GLS Monitoring of Chemotherapy-Induced Cardiotoxicity: Strain Decline Threshold
GLS Threshold Value for Cardiotoxicity
According to BSE/BCOS guidelines (Echocardiography for anthracyclines and/or trastuzumab, 2021), the key criterion for possible subclinical cardiotoxicity is relative decline in LV GLS >15% from baseline while LV ejection fraction remains preserved. A mandatory prerequisite for accurate assessment of temporal changes is the availability of baseline (pre-treatment) GLS measurement.
Classification of Cardiotoxicity by BSE/BCOS (2021)
| Category | Criterion |
|---|---|
| Cardiotoxicity | LV ejection fraction decline >10 absolute percentage points to a value <50% |
| Cardiotoxicity | LV ejection fraction decline >10 absolute percentage points to a value ≥50% with concomitant GLS decline >15% |
| Probable subclinical cardiotoxicity | LV ejection fraction decline <10 absolute percentage points to a value <50% |
| Possible subclinical cardiotoxicity | Relative change in LV GLS >15% from baseline |
Reference Values for LV GLS
According to major meta-analyses and ASE/EACVI guidelines, normal LV GLS is ≤ −20% (absolute value ≥20%). The reference range for healthy adults is −18% … −22%. The EACVI/ASE/Industry consensus (2015) recommended a threshold value of −18% as the lower limit of normal specifically due to inter-vendor variability.
- Normal: −20% ± 2%
- Gray zone: −18% … −20% (requires clinical context)
- Reduced function: > −18%
- Severe impairment: > −14%
Monitoring Schedule
BSE/BCOS (2021) recommends echocardiography every 3 months by default with a personalized approach to serial assessment. A complete minimal BSE examination with cardio-oncology measurements should be performed. Referral to a cardio-oncology service prior to initiation of therapy should be considered in patients with preceding LV systolic dysfunction.
Practical Considerations
GLS values are vendor-dependent: platforms (GE, Philips, Siemens, Canon) produce systematic bias of up to 2–3%, so serial monitoring is best conducted on the same machine. GLS is a more sensitive marker of LV systolic dysfunction than ejection fraction and is particularly relevant for monitoring cardio-oncology patients. All patients with confirmed cardiotoxicity should be referred to a cardio-oncology service.
Frequently asked questions
What GLS decline threshold is considered significant during chemotherapy?
According to BSE/BCOS (2021) — a relative decline in LV GLS >15% from baseline value. With preserved LV ejection fraction, this is classified as possible subclinical cardiotoxicity.
What should be done if GLS declines >15% with normal ejection fraction?
BSE/BCOS (2021) recommends considering referral to a cardio-oncology service for expert evaluation when GLS declines >15% despite normal LV ejection fraction.
How frequently should echocardiography be performed during anthracycline/trastuzumab therapy?
By default every 3 months with a personalized approach to serial assessment (BSE/BCOS, 2021), performing a complete minimal BSE examination with cardio-oncology measurements.
Can the ultrasound machine be changed during serial GLS monitoring?
This is not recommended. GLS values are vendor-dependent: different platforms (GE, Philips, Siemens, Canon) produce bias of up to 2–3%, so monitoring should be conducted on the same machine.
What is the normal LV GLS range?
≤ −20% (absolute value ≥20%); the reference range is −18% … −22%. The EACVI/ASE/Industry consensus (2015) established −18% as the lower limit of normal due to inter-vendor variability.