During cardiac catheteriza- tion, the coronary pattern may be demonstrated by performing simultaneous RVOT angiography and coronary angiography.S4.3.5-2 Coronary com- pression testing generally involves simultaneous coronary angiography or aortography and bal- loon dilation of the RVOT to ascertain whether a balloon expanded stent will compress the cor- onary artery. 3. Additional risk factors for SCD include:S4.3.5-24,S4.3.5-38, a. LV systolic or diastolic dysfunction b. Nonsustained VT, QRS duration 180 ms c. Extensive RV fibrosis by CMR In adults with TOF, inducible sustained VT has been associated with an increased risk of clinical VT or SCD, beyond standard ECG, hemodynamic, and clinical factors.S4.3.5-5 Programmed ventricular stimulation is most useful in risk stratifying pa- tients at moderate risk of SCD rather than as a rou- tine surveillance tool in low-risk populations.S4.3.5-7 4. Cardiac catheterization is the only method that can accurately and reliably determine PA pressure and pulmonary vascular resistance. 5. Symptomatic patients (with dyspnea, chest pain, and/or exercise intolerance otherwise unex- plained) with repaired TOF and severe PR who undergo pulmonary valve replacement often re- port improved functional class after intervention. Improvement in symptoms often correlates with a reduction in RV size and relief of PR.S4.3.5-9 S4.3.5-11 Symptom improvement is more likely in patients with underlying PS and PR than in patients with PR alone. For patients with significant LV or RV dysfunction, pulmonary valve replacement may not be tolerated or sufficient; therefore, evalua- tion by ACHD cardiologists and HF cardiologists is appropriate to decide appropriate course of action, particularly in deciding if a patient may be appropriate for mechanical circulatory support or heart transplant. Table 27. 