R. Te-Frey

Ventricular arrhythmias and implantable cardioverter-defibrillator therapy in patients with continuous-flow left ventricular assist devices: Need for primary prevention?

OBJECTIVES This study sought to evaluate the prevalence and significance of ventricular arrhythmia (VA) and the role of an implantable cardioverter-defibrillator (ICD) in patients supported by a continuous-flow left ventricular assist device (CF-LVAD). BACKGROUND VAs are common in patients supported by CF-LVADs but prospective data to support the routine use of ICDs in these patients are lacking. METHODS All patients supported by long-term CF-LVAD receiving care at our institution were enrolled. The ICDs were interrogated at baseline and throughout prospective follow-up. The VA was defined as ventricular tachycardia/fibrillation lasting >30 s or effectively terminated by appropriate ICD tachytherapy. The primary outcome was the occurrence of VA >30 days after CF-LVAD implantation. RESULTS Ninety-four patients were enrolled; 77 had an ICD and 17 did not. Five patients with an ICD had it deactivated or a depleted battery not replaced during the study. Twenty-two patients had a VA >30 days after LVAD implantation. Pre-operative VA was the major predictor of post-operative arrhythmia. Absence of pre-operative VA conferred a low risk of post-operative VA (4.0% vs. 45.5%; p < 0.001). No patients discharged from the hospital without an ICD after CF-LVAD implantation died during 276.2 months of follow-up (mean time without ICD, 12.7 ± 12.3 months). CONCLUSIONS Patients with pre-operative VA are at risk of recurrent VA while on CF-LVAD support and should have active ICD therapy to minimize sustained VA. Patients without pre-operative VA are at low risk and may not need active ICD therapy.

Validity and Reliability of a Novel Slow Cuff-Deflation System for Noninvasive Blood Pressure Monitoring in Patients With Continuous-Flow Left Ventricular Assist Device

Background—Doppler ultrasound is the clinical gold standard for noninvasive blood pressure (BP) measurement among continuous-flow left ventricular assist device patients. The relationship of Doppler BP to systolic BP (SBP) and mean arterial pressure (MAP) is uncertain and Doppler measurements require a clinic visit. We studied the relationship between Doppler BP and both arterial-line (A-line) SBP and MAP. Validity and reliability of the Terumo Elemano BP Monitor, a novel slow cuff-deflation device that could potentially be used by patients at home, were assessed. Methods and Results—Doppler and Terumo BP measurements were made in triplicate among 60 axial continuous-flow left ventricular assist device (HeartMate II) patients (30 inpatients and 30 outpatients) at 2 separate exams (360 possible measurements). A-line measures were also obtained among inpatients. Mean absolute differences (MADs) and correlations were used to determine within-device reliability (comparison of second and third BP measures) and between-device validity. Bland–Altman plots assessed BP agreement between A-line, Doppler BP, and Terumo Elemano. Success rates for Doppler and Terumo Elemano were 100% and 91%. Terumo Elemano MAD for repeat SBP and MAP were 4.6±0.6 and 4.2±0.6 mm Hg; repeat Doppler BP MAD was 2.9±0.2 mm Hg. Mean Doppler BP was lower than A-line SBP by 4.1 (MAD=6.4±1.4) mm Hg and higher than MAP by 9.5 (MAD=11.0±1.2) mm Hg; Terumo Elemano underestimated A-line SBP by 0.3 (MAD=5.6±0.9) mm Hg and MAP by 1.7 (MAD=6.0±1.0) mm Hg. Conclusions—Doppler BP more closely approximates SBP than MAP. Terumo Elemano was successful, reliable, and valid when compared with A-line and Doppler.

Catheter ablation for ventricular tachyarrhythmias in patients supported by continuous-flow left ventricular assist devices

Ventricular arrhythmias (VAs) are common after implantation of a left ventricular assist device (LVAD) and in a subset of patients may be refractory to medication. Morbidity from VA in this population includes right ventricular failure (RVF). We sought to evaluate the efficacy of catheter ablation for VA in patients with LVAD. A retrospective analysis of patients supported by continuous-flow LVAD referred for catheter ablation of ventricular tachycardia (VT) between 2008 and the present was performed. Seven patients were referred for VT ablation an average of 236 ± 292 days after LVAD implantation. Three patients (42.9%) developed RVF in the setting of intractable arrhythmias. A transfemoral approach was used for six patients (85.7%) and an epicardial for one patient (14.3%). The clinical VT was inducible and successfully ablated in six patients (85.7%). The location of these arrhythmias was apical in three cases (42.9%). A total of 13 VTs were ablated in seven patients. Although the majority had reduction in VA frequency, recurrent VAs were observed in six patients (85.7%). One patient (14.3%) experienced a bleeding complication after the procedure. For patients with a high VA burden after LVAD implantation, VT ablation is safe and feasible, but VA frequently recurs.

Prevalence and timing of bend relief disconnection in patients supported by the late version HeartMate II left ventricular assist device

BACKGROUND On April 4, 2012, the U.S. Food and Drug Administration issued a Class 1R recall of the HeartMate II (Thoratec Corporation, Pleasanton, CA) left ventricular assist device (LVAD) due to spontaneous detachment of the bend relief from its intended position in patients implanted with the most recent version of the HM II. This study examined the incidence and timing of outflow graft bend relief disconnection in patients implanted with the HM II LVAD. METHODS All patients supported with the modified version of the HM II LVAD were asked to report for dedicated abdominal X-ray imaging to assess the position of the bend relief. Also performed was a retrospective review of X-ray images of all patients who had previously been supported with this version but had since received a transplant, undergone LVAD explant, or died. RESULTS Between March 9, 2011, and April 9, 2012, 59 patients underwent primary implant with the modified version HM II. Follow up X-ray images were available for 56 patients (95%). The bend relief was found fully disconnected in 6 of 56 (11%) and partially disconnected in 13 (23%). Two of 6 patients (33%) with full bend relief disconnection and 1 of 13 of the initially partially disconnected patients (7.7%) required urgent surgical intervention due to symptoms of hemolysis and/or heart failure. CONCLUSIONS Bend relief disconnection is common and may be observed immediately after implant but may also develop over time. Full bend relief disconnect may present with hemolysis and/or heart failure symptoms and often requires surgical revision. Surveillance abdominal X-ray imaging should be performed routinely on all patients who were implanted with the modified version HM II.