J. H. Kingma

Body surface mapping of ectopic left and right ventricular activation. QRS spectrum in patients without structural heart disease.

The value of simultaneous 62-lead electrocardiographic recordings in localizing the site of origin of ectopic ventricular activation in a structurally normal heart was assessed by examining body surface QRS integral maps in 12 patients during left and right ventricular (LV and RV) pacing at 182 distinct endocardial sites. A data base of 38 characteristic mean integral maps was composed after visually selecting subgroups with nearly identical total QRS integral morphology and numerically evaluating intrasubgroup pattern uniformity and intersubgroup pattern variability. Corresponding endocardial pacing site locations were computed by a biplane cineradiographic method and outlined as segments on a standardized LV and RV polar projection. LV pacing resulted in 25 markedly different mean total QRS integral patterns, showing higher electrocardiographic sensitivity for anteroseptal (18 patterns) compared with posterolateral regions (seven patterns). RV pacing demonstrated 13 mean total QRS integral patterns, exhibiting less intersubgroup variation and comparatively low electrocardiographic sensitivity for the basal anterior and outflow regions. Comparison of LV with RV pacing revealed that QRS configurations produced at LV apical and LV midseptal sites closely resembled QRS configurations generated at RV apical, RV septal, and RV anterior sites, respectively. Total QRS time integral amplitudes showed considerable intrasubgroup variation but permitted global differentiation of spatially similar QRS patterns obtained during pacing at LV and RV sites. This study demonstrates that the QRS pattern of the total body surface electrocardiogram allows discrimination among 38 different LV and RV segments of ectopic endocardial impulse formation in patients with normal cardiac anatomy.

Localization of the site of origin of postinfarction ventricular tachycardia by endocardial pace mapping. Body surface mapping compared with the 12-lead electrocardiogram

BackgroundThe purpose of this study was to assess the value of body surface mapping and the standard 12-lead ECG in localizing the site of origin of postinfarction ventricular tachycardia (VT) during endocardial pace mapping of the left ventricle. summary Background. The purpose of this study was to assess the value of body surface mapping and the standard 12-lead ECG in localizing the site of origin of postinfarction ventricular tachycardia (VT) during endocardial pace mapping of the left ventricle. Methods and ResultsSimultaneous recordings of 62-lead body surface QRS integral maps and scalar 12-lead ECG tracings were obtained in 16 patients with prior myocardial infarction during a total of 26 distinct VT configurations and during subsequent left ventricular catheter pace mapping at 9 to 24 different endocardial sites. Anatomic pacing site locations were computed by means of a biplane cineradiographic method and plotted on a polar projection of the left ventricle. The QRS integral map and the QRS complexes of the 12 standard leads of eachVT morphology obtained in a particular patient were compared independently with the different paced QRS integral maps and paced QRS complexes of the 12-lead ECG generated in that same patient. The stimulus site locations of the best matching paced QRS integral map and paced QRS complexes of the 12-lead ECG were indicated on the polar projection and subsequently compared with the endocardial location of the corresponding site ofVT origin identified during intraoperative (surgical ablation) or catheter activation sequence mapping (catheter ablation). The localization resolution of pace mapping was established separately for each electrocardiographic technique by computing the size of endocardial areas with similar morphological features of the QRS complex. Pace mapping advocated with body surface mapping or the 12-lead ECG enabled adequate reproduction of the VT QRS morphology in 24 of 26 VTs (92%) and 25 of 26 VTs (96%), respectively. Activation sequence mapping identified the site of origin in 12 of 26 previously observedVT configurations (46%). Ten and 11 VTs were localized by activation sequence mapping and pace mapping combined with body surface mapping or the 12-lead ECG, respectively. Pace mapping applied with body surface mapping identified the site of origin correctly (distance .2 cm) in 8 of 10 compared VTs (80%); an adjacent site (distance between 2 and 4 cm) or a disparate site (distance >4 cm) was identified in the remaining 2 of 10 VTs (20%). Pace mapping used with the 12-lead ECG localized the site of origin correctly in 2 of 11 VTs (18%); the site of origin was identified correctly next to an additional adjacent site in 5 of 11 VTs (55%); and an adjacent site or a disparate site was found in 1 of 11 VTs (9%vo) and 2 of 11 VTs (18%), respectively. The difference in localization accuracy of both electrocardiographic techniques was statistically significant (P=.02). The mean size of endocardial areas where a comparable QRS morphology was obtained during pace mapping was 6.0±4.5 cm2 with the application of body surface mapping and 15.1±12.0 cm2 with the use of the 12-lead ECG. ConclusionsThese results demonstrate that application of the 62-lead instead of the 12-lead ECG during endocardial pace mapping enhances the localization resolution of this mapping technique and enables more precise identification of the site of arrhythmogenesis in the majority of compared postinfarctionVT episodes.

Long-term results of the corridor operation for atrial fibrillation.

OBJECTIVE--To investigate the long-term results of the corridor operation in the treatment of symptomatic atrial fibrillation refractory to drug treatment. BACKGROUND--The corridor operation is designed to isolate from the left and right atrium a conduit of atrial tissue connecting the sinus node area with the atrioventricular node region in order to preserve physiological ventricular drive. The excluded atria can fibrillate without affecting the ventricular rhythm. This surgical method offers an alternative treatment when atrial fibrillation becomes refractory to drug treatment. PATIENTS--From 1987 to 1993, 36 patients with drug refractory symptomatic paroxysmal atrial fibrillation underwent surgery. The in hospital rhythm was followed thereafter by continuous rhythm monitoring and with epicardial electrograms. After discharge Holter recording and stress testing were regularly carried out to evaluate the sinus node function and to detect arrhythmias; whereas Doppler echocardiography was used to measure atrial contraction and size. MAIN OUTCOME MEASURES--Maintained absence of atrial fibrillation without drug treatment after operation; preservation of normal chronotropic response in the sinus node. RESULTS--The corridor procedure was successful in 31 (86%) of the 36 patients. After a mean (SD) follow up of 41 (16) months 25 (69%) of the 36 patients were free of arrhythmias without taking drugs (mean (SE) actuarial freedom at four years 72 (9)%)). Paroxysmal atrial fibrillation recurred in three patients; paroxysmal atrial flutter (two patients) and atrial tachycardia (one patient) developed in the corridor in three others. Among the 31 patients in whom the operation was successful sinus node function at rest and during exercise remained undisturbed in 26 and 25 patients respectively (mean (SE) actuarial freedom of sinus node dysfunction at four years (81(7)%)). Pacemakers were needed in five (16%) of the 31 patients for insufficient sinus node rhythm at rest only. Doppler echocardiography showed maintenance of right atrial contribution to right ventricle filling in 26 of the 31 patients after operation in contrast to the left atrium, which never showed such contribution. His bundle ablation was performed and a pacemaker implanted in the five patients in whom the corridor operation was unsuccessful. CONCLUSION--These results substantiate the idea of this surgical procedure. Modification of the technique is, however, needed to achieve a reliable isolation between left atrium and corridor, which would make this experimental surgery widely applicable in the treatment of drug refractory atrial fibrillation.

Body surface mapping of ectopic left ventricular activation. QRS spectrum in patients with prior myocardial infarction.

To improve electrocardiographic localization of the site of origin of ectopic left ventricular (LV) impulse formation in the heart with prior myocardial infarction, 62-lead body surface QRS integral maps were studied during LV pacing at a total of 221 endocardial sites in 14 patients with previous anterior (AMI), inferior (IMI), lateral (LMI), or anterior and inferior (AMI/IMI) myocardial infarction. The anatomic location of each pacing site was computed using digitized biplane fluoroscopic images and plotted on standardized LV endocardial polar projections. A data base of characteristic AMI and IMI mean QRS integral maps was developed after visually selecting subgroups with nearly identical QRS integral morphology from the ectopic activation sequences produced at 110 sites in eight patients with AMI and at 66 sites in four patients with IMI. Intrasubgroup pattern uniformity and intersubgroup pattern variability were statistically verified. The endocardial pacing site locations belonging to each AMI and IMI subgroup were depicted as segments on the respective LV polar projections. In patients with AMI, a total of 18 typical mean QRS integral patterns were obtained, whereas 22 different mean total QRS integral patterns showing more substantial intersubgroup variation were acquired in patients with IMI. Posterolateral regions exhibited a relatively low electrocardiographic sensitivity (six AMI and five IMI patterns) as compared with anteroseptal regions (12 AMI and 17 IMI patterns). Total QRS integral patterns obtained at 24 sites in one patient with LMI were largely compatible with the IMI mean total QRS integral patterns, whereas the majority of total QRS integral patterns acquired at 21 sites in one patient with AMI/IMI corresponded with the AMI mean total QRS integral patterns. The results show that total body surface QRS integral maps generated during LV pacing in patients with prior myocardial infarction cluster by pattern and that each QRS integral pattern is related to a circumscribed endocardial segment of ectopic impulse formation. The relation between a given QRS integral pattern and the position and size of the corresponding paced segment is dependent on infarct location. The present infarct-specific data base of characteristic total body surface QRS integral patterns provides a clinical tool to obtain detailed electrocardiographic localization of ventricular arrhythmias in patients with previous myocardial infarction.

Exercise capacity after His bundle ablation and rate response ventricular pacing for drug refractory chronic atrial fibrillation

OBJECTIVE: To evaluate exercise capacity of patients with chronic atrial fibrillation in whom His bundle ablation followed by ventricular rate response pacing (VVIR) was carried out because of drug refractoriness. DESIGN: Prospective study. PATIENTS: 25 consecutive patients, all with chronic symptomatic drug refractory atrial fibrillation, underwent His bundle ablation. Before this intervention all patients were on antiarrhythmic drugs to attain acceptable heart rate control and to relief symptoms. MAIN OUTCOME MEASURES: Exercise capacity, including measurements of VO2, was examined before and after a mean interval of seven months following His bundle ablation. RESULTS: Exercise capacity after His bundle ablation increased from a mean of 109 (SD 49) W to 118 (46) W (P < 0.002), but VO2 at peak exercise did not change significantly. Maximum exercise capacity was achieved with a significantly lower maximum driven heart rate than the spontaneous heart rate before ablation. CONCLUSIONS: Exercise capacity of patients who underwent His bundle ablation followed by VVIR pacing remained unchanged or improved during a mean follow up of seven months. Larger patient populations with longer follow up are necessary to examine determinants of improved exercise capacity.

Predictive value of ventricular arrhythmias for patency of the infarct-related coronary artery after thrombolytic therapy.

In animal studies reperfusion of coronary arteries is commonly accompanied by ventricular arrhythmias. It is not certain, however, whether ventricular arrhythmias can be used as a reliable non-invasive marker of reperfusion in humans. Two-channel Holter recordings were obtained from the start of an intravenous infusion of streptokinase until coronary angiography (2.8 (2.7) hours (mean SD)) afterwards) in 57 patients with acute myocardial infarction of less than four hours who were generally not treated with antiarrhythmic drugs. Ventricular arrhythmias occurred in 21 (37%) of the 57 patients: accelerated idioventricular rhythm in 13 patients and non-sustained ventricular tachycardia in 15 patients. Seven patients had both accelerated idioventricular rhythm and non-sustained ventricular tachycardia. Coronary angiography showed a patent infarct-related vessel in 12 (92%) of the 13 patients with accelerated idioventricular rhythm (95% confidence interval 66 to 99%), in 22 (50%) of the 44 patients without accelerated idioventricular rhythm (95% CI 34 to 66%), in 11 (73%) of the 15 patients with non-sustained ventricular tachycardia (95% CI 45 to 92%), and in 23 (55%) (95% CI 39 to 71%) of the 42 patients who did not have non-sustained ventricular tachycardia. Seventeen (81%) of the 21 patients with accelerated idioventricular rhythm, or non-sustained ventricular tachycardia, or both, had a patent infarct-related vessel (95% CI 58 to 94%) as did 17 (47%) of the 36 patients with no ventricular arrhythmia (95% CI 29 to 65%). In patients with accelerated idioventricular rhythm after thrombolysis the infarct-related vessel is almost certain to be patent; but the infarct-related coronary artery can still be patent when no arrhythmia is seen.

A patient in whom self-terminating ventricular fibrillation was a manifestation of myocardial reperfusion.

Self-terminating ventricular fibrillation was recorded in a 47 year old woman without coronary artery or other structural heart disease. Reperfusion was thought to be responsible for the ventricular fibrillation because the arrhythmia started while the ST segment was returning to the baseline during an episode of silent ischaemia that was probably caused by coronary spasm. This case shows that potentially lethal arrhythmias can arise during reperfusion and that ventricular fibrillation during reperfusion may be self-terminating.

Computer assisted management of malignant ventricular arrhythmias

A computer assisted management system is presented to support protocol-guided treatment of patients suffering from life-threatening ventricular arrhythmias. The system advises and keeps track of all relevant information. The setup of the system is flexible, so that deviations from the protocol and enhancements of the stored knowledge can be realized with modest effort. The programs are written in FORTRAN 77. The system runs under the RSX11M operating system on an LSI 11/73.<<ETX>>

Strategy evaluation in patients with sustained ventricular tachycardia and fibrillation by decision network analysis

The authors describe the evaluation of a computer assisted management system to support protocol guided treatment of patients suffering from life threatening ventricular arrhythmias. The system advises and keeps track of all relevant information. The setup of the system is flexible so that derivations from the protocol and enhancements of the stored knowledge can be realized with modest effort. The management system uses FoxPro as database management system, runs under MS-DOS, and communicates with the central departmental database computer by means of PC-NFS through remote shell facilities. The programs for the central database are written in FORTRAN 77. The system runs under the AIX operating system on an IBM RS6000.<<ETX>>

Multisource comparative QRS-wave analysis of premature ventricular beats and monomorph ventricular tachycardia

The authors describe a system for storage and display of QRS morphologies of ventricular arrhythmias from different sources. A substantial reduction of data is achieved by the generation of a so-called morphology atlas, containing only representative QRS complexes. An algorithm is described that groups the different morphologies into families. The hardware configuration of the system consists of a digitizer (resolution 0.1 mm), a personal computer, and a printer/plotter. The PC is connected to the central database computer by a serial RS232 line, using the program Kermit for communication. The PC is used as a virtual terminal for the database and controls the digitizer and graphic display. The setup was tested on 24 patients, each with spontaneous monomorphic sustained ventricular tachycardia (VT) late after myocardial infarction, ventricular premature beats (VPBs) recorded on a 5-channel Holter ECG, and (non)-sustained VT induced during programmed electric simulation. The system performed automatic grouping of morphologies rather well in case of (non)-sustained VTs. The correlation threshold of 60% confirmed the diagnoses of three independent observers. In case of VPBs no threshold could be determined.<<ETX>>