hypothesis that AT has a focal origin. Methods and Results: Twenty-one CHF dogs undergoing 3 to 4 weeks of ventricular pacing at 235 beats/min were studied. Biatrial epicardial mapping of 20 sustained AT episodes (cycle length [CL], 175 ± 53 msec) in 5 dogs revealed an area of earliest activation in the right atrial (RA) free wall (13 episodes), RA appendage (4 episodes), or between the pulmonary veins (3 episodes). Total epicardial activation time during AT (73 ± 19 msec) was similar to that during sinus rhythm (72 ± 13 msec) and on average was <50% of the AT CL. Higher-density mapping of the RA free wall during 30 sustained AT episodes (163 ± 55 msec) in 9 dogs identified a site of earliest activation along the sulcus terminalis most frequently as a stable, focal activation pattern from a single site. Endocardial mapping of 49 sustained AT episodes (156 ± 27 msec) in 10 dogs revealed multiple sites of AT origin arising along the crista terminalis and pulmonary veins. Right and left ATs were terminated with discrete radiofrequency ablation, but other ATs remained inducible. A rapid, left AT generating an ECG pattern of atrial fibrillation was ablated inside the pulmonary vein. Conclusion: AT induced in this CHF model after 3 to 4 weeks of rapid ventricular pacing has an activation pattern consistent with a focal origin. Sites of earliest activation are distributed predominately along the crista terminalis and within or near the pulmonary veins. (J Cardiovasc Electrophysiol, Vol. 14, pp. ***-***, October 2003) [source] Analysis of the Electrocardiographic Waveforms Produced by Right Ventricular Pacing: Relation to the Nonpaced PatternsPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 5 2008HOWARD S. FRIEDMAN M.D. Background: Ventricular aberrant conduction has a confounding effect on the known relationships between the electrocardiogram (ECG) and left ventricular (LV) mass. By relating the ECG of right ventricular pacing to LV mass and to nonpaced recordings, clarification of these effects might emerge. Methods and Results: In 30 patients (age, 81 ± 7 years; 13 women) who had right ventricular paced ECGs and echocardiograms, 24 of who also had nonpaced ECGs, comparative analyses were performed. Although the nonpaced ECGs had strong correlations with various echocardiographic measurements, for paced ECGs, only QRS complex voltage and interventricular septal thickness (IVS) were significantly related. However, paced QRS complex voltage relationships correlated with those of nonpaced QRS complexes, ranging from an r = 0.54, P < 0.006, for the sum of the R in aVL and the S in V-3 to r = 0.78, P < 0.001, for the sum of the R in I and the S in III. Paced ECGs had a QRS complex with a greater spatial amplitude, a longer duration, and a more superior position, and had more deeply inverted T waves than nonpaced ECGs. The differences between the voltages of paced and nonpaced QRS complexes, moreover, diminished as LV mass and/or IVS increased. When compared with nonpaced ECGs, paced ECGs showed the most similarity to nonpaced ECGs having a left bundle branch block (LBBB) pattern. Except for the presence of more superiorly directed QRS complexes, paced impulses were not significantly different (P < 0.008) from nonpaced impulses having a LBBB pattern. Also, the nonpaced ECG pattern had no discernable effect on ECG produced by right ventricular (RV) pacing. Conclusions: Despite having weak relations with echocardiographic measurements, the QRS complex voltage of the paced ECG correlated with those of nonpaced ECGs, and the voltage differences between them were smaller as LV mass increased. [source] Inadvertent Positioning of Pacemaker Leads in the PericardiumPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 10 2003KAMBEEZ BERENJI A patient had a dual chamber pacemaker with endocardial leads implanted chronically. The lead position on chest X ray and the ECG pattern indicated lead malposition, but a CT scan and transesophageal echocardiography were nondiagnostic. Venography indicated that both leads were in the mediastinal and pericardial space. (PACE 2003; 26:2039,2041) [source] Ionic Mechanisms and Vectorial Model of Early Repolarization Pattern in the Surface Electrocardiogram of the AthleteANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 3 2008Eduardo C. Barbosa M.D. Background: The electrocardiogram (ECG) of the athlete displays particular characteristics as a consequence of both electrophysiological and autonomic remodeling of the heart that follows continued physical training. However, doubts persist on how these changes directly interact during ventricular activation and repolarization ultimately affecting surface ECG waveforms in athletes. Objective: This article considers an in deep rationale for the electrocardiographic pattern known as early repolarization based on both electrophysiological mechanisms at cellular level and the vectorial theory of the cardiac activation. Methods: The mechanism by which the autonomic remodeling influences the cardiac electrical activation is reviewed and an insight model of the ventricular repolarization based on ionic models and the vectorial theory of the cardiac activation is proposed. Results: Considering the underlying processes related to ventricular electrical remodeling, we propose that, in athletes' heart: 1) vagal modulation increases regional electrophysiological differences in action potential phases 1 and 2 amplitudes, thus enhancing a voltage gradient between epicardial and endocardial fibers; 2) this gradient affects depolarization and repolarization timing sequences; 3) repolarization wave front starts earlier on ventricular wall and partially overcomes the end of depolarization causing an upward displacement of the J-point, ST segment elevation, and inscription of magnified T-waves amplitudes leading to characteristic surface ECG waveform patterns. Conclusions: In athletes, the association between epicardial to endocardial electrophysiological differences and early repolarization ECG pattern can be demonstrated by the vectorial theory of the ventricular activation and repolarization. [source] Surface Electrocardiographic Patterns and Electrophysiologic Characteristics of Atrial Flutter Following Modified Radiofrequency MAZE ProceduresJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2007JOSEPH G. AKAR M.D., Ph.D. Introduction: The radiofrequency MAZE is becoming a common adjunct to cardiac surgery in patients with atrial fibrillation. While a variety of postoperative arrhythmias have been described following the original Cox-MAZE III procedure, the electrophysiological characteristics and surgical substrate of post-radiofrequency MAZE flutter have not been correlated. We sought to determine the location, ECG patterns, and electrophysiological characteristics of post-radiofrequency MAZE atrial flutter. Methods: Nine consecutive patients with post-radiofrequency MAZE flutter presented for catheter ablation 9 ± 10 months after surgery. Results: Only one patient (11%) had an ECG appearance consistent with typical isthmus-dependent right atrial (RA) flutter. However, on electrophysiological study, 3/9 patients (33%) had typical right counter-clockwise flutter entrained from the cavo-tricuspid isthmus, despite description of surgical isthmus ablation. Six patients (67%) had left atrial (LA) circuits. These involved the mitral annulus in 5/6 cases (83%) despite description of surgical mitral isthmus ablation in the majority (60%). LA flutters had a shorter cycle length compared with RA flutters (253 ± 39 msec and 332 ± 63 msec respectively, P < 0.05). After a mean of 8 ± 4 months following ablation, 8/9 patients (89%) were in sinus rhythm. Conclusion: Up to one-third of post-radiofrequency MAZE circuits are typical isthmus-dependent RA flutters, despite a highly atypical surface ECG morphology. Therefore, diagnostic electrophysiological studies should commence with entrainment at the cavo-tricuspid isthmus in order to exclude typical flutter, regardless of the surface ECG appearance. Incomplete surgical lesions at the mitral and cavo-tricuspid isthmus likely predispose to the development of post-radiofrequency MAZE flutter. [source] 25 Years of Insights into the Mechanisms of Supraventricular ArrhythmiasPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 9 2003NASPE HISTORY SERIES The introduction of programmed electrical stimulation of the heart and intracardiac activation mapping 35 years ago made it possible to study the site of origin or pathway of a supraventricular tachycardia and to gain insight into the tachycardic mechanism. Information from these studies has been the basis for the development of new therapies, like arrhythmia surgery, antitachycardia pacing, and catheter ablation. The correlation of intracardiac findings with the 12-lead ECG during the tachycardia resulted in the recognition of characteristic ECG patterns for the different types of supraventricular tachycardias. Currently, gross localization of the site of origin of the arrhythmia is based on the 12-lead ECG during the arrhythmia with fine tuning using intracardiac activation mapping and pacing. These developments during the past 3 decades make accurate arrhythmia diagnosis possible and allow us to offer curative therapies to many of patients suffering from a supraventricular tachycardia. (PACE 2003; 26:1916,1922) [source] Cardioprotective potential of myricetin in isoproterenol-induced myocardial infarction in wistar ratsPHYTOTHERAPY RESEARCH, Issue 10 2009Roshan Tiwari Abstract The study aimed to evaluate the protective role of myricetin obtained from Vitis vinifera (Vitaceae) on heart rate, electrocardiographic (ECG) patterns, vascular reactivity to catecholamines, cardiac marker enzymes, antioxidant enzymes together with morphological and histopathological changes in isoproterenol (ISO) induced myocardial infarction (MI) in male Wistar rats. Rats treated with isoproterenol (85 mg/kg, administered subcutaneously twice at an interval of 24 h) showed a significant increase in heart rate and ST elevation in ECG, and a significant increase in the levels of cardiac marker enzymes , lactate dehydrogenase (LDH), creatine kinase (CK) and aspartate aminotransferase (AST) in serum. Isoproterenol significantly reduced superoxide dismutase (SOD) and catalase (CAT) activity and increased vascular reactivity to various catecholamines. Pretreatment with myricetin (100 mg/kg, p.o. and 300 mg/kg, p.o.) for a period of 21 days significantly inhibited the effects of ISO on heart rate, levels of LDH, CK, AST, SOD, CAT, vascular reactivity changes and ECG patterns. Treatment with myricetin (100 mg/kg and 300 mg/kg) alone did not alter any of the parameters compared with vehicle treated Wistar rats. Myricetin treated animals showed a lesser degree of cellular infiltration in histopathological studies. Thus, myricetin (100 mg/kg and 300 mg/kg) ameliorates the cardiotoxic effects of isoproterenol and may be of value in the treatment of MI. Copyright © 2009 John Wiley & Sons, Ltd. [source] Atypical Electrocardiographic Features of Cavotricuspid Isthmus-Dependent Atrial Flutter Occurring during Left Atrial Fibrillation AblationANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 3 2010Janice Y. Chyou M.D. Background: Patients who have undergone percutaneous catheter ablation for atrial fibrillation (AF) may develop cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL), which can occur either spontaneously during left atrial (LA) ablation for AF or by induction from sinus rhythm during the procedure. The electrocardiographic (ECG) characteristics of CTI-dependent AFL occurring during LA ablation have not been described. The purpose of this study was to describe the ECG features of CTI-dependent AFL occurring during percutaneous LA catheter ablation for AF. Methods and Results: Of 223 patients presenting for first AF ablation at our institution between May 2004 and February 2008, 20 patients (9%) developed CTI-dependent AFL during LA ablation for AF. CTI-dependent AFL developed spontaneously in 4 patients (20%) and was induced in 16 patients (80%). Among these 20 patients, 3 (15%) had typical ECG patterns and 17 (85%) had atypical ECG patterns. Flutter waves in the inferior leads were biphasic in 10 patients (50%), downward in 3 patients (15%), positive in 3 patients (15%), and not fitting the above classifications in 4 patients (20%). There was no statistically significant association between AFL pattern and LA size, left ventricular ejection fraction, total ablation time, duration of prior AF, or type of prior AF. Conclusion: A majority of patients with CTI-dependent AFL occurring during LA ablation have atypical ECG patterns. Biphasic flutter waves in the inferior leads are common ECG features, occurring in one-half of patients. Right atrial CTI-dependent AFL should be suspected even if the ECG appearance is atypical. Ann Noninvasive Electrocardiol 2010;15(3):200,208 [source] Technical Mistakes during the Acquisition of the ElectrocardiogramANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 4 2009Javier García-Niebla R.N. In addition to knowledge of normal and pathological patterns, the correct interpretation of electrocardiographic (ECG) recordings requires the use of acquisition procedures according to approved standards. Most manuals on standard electrocardiography devote little attention to inadequate ECG recordings. In this article, we present the most frequent ECG patterns resulting from errors in limb and precordial lead placement, artifacts in 12-lead ECG as well as inadequate filter application; we also review alternative systems to the standard ECG, which may help minimize errors. [source] | ||||||||||