Focus Topic: Myocardial Work in Health and Disease
Clinical Investigation
Myocardial Work in Nonobstructive Hypertrophic Cardiomyopathy: Implications for Outcome

https://doi.org/10.1016/j.echo.2020.05.010Get rights and content
Under a Creative Commons license
open access

Highlights

  • Myocardial work parameters are impaired in patients with HCM.

  • CW is associated with adverse events in patients with HCM.

  • Segmental differences of CW were observed among HCM phenotypes.

Background

Noninvasive left ventricular (LV) pressure-strain loop analysis is emerging as a new echocardiographic method to evaluate LV function, integrating longitudinal strain by speckle-tracking analysis and sphygmomanometrically measured blood pressure to estimate myocardial work. The aims of this study were (1) to describe global and segmental myocardial work in patients with hypertrophic cardiomyopathy (HCM), (2) to assess the correlation between myocardial work and other echocardiographic parameters, and (3) to evaluate the association of myocardial work with adverse outcomes.

Methods

One hundred ten patients with nonobstructive HCM (mean age, 55 ± 15 years; 66% men), with different phenotypes (apical, concentric, and septal hypertrophy), and 35 age- and sex-matched healthy control subjects were included. The following myocardial work indices were included: myocardial work index, constructive work (CW), wasted work, and cardiac efficiency. The combined end point included all-cause mortality, heart transplantation, heart failure hospitalization, aborted sudden cardiac death, and appropriate implantable cardioverter-defibrillator therapy.

Results

Mean global CW (1,722 ± 602 vs 2,274 ± 574 mm Hg%, P < .001), global cardiac efficiency (93% [89%–95%] vs 96% [96%–97%], P < .001), and global MWI (1,534 ± 551 vs 1,929 ± 473 mm Hg%) were significantly reduced, while global wasted work (104 mm Hg% [66–137 mm Hg%] vs 71 mm Hg% [49–92 mm Hg%], P < .001) was increased in patients with HCM compared with control subjects. Segmental impairment in CW colocalized with maximal wall thickness (HCM phenotype), and global CW correlated with LV wall thickness (r = −0.41, P < .001), diastolic function (r = −0.27, P = .001), and QRS duration (r = −0.28, P = .001). Patients with global CW > 1,730 mm Hg% (the median value) experienced better event-free survival than those with global CW < 1,730 mm Hg% (P < .001).

Conclusions

Myocardial work, assessed noninvasively using echocardiography and blood pressure measurement, is reduced in patients with nonobstructive HCM; it correlates with maximum LV wall thickness and is significantly associated with a worse long-term outcome.

Keywords

Hypertrophic cardiomyopathy
Myocardial work
Left ventricular pressure-strain loop
Echocardiography

Abbreviations

AUC
Area under the curve
CE
Cardiac efficiency
CW
Constructive work
GLS
Global longitudinal strain
GMWI
Global myocardial work index
HCM
Hypertrophic cardiomyopathy
ICD
Implantable cardioverter-defibrillator
IQR
Interquartile range
LA
Left atrial
LV
Left ventricular
LVEF
Left ventricular ejection fraction
LVH
Left ventricular hypertrophy
PSL
Pressure-strain loop
SCD
Sudden cardiac death
WW
Wasted work

Cited by (0)

Dr. Delgado has received consulting fees from Abbott Vascular. The Department of Cardiology of Leiden University Medical Center has received research grants from Biotronik, Medtronic, Boston Scientific, and Edwards Lifesciences.

Bijoy K. Khandheria, MD, MBBS, FASE, served as guest editor for this report.

Conflicts of Interest: None.