Owners of the pets had also tested positive for Covid and the tests on the animals were up to six weeks after signs of cardiac disease emerged.
The owners had developed respiratory symptoms several weeks before their pets eventually also became ill.
Dr Ferasin added: “We also reported the atypical clinical manifestations characterised by severe heart abnormalities.
“This is a well-recognised complication in people affected by Covid-19 but has never been described in pets before.
“However, Covid-19 infection in pets remains a relatively rare condition and, based on our observations, it seems the transmission occurs from humans to pets, rather than vice versa.”
The study is the first to have identified the alpha variant in domestic pets, and comes from the journal Veterinary Record.
US scientists found in June that household cats are more vulnerable to Coronavirus than dogs.
Around 750 animals were analysed, with findings revealing that eight percent of cats carried Covid antibodies in comparison with less than one percent of dogs.
Experts fear that pets could act as a ‘reservoir’ for the virus – spreading it back to humans again even after it has been removed from populations.