Description

Pathological decrease in the pulse wave amplitude and systolic blood pressure > 10 mm Hg during inspiration
Pathology 1: Cardiac Tamponade (Fixed Space)
- Concept: Ventricular Interdependence
- Fluid restricts outward heart expansion.
- Inspiration → ↑ RV filling → RV cannot expand outward, so interventricular septum bows leftward into LV.
- Severe ↓ LV preload → ↓ SV → SBP drops > 10 mmHg.
Pathology 2: Severe Asthma / COPD (Extreme Pressure)
- Extreme respiratory effort → massive (-) intrathoracic pressure.
  1. Excessive pulmonary blood pooling → severe ↓ LV preload.
  2. Negative pressure “pulls back” on LV wall → ↑ LV afterload (harder to pump blood into extrathoracic aorta).
- SV drops → SBP drops > 10 mmHg.

Causes