BBB Etymology - Warm the cockles of one's heart

The word cockles is used either as a comparison of the shape of the heart with that of a cockleshell, or because the zoological name for cockle is 'cardium' - related to the Greek for heart, as in 'cardiac' - or because the Latin name for the ventricles of the heart is 'cochleae cordis' (the first word of which means snail-shells) because of their appearance.