Telegram Messenger Support for Smoking Cessation After Heart Attack

This randomized controlled trial will evaluate whether a 6-month behavioral intervention delivered via Telegram messenger increases smoking cessation rates in patients after myocardial infarction (MI). Adult smokers hospitalized with acute MI who regularly use Telegram will be randomly assigned to either: * INTERVENTION GROUP: Standard care plus a 6-month Telegram chatbot program providing personalized motivational messages, cognitive-behavioral techniques for craving management, and relapse prevention support. * CONTROL GROUP: Standard care (routine physician advice to quit smoking) plus basic surveys via Telegram without therapeutic content. The primary outcome is 30-day point prevalence abstinence at 6 months, verified by blinded telephone interview with participant and corroborating report from a close relative. Secondary outcomes include changes in cigarette consumption, nicotine dependence, motivation, and intervention engagement metrics. This study addresses the critical gap in smoking cessation support after hospital discharge and could provide evidence for a scalable digital health solution in cardiac secondary prevention.

Inclusion Criteria: * Willing and able to provide written informed consent. * Age 18 years or older. * Hospitalization with a confirmed diagnosis of acute myocardial infarction (MI), including both ST-elevation MI (STEMI) and non-ST-elevation MI (NSTEMI). * Current smoker at the time of index MI: self-reported smoking of at least one cigarette per day in the month prior to hospitalization. * Regular user of the Telegram messenger application (app installed on a personal smartphone). * Possession of a smartphone with internet access and a valid phone number. * Ability and willingness to provide contact information for a close relative or cohabiting person who can verify smoking status at follow-up. Exclusion Criteria: * Smoking cessation more than 1 month prior to the index MI hospitalization. * Physical or cognitive impairment that prevents the use of a smartphone (e.g., severe visual/hearing impairment, inability to read or respond to messages). * Inability to read and understand the Russian language fluently. * Comorbid condition with a life expectancy of less than 1 year. * Active severe mental illness (e.g., psychosis, severe untreated depression) that would impede understanding of the protocol or adherence. * Unwillingness or inability to provide contact details for a close relative for outcome verification.