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Repolarization abnormalities of left ventricular hypertrophy. Clinical, echocardiographic and hemodynamic correlates
Insights
Repolarization abnormalities on ECG are a strong indicator of left ventricular hypertrophy (LVH) in patients not taking digitalis. These ECG changes correlate with increased left ventricular mass and impaired heart function, aiding LVH diagnosis.
Area of Science:
- Cardiology
- Medical Diagnostics
- Electrocardiography
Background:
- Left ventricular hypertrophy (LVH) is a significant cardiovascular condition.
- Electrocardiogram (ECG) findings, particularly repolarization abnormalities, are used to detect LVH.
- The influence of digitalis and other hemodynamic factors on ECG findings in LVH requires clarification.
Purpose of the Study:
- To assess the clinical significance of ECG depolarization abnormalities in diagnosing left ventricular hypertrophy (LVH).
- To correlate ECG findings with echocardiographic/autopsy measurements of left ventricular mass, geometry, and function.
- To evaluate the impact of digitalis use on ECG abnormalities suggestive of LVH.
Main Methods:
- A heterogeneous population of 161 patients was studied.
- ECG findings were analyzed and compared with echocardiographic or autopsy data.
- Patients were stratified based on digitalis use and left ventricular (LV) mass.
Main Results:
- ST depression and T wave inversion (LV "strain") were more prevalent in patients taking digitalis (61%) compared to those not taking it (19%).
- In the absence of digitalis, repolarization abnormalities showed a linear increase with LV mass (p < 0.001) and correlated with reduced ejection fraction, increased LV diameter, and elevated systolic blood pressure.
- LV "strain" alone demonstrated high specificity (95%) and moderate sensitivity (52%) for recognizing LVH.
Conclusions:
- Repolarization abnormalities are a valuable ECG marker for LVH in patients not on digitalis.
- Digitalis significantly increases the occurrence of ECG "strain" patterns, irrespective of LV mass.
- ECG "strain" is a reliable indicator of LVH, even with potential confounding factors.
Abstract:
To evaluate the clinical significance of ECG depolarization abnormalities of left ventricular hypertrophy, ECG findings were related to echocardiographic or autopsy left ventricular mass, geometry and function as well as hemodynamic overload, in a heterogeneous population of 161 patients. ST depression and asymmetric T wave inversion were present in 21/107 patients not receiving digitalis (19%) and in 33/54 (61%) receiving digitalis. In patients not receiving digitalis their prevalence increased linearly from 0% (0/31) with LV mass less than or equal to 100 grams to 100% (8/8) with LV mass over 400 grams (p less than 0.001). Patients taking digitalis manifested "strain" commonly despite a normal LV mass (4/14, 28%), but even more frequently with an LV mass over 200 grams (27/40, 68%) (p less than 0.05). In the absence of digitalis, repolarization abnormalities were also significantly associated with a reduced ejection fraction (8/17 or 47% versus 8/83 or 10%; p less than 0.001), increased LV internal diameter (9/18 or 50% versus 12/89 or 13%; p less than 0.01), and systolic blood pressure over 140 mm Hg (9/29 or 31% versus 7/61 or 11%; p less than 0.05). Increased thickness of the LV wall was not significantly associated with LV "strain" (p = 0.1). In this population, LV "strain" alone performed as well as other single or combined ECG criteria in the recognition of LVH (sensitivity 52%, specificity 95%). Thus, in the absence of digitalis, repolarization abnormalities are a highly useful ECG sign of LVH, despite numerous other factors capable of causing indistinguishable abnormalities.