[Discussion]
Satisfactory long-term management of
atrial fibrillation is seldom
achievable ,fortunately, AVNA combined with permanent pacing therapy is
practically confirmed to significantly reduce cardiac symptoms while
improving quality of life [6] , owing to the
well-established safety and efficacy of this proficient technique[7] , AVNA and permanent pacing is regards as IIa class of
recommendation (evidence level: B) to control heart rate when
pharmacological therapy is inadequate and rhythm control is not
achievable [8] , they are suggested to be a valuable option
in patients with refractory atrial arrhythmia resistant to other
treatment modalities [9] .
Among HCM patients, AF is primarily caused by left atrial dilatation and
remodeling as a common sustained arrhythmia, conversely, AF can
contribute to progressive decline of cardiac function, worsen heart
failure and increase risk of systemic thromboembolism [10] .
Recent years, LBBP provides significant advantage in patients with
conduction disease at the distal His bundle , LBBP emerges for its
better sensing ,a lower and more stable capture threshold[1,2,3] , however, implantation indications of this novel
technique require further clinical investigation, the role of AVJA
combined with LBBP remains unknown in refractory AF and HCM cohorts,
whereas safety and feasibility of AVNA combined with HBP have been
proven in patients with AF and difficulty in rate control by studies of
Vijayaraman P. et al.[4] .
In this case, the rapid ventricular response to AF did not respond
promptly to pharmacological therapies and contributed to ongoing
symptoms, furthermore, this patient had a history of recurrence of AF
after radiofrequency ablation,
therefore, ablation and pacing were accepted by her to achieve better
rate control. Implantation of ICD was reasonable for high risk of sudden
death induced by atrial tachyarrhythmia or HCM, besides her conclusive
history of ventricular fibrillation [11] . By 1.5-year
follow-up of this case, AVJN and LBBP strategy is confirmedly associated
with improvement in symptoms, quality of life, and exercise capacity.
Feasibility and safety of AVJA
combined with LBBP for refractory AF patients with HCM, was concluded by
this case firstly. The situation of refractory AF patients may become
worse if they suffer from HCM meanwhile, because both diseases can
worsen the symptomatic condition of each other, lead to the increasement
of possibility of sudden death and response poorly to drug treatments,
obviously, the combination strategy is a better option, a more
reasonable and efficient treatment than AVNA combined with HBP for these
patients.
In addition, our success may wider the application in HCM patients for
whom pacing therapy is reasonable. The hypertrophy interventricular
septum may make the manoeuvr of pacemaker implantation more challenging,
our report may provide a valuable reference for similar patients. During
the operation of implantation of pacemaker, the lead was moved
approximately 1cm distally towards the RV apex, followed by deeply
screwing the lead helix into the hypertrophy interventricular septum,
this experience of LBBP for HCM patient is also in line with that from
Huang W .et al.[5] .Conventionally, ablation of the
atrioventricular node may produce a slightly faster, more stable escape
rhythm derived from the His bundle with a narrow QRS complex, whereas
ablation lower at the His bundle is likely to produce a slower, broad
QRS complex which may be less reliable. However, the total time of
performance is longed given that the pacemaker and ICD have to be
implanted besides the ablation, after achievement of pacemaker
implantation which serves as a safeguard of ablation, the proximity of
His bundle was chosen as the target of ablation instead of
atrioventricular node in order to reduce total performance time.
Undoubtedly, long-term follow-up and more such cases are needed for
further investigation to evaluate the benefits and safety of AVJA
combined with LBBP strategy.