Daniel Cortez

The spatial QRS-T angle outperforms the Italian and Seattle ECG-based criteria for detection of hypertrophic cardiomyopathy in pediatric patients

INTRODUCTION The spatial peaks QRS-T angle has been shown to differentiate adult patients with hypertrophic cardiomyopathy (HCM) from controls. We hypothesized that the spatial peaks QRS-T angle would, in isolation, be more accurate than the Italian 12-lead ECG Pre-participation Screening criteria or the Seattle criteria for detecting hypertrophic cardiomyopathy (HCM) in pediatric patients. METHODS A retrospective study of pediatric patients with HCM compared to age and gender-matched control patients was undertaken. Significance, odds ratios, sensitivity and specificity of HCM detection of the visually derived spatial peaks QRS-T angle were compared to those of traditional 12-lead ECG criteria using: 1) Italys National Pre-participation Screening Programme criteria; and 2) described criteria from Seattle. RESULTS ECG results from 130 pediatric HCM patients (14.2±4.4years) were compared to 470 control patients (normal echocardiograms, mean age 13.4±4.6years). Mean±standard deviation (SD) values for spatial peaks QRS-T angles were 120.4±40.7 and 21.3±13.7 degrees for HCM and controls, respectively (P<0.001). A spatial peaks QRS-T angle cutoff value of >54.9 degrees yielded greater sensitivity and specificity (93.1% and 98.7%, respectively) for detecting HCM over ECG criteria from Italy (68.5% and 48.1%, respectively) or Seattle (64.6% and 78.9%, respectively) with odds ratios at 1039.70 (95% CI 363.03 to 2977.67), 2.01 (95% CI 1.33 to 3.04) and 6.84 (4.49-10.44), respectively. CONCLUSION In our cohort, a visually derived spatial peaks QRS-T angle has increased sensitivity and specificity for detection of HCM in pediatric patients compared to currently utilized Italian or Seattle ECG criteria.

Vectorcardiographic predictors of ventricular arrhythmia inducibility in patients with tetralogy of Fallot

INTRODUCTION Vectorcardiography (VCG) may have predictive value in Tetralogy of Fallot (TOF) patients undergoing ventricular arrhythmia inducibility (VAI) electrophysiology studies (EPs). MATERIALS AND METHODS Blinded, retrospective analyses of 37 adult TOF patients undergoing EPs prior to pulmonary valve replacements were performed (21 female, median age 37years). VAI was evaluated from EPs and resting 12-lead electrocardiograms, respectively using QRS and heart rate adjusted Q-T intervals, spatial QRS-T angles (peaks), T-wave and QRS-wave (QRSwave vc) component vector root mean squares. Differences were assessed (Student t-tests, Mann Whitney U-tests, Analysis of Variance). Relative risks were calculated. RESULTS 16 patients had VAI (6 monomorphic, 10 polymorphic). Only the QRSwave vc showed significant differences between those with and without VAI, 10.5±2.4 dmV vs. 13.9±4.5dmV, respectively (p=0.002), area under the ROC curve of 0.78 and relative risk of 2.52. CONCLUSION VCG evidence of depolarization differences was significant between TOF patients with and without inducible VA.

In Hypertrophic Cardiomyopathy, the Spatial Peaks QRS-T Angle Identifies Those With Sustained Ventricular Arrhythmias

The spatial peaks QRS‐T (SPQRS‐T) angle differentiates hypertrophic cardiomyopathy (HCM) patients from controls. Increased angle confers arrhythmia risk in other populations.

Lower spatial QRS-T angle rules out sustained ventricular arrhythmias in children with hypertrophic cardiomyopathy.

Introduction The spatial peaks QRS-T angle accurately distinguishes children with hypertrophic cardiomyopathy from their healthy counterparts. The spatial peaks QRS-T angle is also useful in risk stratification for ventricular arrhythmias. We hypothesised that the spatial peaks QRS-T angle would be useful for the prediction of ventricular arrhythmias in hypertrophic cardiomyopathy patients under 23 years of age. METHODS Corrected QT interval and spatial peaks QRS-T angles were retrospectively assessed in 133 paediatric hypertrophic cardiomyopathy patients (12.4±6.6 years) with versus without ventricular arrhythmias of 30 seconds or longer. Significance, positive/negative predictive values, and odds ratios were calculated based on receiver operating characteristic curve cut-off values. RESULTS In total, 10 patients with ventricular arrhythmias were identified. Although the corrected QT interval did not differentiate those with versus without ventricular arrhythmias, the spatial peaks QRS-T angle did (151.4±19.0 versus 116.8±42.6 degrees, respectively, p<0.001). At an optimal cut-off value (124.1 degrees), the positive and negative predictive values of the spatial peaks QRS-T angle were 15.4 and 100.0%, respectively, with an odds ratio of 25.9 (95% CI 1.5-452.2). CONCLUSION In children with hypertrophic cardiomyopathy, the spatial peaks QRS-T angle is associated with ventricular arrhythmia burden with high negative predictive value and odds ratio.

ECG-derived spatial QRS-T angle is strongly associated with hypertrophic cardiomyopathy

INTRODUCTION ECG-derived vectorcardiography (VCG) has diagnostic and prognostic value in various diseases. Hypertrophic cardiomyopathy (HCM), a genetic disease with unexplained left ventricular hypertrophy, is one of the most common causes of sudden cardiac death (SCD) in young persons. Genotype positive status is associated with increased risk of systolic dysfunction, heart failure, and (SCD). Herein, we aimed to determine the diagnostic utility of derived VCG parameters in a large cohort of genotyped HCM patients. METHODS Between 1997 and 2007, genetic testing was performed on 1053 unrelated patients with HCM. Of these, 967 had 12-lead ECGs suitable for computerized derivation of VCG parameters, including the spatial mean and peaks QRS-T angles, spatial ventricular gradient (SVG), spatial QRS, QT, and Tpeak-Tend (TpTe) intervals. ECGs were also evaluated using Seattle ECG criteria. Differences between HCM patients and healthy controls as well as between genotype positive versus genotype negative HCM patients were assessed. RESULTS Spatial peaks (129.3±26.4 vs.30.5±24.2 degrees) and spatial mean QRS-T angles (121.8±38.6 vs. 47.3±27.6 degrees) were significantly higher in patients with HCM than in controls (P<0.001). The spatial peaks and mean QRS-T angles identified 94% and 84% of HCM patients, respectively, while Seattle criteria identified 70.7% of patients (P<0.001). Genotype positive patients had higher spatial mean QRS-T angles, spatial TpTe (P<0.001 respectively), spatial peaks QRS-T angles (P=0.017) and lower SVG (P<0.001) than genotype negative patients. CONCLUSIONS ECG-derived spatial QRS-T angles can differentiate patients with HCM from controls and could provide a better tool than traditional Seattle criteria. Clinical usefulness of VCG to differentiate genotype-negative from genotype-positive patients has yet to be established.

Noninvasive predictors of perioperative atrial arrhythmias in patients with tetralogy of Fallot undergoing pulmonary valve replacement

Patients with tetralogy of Fallot (TOF) have increased risk of atrial arrhythmias.

The S-wave angle identifies arrhythmogenic right ventricular cardiomyopathy in patients with electrocardiographically concealed disease phenotype

BACKGROUND Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) carries risk of sudden death. We hypothesize that the S-wave angle differentiates ARVD/C with otherwise normal electrocardiograms from controls. MATERIALS AND METHODS All patients met Task Force 2010 definite ARVD/C criteria. ARVD/C patients without Task Force depolarization/repolarization criteria (-ECG) were compared to controls. Electrocardiogram measures of QRS duration, corrected QT interval, and measured angle between the upslope and downslope of the S-wave in V2, were assessed. RESULTS Definite ARVD/C was present in 155 patients (42.7 ± 17.3 years, 68.4%male). -ECG ARVD/C patients (66 patients) were compared to 66 control patients (41.8 ± 17.6 years, 65.2%male). Only the S-wave angle differentiated -ECG ARVD/C patients from controls (<0.001) with AU the ROC curve of 0.77 (95%CI 0.53 to 0.71) and odds ratio of 28.3 (95%CI 6.4 to 125.5). CONCLUSION ARVD/C may lead to development of subtle ECG abnormalities distinguishable using the S-wave angle prior to development of 2010 Taskforce ECG criteria.

Pediatric noncompaction patients with high spatial QRS-T angles are at increased risk for ventricular tachycardia

Noncompaction cardiomyopathy (NCCM) patients may develop sustained ventricular arrhythmias (VA). Currently no known electrocardiogram (ECG) parameter has demonstrated predictive value for VA development. The spatial QRS‐T angle has demonstrated ability to identify VA in other cardiomyopathy populations.

Non-invasive electrocardiographic predictors of atrial arrhythmias in patients with the Fontan palliation

BACKGROUND Fontan palliation patients are at risk for atrial arrhythmias post-operatively. This study aimed to evaluate whether differences in depolarization vector magnitude or spatial P-R angle can reliably predict atrial arrhythmias in patients who had undergone Fontan palliation. METHODS A total of 115 patients who had Fontan palliation and post-Fontan catheterization were included. Atrial arrhythmias were identified in 14 patients. Measurements of ECG parameters including QRS vector magnitude, P-R duration, spatial QRS-T angle and spatial P-R angle were performed, and compared between those with and without atrial arrhythmias. RESULTS Only the QRSvm independently differentiated those with and without atrial arrhythmias with multivariate HR of 0.743 (95% CI 0.581 to 0.951). CONCLUSION In Fontan patients, the QRSvm was the only significant independent predictor of atrial arrhythmias.