The neuro-cardiac axis in epilepsy

Epilepsy is a major noncommunicable neurological disorder, most prevalent among patients with cardiovascular (CV) disease (CVD). Epilepsy incurs a higher risk for developing CVD with an odds ratio of 2.25. CVDs can influence the function of the brain, and many brain diseases are linked with CV dysfunction, in a resiprocal relationship (neurocardiac axis). In patients with epilepsy, interactions along this neuro-cardiac axis appear to be involved in CVDs, such as hypertension and cardiac arrhythmias including atrial fibrillation, long QT syndrome, catecholaminergic polymorphic ventricular tachycardia, and sudden cardiac death (SCD) in epilepsy. Heart-brain interactions may comprise 2 wide categories: CV effects of neurological disease and neurological effects of CVD. The pathogenesis of neurogenic CV effects may involve a neurogenic cascade where sudden shifts in autonomic balance lead to an exaggerated catecholamine release. This can occur in acute neurological conditions such as ischemic stroke, intracranial hemorrhage, and epilepsy. Cardiovascular complications comprise the stroke-heart syndrome, neurogenic pulmonary edema and cardiomyopathy, Takotsubo syndrome, cardiac arrhythmias, and SCD. Specific areas of the brain, such as the insular cortex, play key roles in cardiac autonomic regulation, and disorders involving these areas have greater effects on the CV system. On the other hand, CV conditions can adversely influence the neurological system. Atrial fibrillation and intracardiac thrombus can cause cardioembolic strokes, whereas heart failure and severe aortic stenosis might account for cognitive impairment. This neuro-cardiac axis is herein detailed and the heart-lung-brain interactions in patients with epilepsy are pictorially illustrated. The epileptogenic and anti-epileptogenic medications and the results of reports of meta-analyses on the CV outcomes of patients with epilepsy are tabulated.