Vectocardiography as a predictive tool for ventricular tachycardia recurrence during hospitalization

The vectorcardiogram (VCG) offers a three-dimensional view of the heart's electrical activity, providing potentially greater insights into cardiac dynamics than conventional ECG. Despite this, many VCG parameters remain underexplored in clinical practice. Identifying patients with ventricular tachycardias (VT) at higher risk of arrhythmia recurrence during hospitalization is crucial for optimizing care levels and ensuring safe discharge.

This study aims to investigate associations between various VCG parameters and the recurrence of VT during hospitalization.

Digital ECGs were obtained immediately after ventricular tachycardia termination in patients hospitalized for sustained VT or appropriate discharges from implantable cardioverter defibrillators (ICDs) over a three-year period. The ECGs were converted to VCGs using the Kors matrix method, yielding 231 parameters per patient derived from the QRS and T loops. Patients with paced QRS were excluded. Univariable non-parametric analyses were conducted to assess relationships between VCG parameters and VT recurrence, incorporating additional data such as age, sex, cardiological history, admission medications, VT morphology, echocardiographic and laboratory parameters, VT aetiology, and treatment strategies.

The analysis included 65 patients (87.7% male, median age 68,8 years); 20% (13) experienced VT recurrence during hospitalization, and 3.1% (2) developed an arrhythmic storm. Among the patients, 72.3% (47) were admitted for sustained VT (55 monomorphic, 2 polymorphic), and 27.7% (18) for ICD-apropiate therapies. Aetiologies included ischemic (41.5%), non-ischemic cardiomyopathy (38.5%), idiopathic (15.4%), and undetermined causes (4.6%). Management primarily involved amiodarone + beta-blockers (45.3%), beta-blockers alone (21.9%), and amiodarone + beta-blockers + sedation (18.8%). VT ablation during hospitalization was performed in 14 patients (21.5%).

Of the variables collected, only certain VCG parameters were significantly associated with VT recurrence, specifically the dihedral angle between best fit QRS and T loop planes (p<0.019), spatial ventricular gradient vector magnitude (p<0.013), T wave Y-axis area (p<0.006), median T wave Y value at maximum distance from the origin (p<0.015), and maximum T wave Y lead magnitude (p<0.009). The dihedral angle and spatial ventricular gradient vector magnitude were lower in the recurrence group. These two parameters had similar values across VT aetiologies based on the Kruskal-Wallis analysis, while the rest showed uneven distribution.