Valsalva SBP Drop and LVOT Obstruction

Research Background

Left ventricular outflow tract obstruction (LVOTO) is a common pathophysiological change in various cardiac diseases (e.g., hypertrophic obstructive cardiomyopathy, aortic stenosis, etc.). It impedes cardiac ejection and severely affects patient prognosis.Currently, the measurement of LVOTG ≥ 30 mmHg by echocardiography is the gold standard in clinical practice for evaluating the diagnostic value of SBP waveform typing for LVOTO. However, this method is complex to operate, relies on physician experience, and does not allow continuous dynamic monitoring, which limits its application in long-term follow-up and timely adjustment of treatment regimens.Although arterial systolic blood pressure (SBP), as a key hemodynamic indicator, may be associated with the severity of LVOTO (i.e., left ventricular outflow tract gradient, LVOTG), the specific relationship, dynamic change pattern, and clinical applicability between them remain unclear.

Research Objectives

This study aims to evaluate the effectiveness of non-invasive dynamic blood flow monitoring techniques in assessing left ventricular outflow tract obstruction in patients with hypertrophic cardiomyopathy. By prospectively collecting SBP waveform and LVOTG data from patients with obstructive and non-obstructive conditions, we will systematically analyze their correlation and explore their application value in different clinical scenarios.

Study Endpoints

Primary Endpoints

① Correlation coefficient between SBP waveform characteristics and measured LVOTG values;② Sensitivity and specificity of SBP waveforms in differentiating obstructive HCM with left ventricular outflow tract obstruction.

Secondary Endpoints

① Differences in SBP waveform parameters (e.g., waveform peak, waveform duration, etc.) between obstructive and non-obstructive groups;② Consistency between SBP waveform typing and results of traditional clinical imaging methods (e.g., echocardiography);③ Incidence of procedure-related adverse events.

Study Design

This is a prospective, single-center, observational, parallel-controlled study. SBP waveform and LVOTG data will be prospectively collected from obstructive and non-obstructive patients to systematically analyze their correlation.

Gold Standard

Transthoracic echocardiography (TTE) is used as the gold standard in this study.LVOTO is defined as a resting left ventricular outflow tract peak gradient (LVOTG) ≥ 30 mmHg, or an LVOTG ≥ 50 mmHg after provocation testing (e.g., Valsalva maneuver), according to the 2020 ASE guidelines.

Inclusion criteria

1: ① Age ≥ 18 years

2: ② Diagnosed with hypertrophic cardiomyopathy (HCM) by echocardiography, with or without left ventricular outflow tract obstruction

3: ③ Conscious and mentally competent, able to understand and voluntarily sign the informed consent form

4: ④ Able to cooperate with the completion of provocation tests, non-invasive dynamic hemodynamic monitoring, and relevant follow-up examinations.

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Exclusion criteria

• 1: ① Age ≤ 18 years, or pregnant/lactating patients

2: ② Presence of other organic heart or great vessel diseases that cause left ventricular outflow tract obstruction, such as severe aortic stenosis, congenital subaortic membrane, etc.

3: ③ Complicated with persistent atrial fibrillation or other severe arrhythmias that may affect the accuracy of hemodynamic monitoring

4: ④ Previous history of interventional or surgical therapy for left ventricular outflow tract obstruction, including septal ablation or myectomy

5: ⑤ Patients with other conditions considered inappropriate by the investigators (e.g., those with absolute or relative contraindications to provocation tests)

6: ⑥ Patients currently participating in other clinical studies.