Cases of atrial fibrillation (AF) rocketed from just under 70,000 to over 84,000, according to British Heart Foundation (BHF) Scotland.
The data, released as part of BHF Scotland's Ramp up the Red fundraising campaign for heart research, shows the UK has for the first time topped the million mark for the number of people living with the heart rhythm disorder.
High blood pressure, heart valve disease and binge drinking are among the causes alongside the fact people are living longer.
Marjory Burns, director of BHF Scotland, said: "The real danger with AF is that some people don't realise they have it. You can be oblivious to the fact you're five times more likely to have a devastating stroke."