The Qur'anic heart and converging evidence from contemporary cardiac science: From qalb to cardioception.

For most of recorded history, the heart was considered far more than a pump. The Qur'an and Sunnah (ahadith) describe it as the seat of reasoning, faith, emotion, and moral accountability, employing a vocabulary of at least four distinct cardiac terms (qalb, fu'ad, lubb, and sadr) that appear over 200 times in contexts extending well beyond circulation. Arab-Islamic physicians and philosophers, including al-Balkhi, al-Razi, Ibn Sina, and al-Ghazali, built this into a systematic framework linking cardiac physiology to emotion, cognition, and spiritual life, centuries before the Cartesian biomedical model first treated the organ primarily as a hemodynamic pump. This integrative narrative review asks whether contemporary science has moved back toward the earlier view. Evidence is drawn from neurocardiology, cardiac endocrinology, cardioception research, psychophysiology, and studies of interpersonal synchrony. The heart has an intrinsic nervous system with ∼14,000-94,000 neurons, which are capable of autonomous information processing and local reflex processing that operates within central autonomic regulation. It synthesizes oxytocin and releases atrial natriuretic peptide, and these molecules are implicated in social bonding and anxiolysis. Approximately 80% of vagal cardiac fibers carry signals from the heart to the brain, contributing to emotional and perceptual processing alongside descending central regulation. Heartbeat-evoked potentials gate access to emotional stimuli across the cardiac cycle, and heart rate variability indexes the brain's capacity for emotional regulation and sound judgment. In a recent group study, cardiac synchrony between individuals in group settings was associated with collective decision-making performance. It is not claimed that science proves scripture, but instead it is shown that independent scientific disciplines, working without reference to religious texts, have arrived at a portrait of the heart that stands in analogical consonance with descriptions in Islamic tradition over fourteen centuries ago. Limitations are noted where evidence is weak, particularly regarding transplant personality-change reports and cardiac electromagnetic field claims. Future directions include characterizing intrinsic cardiac neuron subtypes in humans, examining the cardiac effects of practices such as dhikr, and designing prospective transplant protocols.