Relationships between cardiac innervation/perfusion imbalance and ventricular arrhythmias: impact on invasive electrophysiological parameters and ablation procedures.

PURPOSE

To assess the relationship between regional myocardial perfusion and sympathetic innervation parameters at myocardial scintigraphy and intra-cavitary electrophysiological data in patients with ventricular arrhythmias (VA) submitted to invasive electrophysiological study and ablation procedure.

METHODS

Sixteen subjects underwent invasive electrophysiological study with electroanatomical mapping (EAM) followed by trans-catheter ablations of VA. Before ablation all patients were studied with a combined evaluation of regional myocardial perfusion and sympathetic innervation by means of tomographic Tc-tetrofosmin and I- metaiodobenzylguanidine cadmium-zinc-telluride (CZT) scintigraphies, respectively. Off-line spatial co-registration of CZT perfusion and innervation data with the three-dimensional EAM reconstruction was performed in every patient.

RESULTS

CZT revealed the presence of myocardial scar in 55 (20 %) segments. Of the viable myocardial segments, 131 (60 %) presented a preserved adrenergic innervation, while 86 (40 %) showed a significantly depressed innervation (i.e. innervation/perfusion mismatch). On EAM, the invasively measured intra-cavitary voltage was significantly lower in scarred segments than in viable ones (1.7 ± 1.5 mV vs. 4.0 ± 2.2 mV, P < 0.001). Interestingly, among the viable segments, those showing an innervation/perfusion mismatch presented a significantly lower intra-cavitary voltage than those with preserved innervation (1.9 ± 2.5 mV vs. 4.7 ± 2.3 mV, P < 0.001). Intra-cardiac ablation was performed in 63 (23 %) segments. On multivariate analysis, after correction for scar burden, the segments showing an innervation/perfusion mismatch remained the most frequent ablation targets (OR 5.6, 95 % CI 1.5-20.8; P = 0.009).

CONCLUSIONS

In patients with VA, intra-cavitary electrical abnormalities frequently originate at the level of viable myocardial segments with depressed sympathetic innervation that frequently represents the ultimate ablation target.