What is the recommended echocardiographic approach to assess diastolic function in patients with arrhythmias (irregular heart rhythms)?

Echocardiographic Assessment of Diastolic Function in Patients with Arrhythmias According to BSE 2024 Guidelines

The BSE 2024 guidelines recommend a modified approach to diastolic function assessment in patients with arrhythmias, focusing on parameters that are less dependent on heart rate and rhythm regularity, with emphasis on tissue Doppler imaging, left atrial volume, and tricuspid regurgitation velocity.

Challenges in Arrhythmia Patients

• Conventional diastolic assessment relies heavily on mitral inflow patterns (E/A ratio), which are significantly affected by irregular heart rhythms 1
• Arrhythmias, particularly atrial fibrillation, render traditional parameters less reliable due to:
  • Variable cycle lengths affecting ventricular filling
  • Loss of organized atrial contraction
  • Beat-to-beat variability in preload conditions

Recommended Parameters for Arrhythmia Patients

Primary Parameters (Less Affected by Arrhythmias)

1. Tissue Doppler Imaging (TDI)

   • Measure e' velocity at septal and lateral mitral annulus
   • Average multiple consecutive beats (minimum 5 beats) for more reliable assessment
   • Abnormal cutoff values remain: septal e' < 7 cm/sec, lateral e' < 10 cm/sec 1

2. E/e' Ratio

   • Average E velocity from 5-10 consecutive cardiac cycles
   • E/e' > 14 strongly suggests elevated left atrial pressure even in arrhythmia patients
   • More reliable than E/A ratio in irregular rhythms 1, 2

3. Left Atrial Volume Index (LAVI)

   • Measure at end-systole from dedicated views maximizing LA dimensions
   • LAVI > 34 mL/m² indicates chronic elevation of filling pressures
   • Remains valid in arrhythmias as a marker of chronic diastolic dysfunction 1

4. Tricuspid Regurgitation Velocity

   • Peak TR velocity > 2.8 m/sec (in absence of pulmonary disease) suggests elevated filling pressures
   • Measure from multiple views to obtain highest velocity
   • Average measurements from multiple beats 1

Supplementary Parameters

1. Pulmonary Vein Flow

   • Assess systolic (S) and diastolic (D) velocities
   • Reduced S/D ratio < 1 suggests elevated filling pressures
   • Increased pulmonary vein Ar velocity duration compared to mitral A duration suggests elevated LVEDP 1

2. Isovolumic Relaxation Time (IVRT)

   • Shortened IVRT suggests elevated filling pressures
   • Measure from multiple beats and average the values 2

3. Mitral Deceleration Time

   • Short DT (< 150 ms) suggests restrictive filling pattern
   • Average from multiple beats for more reliable assessment 2

Practical Approach to Diastolic Assessment in Arrhythmias

1. For Atrial Fibrillation:

   • Disregard E/A ratio assessment (A wave absent or variable)
   • Focus on:
     • Average e' velocity from multiple beats
     • Average E/e' ratio from 5-10 consecutive beats
     • LAVI measurement
     • TR velocity assessment 3, 2

2. For Other Arrhythmias with Variable R-R Intervals:

   • Select beats with similar preceding R-R intervals when possible
   • Average measurements from at least 5 cardiac cycles
   • Rely more heavily on load-independent parameters (e', LAVI) 1

3. For Tachyarrhythmias:

   • Be aware of potential E and A wave fusion
   • Focus on e' velocity and LAVI which are less affected by heart rate
   • Consider using color M-mode propagation velocity (Vp) as an additional parameter 1

Grading Diastolic Dysfunction in Arrhythmia Patients

• Normal Diastolic Function: e' velocities normal, E/e' < 8, normal LAVI, normal TR velocity
• Grade 1 (Mild): Reduced e' velocities, E/e' < 8, possible LA enlargement
• Grade 2 (Moderate): Reduced e' velocities, E/e' 8-14, LA enlargement, elevated TR velocity
• Grade 3 (Severe): Reduced e' velocities, E/e' > 14, LA enlargement, elevated TR velocity 1

Special Considerations

• In patients with atrial fibrillation, at least 5-10 consecutive cardiac cycles should be averaged for all Doppler measurements 3
• For patients with atrial flutter or other regular supraventricular tachycardias, select beats with similar preceding cycle lengths 2
• In patients with paced rhythms, the assessment algorithm should be modified similar to that for patients with bundle branch blocks 1
• Consider global longitudinal strain (GLS) assessment as a complementary tool to identify subclinical LV dysfunction in arrhythmia patients 1

Common Pitfalls to Avoid

• Relying on single-beat measurements in irregular rhythms
• Overinterpreting E/A ratio in tachycardias where E and A waves may be fused
• Failing to average multiple beats for Doppler measurements
• Not accounting for the effects of tachycardia on IVRT and deceleration time
• Overlooking the importance of left atrial volume as a marker of chronic diastolic dysfunction

By following this modified approach that emphasizes parameters less affected by heart rhythm irregularities, clinicians can more accurately assess diastolic function in patients with arrhythmias, leading to better clinical decision-making and patient outcomes.