Drink more, and eat less: advice in obstructive hypertrophic cardiomyopathy

Unmasking Obstruction in Hypertrophic Cardiomyopathy With Postprandial Resting and Treadmill Stress Echocardiography

BACKGROUND

Latent left ventricular outflow tract obstruction (LVOTO) is an important cause of symptoms in patients with hypertrophic cardiomyopathy (HCM) but can be challenging to provoke.

OBJECTIVES AND METHODS

To examine the value of postprandial resting and stress echocardiography and utilization of invasive or enhanced drug therapies (surgical myectomy, alcohol septal ablation, disopyramide, and mavacamten) in patients with postprandial LVOTO. Consecutive HCM patients without LVOTO underwent routine and postprandial echocardiography at rest, with provocation (Valsalva and standing) and after symptom-limited treadmill stress.

RESULTS

Among 252 patients (mean age, 58 years, 39% women), postprandial LVOT gradients were higher compared with routine echocardiography at rest (median, 9.0 [0-38.0] vs 0 [0-14.0] mm Hg; P < .0001) and with provocation (18.5 [0-70.3] vs 1.5 [0-41.0] mm Hg; P < .0001). Postprandial exercise stress echocardiogram (PPXSE) gradients were higher in a subset of 44 patients who underwent both postprandial and fasting stress echocardiography (47.0 [5.3-81.0] vs 17.5 [0-46.0] mm Hg; P < .0001). In total, 49 (19.5%) patients achieved the ≥50 mm Hg threshold under routine conditions (rest/provocation); 90 (35.7%) additional patients achieved postprandial gradients ≥50 mm Hg (rest/provocation/exercise), 38 (15.1%) with PPXSE alone. A total of 71 patients were treated with 91 invasive or enhanced drug therapies, 32 (45.1%) of whom had gradients ≥50 mm Hg only after eating (rest/provocation) and 8 (11.3%) only with PPXSE, with symptom relief in the majority.

CONCLUSIONS

Postprandial echocardiography was useful at unmasking LVOTO in more than one-third of patients who did not have high gradients otherwise. Eating before echocardiography is a powerful provocative tool in the evaluation of patients with HCM.

Obstruction in Hypertrophic Cardiomyopathy: Many Faces

Hypertrophic cardiomyopathy (HCM), the most common inherited cardiomyopathy, exhibits left ventricular hypertrophy not secondary to other causes, with varied phenotypic expression. Enhanced actin-myosin interaction underlies excessive myocardial contraction, frequently resulting in dynamic obstruction within the left ventricle. Left ventricular outflow tract obstruction, occurring at rest or with provocation in 75% of HCM patients, portends adverse prognosis, contributes to symptoms, and is frequently a therapeutic target. Transthoracic echocardiography plays a crucial role in the screening, initial diagnosis, management, and risk stratification of HCM. Herein, we explore echocardiographic evaluation of HCM, emphasizing Doppler assessment for obstruction. Echocardiography informs management strategies through noninvasive hemodynamic assessment, which is frequently obtained with various provocative maneuvers. Recognition of obstructive HCM phenotypes and associated anatomical abnormalities guides therapeutic decision-making. Doppler echocardiography allows monitoring of therapeutic responses, whether it be medical therapies (including cardiac myosin inhibitor therapy) or septal reduction therapies, including surgical myectomy and alcohol septal ablation. This article discusses the hemodynamics of obstruction and practical application of Doppler assessment in HCM. In addition, it provides a visual atlas of obstruction in HCM, including high-quality figures and complementary videos that illustrate the many facets of dynamic obstruction.

2 Cases of Elusive Left Ventricular Outflow Tract Gradient

Patients with hypertrophic cardiomyopathy (HCM) typically have septal hypertrophy and left ventricular outflow tract gradient, usually present at rest with increase under certain hemodynamic conditions. We report 2 cases of HCM in which there was subtle septal hypertrophy; the gradient was detected only postprandially, highlighting the importance of considering postprandial imaging in patients with suspected HCM. (Level of Difficulty: Intermediate.).

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

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.

Lifestyle Modification and Medical Management of Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy is a heterogenous condition associated with a myriad of symptoms. Just as in other disease states, the aim of medical therapy is the alleviation of suffering, improvement of longevity, and the prevention of complications. This article focuses on the associated comorbidities seen in patients with hypertrophic cardiomyopathy, potential lifestyle interventions, and conventional medical treatments for symptomatic hypertrophic cardiomyopathy.

Blood type B antigen is associated with worse New York Heart Association classification in male patients with hypertrophic cardiomyopathy

OBJECTIVE

ABO blood type is associated with cardiovascular diseases. Several studies have suggested sex-related differences in both hypertrophic cardiomyopathy (HCM) clinical features and ABO blood type. However, few data are available regarding the relationship between ABO blood type and HCM clinical features. We aimed to analyze the relationship between ABO blood type and HCM clinical features, and the potential effects of sex on these relationship.

METHODS

A total of 549 patients with HCM were enrolled consecutively. Left ventricular outflow tract gradients at rest (LOVTG-R) were measured by echocardiography. Left ventricular end-diastolic dimension, interventricular septum, left ventricular ejection fraction (LVEF), left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), and left ventricular mass (LVM) were assessed using cardiovascular magnetic resonance imaging.

RESULTS

Compared with the non-B antigen group, patients with B antigen had significantly higher LOVTG-R and LVEF values, worse New York Heart Association (NYHA) classification, lower left ventricular volume index values, as well as no difference in LVM index values. After adjustments for sex, male patients with B antigen still had higher LOVTG-R values and frequency of NYHA classification III/IV as well as lower LVEDV and LVESV index values. These differences were not present in female patients. Additionally, patients with NYHA classification III/IV had lower LVEDV index values.

CONCLUSION

In males, not females, patients with HCM with blood type B antigens exhibited worse cardiac functional capacity, higher LOVTG-R values, and lower left ventricular volume index values. These relationships are a potential indicator for clinical prevention. We speculate that rehydration is more efficient in relieving symptoms in male patients with HCM with B antigens.