Segmental early relaxation phenomenon: Incidence, clinical characteristics, and significance in stress echocardiography

Study objectives: To evaluate the incidence, patient characteristics, and clinical significance of segmental early relaxation phenomenon (SERF) in stress echocardiography. Design: Retrospective interpretation of digitized rest/stress echocardiographic images of 244 consecutive patients undergoing exercise or dobutamine echocardiography with subsequent patient follow-up for outcomes. Setting: Tertiary care referral center. Patients: Two hundred forty-four consecutive patients referred for stress echocardiography (exercise or dobutamine) for various clinical indications. Interventions: None. Measurements and results: SERF was diagnosed as a sudden outward motion of a portion of the left ventricle during early diastole (using frame-by-frame analysis) after peak systole prior to mitral valve opening at rest and after stress. Stress-associated SERF was observed in 71 patients (29.1%), with 25 patients having SERF in more than one segment. Five patients had resting SERF, with two persisting during stress. Ninety-six of 3,658 analyzed segments were positive for SERF. The apical septum and midseptum were most commonly involved in 49% and 18%, respectively. Only 5 of 96 patients (5.2%) had new hypokinesis and SERP in the same segment. No significant differences existed in demographic, clinical, or echocardiographic variables in patients with and without SERF. Follow-up revealed no significant differences in event rates in those with and without SERF. Conclusions: This is the first stress echocardiographic study demonstrating that SERF is a distinct and relatively common stress echocardiographic phenomenon occurring in early diastole regardless of type of stress. SERF occurs predominantly in apical and midseptum in the distribution of the left anterior descending coronary artery. It should not be mistaken for atypical septal motion, ischemia, or dyskinesia, and does not seem related solely to the presence of underlying coronary disease or stress-induced ischemia. No adverse long-term outcomes are seen in patients with SERF and no inducible ischemia.