Contact force mapping and voltage thresholds during high-frequency stimulation of human cardiac ganglionated plexuses†

Historical Perspective of the Cardiac Autonomic Nervous System

The contemporary history of the cardiac autonomic nervous system includes early descriptions of neuroanatomy in the 19th century, followed by an understanding of the physiologic determinants of neurocardiology in the 20th century. Neurology and cardiology preceded the arrival of clinical cardiac electrophysiology, a specialized field in medicine devoted to the diagnosis and treatment of cardiac arrhythmias. The rapid growth in pharmacology, ablation, pacing and defibrillation, associated with significant technological breakthroughs, have resulted in new opportunities for neuromodulation in the 21st century. Small changes in autonomic tone can potentially provide important therapeutic benefits for patients with cardiac and arrhythmia disorders.

Hybrid solid-state SPECT/CT left atrial innervation imaging for identification of left atrial ganglionated plexi: Technique and validation in patients with atrial fibrillation

BACKGROUND

Ablating left atrial (LA) ganglionated plexi (GP), identified invasively by high-frequency stimulation (HFS) during pulmonary vein isolation (PVI), may reduce atrial fibrillation (AF) recurrence. 123I-metaiodobenzylguanidine (123I-mIBG) solid-state SPECT LA innervation imaging (LAII) has the spatial resolution to detect LAGP non-invasively but this has never been demonstrated in clinical practice.

METHODS

20 prospective patients with paroxysmal AF scheduled for PVI underwent 123I-mIBG LAII. High-resolution tomograms, reconstructed where possible using cardiorespiratory gating, were co-registered with pre-PVI cardiac CT. Location and reader confidence (1 [low] to 3 [high]) in discrete 123I-mIBG LA uptake areas (DUAs) were recorded and correlated with HFS.

RESULTS

A total of 73 DUAs were identified, of which 59 (81%) were HFS positive (HFS +). HFS + likelihood increased with reader confidence (92% [score 3]). 64% of HFS-negative DUAs occurred over the lateral and inferior LA. Cardiorespiratory gating reduced the number of DUAs per patient (4 vs 7, P = .001) but improved: HFS + predictive value (76% vs 49%); reader confidence (2 vs 1, P = .02); and inter-observer, intra-observer, and inter-study agreement (κ = 0.84 vs 0.68; 0.82 vs 0.74; 0.64 vs 0.53 respectively).

CONCLUSIONS

123I-mIBG SPECT/CT LAII accurately and reproducibly identifies GPs verified by HFS, particularly when reconstructed with cardiorespiratory gating.

Aging-Induced Biological Changes and Cardiovascular Diseases

Aging is characterized by functional decline in homeostatic regulation and vital cellular events. This process can be linked with the development of cardiovascular diseases (CVDs). In this review, we discussed aging-induced biological alterations that are associated with CVDs through the following aspects: (i) structural, biochemical, and functional modifications; (ii) autonomic nervous system (ANS) dysregulation; (iii) epigenetic alterations; and (iv) atherosclerosis and stroke development. Aging-mediated structural and biochemical modifications coupled with gradual loss of ANS regulation, vascular stiffening, and deposition of collagen and calcium often disrupt cardiovascular system homeostasis. The structural and biochemical adjustments have been consistently implicated in the progressive increase in mechanical burden and functional breakdown of the heart and vessels. In addition, cardiomyocyte loss in this process often reduces adaptive capacity and cardiovascular function. The accumulation of epigenetic changes also plays important roles in the development of CVDs. In summary, the understanding of the aging-mediated changes remains promising towards effective diagnosis, discovery of new drug targets, and development of new therapies for the treatment of CVDs.