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Objective evidence of occult myocardial dysfunction in patients with frequent ventricular ectopy without clinically
Insights
Frequent ventricular ectopic activity (VEA) in asymptomatic individuals may indicate subclinical myocardial dysfunction. These findings suggest subtle left ventricular abnormalities even without apparent heart disease.
Area of Science:
- Cardiology
- Electrophysiology
- Cardiovascular Imaging
Background:
- Frequent ventricular ectopic activity (VEA) is often detected incidentally.
- The association between VEA and subclinical cardiac dysfunction in asymptomatic individuals requires further investigation.
Purpose of the Study:
- To investigate left ventricular (LV) function in asymptomatic individuals with frequent VEA and normal coronary arteriograms.
- To identify potential subclinical myocardial dysfunction associated with frequent and complex VEA.
Main Methods:
- Inclusion of 18 asymptomatic individuals with frequent VEA (>100 b/hr) and normal coronary arteriograms.
- Assessment using 24-hour ambulatory ECG, cardiac catheterization, LV angiography, and hemodynamic measurements.
- Evaluation of LV volumes, end-diastolic pressure, ejection fraction, and myocardial contractility (mean velocity of circumferential fiber shortening).
Main Results:
- 13 individuals (72%) had complex VEA; 8 had undiagnosed hypertension.
- Elevated LV end-systolic volume index (56%), LV end-diastolic volume index (67%), and LV end-diastolic pressure (61%) were observed.
- Impaired myocardial contractility (decreased mean velocity of circumferential fiber shortening <1.0 circ/sec) was found in 56% of individuals.
- LV dysfunction was more prevalent with higher VEA frequencies (>300 b/hr).
Conclusions:
- Subclinical myocardial dysfunction is present in some individuals with frequent VEA, characterized by subtle LV volume and pressure abnormalities.
- Decreased mean velocity of myocardial circumferential fiber shortening indicates impaired contractility.
- The etiologic mechanisms for frequent and complex VEA in this cohort remain undefined.
Abstract:
Eighteen asymptomatic persons without apparent cardiac disease were incidentally discovered to have frequent ventricular ectopic activity (VEA) (more than a mean of 100 b/hr during 24-hour ambulatory ECG examination) and were found by cardiac catheterization to have normal coronary arteriograms. Thirteen persons (72%) also demonstrated complex (multiform or repetitive patterns) VEA and eight persons were found to have undiagnosed hypertension. Examination of left ventricular (LV) angiographic and hemodynamic data of these persons showed elevated LV end-systolic volume index in 10 persons (56%), elevated LV and end-diastolic volume index in 12 persons (67%) and elevated LV end-diastolic pressure in 11 persons (61%). Although ejection fractions of all but three persons were normal, impaired myocardial contractility, as measured by decreased mean velocity of circumferential fiber shortening (less than 1.0 circ/sec), was found in 10 persons (56%). Abnormalities of LV function were more prevalent in persons with higher mean frequencies of VEA (more than 300 b/hr), but did not seem related to the presence of complex VEA. Etiologic mechanisms of the frequent and complex VEA could not be defined. We conclude that subclinical evidence of myocardial dysfunction is present in some persons without apparent cardiac disease who have frequent VEA as evidence by subtle abnormalities of increased LV volumes and end-diastolic pressure and decreased mean velocity of myocardial circumferential fiber shortening.