Although the significant positive effect of the TTM-based ESMI on exercise behavior sustained at 6-month follow-up, the magnitude of the effect waned over time. This phenomenon suggests that the one two-hour patient education session and a booklet about cardiac rehabilitation, plus an eight-week TTM- based ESMI and exercise stage-matched pamphlets, may not be enough to maintain the positive impact on exercise behavior in the long-term (>6 months).