Clinical decision support system (CDSS) is a technology designed to assist physicians and medical stuff with clinical decision-making tasks. It aims to better the safety and quality of patient care, improve patient care treatments and outcomes, decrease the dependence on memory, lower error rates, and decrease response time. CDSS is not intended to replace clinician judgment, but it supports users with the detection and prevention of possible risks to patient safety and encouraging the appropriate usage of evidence-based practice and guidelines. The benefits of the CDSSs contribute in increasing the number of e-health applications in recent years. Cardiology healthcare institutions are adopting such systems in their departments in order to assist cardiologists when making their decisions. This study proposes a set of cardiac DSS requirements and measures the influence of these requirements on software product quality using the ISO/IEC 25010 software quality model. A checklist of cardiac DSS requirements is also presented. As a result, Functional suitability, Reliability, Performance efficiency and Operability external characteristics were identified as the most influenced by cardiac DSS requirements.