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  • After the RFCA neither sustained VT

    2019-04-11

    After the RFCA, neither sustained VT nor the VPCs that triggered the VT were recorded. The patient was fitted with a WCD (LifeVest, Zoll, Pittsburgh, PA, USA) on the third day post-ablation, and sotalol 80mg a day was started. He was discharged from the coronary care unit the following day. During cardiac rehabilitation, the patient׳s medical therapy was dynamically adjusted. The dose of sotalol was temporarily increased to 160mg a day, then gradually decreased, and finally stopped. He satisfactorily progressed in his rehabilitation protocol, and echocardiography revealed some improvement in the LVEF (from 26.6% to 45.2%). He was discharged on the 44th inpatient day with the WCD and on 5mg of oral carvedilol daily, but without any antiarrhythmic drugs. His compliance was satisfactory, and no WCD shocks were recorded after discharge. Three months after the WCD was placed, echocardiography showed further improvement in the LVEF (55.8%). The WCD was then discontinued and the patient was readmitted for a follow-up EPS. A standard programmed stimulation protocol [4] failed to induce sustained VT or any hemodynamic compromise. The patient was advised that ICD order JSH-23 was not mandatory. He agreed to follow-up without an ICD. Oral carvedilol was increased to 10mg/day, and he was discharged. He is closely followed and his multiple coronary risk factors – diabetes mellitus, hypertension, and dyslipidemia – are appropriately managed to prevent any secondary acute coronary events. He has had no episodes of ventricular arrhythmia for eight months.
    Discussion Ventricular arrhythmias are the most common cause of sudden cardiac death related to an MI, especially in the early phase [5]. Although ICDs significantly reduce the incidence of sudden arrhythmic death in patients with LV dysfunction in the late post-MI phase [6–8], prophylactic ICDs implanted within the first 40 days after infarction do not reduce the overall mortality in high-risk patients [9]. Guidelines obtained from clinical trial data recommend against the implantation of an ICD in the early phase of an MI [1,2]. A waiting period of 40 days or 3 months is recommended, depending on whether revascularization is performed. WCDs are external devices capable of automatic detection of ventricular tachyarrhythmias and defibrillation. It has recently been demonstrated that WCDs reduce the incidence of sudden cardiac death in post-MI patients during that waiting period [4]. In the early phase of an MI, patients with poor LV function (LVEF≤35%) are eligible for this device as “bridging therapy”. About 30% of patients with an MI have LVEF persistently ≤35%, which may deteriorate even more, but LVEF improves in about 70% [10]. Some MI patients do not fulfill the criteria for ICD implantation after the waiting period. WCDs “bridge” the time pending a final decision about ICD implantation. Electrical storms in patients during the early phase of an MI are occasionally initiated by abnormal automaticity originating from damaged partially depolarized myocytes or Purkinje fibers [11]. Several studies have reported that RFCA targeting Purkinje potentials in the infarction border zone is an effective means of managing such drug-refractory, repetitive VT after an MI [12–14]. In our case, five-lead telemetry monitoring was helpful in identifying the target monomorphic VPCs triggering the VT, even though these VPCs occurred infrequently. Elimination of the triggering VPCs may not eradicate episodes of VT, which might still be inducible if the substrates persist. Guided by the voltage map, we delivered multiple RFCAs around the origin of the target VPCs. Although we did not strictly test the VT inducibility just after ablation, we demonstrated the non-inducibility of any VTs during the follow-up EPS, in association with significant recovery of the LVEF. As previously reported, the non-inducibility of VT as a procedural end-point of RFCA and a preserved LVEF are known predictors of recurrence after RFCA for an electrical storm [1,15–17]. We believe that we achieved long-term prevention of VT in this patient by the substrate ablation and mechanical and electrical LV remodeling during the waiting period.