Showing papers on "QRS complex published in 1995"

Mechanoelectrical interaction in tetralogy of Fallot. QRS prolongation relates to right ventricular size and predicts malignant ventricular arrhythmias and sudden death.

Abstract: Background Life-threatening ventricular arrhythmia and sudden death remain serious late complications after tetralogy of Fallot repair. Nevertheless, there remains no clear way of predicting which patients are at risk. Methods and Results The study population included a total of 178 adult survivors (mean follow-up, 21.4 years) of tetralogy of Fallot repair who were currently attending our clinic. Mechanoelectrical relations were sought in 41 of the patients (mean follow-up, 23.6 years) who were operated on by one surgeon and who were prospectively studied with a 12-lead ECG, chest radiography, and two-dimensional and Doppler echocardiography. Nine patients (mean follow-up, 17 years) from the total group of 178 were identified as having had sustained ventricular tachycardia (8 with near-miss sudden death), and their ECGs, Holter monitor readings, electrophysiological studies, and chest radiographs were reviewed. The case notes of an additional 4 patients with postoperative sudden cardiac death also were av...

Quantitative measurement of normal and excessive (cor adiposum) subepicardial adipose tissue, its clinical significance, and its effect on electrocardiographic QRS voltage.

Abstract: In summary, adipose tissue in the heart may constitute up to 50% of the cardiac weight. The greater amounts of cardiac adipose tissue are associated with lower total 12-lead QRS voltages.

The utility of clinical, electrocardiographic, and roentgenographic variables in the prediction of left ventricular function.

Abstract: To determine the clinical value of simple, widely available variables in estimating left ventricular (LV) function, we performed an analysis on 14,507 patients presenting with chest pain who were enrolled in the Coronary Artery Surgery Study registry. Of these patients, 4,034 had a normal electrocardiogram, and of these, 91.8% had an LV ejection fraction (EF) > 0.50, 7.6% had an EF of 0.36 to 0.50, and only 0.6% had an EF < or = 0.35. The presence of T-wave abnormalities (with normal QRS), left bundle branch block, electrocardiographic evidence of LV hypertrophy or myocardial infarction, cardiomegaly on chest roentgenogram, basilar rales, or third heart sound significantly decreased the likelihood of normal LVEF. Based on these clinical variables, a logistic regression model with a sensitivity of 68% and a specificity of 74% for identifying subjects with normal EF was developed. It was concluded that in patients with chest pain, consideration of such readily available clinical data provides useful information and may decrease the need for more expensive imaging methods.

Apparatus and method for predicting cardiac arrhythmia by detection of micropotentials and analysis of all ECG segments and intervals

Abstract: An apparatus and method for the acquisition and analysis of electrocardiogram signals, to non-invasively detect and quantify presence of abnormal cardiac conduction patterns in patients at risk of heart disease, e.g. ventricular tachycardia; atrial fibrillation and flutter. Signals from the orthogonal X, Y and Z surface leads are amplified, digitized and either stored for later processing, or processed immediately. The incoming beats can either be R wave-triggered, aligned and ensemble-averaged for studies of patients at risk for ventricular pathologies such as ventricular tachycardia, or P wave-triggered, aligned and ensemble-averaged for studies of patients at risk for atrial pathologies, e.g. atrial fibrillation and flutter. QRS onset and offset, and P wave onset and offset, are calculated for ventricular and atrial post-analysis applications, respectively. The windowed Fourier transform of the second derivative (acceleration) of the signal-averaged ECG is calculated for particular regions of interest for each lead, including the intra-QRS, ST-segment, T and P wave regions. A novel Spectral Change Index, calculated from the resulting "acceleration spectrum" for each lead as well as the composite (X+Y+Z) lead, serves to quantify the degree of spectral "fragmentation" within a prespecified bandwidth. It thereby provides a quantitative index to help stratify patients at risk for potentially lethal cardiac (atrial and ventricular) pathologies.

An accurate stepwise electrocardiographic algorithm for localization of accessory pathways in patients with Wolff-Parkinson-White syndrome from a comprehensive analysis of delta waves and R/S ratio during sinus rhythm.

Abstract: Prediction of accessory pathway location before radio-frequency ablation has become increasingly important for patients with Wolff-Parkinson-White syndrome. However, existing electrocardiographic (ECG) criteria for localization of accessory pathways have several limitations, and the polarity of delta waves has not been well defined. In the present study, 369 patients with a single anterogradely conducting accessory pathway who underwent successful radiofrequency ablation were included. The polarity of delta waves was defined and categorized in detail, and various ECG characteristics of the most preexcited QRS complexes were examined and compared with QRS complexes after successful ablation in the initial 182 patients, which included morphology and polarity of delta waves, initial 20, 40, and 60 ms segments of the preexcited QRS complex, R/S ratio in the precordial leads, R/S ratio in the frontal leads, delta wave axis in the frontal plane, polarity of delta waves in the frontal leads, and polarity of delta waves in the precordial leads. The polarity of the initial 40 ms segment of the most preexcited QRS complexes in each of the frontal leads, and the polarity of the initial 60 ms segment of the most preexcited QRS complex in each of the precordial leads proved to be the best representatives of delta wave polarity in the respective leads.(ABSTRACT TRUNCATED AT 250 WORDS)

Prognostic value of the signal-averaged electrocardiogram and a prolonged QRS in ischemic ana nonischemic cardiomyopathy

Abstract: Studies of electrocardiographic predictors of mortality in patients with chronic heart failure have reached varying conclusions. Differences in the characteristics of the patients studied may explain the conflicting results regarding both a prolonged QRS and an abnormal signal-averaged electrocardiogram (SAE). We therefore investigated the impact of the etiology of heart failure on the prognostic importance of a prolonged QRS and an abnormal SAE in 200 patients with heart failure. Patients were categorized according to etiology of heart failure and electrocardiographic parameters. The mortality of patients with a prolonged QRS was compared with mortality in those with both abnormal and normal SAEs. This was done for the entire group, and separately for those with ischemic and those with nonischemic cardiomyopathy. The mean follow-up was 18.8 months. Nonischemic patients with a prolonged QRS had significantly worse survival than other patients. However, nonischemic patients with an abnormal SAE did not have a worse prognosis than patients with a normal SAE. One-year survival of patients with a prolonged QRS was 71%, compared with 98% in patients with a normal and 87% in patients with an abnormal SAE (p < 0.05). In contrast, a prolonged QRS was not a predictor of poor prognosis in patients with ischemic cardiomyopathy (81% one year mortality). Patients with ischemic cardiomyopathy and an abnormal SAE tended to have a poorer survival than patients with a normal SAE (73% and 81% one year mortality, respectively). Thus, the etiology of heart failure affects the prognostic importance of both a prolonged QRS and an abnormal SAE.

Gender differences and the electrocardiogram in left ventricular hypertrophy

Abstract: We examined the relations of gender differences in electrocardiographic (ECG) voltages and QRS duration to differences in cardiac dimensions and body size between men and women and gender differences in test performance of ECG criteria for the detection of echocardiographic left ventricular hypertrophy in 389 subjects (112 women and 277 men). ECG voltage-duration products were calculated as the product of QRS duration and voltages. Among subjects with normal left ventricular mass and also among subjects with left ventricular hypertrophy, men had longer QRS duration, higher Cornell voltage, higher 12-lead sum of QRS voltage, and higher Cornell and 12-lead voltage-duration products than did women. Significant gender differences in QRS duration, Cornell voltage, the 12-lead sum of voltage and their voltage-duration products remained after adjusting for the greater left ventricular mass, height, and weight in men than women. Comparison of areas under receiver operating characteristic curves using gender-specific criteria demonstrated higher performance of QRS duration, Cornell voltage, the 12-lead sum of QRS voltage, and the respective voltage-duration products for the identification of left ventricular hypertrophy in men than women. Thus, gender differences in body size and left ventricular mass do not completely account for gender differences in QRS duration and voltage measurements, and ECG criteria for left ventricular hypertrophy have lower accuracy in women even when gender differences in partition value selection are taken into account.(ABSTRACT TRUNCATED AT 250 WORDS)

Cure of Interfascicular Reentrant Ventricular Tachycardia by Ablation of the Anterior Fascicle of the Left Bundle Branch

Abstract: Ablation of interfascicular re-entrant tachycardia. Introduction: Fascicular re-entrant ventricular tachycardia (VT) using the anterior fascicle of the left bundle anterogradely is rare and may produce identical QRS morphology during sinus rhythm and VT. Catheter ablation of this type of VT has not been described in detail. Methods and results: In a postinfarct patient with dilated left ventricle and recurrent VT (showing a QRS configuration of right bundle branch, left posterior fascicular block), endocardial recordings from the His-Purkinje system showed that VT was due to interfascicular re-entry. Induction of VT occurred after progressive retrograde conduction delay on increasing the prematurity of the extrastimulus. Anterograde conduction occurred exclusively over the left anterior fascicle, which caused identical QRS morphology during sinus rhythm and VT. During VT, the left posterior fascicle was used retrogradely. The usual target for bundle branch re-entry ablation, the right bundle, did not participate in the re-entrant circuit. While performing left ventricular endocardial mapping, VT was interrupted when positioning the catheter on the left anterior fascicle, and ‘reversed1 nonsustained bundle branch re-entry occurred with anterograde conduction over the posterior fascicle and retrograde conduction over the anterior fascicle. Ablation of conduction in the anterior fascicle led to cure of the VT. Conclusion: Interfascicular re-entrant VT with right bundle branch block, right-axis QRS configuration can be cured by catheter ablation of anterior fascicle conduction.

Effect of Subendocardial Resection on Sinus Rhythm Endocardial Electrogram Abnormalities

Abstract: Background Patients with sustained ventricular tachycardia after acute myocardial infarction frequently have characteristic abnormalities of left ventricular endocardial electrical activity, including fractionated (prolonged, multicomponent, low-amplitude), split (having discrete widely separated deflections), and late (extending after the end of the QRS complex) electrograms. The exact cause and source of these electrograms are not clear. Methods and Results In this study, endocardial electrograms from 18 patients were recorded with a 20-electrode array from the same area immediately before and immediately after resection of subendocardial tissue at the time of surgery for ventricular tachycardia. Electrograms could be compared before and after resection from 298 of 360 (83%) of the electrodes. Before resection, split electrograms were present in 130 (44%) and late components in 81 (27%) of the recordings. Recordings made after resection showed fewer abnormalities, including complete absence of split ele...

Increased dispersion of refractoriness in the absence of QT prolongation in patients with mitral valve prolapse and ventricular arrhythmias.

Abstract: BACKGROUND--The mechanism responsible for the reported high incidence of ventricular arrhythmias in mitral valve prolapse is not clear. Electrocardiographic studies show an increased occurrence of repolarisation abnormalities on the 12 lead surface electrocardiogram, indicating regional differences in ventricular recovery. The purpose of this study was to investigate whether dispersion of refractoriness was an arrhythmogenic mechanism. METHODS--QT dispersion was measured in 32 patients with echocardiographically documented mitral valve prolapse and ventricular arrhythmias on 24 hour Holter recordings. QT dispersion was defined as the difference between the maximum and minimum average QT interval in any of the 12 leads of the surface electrocardiogram. QT dispersion corrected for heart rate was calculated by Bazett's formula. The results were compared with the data from 32 matched controls without a history of cardiac disease. Patients taking drugs that influence the QT interval and patients with a QRS duration > 120 ms were excluded. RESULTS--QT dispersion was greater in patients with mitral valve prolapse than in matched controls (60 (20) v 39 (11 ms) respectively, P < or = 0.001) as was corrected QT (64 (20 ms) v 43 (12 ms) respectively, P < or = 0.001). There was no significant difference in minimum or maximum QT intervals between the two groups. CONCLUSIONS--QT dispersion on the 12 lead surface electrocardiogram was greater in patients with mitral valve prolapse with ventricular arrhythmias than in normal controls, but the maximum QT interval was not increased. The results accord with the hypothesis that regional shortening and lengthening of repolarisation times in patients with mitral valve prolapse may account for the increased dispersion of refractoriness.

A fast and reliable algorithm to localize accessory pathways based on the polarity of the QRS complex on the surface ECG during sinus rhythm.

Abstract: d'AVILA, A., et al.: A Fast and Reliable Algorithm to Localize Accessory Pathways Based on the Polarity of the QRS Complex on the Surface ECG During Sinus Rhythm. Background: Many criteria have been published to localize accessory pathways from the 12-lead EGG during sinus rhythm. This study analyzed whether the localization of an accessory pathway could be predicted by using the polarity of the QRS complex during sinus rhythm on the surface ECG, instead of the delta wave polarity as used in many reports. Methods: The ECGs of 140 patients with an overt and single accessory pathway were evaluated. Eight localizations were taken into account. The precise location was previously known from successful radiofrequency ablation sites. Results: In 128 patients (92%), the new algorithm allowed an accurate diagnosis of the site of implantation of the accessory pathway. Conclusion: Analysis of the polarity of the QRS complex on five electrocardiographic leads provides an easy, fast and reliable way to localize accessory pathways during sinus rhythm.

Spatial Features in Body-Surface Potential Maps Can Identify Patients With a History of Sustained Ventricular Tachycardia

Abstract: Background Regional disparities of ventricular primary-repolarization properties contribute to an electrophysiological substrate for arrhythmias. Such disparities can be assessed from body-surface distributions of ECG QRST areas. Our objective was to isolate and test those features of QRST-area distributions that would be suitable for identifying patients at risk for life-threatening ventricular arrhythmias. Methods and Results We recorded ECGs simultaneously from 120 leads during sinus rhythm for 204 patients taking no antiarrhythmic drugs: half had had sustained ventricular tachycardia (VT); the other half, a myocardial infarction but no history of VT. For each patient, we calculated the QRST area in each lead and, using Karhunen-Loeve (K-L) expansion, reduced these data to 16 coefficients (each relating to one spatial feature, an eigenvector, derived from the total set of 204 QRST-area maps). Using stepwise discriminant analysis, we selected feature subsets that best discriminated between the two groups, and we estimated by a bootstrap procedure using 1000 trials how these subsets would perform on a prospective patient population. The mean diagnostic performance of the classifier for 1000 randomly selected training sets (n=102 in each, with both groups equally represented) increased monotonically with the number of features used for classification. The initial trend for the corresponding test sets (n=102 in each) was the same but reversed when the number of features exceeded eight. For an optimal set of eight spatial features, the sensitivity and specificity of the classifier for detecting patients with VT in 1000 test sets were (mean±SD) 90.3±4.3% and 78.0±6.1%, and its positive and negative predictive accuracies were 80.7±4.2% and 89.2±4.2%, respectively. Use of QRS duration as a supplementary feature to eight K-L coefficients can, in the test sets, increase specificity to 80.9±5.4% and positive predictive accuracy to 82.8±3.9% compared with the results for the optimal number of eight K-L features alone. Conclusions Multiple body-surface ECGs contain valuable spatial features that can identify the presence of an arrhythmogenic substrate in the myocardium of patients at risk for ventricular arrhythmias. Our results compare very favorably with those achieved by any other known test, invasive or noninvasive, for arrhythmogenicity.

ECG Criteria to Distinguish Between Aberrantly Conducted Supraventricular Tachycardia and Ventricular Tachycardia:Practical Aspects for the Immediate Care Setting

Abstract: To reevaluate ECG criteria for distinguishing Supraventricular tachycardia (SVT) with aberrant conduction from ventricular tachycardia (VT), 133 wide QRS tachycardias were recorded in patients undergoing invasive electrophysiological (EP) study. Surface ECG leads (standard 12-lead and MCL leads) were compared to EP recordings to provide a standard for correct diagnosis. Criteria from six studies were pooled to select QRS morphology agreed to be highly specific for SVT or VT (specificity > 90%). Some morphological criteria were modified to simplify analysis for the immediate care setting. Results: Although the 12-lead ECG was useful in distinguishing aberrancy from VT, 13 tachycardias (10%) were misdiagnosed or could not be diagnosed. The MCL1 lead recorded clearly different QRS morphology than lead V1 in 40% of VT cases and was diagnostically inferior to V1.Most established criteria were highly specific for a diagnosis, but not very sensitive as individual criteria. Neither a QRS width of > 0.14 seconds nor a monophasic R wave pattern in lead V1 were valuable in diagnosing VT. Conclusions: In distinguishing SVT with aberrant conduction from VT: (1) Although the 12-lead ECG is valuable, about 1 in 10 wide QRS tachycardias defy differentiation; (2) tachycardias > 190 beats/mm often do not exhibit unequivocal criteria with which to make a certain diagnosis; (3) multiple leads are required for accurate assessment of QRS width, presence of AV dissociation or VA block, QRS axis, and morphological criteria; and (4) the MCL1 lead cannot be substituted for V1 in the use of morphological criteria for VT.

Vectorcardiographic monitoring to assess early vessel patency after reperfusion therapy for acute myocardial infarction

Abstract: Reperfusion therapy has lowered mortality in patients suffering from acute myocardial infarction. Failure to reperfuse is associated with an increased short- and long-term mortality. In a prospective study we used dynamic vectorcardiography to monitor 96 patients with acute myocardial infarction treated with reperfusion therapy to non-invasively assess coronary patency. The results from continuous monitoring were compared to those obtained from angiography. By using trend-analysis of QRS vector difference and ST vector magnitude, we were able to correctly identify 58 of the 70 patients (83%) with a reperfused infarct-related artery, and 19 of the 26 patients (73%) with a persistently occluded artery demonstrated at an early angiogram (diagnostic accuracy 80%). In patients with high-grade collateral flow to the infarct-related area, the results of the vectorcardiographic monitoring and of angiography showed the largest disagreement, whereas the accuracy of vectorcardiographic monitoring was high: 88% among patients without collaterals. The present results suggest that QRS complex and ST segment vectorcardiographic monitoring is a useful tool for assessing early coronary artery patency, and that dynamic vectorcardiography may help in identifying candidates for emergency coronary angiography.

Time domain analysis of the signal averaged electrocardiogram in patients with a conduction defect or a bundle branch block

Abstract: Doubts have been expressed about the clinical usefulness of time domain analysis of the signal averaged electrocardiogram in patients with prolonged QRS complex duration. We studied 147 patients using a signal averaged ECG (40-250 Hz) whose QRS complex was longer than 100 ms. A baseline electrophysiology study was also performed in 128 of these patients. Seventy-seven patients had a minor (QRS 100 ms) conduction defect. Thirty-seven of these 77 had either induced or spontaneous sustained ventricular tachycardia (group I) and 40 had no sustained ventricular tachycardia (group II). Seventy patients had a major (QRS > or = 120 ms) conduction defect, 44 of whom had sustained ventricular tachycardia (group A). The remaining 26 without this condition formed Group B. Group I compared to group II patients had a longer filtered QRS duration (120.8 +/- 14 vs 104.5 +/- 9.5 ms, P or = 145 ms, low amplitude signal duration > or = 50 ms, root mean square of the last 40 ms of the filtered QRS complex or = 120 ms.

Utility of QT dispersion combined with the signal-averaged electrocardiogram in detecting patients susceptible to ventricular tachyarrhythmia

Abstract: A simple algorithm that combines QT dispersion with the signal-averaged electrocardiogram QRS duration provides an extremely sensitive method for predicting spontaneous or inducible ventricular tachyarrhythmias. This new algorithm may prove useful in determining which patients are at risk for ventricular tachyarrhythmia.

ABC of Atrial Fibrillation: AETIOLOGY, PATHOPHYSIOLOGY, AND CLINICAL FEATURES

Abstract: ### Ischaemic heart disease Ischaemic heart disease is probably the most common underlying cause of atrial fibrillation in Britain. In addition, the fast ventricular rate due to atrial fibrillation may cause angina, leading to cardiac ischaemia and heart failure. Atrial fibrillation may complicate acute myocardial infarction in 10-15% of cases and is often a marker of extensive myocardial damage and a poor prognosis, with increased mortality. If atrial fibrillation occurs with an acute myocardial infarction, it tends to occur in the first 24 hours and is usually self limiting. Patients should be observed unless fast atrial fibrillation occurs or the patient is haemodynamically compromised. Atrial fibrillation is also a marker of underlying ventricular dysfunction and a compromised myocardium. Many years after myocardial infarction, ventricular scarring and dilatation often predispose to atrial fibrillation and congestive heart failure. View this table: Hypertension accounted for about half of the cases of atrial fibrillation in the Framingham study. Hypertension contributes to the complications of stroke and thromboembolism in such patients, especially if left ventricular hypertrophy is present. Electrocardiography is useful for screening for left ventricular hypertrophy (for example, with the criteria of Sokolow and Lyon--S wave in V1 and R wave in V5 or V6 of >/=35 mm), and if the electrocardiogram is abnormal the echocardiogram will invariably show left ventricular hypertrophy. Left ventricular hypertrophy on echocardiography is defined by calculating the left ventricular mass index. Left ventricular hypertrophy is considered to be present if the left ventricular mass index is >131 g/m2 in men and >110 g/m2in women Atrial fibrillation may be secondary to left atrial dilatation, which occurs in hypertensive patients, as a consequence of reduced left ventricular compliance. In addition, hypertension may be associated with underlying coronary artery disease, which itself is a risk for atrial fibrillation and thromboembolism. M mode echocardiograms showing left ventricular …

Catheter Ablation of the Left Bundle Branch for the Treatment of Sustained Bundle Branch Reentrant Ventricular Tachycardia

Abstract: 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 pacemaker.

Discrimination of atrial and ventricular signals from a single cardiac lead

Abstract: A method and system for discriminating atrial and ventricular signal components from a single heart lead, and for using this information for identifying an arrhythmia condition as being atrial or ventricular in origin. The invention is effective in identifying P waves occurring in complex signal which includes relatively stronger R waves or other ventricular artifacts which mask the P waves. The contribution of the R wave signal to the complex signal is obtained by filtering, time windowing and transfer function estimation, then the R wave estimate is subtracted from the combined signal to leave the P wave. The ratio of P waves to R waves, P--P and R--R intervals, and their ratios to one another and to fixed values can be estimated, and used in a comparison to discriminate between atrial and ventricular arrhythmia, to thereby enable appropriate treatment.

Long-term evaluation of patients with apical hypertrophic cardiomyopathy

Abstract: Apical hypertrophic cardiomyopathy (AHCM) is characterized by primary hypertrophy localized exclusively in the apex of the left ventricle. Previous studies have indicated that AHCM results in a unique combination of cross-sectional echocardiographic (CSE) and ECG findings (‘giant’ Twave inversion and high R wave voltage in the precordial leads). The aims of this study were: (1) to assess the degree of AHCM in a quantitative fashion (2) to evaluate the possible relationship between apical hypertrophy, quantitatively determined, and ECG findings in patients with AHCM (3) to verify the changes in echocardiographic and ECG parameters over time (4) to define the relationship between the severity of AHCM and the clinical course of such patients. Eleven selected patients with AHCM were studied for an average 6 year follow-up period; there were seven men and four women (age from 18 to 62 years, mean 49). Apical hypertrophy was assessed quantitatively by determining the muscle cross-sectional area in the apical region, which was considered an index of myocardial mass. From the end-diastolic apical four chamber view, endocardial and epicardial contours were digitized in order to obtain the total muscle cross-sectional area of the left ventricle. The walls of the left ventricle were then divided into three regions (basal, intermediate, apical). The final value of each cross-sectional muscle area was obtained from the mean measurements of four independent and blinded observers. In AHCM the apical muscle cross-sectional area (AMA) ranged from 10.3 to 17.9 cm2, mean 13.2 ±2.6 cm2. The comparison between CSE and ECG findings showed that patients with giant negative T wave inversions (T wave >10 mm) and high R wave voltages (R wave >25 mm) had a more severe degree of apical hypertrophy. However, there was incomplete agreement between CSE and ECG findings. During follow-up, negative T wave amplitude increased from 8.5 ±3.4 to 11.9 ±3.6 mm (mean 4.2 ±2.7) in 10 patients (P>0.01) and there was a mild increase of precordial R wave (from 28.0 ±5.9 to 29.3 ± 5.2 mm, mean 1.5 ± 1.6) (P−ns). The AMA change over time, from 13.2 ± 26 to 13.8 ± 2.3 was not significant. All patients were alive at the most recent evaluation, and witliout significant symptomatic deterioration. This study demonstrates a wide spectrum in the degree of severity of apical hypertrophy among patients with AHCM. Furthermore, ECG findings are not uniform and are not significantly related to the severity of the hypertrophy itself Therefore, AHCM should be considered as a part of the morphological spectrum of hypertrophic cardiomyopathy rather than a separate entity with univocal CSE and ECG findings. Follow-up data indicate that despite ECG results worsening over time, a significant progression in apical left ventricular wall thickness does not occur. Changes in negative T wave amplitude are not related to symptoms and are not predictive of the functional severity of AHCM. Finally, the clinical outcome of patients with AHCM seems not be dependent on the entity of apical hypertrophy.

Radiofrequency Ablation of Idiopathic Left Anterior Fascicular Tachycardia

Abstract: Left Anterior Fascicular Tachycardia. Introduction: A 45-year-old man with idiopathic ventricular tachycardia (VT) having a right bundle branch block configuration with right-axis deviation underwent au electrophysiologic test. Methods and Results: Mapping demonstrated a site on the auterobasal wall of the left ventricle where there was an excellent pace map and an endocardial activation time of -20 msec, hut radiofrequency catheter ablation at this site was unsuccessful. At a nearby site, a presumed Purkinje potential preceded the QRS complex by 30 msec during VT and sinus rhythm, and catheter ablation was effective despite a poor pace map and an endocardial ventricular activation time of zero. Conclusion: Idiopathic VT with a right bundle branch configuration and right-axis deviation may originate in the area of the left anterior fascicle. A potential presumed to represent a Purkinje potential may he more helpful than endocardial ventricular activation mapping or pace mapping in guiding ablation of this type of VT.