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Cardiac Ablation Reduces Risk Of Stroke And Alzheimer's Disease

Atrial Fibrillation: image via Texas Arrhythmia InstituteAtrial Fibrillation: image via Texas Arrhythmia Institute New findings by researchers from the Heart Institute at Intermountain Medical Center in Murray, Utah, reveal that a treatment of the most common heart rhythm disorder, affecting more than two million Americans, significantly reduces the risk of stroke, mortality, Alzheimer's disease, and other forms of dementia.

Three to five percent of people over 65 have atrial fibrillation. That common heart rhythm disorder occurs when the atria (the two upper chambers of the heart) are not contracting in unison.  It is characterized by a fluttering, which can be heard through a stethoscope, and possibly, be felt in the pulse, but an EKG would have to confirm it.

Atrial fibrillation may prevent blood from being pumped completely out of the atria, which may cause the blood to pool and clot. If a piece of a blood clot in the atria leaves the heart and becomes lodged in an artery in the brain, a stroke results.  This is the most feared result of atrial fibrillation.

To prevent this from happening, the most common treatment for atrial fibrillation is cardiac ablation, which is kind of like removing rust from a pipe.  Generally a non-invasive procedure, cardiac ablation involves inserting catheters through narrow entry points in the groin or neck and directing the catheters to the heart by images obtained from a fluoroscope.  Once in the right location, the catheter's electrodes send back a variety of electrical measurements to the cardiac arrhythmia specialist.

 

Cardiac Electrophysiology Equipment, Mount Auburn Hospital: ©Mount Auburn HospitalCardiac Electrophysiology Equipment, Mount Auburn Hospital: ©Mount Auburn Hospital

The fluoroscope pinpoints where the arrhythmia is occurring and the specialist will then use the electrodes to destroy tissue which is causing the arrhythmia.  The specialist generally uses radiofrequency energy, thereby either cauterizing the tissue to burn it, or cryoablation to freeze the tissue.

According to the studies reported today, patients with atrial fibrillation treated with catheter ablation are less likely to develop Alzheimer's disease or other forms of dementia, and have a significantly reduced risk of stroke and death compared to atrial fibrillation patients who are not treated with ablation. 

 

Texas Arrhythmia InstituteHeart Rhythm Society, Press release

 


Comments
Oct 28, 2010
by Anonymous

Atrial fibrillation and Alzheimer’s disease

The idea that ineffective left ventricular function and hemodynamic “instability” play an important role in the development of Alzheimer’s disease and vascular dementia has not been substantially developed. For instance, only a few population studies suggest that there is an association between atrial fibrillation and Alzheimer’s disease progression[1]. However, no serious consideration of the mechanism has been provided.

One of the mechanisms that can describe an association between cardiac pathology (i.e. cardiac arrhythmia) and Alzheimer’s disease is the disturbances in the dynamics of regional brain extravascular extracellular fluid[2]. Such consideration of regional brain extravascular extracellular fluid dynamics is also particularly important in light of the fact that certain waste products such as glutamate or calcium can accumulate there causing degradation of certain cellular components thus playing an important role in the pathogenesis of Alzheimer’s disease[3,4].

Such mechanism proposes that the regional brain extravascular extracellular fluid gets moved due to the cyclic changes in the vessel wall deformation, a sort of a “deformation pump”[2]. The operating principle of the “deformation pump” is in the cyclic creation of the boundary layer and in its separation. Thus the movement of the regional brain extravascular extracellular fluid happens as a result of the appearance and separation of the boundary layer at the close proximity to the vascular wall. The obvious implication of this mechanism is the primary involvement of cardiovascular system in the development of Alzheimer’s disease.

Correspondinlgy to theoretical results, the important populaiton-based finding was that the proportion of patients diagnosed with both sick sinus syndrome and Alzheimer’s disease was significantly higher (P < 0.001) compared to the proportion of those patients diagnosed with Alzheimer’s disease and any other discharge diagnoses, followed by the remaining proportions (i.e. atrial fibrillation and Alzheimer’s disease; sinus bradycardia and Alzheimer’s disease)[2].

Rovshan M Ismailov, M.D., M.P.H., Ph.D.

References

[1] Mielke MM, Rosenberg PB, Tschanz J et al. Vascular factors predict rate of progression in Alzheimer disease. Neurology 2007; 69(19):1850-8.
[2] Ismailov RM. New insights into the mechanism of Alzheimer's disease: A multidisciplinary approach . edn. Amazon Kindle, 2010.
[3] Mattson MP. Calcium as sculptor and destroyer of neural circuitry. Exp Gerontol 1992; 27(1):29-49.
[4] Khachaturian ZS. The role of calcium regulation in brain aging: reexamination of a hypothesis. Aging (Milano) 1989; 1(1):17-34.