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[Electrocardiogram in heart failure]
H Tsunakawa1, N Miyamoto, M Kawabata
1Division of Cardiology, Showa University Fujigaoka Hospital.
Insights
Heart failure involves mechanical heart issues, not electrical ones, but ECGs can show changes like P wave alterations due to atrial enlargement. Analyzing RR intervals may also help characterize heart failure progression.
Area of Science:
- Cardiology
- Medical Diagnostics
Background:
- Heart failure is primarily a mechanical cardiac issue, not electrical.
- While not linked to specific ECG patterns, heart failure can cause related electrocardiogram (ECG) findings.
Observation:
- Left atrial enlargement correlates with characteristic P wave changes.
- Cardiac enlargement can lead to dynamic R wave height changes (initial increase, then decrease).
- Myocardial stretch may cause minor conduction disturbances affecting the QRS complex.
Findings:
- ECG criteria for atrial enlargement are critically reviewed.
- Tissue edema and electrode-heart distance influence R wave height changes.
- Reduced RR interval variability and high-frequency components are reported in heart failure.
Implications:
- ECG analysis, including P wave and QRS complex changes, can provide insights into heart failure status.
- RR interval variability analysis offers a complementary method for characterizing heart failure.
- Understanding these ECG manifestations aids in the diagnosis and monitoring of heart failure.
Abstract:
Heart failure is basically a manifestation of mechanical disturbances of the heart, but not of electrical abnormalities and is not associated with specific ECG patterns. Several ECG findings are, however, experienced in cases with heart failure as a result of cardiac chamber enlargement and other related changes. Left atrial enlargement is known to cause characteristic P wave changes, which sometimes show parallel course with the clinical state. ECG criteria for atrial enlargement are critically reviewed. In cases with cardiac enlargement, which was improved in a relatively short period of time, R wave height often showed first increase and then decrease. Tissue edema was thought to be the major reason for the initial increase and the distance between the recording electrode and the heart for the later decrease, although other factors can contribute and modify the findings. Minor conduction disturbances due to myocardial stretch and other reasons may also contribute to changes of QRS complex. Analysis of RR intervals offers another possibility to characterise heart failure. A decrease in variability of the RR intervals and in high frequency components on frequency spectrum has been reported in cases with heart failure.