ISSN:1045-3873    

DOI:10.1111/j.1540-8167.1995.tb00751.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Localization of Ischemia. This study demonstrates the utility of an electrocardiographic Localization of Ischemia. This study demonstrates the utility of an electrocardiographic Inverse solution, coupled with body surface potential mapping (BSPM), in localizing acute ischemia in patients undergoing percutaneous transluminal coronary angioplasty (PTCA). PTCA balloon inflations produce complete occlusion and acute transient ischemia, which can be detected electrocardiographically with BSPM. Comparisons between maps recorded both during and before the inflation of the PTCA balloon allow patient‐ and artery‐specific characterizations of the resulting ischemia. Knowledge of the patient's coronary anatomy and the location of the occlusion site by coronary angiography permit an estimation based on cardiac hemodynamics of the region of myocardium most likely to suffer from PTCA‐induced ischemia. Electrocardiographic inverse solutions provide a means of predicting cardiac potentials from body surface maps. In this study, we describe an inverse solution we have developed to localize the transient ischemia produced by PTCA. To validate the procedure, we compared the locations of predicted ischemia in seven patients with a qualitative estimate of the perfusion region based on fluoroscopic examination of each patient's coronary anatomy and PTCA balloon location. In each case, the region of ischemia predicted by the model included the perfusion zone determined fluoroscopically. These results suggest that electrical changes induced by acute ischemia can be localized with an electrocardiographic inverse sol

ISSN:1045-3873    

DOI:10.1111/j.1540-8167.1995.tb00752.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Serial DFT Measures in Man.Introduction;The defibrillation threshold (DFT) may change throughout the first year following implantation of a cardioverter defibrillator, but it remains uncertain if changes are a consequence of changes in clinical condition or are related to fundamental alterations at the electrode‐tissue interface. The purpose of this study was to evaluate the extent and time course of DFT changes over the first year following implantable cardioverter defibrillator (ICD) surgery when extraneous clinical and device variables potentially affecting the DFT were excluded.Methods and Results.: We prospectively enrolled 61 patients undergoing epicardial or non‐thoracotomy/transvenous ICD therapy into a series of follow‐up studies where the DFT was measured at implant and at 1, 6,12, and 52 weeks following implantation in a uniform manner. Stored energy DFT was measured and recorded for all patients. Patient exclusion criteria were: (1) inability to complete all five measures of the DFT; (2) institution of Class I or Class III antiarrhythmic drugs at any time during the study; (3) lead system changes (relocation or new leads) or programming changes in pulse width or current pathway; or (4) development of a significant change in their clinical status, such as decompensated congestive heart failure or acute ischemia. Only 20 of the 61 patients satisfied the criteria required to complete the study. Two of the excluded patients developed high DFTs, which required reprogramming of the current pathway. Eight patients had an epicardial lead system, and 12 had a nonthoracotomy lead system. The rise in DFT over the first 12 weeks was significant for the eight epicardial lead system patients (P = 0.05) and for the 12 nonthoracotomy lead system patients (P = 0.004). The peak rise in DFT occurred at 1 week for the patients with an epicardial lead system (3.4 ± 1.8 J to 7.9 ± 3.8 J) and at 12 weeks for the patients with a transvenous lead system (10.3 ± 5.3 J to 16.1 ± 7.4 J).Conclusions: This study confirms a transient significant rise in the DFT in the first 12 weeks following ICD surgery that partially returns to the implant value over the remainder of the year. Because specific clinical and technical variables were excluded from this study, the observations made in this patient population suggest that the rise in DFT may be a consequence of changes at the electrode‐tissu

ISSN:1045-3873    

DOI:10.1111/j.1540-8167.1995.tb00753.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AV Node in Dog and Man.IntroductionAdvances in treating patients with dual atrioventricular nodal pathways have called for a better understanding of the morphology of the approaches to the atrioventricular node. In this respect, it has recently been suggested that, in dog, anatomically discrete muscle bundles originating from the sinus node represent the substrate of the dual pathways recognized electrophysiologically in patients with atrioventricular nodal reentrant tachycardia. This concept is at odds with most anatomic studies of the human specialized atrioventricular juuctional area. In this study, therefore, we studied histologically the junctional area in dog hearts, comparing them with our own findings in human heart and the descriptions of the earliest investigators.Methods and Results: Five dog and six human hearts were prepared for histology and sectioned serially in different planes. Reconstructions were then made from each of three dog and two human hearts sectioned in orthogonal planes. Gross differences in the anatomy of the atrioveutricular junctional area and in the structure of the conduction system were obvious between dog and human hearts. The penetrating portion of the conduction axis was longer in the dog, being much more extensively embedded in the central fibrous body. The atrioventricular node, in both dog and man, was composed of a zone of transitional cells overlying a compact region. The zone of transitional cells in the dog was more extensive posteriorly than anteriorly. No bundles insulated anatomically by fibrous tissue were found either in the internodal atrial myocardium or in the approaches to the atrioventricular node. Our findings in both dog and man are comparable with the initial descriptions of the atrioventricular junctional area.Conclusion: Although the disposition of the conduction system in dog and man is basically similar, there are important differences which relate to the gross anatomy. The anatomic substrate for functional duality of the inputs to the atrioventricular node remains unclear, since our study confirms that the concept of insulated atrionodal tracts has no morphologic basis.

ISSN:1045-3873    

DOI:10.1111/j.1540-8167.1995.tb00754.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Sustained Bundle Branch Reentrant VT. Radiofrequency catheter ablation of the left bundle branch (LBB) was attempted in a patient with sustained bundle branch reentry. During sinus rhythm, the QRS had a complete LBB block pattern, and the LBB was activated retrogradely (transseptal). Ablation of the LBB eliminated inducibility of the tachycardia, while the QRS complex and the duration of the HV interval (70 msec) remained unchanged. Successful ablation of the LBB eliminated bundle branch reentry and yet maintained the anterograde conduction properties of the His‐Purkinje system, obviating implantation of a permanent pacemake

ISSN:1045-3873    

DOI:10.1111/j.1540-8167.1995.tb00755.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Internal Cardioversion.introduction: This report describes the electrical conversion of atrial fibrillation in two morbidly obese patients refractory to external cardioversion at 360 J.Methods and Results: The two patients were lightly sedated and underwent placement of decapolar catheters in the coronary sinus and right atrial appendage. All ten electrodes of each decapolar catheter were electrically coupled, and defibrillation was attempted at successively increasing levels using a biphasic decaying exponential waveform generated by an external defibrillator. Both patients were returned to normal sinus rhythm using<10 J without complication.Conclusion: Internal cardioversion is effective in restoration of sinus rhythm in some patients refractory to conventional forms of therapy

ISSN:1045-3873    

DOI:10.1111/j.1540-8167.1995.tb00756.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Pacer‐Cardioverter‐Defibrillator. This article reviews the function of the pacer‐cardioverter‐defibrillator (PCD). Detection of ventricular arrhythmias occurs in two programmable zones, with onset and stability modifiers available to diminish overdetection of sinus tachycardia and atrial fibrillation, respectively. The sensing circuitry utilizes an auto‐adjusting sensitivity with exponential decay to allow detection of low‐amplitude ventricular fibrillation electrograms without T wave oversensing. Treatment can be accomplished by tiered therapy with two types of antitachycardia pacing, cardioversion and defibrillation. Cardioversion and defibrillation shocks are programmable between single pathway when two leads are used and simultaneous or sequential shock delivery when a three‐lead system is used. A telemetered marker channel and electrogram aid in assessing device function during implantation and follow‐up. Previously published literature is cited to expand on various aspects of PCD function

ISSN:1045-3873    

DOI:10.1111/j.1540-8167.1995.tb00757.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Classification of Atrial Fibrillation.Introduction: Clinical aspects of paroxysmal atrial fibrillation are heterogeneous. The attacks of atrial fibrillation may differ in their duration frequency and presence and severity of symptoms. Therefore, a proposal for a clinical classification of paroxysmal atrial fibrillation may be helpful. We tested a new classification system in a cohort of 51 consecutive hospitalized patients with paroxysmal atrial fibrillation.Methods and Results: Paroxysmal atrial fibrillation was subdivided into three classes. Class I included a first attack of symptomatic atrial fibrillation either with spontaneous termination (IA) or requiring cardioversion because of poor tolerance (IB). Class II included recurrent attacks in untreated patients within three subgroups: IIA with no symptoms, IIB withwith 1 symptomatic attack per 3‐month period. Class III included recurrent atrial fibrillation unresponsive to one or more antiarrhythmic agents for prevention of recurrences. Class III also consisted of three subgroups: IIIA with no or mild symptoms, IIIB with2 minutes and<7 days in duration) were fulfilled by 51 patients (29 men, 22 women; mean age 61 ± 14 years). Structural heart disease was present in 31 patients; the atrial fibrillation was idiopathic in 18 (35%). All 51 patients could be classified within the three classes and their subgroups: 14 patients (27%) in Class I, 13 (25%) in Class II, and 24 (47%) in Class III. The incidences of idiopathic atrial fibrillation were 21%, 30%, and 45% of the patients in Classes I, II, and III, respectively.Conclusions: Based on this new classification system, all hospitalized patients with paroxysmal atrial fibrillation could be classified. This classification may be useful to delineate better the clinical subgroups of patients with paroxysmal atrial fibrillation, to characterize better the patient population in future studies, and to improve treatment st

ISSN:1045-3873    

DOI:10.1111/j.1540-8167.1995.tb00758.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:1045-3873    

DOI:10.1111/j.1540-8167.1995.tb00759.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY