C4A and atrial fibrillation: An increased inflammatory state ‒ expressed clinically as increased levels of circulating C-reactive protein ‒ has been linked to ventricular tachycardia in patients with ARVC 61, and increased inflammation ‒ defined by increased serum levels of C-reactive protein, C3, and C4 ‒ has been found to increase the risk of atrial fibrillation 62.