William Jackson, also known as Billy, died at the Sunderland Royal Hospital last September after he was "deliberately targeted" by Sarah Daniel.
Billy, 71, suffered from pre-existing health problems and was found unconscious by his neighbour after the break-in at his home in Washington.
He was taken to hospital where he died after a series of further cardiac arrests.
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Prosecutors said he died "because of the stress caused by being the victim of the burglary".
David Bulmer, 20, of Bramston Way in Washington, and Sarah Daniel, 33, of Waterloo Walk, also Washington, both denied manslaughter.
They both admitted being at the house so Daniel could sell stolen goods to Billy but denied they were there to burgle him.
After a trial at Newcastle Crown Court, Daniel was convicted of manslaughter and conspiracy to burgle him.
Bulmer, who said he did not know Mr Jackson and had gone along with the women to sell stolen goods but did not know there was to be a burglary, was cleared of both charges.
Leanne English, 39, of Waterloo Walk, who waited outside Mr Jackson's home while her partner Daniel went in, denied conspiracy to commit burglary againstMr Jackson but has now been found guilty.
Prosecutors said English was involved in the planning and aftermath of the raid.
Daniel and Bulmer were also convicted of an aggravated burglary at a different address the week before the tragedy.
All three have now been remanded in custody and will be sentenced on July 8.
Judge Penny Moreland told the trio: "I will sentence you for the offences which the jury have convicted you of on July 8.
"You are remanded in custody until that date."
The court heard Billy was targeted because he was known to sell cigarettes and tobacco, which he kept in his home.
Prosecutor Jamie Hill QC told the court: "Mr Jackson was 71 years of age and lived in the Concord area of Washington at Hertburn Gardens.
"He had a number of health issues, not least an advanced heart condition. He had diabetes and issues with mobility.
"Although he lived alone, he had a partner called Linda Ord and she would visit him daily.
"Mr Jackson was quite well known in the area, he sold tobacco and cigarettes from his flat."
The court heard it was the cigarettes and tobacco that drew the attention to his flat on September 24.
Mr Hill said: "As to what happened precisely in the flat only Bulmer and Daniel know as sadly Mr Jackson is no longer with us. He suffered a heart attack asthe defendants left and he died a number of hours later in hospital."
Mr Hill told the court that it was Mr Jackson's neighbour's dog who raised the alarm as he began barking and added: "He (the neighbour) said he found himslumped on the kitchen floor and unconscious.
"He had suffered a cardiac arrest, he called 999.
"Eventually paramedics arrived and they managed to keep Mr Jackson alive until they reached the Sunderland Royal.
"He died in the early hours of the next morning after a series of further cardiac arrests."
Mr Hill told jurors that it was the prosecution's case that the pensioner died because he was subjected to "that stressful ordeal".
Mr Hill said: "He died because of the stress caused by being the victim of the burglary."
Bulmer and Daniel had also denied but were convicted of aggravated burglary relating to a separate incident against a different victim, Barry Clark.
Daniel was convicted of two counts of fraud by false representation and English convicted of common assault against Mr Clark, who was a neighbour of Daniel and English.
The court heard that the women had originally befriended Mr Clark, who lived alone after he relocated to the region.
Mr Hill said that on on the evening of September 17, days before Mr Jackson was targeted, Bulmer and Daniel attended Mr Clark's address where they tookcash, a mobile phone and a bank card while armed with a baseball bat, which they used to strike him on the leg.
The common assault charge against English occurred a few months prior, on June 18, after she held up Mr Clark's arm in a nearby underpass while Daniel stole his wallet.
She later used a card to withdraw £290 from a cash machine on two separate occasions.
After the verdicts, Detective Sergeant Steve Brown, of Northumbria Police, said: “This is an absolutely tragic case and our thoughts go out to Billy’s family and friends.
“The last seven months ever since this incident has been incredibly difficult for them, and I would like to thank them for their amazing bravery, poise and cooperation throughout.
“Billy was a vulnerable man who should have been safe inside his own home. However, on the night in question, Sarah Daniel and Leanne English turned up at his door with the intent of stealing tobacco and cigarettes from him.
“While English waited outside, Daniel entered Billy’s home – something that tragically resulted in the victim suffering a cardiac arrest just minutes later.
“The defendants should be absolutely ashamed of themselves and I sincerely hope this outcome can provide some comfort to Billy’s family at this unimaginable time.”