Pāṇini sūtras

hṛd is optionally the substitute for hṛdaya, when the words śoka, and roga or the affix ṅyañ follows.

1. vāवा

   Part	Lexeme	Sandhi form	Meaning	Stem
   vव्	vāवा	vāवा	optionally	vāवा

2. śoka+ṣyaṅ+rogeṣuशोक+ष्यङ्+रोगेषु

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   śश्	śokaशोक	śokaशोक	śoka [word]शोक [wओर्द्]	śokशोक् + plus aअ
   ṣष्	ṣyaṅष्यङ्	ṣyaṅष्यङ्	ṣyaṅष्यङ्	ṣyaṅष्यङ्
   rर्	rogaरोग	rogeṣuरोगेषु	roga [word]	rogरोग् + plus eṣuएषु

Anuvṛtti

1. uttara+padeउत्तर+पदे 6·3·1

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   uउ	uttaraउत्तर	uttaraउत्तर	last	uttarउत्तर् + plus aअ
   pप्	padaपद	padeपदे	word	padपद् + plus eए

2. hṛd+lekha+yat+aṇ+lāseṣuहृद्+लेख+यत्+अण्+लासेषु 6·3·50

   Part	Lexeme	Sandhi form	Meaning	Stem
   hह्	hṛdहृद्	hṛdहृद्	hṛd [word]हृद् [wओर्द्]	hṛdहृद्