From the Guidelines
The S1Q3T3 pattern on an electrocardiogram (ECG) is a classic finding suggestive of acute pulmonary embolism, characterized by a deep S wave in lead I, a Q wave in lead III, and an inverted T wave in lead III, and should prompt further diagnostic evaluation with more definitive tests such as CT pulmonary angiography, especially when combined with clinical symptoms like sudden dyspnea, chest pain, or risk factors for thromboembolism.
Definition and Clinical Significance
The S1Q3T3 pattern is a specific electrocardiographic finding that occurs due to right ventricular strain and acute cor pulmonale resulting from sudden obstruction of pulmonary blood flow, as noted in studies such as 1. This pattern is associated with more severe forms of pulmonary embolism and may be found in right ventricular strain of any cause.
Diagnostic Considerations
While the S1Q3T3 pattern is suggestive of pulmonary embolism, it is neither highly sensitive nor specific for the condition, being present in only about 20% of confirmed cases, as discussed in 1 and 1. Other ECG findings that may accompany pulmonary embolism include sinus tachycardia, right bundle branch block, and right axis deviation.
Clinical Approach
Given the limitations of the S1Q3T3 pattern in diagnosing pulmonary embolism, a comprehensive clinical approach is necessary. This includes evaluating clinical symptoms such as sudden dyspnea, chest pain, and risk factors for thromboembolism, as well as utilizing more definitive diagnostic tests like CT pulmonary angiography, as recommended in 1 and 1.
Key Points
- The S1Q3T3 pattern is a classic ECG finding in acute pulmonary embolism.
- It is associated with right ventricular strain and acute cor pulmonale.
- The pattern is neither highly sensitive nor specific for pulmonary embolism.
- Further diagnostic evaluation with CT pulmonary angiography is recommended when the S1Q3T3 pattern is present, especially with clinical symptoms or risk factors for thromboembolism, as supported by studies such as 1.
From the Research
S1Q3T3 Pattern on an Electrocardiogram (ECG)
The S1Q3T3 pattern on an electrocardiogram (ECG) is a specific abnormality that has been associated with pulmonary embolism (PE) 2. This pattern is characterized by an S wave in lead I, a Q wave in lead III, and an inverted T wave in lead III.
Clinical Significance
The S1Q3T3 pattern is considered a significant finding in patients with suspected PE, as it may indicate the presence of a pulmonary embolus 2. However, it is essential to note that this pattern can also be seen in other conditions, such as pneumothorax 3.
Diagnosis and Management
The diagnosis of PE is typically made using a combination of clinical evaluation, laboratory tests, and imaging studies, such as computed tomographic pulmonary angiography (CTPA) 4. The management of PE depends on the severity of the condition and may include anticoagulation, thrombolytic therapy, or surgical embolectomy 4, 5.
Key Points
- The S1Q3T3 pattern on an ECG is associated with pulmonary embolism (PE) 2.
- This pattern can also be seen in other conditions, such as pneumothorax 3.
- The diagnosis of PE is typically made using a combination of clinical evaluation, laboratory tests, and imaging studies 4.
- The management of PE depends on the severity of the condition and may include anticoagulation, thrombolytic therapy, or surgical embolectomy 4, 5.