Heart failure, arrhythmia and syncope

A different question

So far in Learn, most testing has been about chest pain or other symptoms of ischemia. Table 2.4 of the 2023 multimodality AUC covers a different group: patients without symptoms of ischemia who have another cardiovascular condition, such as heart failure, arrhythmia or syncope, or who have had a heart transplant Winchester et al., 2023, Table 2.4. The question being asked is not “is this angina?” It is “could coronary disease be causing, or contributing to, this condition?”

These scenarios are for stable patients. The AUC says its scenarios are not meant for acute conditions such as acute coronary syndrome or acute decompensated heart failure Winchester et al., 2023, Assumption 5.

Heart failure

Table 2.4 rates newly diagnosed heart failure with preserved ejection fraction (HFpEF) and with reduced ejection fraction (HFrEF), in patients whose resting heart function has been assessed but who have not yet had a coronary evaluation. The AUC counts heart failure as stages B, C and D Winchester et al., 2023, Definitions for Table 2.4.

The 2023 AUC gives little narrative for these rows. The PET AUC, which rates the same kind of patient for PET only, explains the thinking. Coronary disease is among the most common causes of heart failure, and surgical revascularization of ischemic HFrEF is linked to better survival, so finding this modifiable cause matters. For HFpEF it is more nuanced: ischemia is one contributor among several, including left ventricular hypertrophy and stiffening, vascular stiffening and kidney dysfunction. In HFpEF with a low clinical chance of coronary disease, the yield of stress PET will generally be suboptimal (though testing may help in selected patients), and when the chance is intermediate or high, looking for ischemia as a cause or contributor is appropriate Schindler et al., 2025, Section 3.

For anatomy, the SCCT consensus notes that CCTA is especially helpful in a new cardiomyopathy when obstructive coronary disease needs to be excluded, a job traditionally done by invasive angiography Narula et al., 2021, Section 4.7.

Arrhythmia

Table 2.4 covers infrequent premature ventricular contractions (PVCs), frequent PVCs or nonsustained ventricular tachycardia (VT), paroxysmal supraventricular tachycardia, new-onset atrial fibrillation (AF) or flutter, high-risk patients before antiarrhythmic drugs, exercise-induced VT, sustained VT and ventricular fibrillation (VF). Definitions matter here: infrequent PVCs are 30 or fewer per hour, and frequent PVCs are more than 30 per hour Winchester et al., 2023, Definitions for Table 2.4.

The PET AUC’s reasoning explains why the ratings vary so much between rhythms Schindler et al., 2025, Section 5:

• Ischemia is a key cause in only a small subset of arrhythmias, and AF is mostly not thought to be primarily ischemic.
• Ischemia is a primary cause of VF, and an old infarct can be the substrate for VT and PVCs.
• After a myocardial infarction, monomorphic VT is typically scar-related re-entry rather than acute ischemia. Transient ischemia is the more usual trigger of polymorphic VT. If ischemia is suspected, testing and any revascularization should come before catheter ablation when possible.
• The meaning of PVCs depends on whether there is underlying heart disease, and a low PVC burden has no prognostic significance by itself.
• With new AF, coronary disease is one of many risk factors, so testing depends on the clinical risk of coronary disease and on ejection fraction.

Syncope

The AUC defines syncope as an abrupt, brief, complete loss of consciousness with loss of postural tone and rapid spontaneous recovery, presumed to come from reduced blood flow to the brain Winchester et al., 2023, Definitions for Table 2.4. It splits scenarios by what the initial evaluation suggests: a cardiovascular abnormality, or another cause. These scenarios were revised to match the 2017 ACC/AHA/HRS syncope guideline, which bases testing on history, examination and ECG Winchester et al., 2023, Section 8, Discussion.

The PET AUC explains the logic. The task is to separate cardiovascular from noncardiac causes. Syncope in someone with heart disease, or during exertion, is more likely to be cardiovascular. Myocardial infarction and ischemia are uncommon causes of syncope, and outside a massive infarct coronary disease is a rare cause, so when the coronary risk is low the diagnostic focus belongs elsewhere Schindler et al., 2025, Section 6.

After a heart transplant

Cardiac allograft vasculopathy (CAV) is a diffuse, progressive narrowing of the coronary arteries after transplant, and patients are commonly without symptoms. Yearly screening has been the practice Narula et al., 2021, Section 4.9. The 2023 AUC added screening for transplant vasculopathy to Table 2.4 Winchester et al., 2023, Section 8, Discussion. The PET AUC explains why invasive angiography alone is not an ideal screen: low yield, limited sensitivity for diffuse disease, procedural risk and cost, and relative contraindications from the high rate of kidney dysfunction Schindler et al., 2025, Scenario 38. The SCCT consensus says CCTA may be an alternative in selected settings, depending on local expertise and kidney function Narula et al., 2021, Section 4.9.

Open a heart failure scenario in the builder →, or start from the definition of syncope and the definition of heart failure used by the criteria.