From the Guidelines
The presence of a negative T wave in leads V1 and V2 with a short PR interval in a patient with a third-degree atrioventricular block is most likely indicative of an underlying cardiac conduction abnormality, and management should focus on addressing the underlying condition to prevent morbidity and mortality. The ECG findings described are not typical of a third-degree atrioventricular block, which is characterized by a complete block of electrical conduction between the atria and ventricles, resulting in no association between P waves and QRS complexes 1. The presence of a short PR interval suggests that there may be an accessory electrical pathway, such as in Wolff-Parkinson-White syndrome, which can bypass the normal conduction delay at the AV node and result in pre-excitation of the ventricles. However, the provided evidence does not directly support this diagnosis in the context of a third-degree atrioventricular block. Key considerations in interpreting ECG findings include:
- The QRS duration and morphology, which can indicate the presence of a conduction abnormality such as a bundle branch block 1
- The presence and direction of T waves, which can indicate ischemia, infarction, or other cardiac conditions 1
- The PR interval, which can indicate the presence of an accessory electrical pathway or other conduction abnormality 1 Given the complexity of ECG interpretation and the potential for variability in individual patients, it is essential to consider the clinical context and correlate ECG findings with symptoms and other diagnostic tests to guide management and prevent adverse outcomes. In patients with a third-degree atrioventricular block, management may involve pacing or other interventions to maintain a stable heart rate and prevent complications such as syncope or heart failure.
From the Research
Significance of Negative T Wave in Leads V1 and V2
- A negative T wave in leads V1 and V2 can be associated with various cardiac conditions, including ischemic heart disease 2.
- In the context of a short PR interval, it may indicate the presence of an accessory electrical pathway, such as in Wolff-Parkinson-White syndrome 3.
- The presence of a negative T wave in leads with ST elevation can be associated with adverse prognosis in patients with acute myocardial infarction, particularly if presenting more than 2 hours after symptom onset 4.
- A giant negative T wave in the acute phase of Q wave myocardial infarction can predict R wave recovery and preservation of left ventricular function 5.
Clinical Implications
- In a patient with a DIII (Third Degree) atrioventricular block, the presence of a negative T wave in leads V1 and V2 with a short PR interval may require further evaluation to rule out underlying conditions such as Wolff-Parkinson-White syndrome or ischemic heart disease 3, 2.
- The clinical significance of a negative T wave in this context should be interpreted in conjunction with other electrocardiographic and clinical findings, as well as the results of additional diagnostic tests 4, 5, 2.