Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
electrocardiograph is a noun meaning "medical instrument that records electric currents associated with contractions of the heart". It carries one recorded sense.
medical instrument that records electric currents associated with contractions of the heart
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for electrocardiograph come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.