From the Guidelines

No, heart disease is not the same as Coronary Artery Calcium (CAC) score.

The presence of coronary calcium indicates atherosclerosis of coronary arteries, but it does not necessarily reflect the presence of significant coronary stenosis, which is a key component of heart disease 1.
A CAC score of 0 has a high negative predictive value for ruling out significant coronary narrowing, but it does not rule out noncalcified plaque, and clinical judgment about risk should prevail 1.

The CAC score is a useful tool in refining risk assessment for preventive interventions, such as statin therapy, in individuals with intermediate predicted risk 1.
The extent of coronary calcification correlates with the extent of the total coronary plaque burden, but it is not a direct measure of heart disease 1.
A high CAC score is associated with an increased risk of cardiovascular events, but it is not a guarantee of heart disease, and other factors such as family history and traditional risk factors should be considered 1.

The CAC score should be used as a decision aid in select adults to facilitate the clinician-patient risk discussion, rather than as a screening test for all 1.
The absence of coronary calcium does not rule out noncalcified plaque, and clinical judgment about risk should prevail 1.
The CAC score can be used to reclassify risk upward or downward in a significant proportion of individuals, which can help guide shared decision-making about preventive interventions 1.

From the Research

Heart disease, also known as coronary artery disease, occurs when the coronary arteries, which supply blood to the heart muscle, become hardened and narrowed due to the buildup of cholesterol-containing deposits called plaques 2.
Coronary Artery Calcium (CAC) score is a measure of the amount of calcium in the coronary arteries, which is an indicator of atherosclerosis, a condition in which the arteries become narrowed and hardened due to the buildup of plaque 3.

A CAC score of greater than 0 is associated with an increased risk of major adverse cardiovascular and cerebrovascular events (MACE) compared to a CAC score of 0 in both asymptomatic and symptomatic populations without established coronary artery disease 3.
The CAC score is a stronger predictor of coronary heart disease (CHD) events than carotid plaque score, and it improves prediction, discrimination, and reclassification of CHD events 4.
The CAC score can be used to update a "pretest" CHD risk estimate, such as the 10-year Framingham Risk Score, and it provides incremental improvements in the C-statistic for the prediction of sudden cardiac death (SCD) among individuals with a 10-year risk <7.5% and 7.5% to 20% 5, 6.

Heart disease is a broad term that encompasses various conditions, including coronary artery disease, heart failure, and arrhythmias, whereas CAC score is a specific measure of coronary atherosclerosis 2.
A CAC score of 0 does not necessarily mean that an individual is free of heart disease, as it only measures the amount of calcium in the coronary arteries and not other factors that may contribute to heart disease 3.

The CAC score can be used as a reliable indicator of coronary artery disease, particularly in asymptomatic individuals, and it can help direct treatment and prevent deaths 2.
The CAC score can be used in combination with conventional cardiovascular risk factors to improve risk stratification and prediction of cardiovascular events 5, 6.