Hypertension and atrial fibrillation: evidence of progressive atrial remodeling with electrostructural correlate in a conscious chronically instrumented ovine model.
ABSTRACT Hypertension accounts for more atrial fibrillation (AF) than any other predisposing factor.
The purpose of this study was to characterize the time course, extent, and electrostructural correlation of atrial remodeling in chronic hypertension.
Thirty-two sheep were studied: 21 with induced "one-kidney, one-clip" hypertension and 11 controls. Sequential closed-chest electrophysiologic studies were performed in 12 conscious animals (6 hypertensive, 6 controls) to evaluate progressive remodeling over 15 weeks. Additional atrial structural/functional analyses were performed in 5 controls and at 5, 10, and 15 weeks of hypertension (five per time point) via histology/cardiac magnetic resonance imaging to correlate with open-chest electrophysiologic parameters.
The hypertensive group developed a progressive increase in mean arterial pressure (P <.001). Mean effective refractory periods were uniformly higher at all time points (P <.001). Progressive biatrial hypertrophy (P = .003), left atrial dysfunction (P <.05) and greater AF inducibility were seen early with increased inflammation from 5 weeks of hypertension. In contrast, significant conduction slowing (P <.001) with increased heterogeneity (P <.001) along with increased interstitial fibrosis resulted in longer and more fractionated AF episodes only from 10 weeks of hypertension. Significant electrostructural correlation was seen in conduction abnormalities and AF inducibility with both atrial inflammation and fibrosis.
Hypertension is associated with early and progressive changes in atrial remodeling. Atrial remodeling occurs at different time domains in chronic hypertension with significant electrostructural correlation of the remodeling cascade. Early institution of antihypertensive treatment may prevent formation of substrate capable of maintaining AF.
- SourceAvailable from: link.springer.com[show abstract] [hide abstract]
ABSTRACT: BACKGROUND: Recently, catheter-based renal sympathetic denervation (RSD) has been verified to be safely used to substantially reduce the levels of blood pressure, left ventricular hypertrophy, sleep apnea severity and norepinephrine spillover, and improve glucose tolerance. All these pathological changes are recognized as independent risk factors for the development and recurrence of atrial fibrillation (AF). A randomized, single-blind, parallel-control, multicenter clinical trial is being conducted to compare RSD with antiarrhythmic drugs (AAD) in patients with drug-resistant hypertension and symptomatic AF (RSDforAF trial).Methods/design: Patients with drug-resistant hypertension and symptomatic AF will be randomized to RSD and the drug treatment groups. Patients will be followed for 12 months until study closure. Up to 200 patients may be enrolled in six medical centers in China. The primary objective is to study the effects of RSD on AF burden and blood pressure in patients with hypertension and symptomatic AF. DISCUSSION: RSDforAF trial will test the hypothesis that RSD is superior to AAD in reducing AF burden and blood pressure in patients with drug-resistant hypertension and symptomatic AF.Trial registration: The trial is registered at www.clinicaltrials.gov, registry number: NCT01713270.Trials 06/2013; 14(1):168. · 2.21 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: Renal artery denervation (RDN) has been introduced as an ablation procedure that can effectively treat drug-resistant forms of hypertension. The ablative lesions reduce the afferent and efferent sympathetic nerve traffic to and from the kidneys, thus improving blood pressure control. Because of better control of blood pressure, and because the procedure reduces central sympathetic output to sensitive structures within the cardiovascular system, it has been hypothesized that RDN may be a valuable antiarrhythmic intervention. Preliminary results using RDN for atrial fibrillation control are promising. This review focuses on the mechanisms by which RDN may function as an antiarrhythmic treatment and early clinical results.Current Cardiology Reports 09/2013; 15(9):392.
- [show abstract] [hide abstract]
ABSTRACT: Atrial fibrillation (AF) is the most common arrhythmia and is associated with significant morbidity and mortality. The autonomic nervous system contributes to the creation of AF substrates. Atrial electrophysiology is differently influenced by sympathetic and parasympathetic activation. Several strategies are available to modulate the complex interaction between the autonomic nervous system and the heart. However, different approaches target the problem differently making the prediction of arrhythmogenic and/or antiarrhythmic effects difficult. We discuss the role of the autonomic nervous system on the development of a substrate for AF and explore the potential antiarrhythmic and/or arrhythmogenic effect of modulation of the autonomic nervous system by renal sympathetic denervation, ganglionated plexi ablation, ganglion stellatum ablation, high thoracic epidural anesthesia, low-level vagal nerve stimulation and baroreflex stimulation.Journal of the American College of Cardiology 10/2013; · 14.09 Impact Factor