Discussion
Percutaneous hemodynamic support with Impella CP (Abiomed, Danvers, MA)
support during PVI/PWI to the best of our knowledge has not been
reported in the literature. Pubmed search did not yield case reports
where Impella CP was used for hemodynamic support during PVI/PWI.
Mantini et al. 2019 reported five series of patients with atrial
arrhythmias who underwent various ablation techniques under various
mechanical circulatory support (MCS) modalities. The MCS modalities
included ECMO, LVADs, and Impella support. However, the only patient in
their case report who had atrial fibrillation was cannulated for ECMO
and AV node ablation, and pacemaker insertion is done (2). In a similar
case report by Kamada et al. 2016, they described a case of
tachycardia-induced cardiomyopathy secondary to persistent AF/RVR
refractory to rhythm control both pharmacologically and electrically.
However, PVI successfully achieved, intra-aortic balloon for MCS was
only used after intra-procedurally (3) the patient became
hemodynamically unstable. In contrast, our patient had Impella CP at the
start of the procedure. Cheruvu et al. 2014, also reported on a
successful ablation of refractory AVNRT in a patient on ECMO due to
cardiogenic shock (4).
To date, there are no ACC/AHA/HRS/EHRA recommendations regarding PVIs or
atrial arrhythmia ablations on MCS.
Most of the literature on mechanical support with Impella has been
centered around its use in hemodynamically unstable ventricular
tachycardia ablations. Activation and entrainment mapping techniques
during ablation of ventricular tachycardias requires the patient to be
in continuous VT, which may not be hemodynamically tolerated, may lead
to end-organ hypoperfusion and damage(5,6). The use of left ventricular
support provides a better augmentation of cardiac output during ablation
for ventricular arrhythmias in at-risk patients.
In our article, we report on a 61-year-old male who developed
cardiogenic shock due to tachycardia-induced cardiomyopathy due to
persistent AF/RVR complicated by the cardiorenal syndrome. AF was both
medically and electrically refractory, PVI under Impella support was
pursued. There was instantaneous LVEF recovery, improvement in the RV
function, and reversal of resultant end-organ failure.
Animal models have shown that, at the cellular level, high ventricular
rates usually result in abnormal calcium handling and reduced
energy-storing required for both myocardial relaxation and contractility
(7). Changes at the cellular level lead to myocyte elongation, myofibril
disorganization, and derangement in the extracellular matrix (7,8).
Over time, LV dysfunction occurs with LV dilatation and eventually RV
failure and RV dilation. RV and LV volumes increase, LVEDP significantly
increases due to the increase in LV wall stress(7–9). The loss of
atrial contribution to diastole in a patient with AF/RVR, especially in
patients with Grade 2 diastolic dysfunction leads to elevation of the
left atrial volume and pressure, decrease preload and further decrease
cardiac output(10). For all of these reasons, patients with AF/RVR can
present with cardiogenic shock.
To reverse this spiraling cycle of myocardial dysfunction and heart
failure symptoms for patients in AF/RVR, the CASTLE AF trial, which
randomized 398 patients to PVI versus standard care, which included
maintenance of sinus rhythm. The result showed about a 38% reduction in
the primary outcome of all-cause mortality and hospitalization for
worsening heart failure (11). CAMTAF Trial reached a similar conclusion,
that catheter ablation is effective in restoring sinus rhythm in
patients with persistent AF and HF(12).
Atrioventricular junctional ablation with biventricular pacing
(AVJA/BiV) in patients with non-ischemic cardiomyopathy is useful for
treating AF/RVR associated with HF(1).
However, Khan et al. in 2008 conducted the PABA-CHF trial, where they
assigned NYHA II or III heart failure patients with drug-refractory AF
and EF less than 40% to undergo PVI or AVJA/BiV. They conclude at the
end of the trial that PVI was superior to AVJA/BiV in the following
outcomes: freedom for atrial fibrillation, EF recovery, LA size,
functional capacity and quality of life(13)
The utilization of the Impella device for circulatory support for
mapping ventricular arrhythmias have been well published. (5,6)
Due to the effectiveness of PVI/PWI in patients with tachycardia-induced
cardiomyopathy and cardiogenic shock, the Impella CP can be considered
an effective MCS to provide hemodynamic stability during mapping and
ablation of atrial arrhythmias not only limited to AF/RVR.
The use of the Impella allows time for accurate mapping in the case of
atrial re-entrants tachycardia. For PVI/PWI, it allows adequate time for
exit block testing and also posterior wall isolation with radiofrequency
ablation after the cryoablation of the pulmonary vein ostia. It frees
the operator’s mind to do thorough mapping and ablation with the
knowledge that the patient is receiving adjustable support based on
hemodynamic demands during the procedure.
Its use in electrophysiology laboratories is gaining popularity but for
ventricular arrhythmia ablations for now. However, this case report is
purposed to raise the awareness of the Impella’s utility advanced HF.
Mainly in cases where ablative techniques are required to achieve
hemodynamic stability in HF patients for which the atrial arrhythmia has
been determined to be contributing significantly to the patient’s
deterioration and hemodynamic instability.