Early post-procedural mortality occurred in 5% of cases of radiofrequency catheter ablation in patients with scar-related ventricular tachycardia (VT), with more than half of the events occurring in hospital, a trial of a contemporary cohort of patients has found.
The large registry study, performed by the International VT Ablation Center Collaborative Group, determined that early mortality may be predicted by clinical and procedural variables that indicate poorer clinical status and worse procedural outcomes, including low left ventricular ejection fraction (LVEF), chronic kidney disease, presentation with VT storm, presence of unmappable VTs, and post-procedural VT recurrence.
Radiofrequency catheter ablation has become a standard component of management strategies for recurrent VT that results from ventricular scar. But early mortality post-procedure has not been previously investigated, and nor has a mortality beneﬁt of catheter ablation been proven. Death due to worsening heart failure is common in this population, and predictors of death in this group are also predictors of death in advanced heart failure. VT in this setting may be an indication of worsening heart failure rather than a change in the underlying arrhythmic substrate.
The study, published by Pasquale Santangeli (Hospital of the University of Pennsylvania, Philadelphia, USA) and others in the Journal of The American College of Cardiology, aimed to evaluate early mortality after catheter ablation of scar-related VT. Early mortality in these patients is a reflection of patient baseline characteristics, as well as acute hospital care. Associations between clinical and procedural variables and early mortality (within 31 days of the procedure) were tested in patients with structural heart disease undergoing radiofrequency catheter ablation of VT at 12 international centres.
Of the 2,061 patients, 47% had non-ischaemic cardiomyopathy, 33% had severe heart failure symptoms, and 35% presented with VT storm. The researchers found that 56% had unmappable arrhythmias, and VT was demonstrated to be non-inducible after ablation in only 67%. Early mortality occurred in 100 (5%) cases, and 54 (3%) patients died before hospital discharge, including 12 (0.6%) after a major procedure-related complication.
The sickest patients had a higher risk of early mortality, as did procedural factors—multivariable analysis found a signiﬁcant association between early mortality and LVEF, chronic kidney disease, presentation with VT, and presence of unmappable VTs. Recurrent VT was also associated with an increased risk of subsequent death and early mortality, although only 22% of deaths were known to be arrhythmic, and half were known not to be. Even among those who died after recurrence of VT, death was known to be VT-related in only 40%.
The authors concluded that identiﬁcation of such features may prompt early consideration for haemodynamic support or other care to help mitigate later potential complications, and that further prospective studies are necessary to identify the best therapeutic strategies to reduce early mortality in patients undergoing catheter ablation of scar-related VT.
In an accompanying editorial, Frédéric Sacher (Centre Hospitalier Universitaire de Bordeaux, Bordeaux, France) and Ruairidh Martin (Centre Hospitalier Universitaire de Bordeaux, Bordeaux, France and the Newcastle University, Newcastle, United Kingdom) commended the authors for presenting outcome data from such a large cohort of patients after VT ablation. They said that the results are likely to reﬂect typical clinical practice and can inform practising physicians in decision-making for VT ablation. “These results are in keeping with randomised trials, and make progress in explaining the difﬁculty in demonstrating a mortality beneﬁt from VT ablation. [The researchers] have provided useful data on the sources of these difﬁculties, which will help to guide future investigations.”
Sacher and Martin also highlighted the importance of timing in VT ablation. “VT ablation is still viewed by many physicians as a last resort treatment. However, ablation earlier in the course of the disease, when there are fewer comorbidities, may be associated with lower risk and improved outcome.”
They added: “The management of these patients, therefore, requires attention to the management of heart failure and appropriate measures to support the cardiac output in the peri-procedural period, such as percutaneous haemodynamic support to stabilise the patient before ablation. This approach also highlights the importance of identifying patients in whom intractable heart failure is likely to result in early death, regardless of arrhythmic status. Although we all strive to avoid deaths at the time of VT ablation, we must also try to avoid unnecessary VT ablation at the time of death.”