title: Relationships between cardiac innervation/perfusion imbalance and ventricular arrhythmias: impact on invasive electrophysiological parameters and ablation procedures.
abstract: OBJECTIVE
  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 tomographic99mTc-tetrofosmin and123I- 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.
authors.affiliation: Fondazione Toscana Gabriele Monasterio, Via Moruzzi, 1, 56124, Pisa, Italy. gimelli@ftgm.it.
authors.forename: Alessia
authors.identifier: http://orcid.org/0000-0003-3378-1723
authors.initials: A
authors.lastname: Gimelli
authors.affiliation: Cardio-Thoracic and Vascular Department, University Hospital of Pisa, Pisa, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Menichetti
authors.affiliation: Cardio-Thoracic and Vascular Department, University Hospital of Pisa, Pisa, Italy.
authors.forename: Ezio
authors.initials: E
authors.lastname: Soldati
authors.affiliation: Cardio-Thoracic and Vascular Department, University Hospital of Pisa, Pisa, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Liga
authors.affiliation: Cardio-Thoracic and Vascular Department, University Hospital of Pisa, Pisa, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Vannozzi
authors.affiliation: Fondazione Toscana Gabriele Monasterio, Via Moruzzi, 1, 56124, Pisa, Italy.|CNR, Institute of Clinical Physiology, Pisa, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Marzullo
authors.affiliation: Cardio-Thoracic and Vascular Department, University Hospital of Pisa, Pisa, Italy.
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Bongiorni
mesh_terms: D000293:Adolescent; D000328:Adult; D018780:Body Surface Potential Mapping / Q000379:methods*; D005260:Female; D006329:Heart Conduction System / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D055420:Perfusion Imaging / Q000379:methods; D025321:Surgery, Computer-Assisted / Q000379:methods; D013564:Sympathetic Nervous System / Q000000981:diagnostic imaging / Q000503:physiopathology; D017180:Tachycardia, Ventricular / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult
keywords: Ablation; Perfusion; SPECT; Sympathetic innervation; Ventricular arrhythmias