Prevalence of postural T wave changes in mitral valve prolapse: a quantitative study

Area of Science:

• Cardiology
• Electrophysiology
• Echocardiography

Background:

• Mitral valve prolapse (MVP) is a common valvular heart condition.
• Electrocardiogram (ECG) abnormalities, particularly T wave changes, can occur in MVP.
• The clinical significance of these ECG changes in asymptomatic MVP requires further investigation.

Purpose of the Study:

• To investigate and quantify abnormal ECG T wave changes in asymptomatic individuals with MVP.
• To compare these T wave changes with those in a healthy control group.
• To explore the relationship between echocardiographic findings and T wave axis deviation in MVP.

Main Methods:

• A case-control study involving 36 asymptomatic individuals with MVP and 27 healthy controls.
• Standard 12-lead ECGs were recorded, with particular attention to T wave axis and QRS-T angle.
• Echocardiography was used to assess mitral valve morphology, including bowing or rounding.

Main Results:

• A significant leftward shift in the mean frontal plane T wave axis was observed upon standing in the MVP group (T wave axis ≤ 0° in 44% vs. 7.4% in controls).
• The QRS-T angle widened to > 60° in 50% of MVP subjects, a significantly higher proportion than in controls.
• Marked left axis deviation (T wave axis ≤ -30°) and prolonged QTc interval were exclusively found in the MVP group (P < 0.05).

Conclusions:

• Asymptomatic mitral valve prolapse is associated with distinct and quantifiable ECG T wave abnormalities, particularly leftward axis deviation and widened QRS-T angles upon standing.
• These findings suggest that T wave changes on ECG may serve as a marker for MVP, even in the absence of symptoms.
• Intermediate T wave axis shifts were observed in MVP patients with specific echocardiographic features like mitral valve bowing, indicating a potential link between valve morphology and electrical changes.