Evaluation Of Left Ventricular Hypertrophy Research Articles

Editor’s choice to the april 2023 issue

Editor’s choice to the april 2023 issue

Role of cardiovascular magnetic resonance in the clinical evaluation of left ventricular hypertrophy: a 360° panorama.

Left ventricular hypertrophy (LVH) is a frequent imaging finding in the general population. In order to identify the precise etiology, a comprehensive diagnostic approach should be adopted, including the prevalence of each entity that may cause LVH, family history, clinical, electrocardiographic and imaging findings. By providing a detailed evaluation of the myocardium, cardiovascular magnetic resonance (CMR) has assumed a central role in the differential diagnosis of left ventricular hypertrophy, with the technique of parametric imaging allowing more refined tissue characterization. This article aims to establish a parallel between pathophysiological features and imaging findings through the broad spectrum of LVH entities, emphasizing the role of CMR in the differential diagnosis.

Improved evaluation of left ventricular hypertrophy using the spatial QRS-T angle by electrocardiography

Electrocardiographic (ECG) signs of left ventricular hypertrophy (LVH) lack sensitivity. The aim was to identify LVH based on an abnormal spatial peaks QRS-T angle, evaluate its diagnostic performance compared to conventional ECG criteria for LVH, and its prognostic performance. This was an observational study with four cohorts with a QRS duration < 120 ms. Based on healthy volunteers (n = 921), an abnormal spatial peaks QRS-T angle was defined as ≥ 40° for females and ≥ 55° for males. In other healthy volunteers (n = 461), the specificity of the QRS-T angle to detect LVH was 96% (females) and 98% (males). In patients with at least moderate LVH by cardiac imaging (n = 225), the QRS-T angle had a higher sensitivity than conventional ECG criteria (93–97% vs 13–56%, p < 0.001 for all). In clinical consecutive patients (n = 783), of those who did not have any LVH, 238/556 (43%) had an abnormal QRS-T angle. There was an association with hospitalization for heart failure or all-cause death in univariable and multivariable analysis. An abnormal QRS-T angle rarely occurred in healthy volunteers, was a mainstay of moderate or greater LVH, was common in clinical patients without LVH but with cardiac co-morbidities, and associated with outcomes.

Differentiation of hypertensive heart disease and hypertrophic cardiomyopathy with myocardial stiffness measurements: a shear wave imaging study using ultra-high frame rate echocardiography

Abstract Background Recently, cardiac shear wave (SW) elastography, based on high frame rate (HFR) echocardiography, has been proposed as new non-invasive technique for assessing myocardial stiffness. As myocardial stiffness increases with increasing wall stress, differences in measured operating myocardial stiffness do not necessarily reflect differences in intrinsic myocardial properties, but can also be caused by mere changes in loading or chamber geometry. This complicates myocardial stiffness interpretation for different types of pathologic hypertrophy. Purpose To explore the relationship between myocardial stiffness and underlying pathological substrates for cardiac hypertrophy. Methods We included 20 patients with hypertension (HT) and myocardial remodelling (59±14 years, 75% male), 20 patients with hypertrophic cardiomyopathy (HCM) (59±16 years, 60% male) and 20 healthy controls (56±14 years, 75% male). Left ventricular (LV) parasternal long axis views were acquired with an experimental HFR scanner at 1293±362 frames per seconds. Propagation velocity of SW occurring after mitral valve closure in the interventricular septum (IVS) served as measure of operating myocardial stiffness (Figure A). To compare myocardial stiffness among hearts with differing loading conditions and chamber geometry, SW velocities were normalized to end-diastolic wall stress, estimated at IVS from regional wall thickness, longitudinal and circumferential regional radii of curvature, and non-invasively estimated LV end-diastolic pressure (EDP). Results SW velocities differed significantly between groups (p&amp;lt;0.001). The controls had the lowest SW velocities (4.02±0.97 m/s), whereas values between HT and HCM group were comparable (6.46±0.99 m/s vs. 7.00±2.10 m/s; p=0.738). Considering end-diastolic wall stress, HCM patients had the same SW velocity at lower wall stress compared to HT (Figure B), indicating higher myocardial stiffness in the HCM group. SW velocities normalized for wall stress indicated significantly different myocardial stiffness among all groups (p&amp;lt;0.001) (Figure C). In a multiple linear regression model, the underlying pathological substrate independently influenced SW velocity (beta 1.37, 95% CI (0.78–1.96); p&amp;lt;0.001), while wall stress did not significantly affect its value (p=0.479). Conclusions Our study demonstrated that SW elastography can detect differences in myocardial stiffness in hypertensive heart and hypertrophic cardiomyopathy. Additionally, our results suggest that SW velocity is dominated by underlying myocardial tissue properties. We hypothesize that differential changes in cardiomyocytes and/or the extracellular matrix contribute to the differential myocardial stiffening in different pathologic entities of LV hypertrophy. Thus, SW elastography could provide useful novel diagnostic information in the evaluation of LV hypertrophy. Figure A, B, C Funding Acknowledgement Type of funding source: None

Relationship of carotid arterial functional and structural changes to left atrial volume in untreated hypertension

The contribution of arterial functional and structural changes to left ventricular (LV) diastolic dysfunction has been the area of recent research. There are some studies on the relationship between arterial stiffness (a.s.) and left atrial (LA) remodelling as a marker of diastolic burden. Little is known about the association of arterial structural changes and LA remodelling in hypertension (H).Aim The aim of this study was to examine the relationship between carotid a.s. and intima-media thickness (IMT) and LA volume in subjects with H. The study included 245 previously untreated hypertensives (166 women and 79 men, mean age 53.7 ± 11.8 years). Each patient was subjected to echocardiography with measurement of LA volume, evaluation of left ventricular hypertrophy (LVH) and LV systolic/diastolic function indices, integrated assessment of carotid IMT and echo-tracking of a.s. and wave reflection parameters.Results Univariate regression analysis revealed significant correlations between indexed LA volume and selected clinical characteristics, echocardiographic indices of LVH and LV diastolic/systolic function and a.s./wave reflection parameters. The following parameters were identified as independent determinants of indexed LA volume on multivariate regression analysis: diastolic blood pressure (beta = -0.229, P< 0.001), left ventricular mass index (LVMI; beta = 0.258, P< 0.001), E/e’ index (ratio of early mitral flow wave velocity – E to early diastolic mitral annular velocity – e’; beta = 0.266, P= 0.001), augmentation index (AI; beta = 0.143, P= 0.008) and body mass index (BMI; beta = 0.132, P= 0.017). No correlations between indexed LA volume and IMT were found.Conclusion There is a significant relationship between carotid arterial stiffness but not intima-media thickness and LA volume in patients with untreated hypertension.

Design and rationale of the ATHENA study--A 12-month, multicentre, prospective study evaluating the outcomes of a de novo everolimus-based regimen in combination with reduced cyclosporine or tacrolimus versus a standard regimen in kidney transplant patients: study protocol for a randomised controlled trial.

BackgroundImmunosuppression with calcineurin inhibitors remains the mainstay of treatment after kidney transplantation; however, long-term use of these drugs may be associated with nephrotoxicity. In this regard, the current approach is to optimise available immunosuppressive regimens to reduce the calcineurin inhibitor dose while protecting renal function without affecting the efficacy. The ATHENA study is designed to evaluate renal function in two regimens: an everolimus and reduced calcineurin inhibitor-based regimen versus a standard treatment protocol with mycophenolic acid and tacrolimus in de novo kidney transplant recipients.Method/DesignATHENA is a 12-month, multicentre, open-label, prospective, randomised, parallel-group study in de novo kidney transplant recipients (aged 18 years or older) receiving renal allografts from deceased or living donors. Eligible patients are randomised (1:1:1) prior to transplantation to one of the following three treatment arms: everolimus (starting dose 1.5 mg/day; C0 3–8 ng/mL) with cyclosporine or everolimus (starting dose 3 mg/day; C0 3–8 ng/mL) with tacrolimus or mycophenolic acid (enteric-coated mycophenolate sodium at 1.44 g/day or mycophenolate mofetil at 2 g/day) with tacrolimus; in combination with corticosteroids. All patients receive induction therapy with basiliximab. The primary objective is to demonstrate non-inferiority of renal function (eGFR by the Nankivell formula) in one of the everolimus arms compared with the standard group at month 12 post transplantation. The key secondary objective is to assess the incidence of treatment failure, defined as biopsy-proven acute rejection, graft loss, or death, among the treatment groups. Other objectives include assessment of the individual components of treatment failure, incidence and severity of viral infections, incidence and duration of delayed graft function, incidence of indication biopsies, slow graft function and wound healing complications, and overall safety and tolerability. Exploratory objectives include evaluation of left ventricular hypertrophy assessed by the left ventricular mass index, evolution of human leukocyte antigen and non-human leukocyte antigen antibodies, and a cytomegalovirus substudy.DiscussionAs one of the largest European multicentre kidney transplant studies, ATHENA will determine whether a de novo everolimus-based regimen can preserve renal function versus the standard of care. This study further assesses a number of clinical issues which impact long-term outcomes post transplantation; hence, its results will have a major clinical impact.Trial registrationClinicaltrials.gov: NCT01843348, date of registration – 18 April 2013; EUDRACT number: 2011-005238-21, date of registration – 20 March 2012Electronic supplementary materialThe online version of this article (doi:10.1186/s13063-016-1220-9) contains supplementary material, which is available to authorized users.

Spirito–Maron Echocardiographic Score: A Marker for Morphological and Physiological Assessment of Patients with Hypertrophic Cardiomyopathy

The heterogeneous distribution of hypertrophy in hypertrophic cardiomyopathy (HCM) limits the echocardiographic conventional measurements accuracy in the evaluation of left ventricular hypertrophy (LVH). The aim of this study was to assess the correlation of the echocardiographic Spirito-Maron score (SMS) with left ventricle (LV) mass quantification by cardiac magnetic resonance (CMR) and with LV diastolic function. Left ventricle diastolic function parameters, SMS, LV mass (American Society of Echocardiography formula), and maximal wall thickness (MWT) were evaluated by two-dimensional (2D) transthoracic echocardiography. The SMS was obtained by adding the MWT of 4 LV segments, at the mitral valve or papillary muscles short-axis views. Echocardiographic parameters of LVH, including SMS, were correlated with LV mass obtained by CMR and with E/e' ratio. We included 45 patients (60% male, mean age 48 ± 18 years), who underwent 2D echocardiography. Twenty-two of them performed a CMR study. A positive correlation was found between SMS and CMR LV mass (r = 0.80; P < 0.001), whereas MWT (r = 0.62; P = 0.002) and the 2D LV mass (r = 0.60; P = 0.011) presented a lower correlation with CMR LV mass. The SMS was significantly correlated with E/e' ratio (r = 0.60; P = 0.007), whereas a nonsignificant correlation was found with MWT (r = 0.41; P = 0.081) and 2D LV mass (r = 0.22; P = 0.400). Spirito-Maron score presents a highly positive correlation with CMR LV mass and with diastolic dysfunction severity in HCM patients. SMS is a reliable quantitative LVH measurement method and seems to provide more comprehensive morphological and physiological information than 2D echocardiographic conventional parameters used to estimate LVH.

Role of cardiovascular ultrasound in patients with chronic renal disease

Cardiovascular events are very common in patients with chronic kidney disease (CKD). Echocardiography and vascular ultrasound provide important information on ventricular remodeling, systolic and diastolic function and presence of valvular and arterial disease. Thus, in CKD patients cardiovascular echography is a very useful tool for initial evaluation, prognosis and follow-up. The present review analyzes the role of cardiovascular ultrasound in CKD patients, assessing in particular the evaluation of left ventricular hypertrophy, systolic and diastolic dysfunction, left atrial remodeling, coronary heart disease, cardiac resynchronization therapy, valvular calcifications, pericardial disease, vascular calcifications and arterial stiffness. Le patologie cardiovascolari sono molto comuni nei pazienti con insufficienza renale cronica. L’ecografia cardiovascolare fornisce importanti informazioni sul rimodellamento ventricolare sinistro, sulla disfunzione sistolica e diastolica, sulla presenza di valvulopatie e patologia vascolare. Pertanto, nei pazienti con insufficienza renale cronica l’ecografia è uno strumento molto utile per la valutazione iniziale, la prognosi e il follow-up. Questa review analizza il ruolo dell’ecografia cardiovascolare nei pazienti con insufficienza renale cronica, valutando in particolare l’ipertrofia ventricolare sinistra, la funzione sistolica e diastolica, il rimodellamento atriale sinistro, la presenza di un’eventuale coronaropatia, la terapia di risincronizzazione, le calcificazioni valvolari, le malattie del pericardio, le calcificazioni vascolari e la rigidità arteriosa.

Cardiovascular Magnetic Resonance Validation of Echocardiographic Evaluation of Left Ventricular Hypertrophy

Cardiovascular Magnetic Resonance Validation of Echocardiographic Evaluation of Left Ventricular Hypertrophy

Evaluation of left ventricular hypertrophy in hypertensive patients with echocardiographic myocardial videodensitometry normalized by displacement

Left ventricular hypertrophy (LVH) is an important predictor of cardiovascular morbidity and mortality. To investigate the feasibility of the myocardial grayscale intensity (GI) normalized by displacement (d) to discriminate between healthy and hypertrophic myocardium in hypertensive patients, sixty hypertensive patients and sixty age and sex-matched healthy volunteers were involved in this study. The peak d and the maximal GI [GI(max)] and minimal GI [GI(min)] for the middle interventricular septal (IVS) and the middle posterior wall (PW) at the level of papillary muscle were obtained from the standard parasternal long axis views using tissue tracking (TT) and videodensitometric analysis, respectively. The GI and the cyclic variation of GI (CVGI) normalized by d were calculated. The results showed that the d both for IVS and PW, the amplitude of CVGI for IVS in hypertensive patients with LVH were smaller than the ones without LVH and the normal subjects. But, the CVGI/d both for IVS and PW in hypertensive patients with LVH were all greater than the ones without LVH and the normal subjects. Moreover, the parameter, CVGI/d correlated positively with left ventricular mass index (LVMI). So, the method employed in this study, videodensitometric analysis in combination with TT allow objective and accurate determination of LVH and CVGI/d is a sensitive indicator for hypertensive patients with LVH.

Secondary and primary repolarization changes in left ventricular hypertrophy: a model study

The contributions of reduced conduction velocity (CV) and prolonged action potential duration (APD) to QT interval prolongation and T wave and T vector loop morphology in left ventricular hypertrophy (LVH) were studied using an analytical computer model. Three types of anatomic LVH were simulated: concentric and eccentric hypertrophy, and left ventricular dilatation. In each LVH type, depolarization changes were simulated by CV slowing and primary repolarization changes by APD prolongation. Both CV slowing and APD prolongation prolonged the QT interval; however, the secondary and primary repolarization changes differed in additional electrocardiogram (ECG) characteristics creating specific vectorcardiographic/ECG patterns. The secondary repolarization changes were characterized by prolonged QT interval, accompanied by pronounced QRS changes, including increased maximum spatial QRS vector magnitude, prolonged QRS duration, QRS morphology consistent with intraventricular conduction delay, lower values of the T/QRS duration ratio, increased maximum spatial T vector magnitude, narrow and prolonged discordant T vector loops, and discordant tall T waves creating a pattern of ST strain in the precordial ECG leads. QT prolongation in primary repolarization changes was accompanied with inconsiderable changes of QRS amplitude and duration, higher values of the T/QRS duration ratio, widened rounded T loops, and notched or bifid T waves in left precordial leads of the 12-lead ECG. These simulation data are consistent with the accumulated evidence suggesting that LVH induces changes in CV and APD. Our results emphasize the need for simultaneous consideration of morphologic QRS and T wave patterns together with QT prolongation in clinical evaluation of LVH.

Valoración del riesgo cardiovascular en la fase transversal del estudio Mediterránea

Introduction and objectivesThe Mediterranean study quantifies high cardiovascular risk (HCR), consistency between REGICOR (R) and low risk SCORE (LS) scales, altered blood pressure (ABP) values in hypercholesterolemia (HC) without any history of hypertension (HT), high total cholesterol (HTC) values with HT with no background of HC and cardiac and renal damage in hypertensive patients. Patients and methodsA national, cross-sectional and multicenter study was performed with the participation of 751 physicians. The physicians individually evaluated 7,973 patients with HT and 5,319 with HC. HCR was defined as over 10% with R and 5% with LS. Intra-class correlation coefficient (ICC) and Pearson coefficient (r) were calculated. The percentages of ABP and HTC were quantified. Creatinine (cr) value, glomerular filtration rate using Cockroft-Gault (CG), and prevalence of left ventricular hypertrophy (LVH) were analyzed. ResultsRegarding hypertensive patients: 17.3% HCR with R and 26.1% with LS. ICC=0.222 (p<0.0001), r=0.61 (p<0.0001), 64.7% HTC. There was no evaluation of LVH in 31.2% and a prevalence of 5.1%, prevalence of lesion and kidney failure (KF) of 4.7% and 1.6% respectively based on CR and 15.9% KF by CG.In HC patients, there was 21.1% of HCR with R and 21.5% with LS; ICC=0.190 (p<0.0001), r=0.64 (p<0.0001) and 33.7% ABP. ConclusionsThe SCORE scale identifies more patients with HCR than the REGICOR one in HT patients and a similar amount in HC patients. Consistency between both scales is poor. A significant ABP/HTC was found. In HT patients, the patients who were not evaluated for LVH and the percentage of KF are important.

Update on left ventricular hypertrophy

Summary Detection and evaluation of left ventricular hypertrophy of unknown etiology by echocardiography is important in every cardiology practice. Causes of left ventricular hypertrophy include sarcomeric protein disorders (classical hypertrophic cardiomyopathy), metabolic disease (glycogen storage disease including LAMP2 deficiency, PRKAG2 mutations, Fabry disease), syndromic hypertrophic cardiomyopathy (Noonan’s syndrome, LEOPARD syndrome, etc.) and miscellaneous causes including systemic hypertension, amyloidosis, athlete’s heart and pheochromocytoma. Although there are several echocardiographic changes quite typical for some of the disorders, most changes are not 100% specific. ECG findings and symptoms provide important additional information. Genetic testing is increasingly important. Nowadays, a combination of ECG findings, symptoms, family history, genetic testing and findings of echocardiography provide the best means for differentiation of left ventricular hypertrophy.

The Evaluation of Left Ventricular Hypertrophy in Hypertensive Patients with Subclinical Hyperthyroidism

The aim of this prospective cross-sectional study was to investigate the hypertrophic effects of endogenous subclinical hyperthyroidism on myocardium and early development of left ventricular hypertrophy (LVH) in essential hypertensive patients accompanied by endogenous subclinical hyperthyroidism. A total of 31 consecutive patients with stage I hypertension were included in the study. Sixteen of them also had endogenous subclinical hyperthyroidism that they were unaware before. The patients and the controls formed out of ten healthy subjects all underwent an investigation of thyroid functions and cardiologic evaluation. The mean wall thickness of the left ventricle in the stage I hypertensive group with endogenous subclinical hyperthyroidism (group I) was significantly increased as compared with both hypertensive patients without thyroid disease (group II) and the control subjects. The mean left ventricle mass was also significantly higher in group I than group II. Both of the patients' groups had an increased prevalence of LVH as compared with the controls. In this study, hypertensive patients with subclinical hyperthyroidism presented more increase in left ventricular mass, suggesting that subclinical hyperthyroidism may contribute to left ventricular hypertrophy forming a natural progression to hypertension. The hypertensive population should always be screened for endogenous subclinical hyperthyroidism, and should be examined for the criteria of left ventricular hypertrophy by echocardiography in early stages.

Increased oxidative stress in hypertensive patients with borderline left ventricular mass evaluated by electrocardiography

P-369 Key Words: Oxidative Stress, Left Ventricular, Electrocardiography

Diagnostic effectiveness of spatial indices of computed vectorcardiography for evaluation of left ventricular hypertrophy

The paper shows how the spatial indices of a cardiac signal obtained from recording high-performance signal-average EGG may be useful in diagnosing left ventricular hypertrophy.

Subcostal ecocardiography for the evaluation of left ventricular hypertrophy in older populations.

P27 Background: Left ventricle (LV) hypertrophy is a major risk factor for mortality and morbidity. Unfortunately, the echocardiographic evaluation of LV mass from the parasternal (PS) approach is frequently limited in older, obese or emphysematous individuals. This poses a selection bias to the epidemiological assessment of LV hypertrophy. Methods: In order to assess whether the subcostal (SC) view may reliably substitute the PS view to evaluate LV mass in older adults, 614 unselected persons aged ≥65 years participating in a population-based survey on heart failure in the elderly, and 54 randomly selected healthy individuals 35-64 years old, underwent a complete echocardiographic examination including M-mode PS and SC scanning. Results: Overall, both PS and SC views were available for LV mass estimate (Devereux’s formula) in 314 subjects(age: 69.9±0.5 years, mean±SEM) with normal LV kinetics and sinus rhythm. The SC view underestimated (p&lt;0.001) LV diastolic dimension (LVDD) and overestimated (p&lt;0.012) free wall thickness (FWT), whereas septum thickness was similar in the two views. As a consequence, LV mass was underestimated from the SC view (76.2±1.2 g/m 2 ) as compared to the PS view (87.9±1.4 g/m 2 ; p&lt;0.001). The SC view was 99% specific but only 25% sensitive for the diagnosis of LV hypertrophy (LV mass &gt;116 and &gt;104 g/m 2 in men and women, respectively), based on the PS view. When age, body weight and gender were entered in multivariate regression models with the SC measures, the first two variables significantly contributed to the prediction of both LVDD and FWT, and gender only to the prediction of LVDD. LV mass was recalculated using measures from the SC view, corrected on the basis of the regression equations. The corrected value did not differ from that obtained from the PS view and the sensitivity of the SC view for the diagnosis of LV hypertrophy increased to 51% with unmodified specificity (98%). Conclusions: The SC view significantly underestimates LV mass. However, correction for simple demographic and anthropometric variables greatly improves its reliability for estimating LV mass and hypertrophy in unselected older adults.

A novel method for indexing echocardiographic left ventricular mass in infants, children and adolescents: evaluation of obesity-induced left ventricular hypertrophy.

Measurement of left ventricular mass (LVM) is important to the diagnosis of left ventricular hypertrophy in children with various cardiovascular diseases. The purpose of this study was to determine the most appropriate method for standardization of LVM and to evaluate obesity-induced left ventricular hypertrophy in children across the entire age range, from infancy through adolescence. We studied 928 children and adolescents (527 males, 401 females), aged 0-17 years, who were classified into two groups by degree of obesity. Left ventricular mass was calculated by M-mode echocardiography using the formula of Devereux et al. and was indexed using body size (body length, bodyweight or body surface area) raised to a non-integer power using logarithmic transformation of measurements in children without obesity. The body length, bodyweight and body surface area exponents were 1.85, 0.88 and 1.15, respectively, in males, and 1.72, 0.82 and 1.08, respectively, in females. Whereas indexing of left ventricular mass by body length both in males and in females revealed significant differences between the two groups, indexing using bodyweight or body surface area exponents did not manifest left ventricular hypertrophy induced by obesity. It is suggested that applying body length exponents 1.85 in males and 1.72 in females is an appropriate method for indexation of LVM in children and adolescents. This method is particularly useful for the evaluation of left ventricular hypertrophy in children.

Usefulness of TI-201 SPECT Imaging in Evaluation of Left Ventricular Hypertrophy and Dilation in Patients with Previous Myocardial Infarction

Using short axis slices of Tl-201 myocardial SPECT images, total left ventricular (LV) mass, perfused LV mass, defect size, defect mass, ratio of total LV area to cavity area (T/C), ratio of radius of total LV area to radius of cavity area (TR/CR), and ratio of wall thickness to radius of cavity area (W/R) were obtained. The left ventricular ejection fraction (LVEF) was calculated using blood pool imaging studies. A total of 33 patients with old myocardial infarctions were studied. The patients were divided into group 1 (n = 16) with no history of heart failure, and group 2 (n = 17) with a history of heart failure. The LVEF (P less than 0.001), T/C (P less than 0.005), TR/CR (P less than 0.005) and W/R (P less than 0.001) were significantly lower, while the total LV mass (P less than 0.001) and perfused LV mass (P less than 0.01) were significantly higher in group 2. In the whole group of 33 patients, there was inverse linear correlation between the total LV mass and LVEF (r = -0.82), perfused LV mass and LVEF (r = -0.67), and defect mass and LVEF (r = -0.59). There was linear correlation between W/R and LVEF (r = 0.64). Nonlinear correlations were found between T/C and LVEF (r = 0.81) and TR/CR and LVEF (r = 0.80). Tl-201 myocardial SPECT imaging is useful for the evaluation of LV hypertrophy and cavity dilation in patients with previous myocardial infarction.

MRI Evaluation of Left Ventricular Hypertrophy in a Canine Model of Aortic Stenosis

The progression of ventricular myocardial mass in nine puppies with experimental left ventricular hypertrophy and three controls was observed over a period of 7 months using magnetic resonance imaging (MRI). Left ventricular hypertrophy was created by surgically induced aortic stenosis when the puppies were 1 month old. Quantification of the progression of the left ventricular mass due to aortic stenosis as compared to the controls of similar age was then performed during the subsequent 7 months. Cardiac gated spin-echo technique was used for the imaging of the heart. Novel edge detection techniques were applied for automated identification of the border of the myocardium for measurement. Methods for correction of partial volume effect were applied in the analysis of the data. Clear-cut differences in myocardial mass (P less than .001) and in radius-to-wall thickness ratio (r/h, P less than .02) between puppies with aortic stenosis and controls were observed. The differences in end-diastolic volume between the two groups, however, were significant during the initial phase of hypertrophic compensation (P less than .001) and insignificant (P greater than .05) during the long-term phase of hypertrophic compensation. The results demonstrated that MRI is applicable in serial assessment of myocardial hypertrophy.