Abnormal right ventricular myocardial strain generation in mild pulmonary hypertension

BACKGROUND: Although right ventricular (RV) dyssynchrony has been identified in patients with severe pulmonary hypertension due to significant RV enlargement and compromise in systolic function, a more clinically relevant question pertains to RV mechanical properties in patients with mild elevation in pulmonary artery systolic pressures (PASP). METHODS: Several echocardiographic parameters and peak longitudinal strain were measured in 40 patients and divided into two groups of 20 patients based on their PASP. RESULTS: Group I included 20 individuals (mean age 48 +/- 16 years with a mean PASP of 27 +/- 5 mmHg) and Group II included 20 patients (mean age 63 +/- 14 years with a mean PASP of 49 +/- 7 mmHg.) All time intervals were adjusted for heart rate. RV fractional area change and tricuspid annular plane systolic excursion for Group I (62 +/- 12% and 2.74 +/- 0.56 cm) and Group II (49 +/- 14%; P < 0.02 and 2.09 +/- 0.40; P < 0.002) were both normal. However, Group II had lower peak longitudinal RV free wall (RVF) strain (-27.3 +/- 7.1 % vs. -31.9 +/- 8.7%, P < 0.04), longer time to peak RVF strain (448 +/- 57 ms vs. 411 +/- 43 ms; P < 0.03) and evidence of significant RV dyssynchrony (-83 +/- 55 ms vs. 1 +/- 17 ms, P < 0.00001) in contrast to Group I. CONCLUSION: In conclusion, mild elevations in PASP affect the mechanical properties of the RV and result in RV dyssynchrony despite absence of gross abnormalities in RV size or function.