RESUMO
3DQRSarea is a strong marker for cardiac resynchronization therapy and can be obtained by taking the (i) summation or the (ii) difference of the areas subtended by positive and negative deflections in X, Y, Z vectorcardiographic electrocardiogram (ECG) leads. We correlated both methods with the instantaneous-absolute-3D-voltage-time-integral (VTIQRS-3D). 3DQRSarea consistently underestimated the VTIQRS -3D, but the summation method was a closer and more reliable approximation. The dissimilarity was less apparent in left bundle branch block (r2 summation .996 vs. difference .972) and biventricular paced ECGs (r2 .996 vs. .957) but was more apparent in normal ECGs (r2 .988 vs. .653).
Assuntos
Vetorcardiografia , Humanos , Vetorcardiografia/métodos , Terapia de Ressincronização Cardíaca/métodos , Bloqueio de Ramo/fisiopatologia , Bloqueio de Ramo/terapia , Masculino , Eletrocardiografia/métodos , Reprodutibilidade dos Testes , Feminino , Sensibilidade e Especificidade , Diagnóstico por Computador/métodos , AlgoritmosRESUMO
An elderly man with severe chronic obstructive pulmonary disease and a history of complete heart block with pacemaker placement was found to have pacemaker lead infection and required device extraction. He had a standard dual chamber pacemaker in place, however the ECG obtained showed paced QRS complexes with presence of R wave in lead V1 and QS in lead I suggestive of left ventricular pacing. Additional imaging with CT scan obtained for confirmation revealed that the heart was displaced to the left posterior hemithorax secondary to pulmonary disease. Due to significant posterolateral rotation of the heart, a right ventricular paced rhythm can demonstrate Q/S waves in the lateral leads (I, aVL, V5-6) and R waves in the right precordial leads (V1-3). This can be misdiagnosed as a left ventricular paced rhythm.