How can anxiety provoke an irregular heartbeat?

Anxiety can provoke an irregular heartbeat through a variety of mechanisms. To explain this phenomenon, it is important to understand the role that emotions play in regulating our cardiovascular system.

Physiologically, anxiety and fear trigger a “fight-or-flight” response within the autonomic nervous system (ANS). This response increases the activity of both sympathetic (excitatory) and parasympathetic (inhibitory) components of the ANS. By increasing sympathetic activity, catecholamines (epinephrine and norepinephrine) are released into circulation provoking increased heart rate, or tachycardia. Increased Parasympathetic activity results in bradycardia by stimulating vagal stimulation on sinoatrial node pacemaker cells in the heart leading to slowed heart rate or arrhythmia such as premature ventricular contractions or atrial fibrillation. Simultaneously, adrenaline triggers constriction of peripheral blood vessels to increase pressure while decreasing overall cardiac output which can also lead to further irregularities in rhythm such as palpitations or prolonged QT intervals on electrocardiograms resulting from prolonged wave depolarization duration times due to heightened noradrenergic tone.

Thus Anxiety can lead to a variety of cardiac irregularities due its profound effects on both sympathetic & parasympathetic systems influencing sinus & atrioventricular conduction pathways leading propensity for cardiac arrhythmias likely secondary overstimulation from adrenergic hormones released during emotional states such as anxiety & fear.