From the Guidelines
Pulsus parvus et tardus is distinguished from a normal carotid pulse by its slow-rising and diminished characteristics.
Key Characteristics
- Slow-rising: The pulse takes longer to reach its peak amplitude, indicating a delay in the transmission of pressure from the heart to the peripheral arteries.
- Diminished: The pulse has a lower amplitude than normal, indicating a reduction in the volume of blood being pumped with each heartbeat.
Clinical Significance
This type of pulse is often associated with severe aortic stenosis 1, a condition where the aortic valve becomes narrowed, obstructing blood flow from the heart to the rest of the body. The slow-rising and diminished characteristics of pulsus parvus et tardus are due to the increased resistance to blood flow caused by the narrowed valve.
Diagnostic Considerations
In patients with suspected aortic stenosis, a meticulous history and physical examination should be performed, including assessment of the carotid pulse, to establish the "pre-test probability" of a valve lesion 1. Further evaluation with echocardiography and cardiac catheterization may be necessary to confirm the diagnosis and assess the severity of the condition.
Important Notes
- The presence of pulsus parvus et tardus may be absent in elderly patients with severe aortic stenosis due to the effects of aging on the vasculature 1.
- Pulsus parvus may also occur with severely reduced cardiac output from any cause 1.
From the Research
Characteristics of Pulsus Parvus et Tardus
- Pulsus parvus et tardus is a clinical finding characterized by a small, weak pulse with a delayed systolic peak 2, 3, 4, 5.
- It is often associated with aortic stenosis (AS), a condition where the aortic valve becomes narrowed, obstructing blood flow from the heart 2, 3, 4, 5.
- The delayed systolic peak is due to the increased opposition to forward flow caused by the narrowed aortic valve, resulting in a protracted pressure rise 5.
Comparison to Normal Carotid Pulse
- A normal carotid pulse has a rapid upstroke and a sharp peak, whereas a pulsus parvus et tardus has a slow upstroke and a delayed peak 2, 4, 5.
- The pulse pressure, which is the difference between the systolic and diastolic blood pressures, is often lower in patients with pulsus parvus et tardus 4.
- The duration of the pulse wave, measured from the beginning of the upstroke to the peak, is longer in patients with pulsus parvus et tardus 2, 6.
Diagnostic Value
- Pulsus parvus et tardus is a diagnostic sign for severe aortic stenosis, with a high sensitivity and specificity 2, 3, 4.
- The use of Doppler flow characteristics, such as the effective acceleration time, can improve the accuracy of detecting pulsus parvus et tardus waveforms on spectral Doppler ultrasound 6.
- The consideration of Doppler flow characteristics can be useful in streamlining diagnostic and therapeutic measures, especially in the outpatient setting 3.