GUEST WRITER: MICHAEL OWEN

For the past 2 weeks, we have discussed two algorithms used for determining the presence & grade of diastolic function. If you missed out or want to review them, you can find them here:

1. Correct Techniques to Acquire Diastology Measurements 
2. Mastering Diastology: Part 1
3. Mastering Diastology: Part 2

This week, we are going to discuss assessing diastolic function in patients with arrhythmia’s.

DIASTOLIC FUNCTION IN SPECIAL POPULATIONS

When patients fall into the following categories, the assessment of diastolic function changes, we are unable to use the algorithms provided in previous blog series:

• Arrhythmia (Atrial Fibrillation, Sinus Tachycardia, Bundle Branch Block)
• Cardiomyopathy (Hypertrophic, Restrictive)
• Valvular Regurgitation (Mitral, Aortic)
• Valvular Stenosis (Mitral)
• Heart Transplant

The guidelines break down each disease individually. Remember, the more of the following parameters you can combine, the stronger the case for left ventricular elevated filling pressures.

ATRIAL FIBRILLATION

There are elevated filling pressures if any of the following are true:

• Mitral E-wave acceleration rate > 1900 cm/s²
• IVRT < 65 msec
• Deceleration time of pulmonary venous diastolic wave < 220 msec
• Mitral E-wave to color VP ratio > 1.4
• Mitral E-wave to septal e’ ration (E/e’) > 11

Other supportive findings that suggest elevated filling pressures with atrial fibrillation patients include:

• Reduced tissue Doppler velocities
• L-wave > 20 cm/sec seen in mitral inflow or tissue Doppler spectrum
• Reduced beat-to-beat variations in velocity (suggestive of increased LA pressure)

SINUS TACHYCARDIA

There are elevated filling pressures if any of the following are true:

• Mitral inflow shows predominant early filling in patients with EF <50%
• IVRT < 70 msec
• Pulmonary venous systolic filling fraction < 40%
• Average E/e’ >14

If mitral E and A-wave are fused together, you may use a compensatory beat following a PVC to measure the E and A-wave velocities and assess diastolic function.

If average E/e’ is unobtainable or not used routinely in your lab, use “septal E/e’ >15” or “lateral E/e’ >13” to determine elevated filling pressures.

Pulmonary venous systolic filing fraction can be calculated as follows:

VTI of S-wave / (VTI of S-wave + VTI of D-Wave)

BUNDLE BRANCH BLOCK

As long as there is no fusion of the mitral E and A-waves, the variables used to grade diastolic function likely remain valid. You can make your way back up to the flow charts.