Personalized Heart Modeling May Improve Treatment of Arrhythmias
The first use of computational modeling in cardiac patient care may improve targeting and reduce damage associated with treating post-heart attack arrhythmias.
During a heart attack, an abnormally fast heart rhythm called ventricular tachycardia, or VT, triggered by excess electrical activity in the ventricles, can cause sudden cardiac death. Using catheter-based radio-frequency energy to destroy, or ablate, the misfiring tissue can help restore correct heart rhythms. However, the success of the approach is limited by the current electrical mapping techniques used to select the ablation target, which are slow and invasive and can cause extensive tissue damage.
A study published Sept. 3 in Nature Biomedical Engineering describes the use of a personalized “virtual” heart to eliminate the need for invasive electrical mapping. The virtual-heart arrhythmia ablation targeting approach, or VAAT, uses MRI to construct 3D models of a patient’s heart, then evaluates electrical properties of the tissue to identify the best ablation target for that patient.
The researchers previously showed that this modeling method could help predict arrhythmia risk in patients following heart attacks. The new report extends the use of the VAAT approach, incorporating algorithms that determine the smallest ablation targets that will minimize risk of future VT.
In a retrospective study on five pigs, VAAT-identified targets overlapped with ablated regions in the animals whose ablations were successful and did not match the regions targeted in unsuccessful ablations. Retrospective analyses of 21 people with successful VT ablation revealed consistent matching of VAAT-identified targets and the actual ablation targets; in several cases the VAAT-modeled lesion would have been smaller than what the patient received. The VAAT approach was also able to identify targets in a small group of patients with pacemakers, which can reduce the quality of MRI images.
An initial prospective study of five patients at two different medical centers showed that the VAAT approach is feasible in a clinical setting, with three patients receiving successful ablations and two determined not at risk for VT. The authors suggest that a large prospective study should be conducted to evaluate VAAT’s efficacy and long-term patient outcomes.