Left Ventricular Hypertrophy: The Relationship between the Electrocardiogram and Cardiovascular Magnetic Resonance Imaging

Abstract

Conventional assessment of left ventricular hypertrophy (LVH) using the electrocardiogram (ECG), for example, by the Sokolow-Lyon, Romhilt-Estes or Cornell criteria, have relied on assessing changes in the amplitude and/or duration of the QRS complex of the ECG to quantify LV mass. ECG measures of LV mass have typically been validated by imaging with echocardiography or cardiovascular magnetic resonance imaging (CMR). However, LVH can be the result of diverse etiologies, and LVH is also characterized by pathological changes in myocardial tissue characteristics on the genetic, molecular, cellular, and tissue level beyond a pure increase in the number of otherwise normal cardiomyocytes. For example, slowed conduction velocity through the myocardium, which can be due to diffuse myocardial fibrosis, has been shown to be an important determinant of conventional ECG LVH criteria regardless of LV mass. Myocardial tissue characterization by CMR has emerged to not only quantify LV mass, but also detect and quantify the extent and severity of focal or diffuse myocardial fibrosis, edema, inflammation, myocarditis, fatty replacement, myocardial disarray, and myocardial deposition of amyloid proteins (amyloidosis), glycolipids (Fabry disease), or iron (siderosis). This can be undertaken using CMR techniques including late gadolinium enhancement (LGE), T1 mapping, T2 mapping, T2* mapping, extracellular volume fraction (ECV) mapping, fat/water-weighted imaging, and diffusion tensor CMR. This review presents an overview of current and emerging concepts regarding the diagnostic possibilities of both ECG and CMR for LVH in an attempt to narrow gaps in our knowledge regarding the ECG diagnosis of LVH. Ann Noninvasive Electrocardiol 2014;19(6):524-533 noninvasive techniques; electrocardiography; cardiac MRIThe diagnosis of left ventricular hypertrophy (LVH) in clinical practice is a finding that requires the attention of the clinician. It has been documented that LVH detected by echocardiography or the electrocardiogram (ECG) is a risk factor for cardiac morbidity or mortality which is independent of other known risk factors including blood pressure and left ventricular mass. 1-3In hypertensive patients, the finding of LVH in a patient has a direct impact on therapy. LVH detected by both echocardiography and ECG define target organ damage, and according to the European Society of Cardiology guidelines 4 the Address for correspondence : Ljuba Bacharova, M.D., D.S.c., M.B.A., International Laser Center, Ilkovicova 3, 841 presence of target organ damage is a key factor in the management of the hypertensive patient. It has also been shown that antihypertensive therapy decreases signs of LVH by echocardiography or ECG that are associated with improvement of the clinical status and prognosis of a hypertensive patient, [5][6][7] and thus the benefit of antihypertensive therapy can be monitored. However, these straightforward statements lead to a number of unanswered questions.It has repeatedly been documented that the diagnostic perform...

Optimized electrocardiographic criteria for the detection of left ventricular hypertrophy in obesity patients

“…LVM was estimated by 2D echocardiography, despite reports demonstrating superior accuracy of cardiac magnetic resonance imaging, especially in obesity patients . However, echocardiography is known to have good reproducibility for the diagnosis of LVH and remains the most frequently used method in clinical practice .…”

Evaluation of Peguero-Lo Presti Criteria for Assessment of Left Ventricular Hypertrophy.

“…But, it is dependent on active and passive electrical properties of the heart and torsum. These in turn are modified by influencing factors such as distance of left ventricular cavity-electrode, the location of the surface electrode, individual antrophometric differences, conduction abnormalities, fibrosis of the myocardium, and lung pathology 18,19 In addition, it has been described that the ECG voltage may vary significantly from day to day, between patients, or even within the same patient. 13,20 All of these factors may attenuate the reproducibility of the test, leading to diagnostic errors.…”

“…Transthoracic echocardiography was used as a method of reference to estimate left ventricular mass. 7 All echocardiograms were recorded by a cardiologist. The LV was visualised with the patient lying in a modified left lateral decubitus position, with the ultrasound probe at the left parasternal window angled to visualise the heart in the long axis view.…”

A Clinical Application of the “Brody Effect”

“…ECG measures of LV mass have typically been validated by imaging such as echocardiography. 5 Decreases in R-wave amplitude were evaluated in myocardial ischemic infarction in previous reports. 6 For further investigation of the effects on the amplitudes, this study evaluates amplitude and the blood volume of the heart when myocardial mass is stable.…”