In clinical practice, timely diagnosis of cancer therapy–related cardiac dysfunction (CTRCD) could be improved via combined use of echocardiography 3-dimensional (3-D) left ventricular ejection fraction (LVEF), global longitudinal strain (GLS), and global circumferential strain (GCS).

• Researchers assessed the correctness of an algorithm employing echocardiography and serum biomarkers for the timely diagnosis of CTRCD defined using cardiovascular magnetic resonance (CMR).

• In this cohort study, a total of 136 women (mean [SD] age, 51.1 [9.2] years) with human epidermal growth factor receptor 2–positive early-stage breast cancer were included.

• Exposures included sequential therapy with anthracyclines and trastuzumab.

• Good discriminatory accuracy for concurrent CMR-detected CTRCD was achieved with a combined approach of using echocardiographic 3-D LVEF, GLS, and GCS, but not by high-sensitivity troponin I and B-type natriuretic.

• The likelihood of CTRCD as defined by CMR was 1.0% when none of the 3-D LVEF, GLS, and GCS CTRCD criteria were met.