Vectorcardiography Findings Are Associated with Recurrent Ventricular Arrhythmias and Mortality in Patients with Heart Failure Treated with Implantable Cardioverter-Defibrillator Device

Abstract

<b><i>Background:</i></b> There is a need for refined risk stratification of sudden cardiac death and prediction of ventricular arrhythmias to correctly identify patients who are expected to benefit the most from implantable cardioverter-defibrillator (ICD) therapy. <b><i>Methods:</i></b> We conducted a registry-based retrospective observational study on patients with either ischemic (ICMP) or nonischemic dilated cardiomyopathy (NICMP) treated with ICD between 2002 and 2013 at a tertiary referral center. We evaluated 3 vectorcardiography (VCG) indices; spatial QRS-T angle, QRS vector magnitude (QRSvm), and T-wave vector magnitude (Twvm), and their association with all-cause mortality and ventricular arrhythmias. The VCG indices were automatically computed from resting 12-lead electrocardiograms before ICD implantation. <b><i>Results:</i></b> 178 patients were included in the study; 53.4% had ICMP, 79.2% were male, and mean ejection fraction was 27.4%. During the follow-up (median 89 months), 40 patients (23%) died; 31% had appropriate ICD therapy. In multivariate analysis with dichotomized variables, QRS-T angle >152° and Twvm <0.38 mV were significantly associated with increased mortality: HR 2.64 (95% CI 1.14–6.12, <i>p</i> = 0.02) and HR 5.30 (95% CI 2.31–12.11, <i>p</i> < 0.001), respectively. QRSvm <1.54 mV was borderline significant with mortality outcome (<i>p</i> = 0.10). The composite score of all 3 VCG indices, a score of 3, conferred an increased risk of mortality (including heart failure mortality) in multivariate analysis: HR 13.80 (95% CI 3.44–55.39, <i>p</i> < 0.001). <b><i>Conclusion:</i></b> The spatial QRS-T angle and Twvm are emerging VCG indices which are independently associated with mortality in patients with reduced left ventricular ejection fraction due to ICMP or NICMP. Using a composite score of all 3 vector indices, a maximum score was associated with poor long-term survival.

Electrocardiographic Parameters Associated with Adverse Outcomes in Children with Cardiomyopathies

“…In the present study, we outlined electrocardiographic risk factors associated with unfavorable outcomes among patients with cardiomyopathies. In adults with both dilated and hypertrophic cardiomyopathy, a greater QRS-T angle has been associated with unfavorable outcomes [ 2 , 3 , 4 , 6 ]. Similarly, in our study we observed a significantly greater QRS-T angle in patients with MACE, independently of the type of cardiomyopathy.…”

“…In adult patients with idiopathic dilated cardiomyopathy, a relationship between greater QRS-T angle and mortality, risk of an ICD shock or rehospitalization due to heart failure had been observed, with cut-off values ranging between >90° and 152° [ 2 , 3 , 4 ]. In our cohort, we observed a mean spatial QRS-T angle of 133° among patients with adverse outcomes, which seems to be in agreement with adult reports.…”

“…In adults with non-ischemic dilated cardiomyopathies, a greater QRS-T angle is a risk factor for ventricular arrhythmias, re-hospitalizations due to heart failure, and increased mortality [ 2 , 3 , 4 ]. A similar observation was made in patients with hypertrophic cardiomyopathy (HCM) in whom a wider QRS-T angle was associated with greater risk for ventricular arrhythmia [ 5 , 6 ].…”

A Comparison of Personalized and Generalized LSTM Neural Networks for Deriving VCG from 12-Lead ECG

“…Table 1 lists the clinical applications of these parameters that have been validated in the literature. The spatial QRS-T angle parameter has been shown to be useful for risk stratification for cardiac events, evaluation of incident coronary disease and heart failure, and efficacy of therapy for adult hypertension and diabetes mellitus [5]. For example, in the PTB diagnostic database [3,4] ECG used in this study, the mean and standard deviation of the Spatial QRS-T angles from patients with MI and healthy controls were 87.9 • ± 46.84 • and 52.95 • ± 35.76 • , respectively, as computed using the VCG parameter extraction algorithms described in this study.…”