A left ventricular lead implantation at the latest site based on four-dimensional computed tomography: a case report

Background: Cardiac resynchronization therapy (CRT) could be an effective therapy for patients suffering from severe heart failure (HF) despite optimal medical therapy. However, it has been reported that about 30% of patients receive ineffective results even if CRT has been performed. In a recent study, four-dimensional computed tomography (4DCT) was shown to be useful for pre-operative planning in transcatheter aortic valve intervention. The 4DCT is reconstructed with 10% increments over the cardiac cycle so that the displacement of the myocardium can be evaluated over time. From the above, we considered that the most delayed site where we would implant the left ventricular (LV) lead could be recognized by 4DCT. Case summary: A 55-year-old man with a recurrent admission for HF indicated for CRT was referred to our hospital. In this patient, the 12-lead electrocardiogram (ECG) showed a relatively narrow QRS complex with a left bundle branch block pattern. An echocardiography demonstrated severe LV dysfunction. Although no dyssynchrony was detected, the LV lead was inserted into the most delayed site based on the 4DCT. Three-month later, the ejection fraction increased and the cardiothoracic ratio obviously shortened. Discussion: We experienced a case in which we could evaluate the effective implantation site for the LV lead based on the 4DCT even though the effective site was not detected by echocardiography, and we could implant the LV lead at that effective site. The 4DCT may be useful for implanting LV leads in effective sites.