The two-year Deloitte & Touche partnership is expected to raise £250,000 for the charity. Some 10,000 employees took part in the vote, and also chose the Leukaemia Research Fund.
The firm drew up an initial list of more than 100 charities, and a shortlist of 10 was chosen by a committee before the matter was put to a staff vote. Its previous charity partners were ChildLine and Marie Curie Cancer Care.
The partnership will run for at least 18 months from February. The money raised will go towards funding nurses who care for patients with heart disease in their homes.
The charity will also launch a direct mail appeal around Valentine's Day asking for money to pay for 30 nurses to care for heart disease patients.
The appeal includes a prize draw to win a holiday in Australia. Supporters will be asked to write a love note and place it in their local BHF shop window or on the dedicated campaign website.
"Most people haven't heard of British Heart Foundation nurses and what they do," said Betty McBride, the foundation's head of campaigns. This campaign will explain to people who the nurses are, what they do and why their jobs are so important."
Veronica McCarthy, social responsibility manager at Comet, said: "The consensus was an overwhelming and resounding 'yes' to the British Heart Foundation. Many of our colleagues will be able to relate to the charity's work through knowing a friend or family member who is a victim of heart disease."