Phenotyping Left Ventricular Obstruction With Postprandial Re-Test Echocardiography in Hypertrophic Cardiomyopathy

https://doi.org/10.1016/j.amjcard.2020.03.004Get rights and content

HIGHLIGHTS

  • Meal-related hemodynamics favors obstruction in hypertrophic cardiomyopathy (HC).

  • Unawareness of meal-related fluctuant obstruction may be clinically confounding.

  • Postprandial echocardiography may elicit obstruction in over fasting stressors.

  • Workup should include postprandial re-test echocardiography for HC phenotyping.

  • Postprandial echocardiography phenotyping may be relevant in targeting HC therapy.

Dynamic left ventricular (LV) obstruction has important clinical and therapeutic implications in patients with hypertrophic cardiomyopathy (HC). Although absent at rest, LV obstruction may be elicited using varying stressors. Meal-related hemodynamic changes may favor LV obstruction and support postprandial (PP) symptoms in HC patients. The aim of this study was to evaluate PP-LV obstruction inducibility in HC patients in comparison with fasting Valsalva maneuver and exercise test. Ninety-two HC patients without LV obstruction underwent at-rest Transthoracic Echocardiography (TTE) during Valsalva maneuver and exercise test under fasting condition followed by at-rest re-test PP-TTE 30 to 60 minutes after a standardized midday meal. LV obstruction was noted and classified as being related to systolic anterior motion (SAM) of the mitral valve (SAM-related) and/or non-SAM-related (mid-cavity or apical), and intraventricular gradient was measured. At-rest re-test PP-TTE showed significant intraventricular gradient (>30 mm Hg) in 68 patients (60 SAM-related, 8 non-SAM related, 30 combined) with a higher prevalence (74%) of HC phenotype re-classified as obstructive compared with the fasting Valsalva maneuver (23%) or exercise test (33%) (p < 0.001). At multivariate analysis, a clinical history of PP symptoms and mitral anterior leaflet length and/or LV outflow ratio >2 were independently correlated with PP-TTE obstruction. In conclusion, PP TTE re-test is a simple and effective approach to unmask latent LV dynamic obstruction in daily clinical practice over fasting Valsalva maneuver or exercise test. PP clinical phenotype refinement may be relevant in targeting and evaluating HC therapy.

Section snippets

Methods

Four-hundred and fifty patients with HC were referred for diagnostic and therapeutic workup. Out of 450 subjects, 406 patients fulfilled HC diagnostic criteria, including an unexplained hypertrophy (maximal wall thickness > 15 mm) in the absence of other cardiac or systemic conditions capable of producing a similar degree of LV hypertrophy.17 In patients with a maximal wall thickness of 13 to 15 mm, HC was diagnosed in the presence of other markers, such as mitral valve systolic anterior motion

Results

Clinical and echocardiographic characteristics of the study group are summarized in Table 1. The occurrence of a new obstructive phenotype in the fasting condition (following Valsalva maneuver and exercise test) and at-rest re-test PP-TTE in the enrolled 92 nonobstructive HC patients is reported in Figure 1 and Table 2. A significant IVG (>30 mm Hg) was inducible at fasting TTE in 21 patients during Valsalva maneuver and 30 patients during exercise. The mechanism of LV obstruction was

Discussion

The main finding of this study is the high rate (74%) of postmeal LV obstructive re-phenotype in HC patients, without evidence of obstruction during at-rest fasting TTE. Showing a higher rate of LV obstruction than fasting Valsalva maneuver and exercise test, re-test PP-TTE may be included in clinical practice for work-up refinement in HC patients.

Dynamic LV obstruction is an important determinant of an unfavorable clinical course and should be considered a therapeutic target in HC patients.1, 2

Authors’ Contribution

Giovanni La Canna: Conceptualization, Methodology, Writing-original draft preparation, Writing- reviewing and editing. Iside Scarfò: Data curation, Software, Investigation, Project administration, Visualization, Writing-original draft preparation. Iryna Aredar: Data curation, Software, Visualization, Formal analysis. Emanuela Alati: Software, Investigation, Validation. Ilaria Caso: Visualization, Investigation, Data curation. Ottavio Alfieri: Supervision, Writing-reviewing and Editing.

Disclosures

The authors have no conflicts of interest to disclose.

References (30)

  • S Lafitte et al.

    Paradoxical response to exercise in asymptomatic hypertrophic cardiomyopathy: a new description of outflow tract obstruction dynamics

    J Am Coll Cardiol

    (2013)
  • BJ Maron et al.

    Circadian patterns in the occurrence of malignant ventricular tachyarrhythmias triggering defibrillator interventions in patients with hypertrophic cardiomyopathy

    Heart Rhythm

    (2009)
  • MS Maron et al.

    Effect of left ventricular outflow tract obstruction on clinical outcome in hypertrophic cardiomyopathy

    N Engl J Med

    (2003)
  • MS Maron et al.

    Hypertrophic cardiomyopathy is predominantly a disease of left ventricular outflow tract obstruction

    Circulation

    (2006)
  • BJ. Maron

    Clinical course and management of hypertrophic cardiomyopathy

    N Engl J Med

    (2018)
  • Cited by (10)

    View all citing articles on Scopus
    View full text