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Biphasic changes in left ventricular end-diastolic pressure during dynamic exercise in patients with nonobstructive
Y Takeichi1, M Yokota, M Iwase
1Cardiovascular Division, Nagoya University, Graduate School of Medicine, Japan.
Insights
In hypertrophic cardiomyopathy (HCM) patients, left ventricular end-diastolic pressure (LVEDP) changes during exercise can be biphasic, potentially indicating improved coronary microcirculation. This biphasic response was linked to milder disease and reversed with propranolol.
Area of Science:
- Cardiology
- Exercise Physiology
- Cardiac Imaging
Background:
- Hypertrophic cardiomyopathy (HCM) is known for impaired resting diastolic function.
- Serial changes in left ventricular end-diastolic pressure (LVEDP) during dynamic exercise in HCM patients remain poorly characterized.
Purpose of the Study:
- To investigate the serial changes in LVEDP during dynamic exercise in patients diagnosed with HCM.
- To compare exercise-induced hemodynamic responses between different patient groups within HCM.
Main Methods:
- Simultaneous measurement of LV pressure and dimensions during supine bicycle exercise in 20 HCM patients and 5 healthy controls.
- Performance of exercise thallium-201 scintigraphy to assess myocardial perfusion.
- Categorization of HCM patients into two groups based on LVEDP response patterns during exercise.
Main Results:
- One group of HCM patients (n=11) showed a progressive LVEDP increase during exercise (12 to 28 mm Hg).
- A second group (n=9) exhibited biphasic LVEDP changes (14 to 27 then 16 mm Hg).
- Biphasic changes were associated with higher LV peak positive dP/dt, shorter pressure half-time, lower LV hypertrophy scores, less severe perfusion defects, and disappeared with propranolol.
Conclusions:
- Biphasic LVEDP changes during exercise in HCM may reflect improved coronary microcirculation due to beta-adrenergic stimulation.
- This response pattern appears in milder to moderate HCM and is influenced by medication like propranolol.
Objectives:
The aim of this study was to clarify the serial changes in left ventricular (LV) end-diastolic pressure (LVEDP) during dynamic exercise in patients with hypertrophic cardiomyopathy (HCM).
Background:
Although HCM is characterized by impaired resting LV diastolic function, serial changes in LVEDP during exercise have not been characterized.
Methods:
We simultaneously measured LV pressure and LV dimensions during symptom-limited supine bicycle exercise in 5 healthy individuals and 20 patients with HCM. Exercise thallium-201 scintigraphic studies were also performed.
Results:
The LVEDP (baseline: 12 +/- 5 mm Hg) progressively increased to a maximum value at peak exercise (28 +/- 8 mm Hg) in 11 patients with HCM (group I). In the remaining nine patients with HCM (group II), changes in LVEDP during exercise were biphasic, with an initial progressive increase and a subsequent gradual decline up to peak exercise (14 +/- 4 mm Hg at baseline, 27 +/- 5 mm Hg at the critical heart rate, 16 +/- 3 mm Hg at peak exercise). Exercise-induced changes in LV dimensions and LV peak systolic pressures were similar in both groups. However, the maximum first derivative of LV pressure was greater and the LV pressure half-time was shorter in group II than in group I at a similar peak exercise heart rate. The biphasic changes in LVEDP disappeared by pretreatment with propranolol. The LV hypertrophy scores were higher in group I than in group II. Exercise thallium-201 images showed more severe perfusion defects in group I than in group II patients.
Conclusions:
The biphasic changes in LVEDP seen during exercise may be related to improved coronary microcirculation in response to beta-adrenergic stimulation in patients with mild to moderate HCM.