Both AAs and VAs are common in patients with severe heart failure under LVAD support; furthermore, VAs have been reported in about 20% of LVADs patients , with some of them being refractory to various therapies. AAs are also common in patients under LVAD support and are associated with increased readmission and mortality rates . In Japan, long-term LVAD use has become a necessity due to an extreme shortage of donor hearts, requiring a more efficient management of such arrhythmia-related issues .
We have reported the case of a patient who developed VAs 8 months after LVAD implantation and sustained VF for the following 4 years. To date, there have been several case reports revealing the tolerability of sustained VF under LVADs; furthermore, we have also experienced some cases of sustained VF without progressive organ dysfunction . However, hemodynamics is not preserved in some patients under sustained VF, and the clinical factors that determine the tolerability of sustained VF remain unknown . The patient in the present case tolerated sustained VF for the longest duration about 3 years reported in the published literature. However, after the onset of AF, the patient gradually developed right heart failure and it was worsened further after he developed persistent AF. The current case suggested the hemodynamic status of VF under LVAD might be determined by other surrounding factors such as atrial function and the change of sinus or atrial pacing rhythm to AF led to the disappearance of regular RA contractions. Consequently, the atrial wave of RAP disappeared and the pressure wave pattern of RAP and RV completely flattened. The subsequent reductions in the RA and RV outputs supposedly led to a worsening of the patient’s right heart failure.
Right atrial contraction contributes to approximately 15–30% of the RV stroke volume; however, its contribution differs across patients with heart failure. The development of AF generally decreases the cardiac output , whereas the derangement of AF in cardiac output is somewhat counteracted under LVAD support. Enriquez et al. have demonstrated no significant differences in peak VO2 during a cardiopulmonary exercise test between patients with and without AF under LVAD support . Conversely, the incidence of heart failure hospitalization has reportedly increased due to AF, suggesting that the right side of the heart remains sensitive to the hemodynamic effects of AF. A small case series demonstrated an improvement in right heart failure after catheter ablation of AF in patients with LVADs ; therefore, rhythm control may be an important strategy for managing right heart failure for this group of patients. If it was difficult to control of our patient’s right heart failure, we considered the catheter ablation of AF. In the present case, the pulmonary artery pulsatility index, which was reported to correspond to RV stroke volume , was somewhat maintained in sinus rhythm even under the sustained VF, whereas it significantly decreased by the development of AF. Several clinical conditions of right heart failure enhance the impact of right atrial function . D’Alto et al. have also demonstrated the enhanced impact of right atrial function in idiopathic pulmonary artery hypertension . Specifically, the contribution of AAs is significantly enhanced in sustained VF, in which the fibrillating ventricle has minimal contribution to the systemic output, and the coexistence of AAs and VAs may be critical. The current case highlights the significance of right atrial function as a determinant of hemodynamics in patients with sustained VF under LVAD support and suggests a non-invasive approach for the treatment of heart failure.
According to the risk of thromboembolism, it is complicated in patients with AF under LVAD support. There was a report of thromboembolism risk in patients with AF under LVAD , whereas a recent meta-analysis exhibited the presence of AF did not increase the risk of thromboembolism .
This case also emphasizes the difficulty of diagnosing AF under sustained VF. The findings on electrocardiogram of patients under sustained VF remain unchanged when AF is newly developed. Therefore, the detection of AF may be difficult, and monitoring of device records, mitral flow visualization using echocardiography or visualization of pressure wave by Swan-Ganz catheter is required. The occurrence of newly developed AF under sustained VF is a rare case; however, the understanding of the hemodynamic effect of these arrhythmias under LVAD support is much informative for future cases of LVAD support.
Indeed, AF might be a sign or symptom of a deterioration of HF, however, the risk of new development of AF is complicated under LVAD. For instance, Deshmukh A et al. demonstrated paroxysmal AF was improved after LVAD implantation due to improvement of electroanatomical remodeling . On the other hand, LVAD related complications such as AR and right heart failure might also impose the excessive burden to atrium leading to AF progression. The determining factor of AF progression in the current study was beyond the scope of the current case report.
We report the case of a patient with sustained VF for 3 years under LVAD support who had worsening of heart failure with new onset of AF. The hemodynamic characteristics of stabilized sustained VF under LVADs have not been fully elucidated, however this case showed the contribution of AAs is significantly enhanced in sustained VF.