From the Guidelines
Troponin levels after sustained ventricular tachycardia (VT) are expected to be below 0.04 ng/mL or 40 ng/L, but can rise due to myocardial strain, with elevations commonly seen within 4-6 hours after the event. When interpreting troponin levels in this context, it's crucial to consider the clinical scenario, including the duration of VT, hemodynamic stability, and the presence of underlying heart disease. The pattern of troponin elevation can provide valuable insights: a modest rise with subsequent fall may indicate demand ischemia from the tachycardia itself, whereas persistently rising levels or significant elevations (>100 ng/L) could suggest underlying coronary artery disease or myocardial damage, necessitating further evaluation 1. Key points to consider include:
- The timing of troponin measurements, with serial assessments recommended at baseline, 3-6 hours, and 12-24 hours post-event to track the pattern of elevation.
- The degree of elevation, which typically correlates with the duration and severity of the VT episode.
- The importance of interpreting troponin results in the context of the VT episode, including the presence of underlying heart disease and hemodynamic stability. It's also important to note that, according to the universal definition of myocardial infarction 1, any increase in cardiac biomarkers, including troponin, after a cardiac event indicates myocyte necrosis and is associated with an impaired outcome.
From the Research
Normal Troponin Range After Sustained Ventricular Tachycardia (VT)
There are no direct studies that provide a normal troponin range after sustained ventricular tachycardia (VT). However, some studies provide information on troponin levels in relation to cardiac conditions:
- A study published in 2011 2 found that the degree of troponin elevation was predictive of early mortality and longer-term mortality in patients with non-ST-segment elevation acute coronary syndromes (NSTE ACS).
- Another study from 2016 3 found that high-sensitivity cardiac troponin T (hs-cTnT) levels were elevated in 44.2% of patients with supraventricular tachyarrhythmias, but the association with cardiovascular events was low.
- A case report from 2014 4 presented two cases of patients with elevated troponin I levels after an acute episode of paroxysmal supraventricular tachycardia with normal coronary arteries via angiography.
- A study from 2021 5 found that troponin concentrations were similar at presentation in type 1 and type 2 myocardial infarction and in acute and chronic myocardial injury.
Key Findings
- The degree of troponin elevation is an independent predictor of morbidity and mortality 2.
- Elevated troponin levels can occur in patients with supraventricular tachyarrhythmias, but the association with cardiovascular events is low 3.
- Abnormal troponin elevations can be seen in patients presenting with paroxysmal supraventricular tachycardia and angiographically-normal coronary arteries 4.
- Troponin concentrations at presentation are insufficient to distinguish type 1 myocardial infarction from other causes of myocardial injury or infarction in practice 5.