ABSTRACT
INTRODUCTION: Parkinson disease (PD), pure autonomic failure (PAF), and multiple system atrophy (MSA) are characterized by intra-cerebral deposition of the protein alpha-synuclein and are termed synucleinopathies. Lewy body synucleinopathies involve decreased cardiac sympathetic innervation and functional abnormalities in residual noradrenergic terminals. This observational, retrospective, cohort study describes long-term trends in indices of cardiac sympathetic innervation and function in synucleinopathies. METHODS: Patients with PD (Nâ¯=â¯31), PAF (Nâ¯=â¯9), or MSA (Nâ¯=â¯9) underwent repeated 18F-dopamine positron emission tomography (median follow-up 3.5 years). Interventricular septal 18F-dopamine-derived radioactivity 8â¯min after tracer injection (8' Radioactivity) was used as an index of sympathetic innervation and the slope of mono-exponential decline of radioactivity between 8 and 25â¯min (k8'-25') as an index of intraneuronal vesicular storage. Healthy volunteers (HVs) (Nâ¯=â¯33) and individuals at high risk of PD (Nâ¯=â¯15) were controls. RESULTS: Upon initial evaluation the groups with PD and orthostatic hypotension (OH), PAF, or PD and no OH had low mean 8' Radioactivity compared to HVs (pâ¯<â¯0.0001, pâ¯=â¯0.0002, pâ¯=â¯0.006) and had elevated k8'-25' (pâ¯=â¯0.0007, pâ¯=â¯0.007, pâ¯=â¯0.06). There was no significant difference between MSA and HVs. In PD 8' Radioactivity decreased by a median of 4% per year and did not decrease in MSA. k8'-25' values did not change during follow-up in any group. CONCLUSIONS: Neuroimaging evidence of decreased vesicular uptake in cardiac sympathetic nerves is present upon initial evaluation of patients with Lewy body synucleinopathies and may provide a biomarker of catecholaminergic dysfunction early in the disease process.
Subject(s)
Lewy Body Disease/diagnostic imaging , Multiple System Atrophy/diagnostic imaging , Parkinson Disease/diagnostic imaging , Pure Autonomic Failure/diagnostic imaging , Sympathetic Nervous System/diagnostic imaging , Ventricular Septum/innervation , Adult , Aged , Case-Control Studies , Disease Progression , Dopamine , Female , Fluorine Radioisotopes , Heart/diagnostic imaging , Heart/innervation , Humans , Hypotension, Orthostatic/diagnostic imaging , Hypotension, Orthostatic/metabolism , Hypotension, Orthostatic/physiopathology , Lewy Body Disease/metabolism , Lewy Body Disease/physiopathology , Male , Middle Aged , Multiple System Atrophy/metabolism , Multiple System Atrophy/physiopathology , Myocardium/metabolism , Parkinson Disease/metabolism , Parkinson Disease/physiopathology , Positron-Emission Tomography , Pure Autonomic Failure/metabolism , Pure Autonomic Failure/physiopathology , Sympathetic Nervous System/metabolism , Sympathetic Nervous System/physiopathology , Synaptic Vesicles/metabolism , Synucleinopathies/diagnostic imaging , Synucleinopathies/metabolism , Synucleinopathies/physiopathology , Ventricular Septum/diagnostic imaging , Ventricular Septum/metabolismABSTRACT
BACKGROUND: Irrigated radiofrequency (RF) ablation can be insufficient to eliminate intramurally located septal atrial flutter (AFL) and ventricular tachycardia (VT) circuits. Bipolar ablation between 2 ablation catheters may be considered for such circuits. OBJECTIVE: To evaluate the utility of bipolar irrigated ablation to terminate arrhythmias resistant to unipolar ablation. METHODS: In vitro: Bipolar and sequential unipolar RF ablation lesions were placed on porcine ventricular tissue in a saline bath to assess for lesion transmurality. Clinical: 3 patients with atypical septal flutter (AFL), 4 patients with septal VT, and 2 with left ventricle free-wall VT, all of whom failed sequential unipolar RF ablation, underwent bipolar RF ablation using irrigated catheters placed on either surface of the interatria/interventricular septum and left ventricle free-wall, respectively. RESULTS: In vitro: Bipolar RF was found to be more likely to achieve transmural lesions (82% vs 33%; P = .001) and could do so in tissues with thicknesses of up to 25 mm. Clinical: All 5 AFLs (3 patients) were successfully terminated with bipolar RF. In follow-up, AFL recurred in 2 of the 3 patients and atrial fibrillation and AFL recurred in 1 of the 3. All 3 thereafter underwent repeat procedures with successful maintenance of sinus rhythm in 2 of the 3 patients (6-month follow-up). In the VT subgroup, 5 of 6 septal VTs and 2 of 3 free-wall VTs were terminated successfully during ablation. In follow-up (12 months), 2 of the 4 patients in the septal bipolar group and 1 of the 2 patients in the free-wall group remained free of VT. CONCLUSIONS: Bipolar RF can be used to terminate arrhythmias in select patients with tachyarrhythmias.
Subject(s)
Atrial Flutter/surgery , Catheter Ablation/methods , Electrocardiography , Heart Conduction System/surgery , Heart Rate/physiology , Tachycardia, Ventricular/surgery , Ventricular Septum/innervation , Aged , Animals , Atrial Flutter/physiopathology , Disease Models, Animal , Female , Follow-Up Studies , Heart Conduction System/physiopathology , Humans , Male , Swine , Tachycardia, Ventricular/physiopathology , Treatment OutcomeABSTRACT
Ablation of accessory tracts in the posteroseptal region can be challenging, as illustrated by these 2 cases. Familiarity of the anatomy of this region and recognition of the ECG patterns can help identify the AP origin and potentially improve success rates of ablation. The isoelectric initial preexcited QRS complex with rSR' pattern in lead V1 of the surface ECG but not the relatively earlier local ventricular activation at PSMA region may indicate a left-sided ablation approach for these APs.
