Objective To evaluate segmental right ventricular (RV) dysfunction in pulmonary hypertension (PH) using cardiac magnetic resonance (CMR).

Design Cross-sectional analysis in a retrospective cohort of consecutive adult patients.

Setting Mount Sinai Hospital in New York.

Patients 192 patients with known or suspected PH undergoing right heart catheterisation and CMR. PH was defined as mean pulmonary artery pressure ≥25 mm Hg. Abnormal RV ejection fraction (RVEF) was defined as <50%. Patients were classified into: group 1 (no PH, normal RVEF; n=40), group 2 (PH, normal RVEF; n=41) or group 3 (PH, abnormal RVEF; n=111).

Interventions CMR and right heart catheterisation within a 2-week interval.

Main outcome measures On cine CMR images, the stack of RV short-axis views was divided into two equal halves. Basal and apical RVEF were calculated using Simpson's method, and a ratio of basal-to-apical RVEF (RVEF_ratio) was derived.

Results Basal RVEF did not differ between groups 1 and 2 (63±8% vs 64±8%; p=1); however, patients in group 2 had significantly lower apical RVEF (46±13% vs 58±10%; p<0.01) and higher RVEF_ratio (median 1.4 vs 1.1; p<0.01). Both apical and basal RVEF were reduced in group 3 compared with groups 1 and 2 (p<0.01), and the RVEF_ratio increased with increasing PH severity (p<0.01 for trend). An apical RVEF <50% was more sensitive than global RV dysfunction for the detection of PH.

Conclusions Apical dysfunction appears to occur before global RVEF decreases in chronic PH, potentially constituting an early and sensitive marker of RV dysfunction in this setting.