A clinical-in silico study on the effectiveness of multipoint bicathodic and cathodic-anodal pacing in cardiac resynchronization therapy.

Up to one-third of patients undergoing cardiac resynchronization therapy (CRT) are nonresponders. Multipoint bicathodic and cathodic-anodal left ventricle (LV) stimulations could overcome this clinical challenge, but their effectiveness remains controversial. Here we evaluate the performance of such stimulations through both in vivo and in silico experiments, the latter based on computer electromechanical modeling. Seven patients, all candidates for CRT, received a quadripolar LV lead. Four stimulations were tested: right ventricular (RVS); conventional single point biventricular (S-BS); multipoint biventricular bicathodic (CC-BS) and multipoint biventricular cathodic-anodal (CA-BS). The following parameters were processed: QRS duration; maximal time derivative of arterial pressure (dPdtmax); systolic arterial pressure (Psys); and stroke volume (SV). Echocardiographic data of each patient were then obtained to create an LV geometric model. Numerical simulations were based on a strongly coupled Bidomain electromechanical coupling model. Considering the in vivo parameters, when comparing S-BS to RVS, there was no significant decrease in SV (from 45 ± 11 to 44 ± 20 ml) and 6% and 4% increases of dPdtmax and Psys, respectively. Focusing on in silico parameters, with respect to RVS, S-BS exhibited a significant increase of SV, dPdtmax and Psys. Neither the in vivo nor in silico results showed any significant hemodynamic and electrical difference among S-BS, CC-BS and CA-BS configurations. These results show that CC-BS and CA-BS yield a comparable CRT performance, but they do not always yield improvement in terms of hemodynamic parameters with respect to S-BS. The computational results confirmed the in vivo observations, thus providing theoretical support to the clinical experiments

External implantable defibrillator as a bridge to reimplant after explant for infection: Experience from two centers

Background: The management of patients explanted for implantable converter defibrillator (ICD) infections may be complex when anti-bradycardia pacing and tachyarrhythmia protection are needed. We aimed to test the efficacy and safety of a conventional ICD externally connected to a transvenous dual-coil lead as bridging therapy before the reimplantation. Methods and results: We enrolled seven patients explanted for ICD infections and needed prolonged antibiotic therapy in two high-volume hospitals in Italy and treated them with a passive-can external ICD for a mean of 13 (4\u201330) days before reimplant. One patient experienced an electrical storm, efficaciously recognized by the external ICD and treated with antitachycardia pacing and shocks. On-demand pacing was granted for all the patients. No device-related complications were reported. Conclusions: An external ICD seems safe and efficacious as a bridge to reimplant in patients explanted for ICD infections

Management of patients explanted for implantable cardioverter defibrillator infections: Bridge therapy with external temporary ICD

In case of cardiacimplantable electronicdevice (CIED)-related infections, it is mandatory to completely remove the device and administer prolonged antibiotic therapy. The management of patients explanted for an implantable defibrillator (ICD) infection is complex especially in patients needing anti-bradycardia pacing or tachyarrhythmia protection. We tested the efficacy and safety of a conventional ICD externally connected to a transvenous dual-coil lead as bridging therapy before the reimplant, comparing outcomes with a historical cohort of patients (N\ua0=\ua0113) treated with temporary transvenous pacing. We enrolled 18 patients explanted for ICD infection and needing prolonged antibiotic therapy in three high-volume Italian centers. They received an external ICD stand-by for a mean of 16.5 (4-30) days before the reimplant

Persistence of ICD indication at the time of replacement in patients with initial implant for primary prevention indication: Effect on subsequent ICD therapies

AbstractBackgroundIndication to implantable cardioverter defibrillator (ICD) for primary prevention of sudden death relies on left ventricular ejection fraction (LVEF). We measured the proportion of patients in whom indication to ICD persisted at the time of generator replacement (GR) and searched for predictors of appropriate therapies after GR.MethodsWe identified all consecutive patients who had received an ICD at our hospital, for LVEF ≤35% and no previous arrhythmias or unexplained syncope. Then, we included the 166 patients who outlived their first device and underwent GR.ResultsAt the time of GR (mean follow-up 59 ± 20 months), ICD indication (i.e. LVEF ≤35% or previously treated ventricular arrhythmias) persisted in 114 (69%) patients. After GR, appropriate ICD therapies were delivered in 30 (26%) patients with persistent ICD indication and in 12 (23%) of the remaining patients (p = 0.656). Nonetheless, the annual rate of therapies was higher in the first group (1.08 versus 0.53 events/year; p < 0.001), as well as the rate of inappropriate therapies (0.03 versus 0 events/year; p = 0.031). The only independent predictor of appropriate ICD therapies after GR was the rate of shocks received before replacement (Hazard Ratio: 1.41; 95% confidence interval: 1.01–1.96; p = 0.041).ConclusionIn heart failure with reduced LVEF, ICD indication persisted at the time of GR in 69% of patients. However, even in the absence of persistent ICD indication at GR, the risk of recurrence of arrhythmic events was not null