From the Guidelines
In patients presenting with symptoms suggestive of pulmonary embolism (PE), such as dyspnea, chest pain, and syncope, I recommend immediate evaluation and consideration for diagnostic testing, as the clinical presentation alone is not sufficient to confirm or exclude the diagnosis. The European Society of Cardiology guidelines 1 emphasize the importance of evaluating the likelihood of PE based on clinical presentation, which includes symptoms such as dyspnea, chest pain, and syncope. These symptoms are present in over 90% of patients with PE, with dyspnea, tachypnea, or chest pain being the most common presentations.
Some key points to consider in the evaluation of PE include:
- The presence of predisposing factors for venous thromboembolism (VTE), which can increase the likelihood of PE
- The use of clinical signs and symptoms, such as the S1Q3T3 pattern on electrocardiogram (ECG), to increase the index of suspicion for PE
- The importance of diagnostic testing, such as imaging studies, to confirm the diagnosis of PE
- The need for prompt treatment, including anticoagulation, to reduce the risk of morbidity and mortality associated with PE.
The S1Q3T3 pattern on ECG, mentioned in the question, is a specific finding that may be associated with PE, particularly in the context of right ventricular strain 1. However, this finding is not specific to PE and can be seen in other conditions as well. Therefore, it is essential to consider the clinical presentation as a whole and to use diagnostic testing to confirm the diagnosis.
In terms of diagnostic testing, the European Society of Cardiology guidelines 1 recommend the use of imaging studies, such as computed tomography pulmonary angiography (CTPA), to confirm the diagnosis of PE. The choice of diagnostic test will depend on the clinical presentation and the availability of testing modalities.
Overall, the evaluation and management of PE require a comprehensive approach that takes into account the clinical presentation, predisposing factors, and diagnostic testing results. Prompt recognition and treatment of PE are critical to reducing the risk of morbidity and mortality associated with this condition.
From the Research
Electrocardiographic Findings in Pulmonary Embolism
- The S1Q3T3 pattern is a well-known electrocardiographic (ECG) finding in patients with pulmonary embolism (PE) 2
- Other ECG changes associated with PE include right bundle-branch block, right-axis deviation, and T-wave inversion in medial precordial leads 2
- The mechanism responsible for these ECG changes may be associated with myocardial ischemia, acute right ventricular overload, or vagal reflex 2
Prognostic Value of Electrocardiography Score for Pulmonary Embolism
- A 21-point electrocardiogram scoring system can help emergency physicians stratify the risk of a patient with an acute presentation of pulmonary embolism 3
- The electrocardiogram score has been shown to have strong usefulness in assessing prognosis of patients presenting with acute pulmonary embolism 3
- The S1Q3T3 pattern can be spontaneous and resolving in some cases of pulmonary embolism 3
Anticoagulation Management in Patients with Pulmonary Embolism
- The majority of patients with acute PE spend most of their first 48 hours outside of the therapeutic range of anticoagulation when treated with guideline standard dosing of unfractionated heparin 4, 5
- Most patients are able to achieve at least one therapeutic level within the first 48 hours, but fewer are able to maintain therapeutic levels 5
- The optimal strategy for transitioning patients from full-intensity to reduced-intensity heparin during ultrasound-assisted catheter-directed thrombolysis has yet to be established 6