Although cocaine and alcohol were found in Silhesha Sunderland’s body, they played no part in her death, said Lancashire coroner James Newman
He recorded a verdict that Silhesha, aged 22, died of natural causes.
And her family were urged to get their hearts checked as a precaution after the inquest heard the cause of death was unclear.
The Preston inquest heard that Silhesha, of Garforth Crescent, Bamber Bridge, had been enjoying a party at home with her partner and a family friend. Silhesha had complained of stomach pains and had taken a painkilling tablet
M6, M61 and M55 delays in Preston due to Blackpool Air Show and Lake District holiday traffic
Car crash on M6 brings Preston motorway traffic to a halt with severe delays expected
Driver caught 'snoring merrily away' on the M6 near Bamber Bridge with full-beam headlights and engine running
Thunderstorms and heavy downpours of rain predicted to hit Lancashire as Met Office issues yellow weather warning
Two Preston men arrested after serious assault near Harris Museum
The friends stayed up drinking and chatting until the early hours
Her partner Mark Stott got up on December 27 and found Silhesha in the bathroom, slumped back against the bath.
Paramedics were called and tried to revive her but she was pronounced dead.
Mr Newman told the inquest that a pathologist had been unable to determine a cause of death.
Although Silhesha had been drinking and had taken cocaine, they were at low levels.
And although there was evidence of her having vomited, that had not caused her death.
Mr Newman said there were also no signs of injury or issues with vital organs which could have caused her death.
He said: “Whatever happened to Silhesha was a sudden and catastrophic event. I don’t think she would have known anything about it.”
He endorsed a GP’s suggestion that the family have an ECG test to double check for heart problems.