Quantitation of myocardial fibrosis and its relation to function in essential hypertension and hypertrophic cardiomyopathy

Treatment of myocardial interstitial fibrosis in pathological myocardial hypertrophy

Pathological myocardial hypertrophy can be caused by a variety of diseases, mainly accompanied by myocardial interstitial fibrosis (MIF), which is a diffuse and patchy process, appearing as a combination of interstitial micro-scars and perivascular collagen fiber deposition. Different stimuli may trigger MIF without cell death by activating a variety of fibrotic signaling pathways in mesenchymal cells. This manuscript summarizes the current knowledge about the mechanism and harmful outcomes of MIF in pathological myocardial hypertrophy, discusses the circulating and imaging biomarkers that can be used to identify this lesion, and reviews the currently available and potential future treatments that allow the individualized management of patients with pathological myocardial hypertrophy.

Quantification of myocardial fibrosis using noninvasive T2-mapping magnetic resonance imaging: Preclinical models of aging and pressure overload

Noninvasive imaging of cardiac fibrosis is important for early diagnosis and intervention in chronic heart diseases. Here, we investigated whether noninvasive, contrast agent-free MRI T₂ -mapping can quantify myocardial fibrosis in preclinical models of aging and pressure overload. Myocardial fibrosis and remodeling were analyzed in two animal models: (i) aging (15-month-old male CF-1 mice vs. young 6- to 8-week-old mice), and (ii) pressure overload (PO; by transverse aortic constriction in 4- to 5-month-old male C57BL/6 mice vs. sham-operated for 14 days). In vivo T₂ -mapping was performed by acquiring data during the isovolumic and early diastolic phases, with a modified respiratory and ECG-triggered multiecho TurboRARE sequence on a 7-T MRI. Cine MRI provided cardiac morphology and function. A quantitative segmentation method was developed to analyze the in vivo T₂ -maps of hearts at midventricle, apex, and basal regions. The cardiac fibrosis area was analyzed ex vivo by picro sirius red (PSR) staining. Both aged and pressure-overloaded hearts developed significant myocardial contractile dysfunction, cardiac hypertrophy, and interstitial fibrosis. The aged mice had two phenotypes, fibrotic and mild-fibrotic. Notably, the aged fibrotic subgroup and the PO mice showed a marked decrease in T₂ relaxation times (25.3 ± 0.6 in aged vs. 29.9 ± 0.7 ms in young mice, p = 0.002; and 24.3 ± 1.7 in PO vs. 28.7 ± 0.7 ms in shams, p = 0.05). However, no significant difference in T₂ was detected between the aged mild-fibrotic subgroup and the young mice. Accordingly, an inverse correlation between myocardial fibrosis percentage (FP) and T₂ relaxation time was derived (R²  = 0.98): T₂ (ms) = 30.45 - 1.05 × FP. Thus, these results demonstrate a statistical agreement between T₂ -map-quantified fibrosis and PSR staining in two different clinically relevant animal models. In conclusion, T₂ -mapping MRI is a promising noninvasive contrast agent-free quantitative technique to characterize myocardial fibrosis.

Right ventricular fibrosis and dysfunction: Actual concepts and common misconceptions

Fibrosis and remodeling of the right ventricle (RV) are associated with RV dysfunction and mortality of patients with pulmonary hypertension (PH) but it is unknown how much RV fibrosis contributes to RV dysfunction and mortality. RV fibrosis manifests as fibroblast accumulation and collagen deposition which may be excessive. Although extracellular matrix deposition leads to elevated ventricular stiffness, it is not known to which extent it affects RV function. Various animal models of pulmonary hypertension have been established to investigate the role of fibrosis in RV dysfunction and failure. However, they do not perfectly resemble the human disease. In the current review we describe the major characteristics of RV fibrosis, molecular mechanisms regulating the fibrotic process, and discuss how therapeutic targeting of fibrosis might affect RV function.

Measuring Water Distribution in the Heart: Preventing Edema Reduces Ischemia-Reperfusion Injury

Background

Edema is present in many heart diseases, and differentiation between intracellular (ICW) and extracellular (ECW) myocardial water compartments would be clinically relevant. In this work we developed a magnetic resonance imaging–based method to differentiate ICW and ECW and applied it to analyze ischemia–reperfusion–induced edema.

Methods and Results

Isolated rat hearts were perfused with gadolinium chelates as a marker of extracellular space. Total water content was measured by desiccation. Gadolinium quantification provided ECW, and ICW was calculated by subtraction of ECW from total water content. In separate experiments, T1, T2, diffusion‐weighted imaging and proton‐density parameters were measured in isolated saline‐perfused hearts. In in‐situ rat hearts, ECW and ICW were 79±10 mL and 257±8 mL of water per 100 g of dry tissue, respectively. After perfusion for 40 minutes, ECW increased by 92.4±3% without modifying ICW (−1±3%). Hyposmotic buffer (248 mOsm/L) increased ICW by 16.7±2%, while hyperosmotic perfusion (409 mOsm/L) reduced ICW by 26.5±3%. Preclinical imaging showed good correlation between T2 and diffusion‐weighted imaging with ECW, and proton‐density correlated with total water content. Ischemia–reperfusion resulted in marked myocardial edema at the expense of ECW, because of cellular membrane rupture. When cell death was prevented by blebbistatin, water content and distribution were similar to normoxic perfused hearts. Furthermore, attenuation of intracellular edema with hyperosmotic buffer reduced cell death.

Conclusions

We devised a method to determine edema and tissue water distribution. This method allowed us to demonstrate a role of edema in reperfusion‐induced cell death and could serve as a basis for the study of myocardial water distribution using magnetic resonance imaging.

Hypertrophic cardiomyopathy: Cardiac structural and microvascular abnormalities as evaluated with multi-parametric MRI

PURPOSE

To determine the relationship between myocardial structural and microvascular abnormality in hypertrophic cardiomyopathy (HCM) by multi-parametric cardiac MRI.

MATERIALS AND METHODS

Twenty-four HCM and eighteen controls were retrospectively included. Left ventricle mass (LVM), LV end-systolic and end-diastolic volume (LVESV, LVEDV), LV ejection fraction (LVEF), and 16-segment wall thickness at ES and ED (SESWT, SEDWT) were assessed with a 2D cine-MRI. Myocardial perfusion (reflected by K(trans)), interstitial volume (Ve) and mean transmit time (MTT) were evaluated with a model-dependent dynamic contrast-enhanced MRI. Myocardial fibrosis was assessed with late gadolinium enhancement (LGE) imaging.

RESULTS

K(trans) was significantly decreased in LGE-present (0.74±0.15mL/g/min) against LGE-absent (0.55±0.14mL/g/min, p=0.030) and normal group (0.81±0.32mL/g/min, p<0.001), but was unchanged in LGE-absent against normal group (p>0.05). Ve and MTT were significantly increased in LGE-present (Ve: 26.7±15.7%; MTT: 28.6±21.3s) against LGE-absent (37.6±18.3%; 49.8±30.5s) and normal group (19.7±6.9%; 15.1±3.9s; all p<0.001), and were significantly increased in LGE-absent against normal group (p<0.001). LGE significantly correlated to K(trans), Ve, MTT, and SESWT (ρ=0.232, -0.247, -0.443, and -0.207, respectively). K(trans) negatively correlated to SEDWT and SESWT (ρ=-0.224 and -0.231). Ve and MTT positively correlated to SEDWT (Ve: ρ=0.223; MTT: ρ=0.239) and SESWT (Ve: ρ=0.248; MTT: ρ=0.254).

CONCLUSIONS

Consistent relationship was determined between myocardial structural abnormality and microvascular dysfunction in HCM.

Murine models of diastolic dysfunction and heart failure with preserved ejection fraction

Left ventricular diastolic dysfunction leads to heart failure with preserved ejection fraction, an increasingly prevalent condition largely driven by modern day lifestyle risk factors. As heart failure with preserved ejection fraction accounts for almost one-half of all patients with heart failure, appropriate nonhuman animal models are required to improve our understanding of the pathophysiology of this syndrome and to provide a platform for preclinical investigation of potential therapies. Hypertension, obesity, and diabetes are major risk factors for diastolic dysfunction and heart failure with preserved ejection fraction. This review focuses on murine models reflecting this disease continuum driven by the aforementioned common risk factors. We describe various models of diastolic dysfunction and highlight models of heart failure with preserved ejection fraction reported in the literature. Strengths and weaknesses of the different models are discussed to provide an aid to translational scientists when selecting an appropriate model. We also bring attention to the fact that heart failure with preserved ejection fraction is difficult to diagnose in animal models and that, therefore, there is a paucity of well described animal models of this increasingly important condition.

Atrophic cardiomyocyte signaling in hypertensive heart disease

Cardinal pathological features of hypertensive heart disease (HHD) include not only hypertrophied cardiomyocytes and foci of scattered microscopic scarring, a footprint of prior necrosis, but also small myocytes ensnared by fibrillar collagen where disuse atrophy with protein degradation would be predicted. Whether atrophic signaling is concordant with the appearance of HHD and involves oxidative and endoplasmic reticulum (ER) stress remains unexplored. Herein, we examine these possibilities focusing on the left ventricle and cardiomyocytes harvested from hypertensive rats receiving 4 weeks aldosterone/salt treatment (ALDOST) alone or together with ZnSO₄, a nonvasoactive antioxidant, with the potential to attenuate atrophy and optimize hypertrophy. Compared with untreated age-/sex-/strain-matched controls, ALDOST was accompanied by (1) left ventricle hypertrophy with preserved systolic function; (2) concordant cardiomyocyte atrophy (<1000 μm²) found at sites bordering on fibrosis where they were reexpressing β-myosin heavy chain; and (3) upregulation of ubiquitin ligases, muscle RING-finger protein-1 and atrogin-1, and elevated 8-isoprostane and unfolded protein ER response with messenger RNA upregulation of stress markers. ZnSO₄ cotreatment reduced lipid peroxidation, fibrosis, and the number of atrophic myocytes, together with a further increase in cell area and width of atrophied and hypertrophied myocytes, and improved systolic function but did not attenuate elevated blood pressure. We conclude that atrophic signaling, concordant with hypertrophy, occurs in the presence of a reparative fibrosis and induction of oxidative and ER stress at sites of scarring where myocytes are atrophied. ZnSO₄ cotreatment in HHD with ALDOST attenuates the number of atrophic myocytes, optimizes size of atrophied and hypertrophied myocytes, and improves systolic function.

Myocardial fibrosis in patients with symptomatic obstructive hypertrophic cardiomyopathy: correlation with echocardiographic measurements, sarcomeric genotypes, and pro-left ventricular hypertrophy polymorphisms involving the renin-angiotensin-aldosterone system

INTRODUCTION

Hypertrophic cardiomyopathy (HCM) is a heterogeneous disorder of the cardiac sarcomere, resulting in myocyte hypertrophy and disarray, interstitial fibrosis, and cardiac dysfunction. Our aim was to determine whether the amount of fibrosis in HCM correlates with echocardiographic measures of diastolic dysfunction, presence of HCM-susceptibility mutations, or polymorphisms in the renin-angiotensin-aldosterone system (RAAS).

METHODS

Surgical specimens from patients with obstructive HCM undergoing septal myectomy at the Mayo Clinic (2001-2004) were examined and compared with autopsy-derived tissues from age- and sex-matched normal controls. Digital image analysis was used to quantitate the fibrosis in representative microscopic sections. Genotyping was performed for myofilament-HCM using polymerase chain reaction, high-performance liquid chromatography, and direct DNA sequencing. RAAS polymorphism status was similarly established.

RESULTS

The study included 59 HCM cases and 44 controls. Patients with HCM exhibited more fibrosis (mean 17%, range 3-45%) than controls (mean 8%, range 3-17%) (P<.0001). A significant relationship existed between amount of fibrosis and maximum wall thickness (P=.02), left ventricular ejection fraction (P=.02), and peak early/late diastolic mitral annulus velocity (E/A ratio) (P=.002). Although there was no association between amount of fibrosis and myofilament-HCM genotype status or polymorphisms in the RAAS cascade, there was a trend toward more fibrosis in patients with > or =1 C-encoding allele in CYP11B2-encoded aldosterone synthase.

CONCLUSIONS

Patients with HCM undergoing septal myectomy had significantly more myocardial interstitial fibrosis than controls. The amount of fibrosis in HCM patients correlated with degree of septal hypertrophy and left ventricular systolic and diastolic function. Notably, neither mutations in cardiac myofilament proteins or polymorphisms in RAAS exhibited strong associations with severity of myocardial fibrosis.

Diagnosis and treatment of myocardial fibrosis in hypertensive heart disease

Although hypertensive heart disease (HHD) is clinically characterized by development of left ventricular hypertrophy in the absence of a cause other than arterial hypertension, changes in the composition of myocardial tissue also develop in arterial hypertension, leading to structural remodeling of the myocardium (eg, fibrosis). Myocardial fibrosis is the major determinant of diastolic dysfunction/failure in patients with HHD. Recent available data on the determination of serum concentrations of collagen-derived serum peptides, as well as quantitative analysis of echoreflectivity to address the presence of fibrosis in the myocardium of hypertensive patients, are promising. In addition, preliminary data suggest that the goal of reducing myocardial fibrosis is achievable using specific pharmacological agents in patients with HHD.

Are Myocardial Fibrosis and Diastolic Dysfunction Reversible in Hypertensive Heart Disease?

Diastolic dysfunction is an important factor contributing to the appearance of symptomatic heart failure, particularly among elderly women with arterial hypertension. In hypertensive heart disease, the presence of cardiac fibrosis is an important determinant of abnormal myocardial stiffness that contributes to diastolic dysfunction. Recent studies indicate the feasibility of a pharmacology-based regression of fibrosis and improvement in diastolic stiffness.

Depth variation bias and interaction with gain setting in ultrasonic tissue characterization by integrated backscatter analysis

Integrated backscatter signal (IBS) has been proposed as a tool to measure cardiac fibrosis. To overcome problems associated with machine settings and attenuation of the chest wall, IBS has been expressed in relation to posterior pericardium, as a variation across cardiac cycle, or both. Depth of the reflecting structure has never been considered as a source of variability. Accordingly, we studied the effect of structure depth on IBS and examined its interaction with gain setting. Backscatter signals were recorded from plastic phantoms containing identical structures set at increasing depth and in 1 healthy volunteer using silicone spacers to modify depth, on a wide range of gain settings. In the phantom, IBS signal linearly decreased with increasing depth and nonlinearly increased with increasing gain (all r(2) > 0.97). In the healthy volunteer, results from septum were very similar to the phantom experiment. Values of septal IBS were adjusted using multiple regression coefficients for gain and depth from the phantom experiment and resulted in a near-complete offset of effect of depth and gain on septal IBS (P = not significant for both gain and depth). These assumptions were also used to compare IBS analysis between hypertensive patients and patients with hypertrophic cardiomyopathy. Thus, depth and its relation with gain should be taken into account and might be almost fully predicted. Using appropriate regression modeling may allow analysis in optimal imaging conditions, tolerating between-patient comparisons even in limited diastolic frames.

Myocardial scarring in asymptomatic or mildly symptomatic patients with hypertrophic cardiomyopathy

OBJECTIVES

We sought to ascertain whether myocardial scarring occurs in living unselected patients with hypertrophic cardiomyopathy (HCM).

BACKGROUND

Myocardial scarring is known to occur in select HCM patients, who were highly symptomatic prior to death or who died suddenly. The majority of HCM patients, however, are minimally symptomatic and have not suffered sudden death.

METHODS

Cine and gadolinium-enhanced magnetic resonance imaging was performed in 21 HCM patients who were predominantly asymptomatic. Gadolinium hyperenhancement was assumed to represent myocardial scar, and the extent of scar was compared to left ventricular (LV) morphology and function.

RESULTS

Scarring was present in 17 patients (81%). Scarring occurred only in hypertrophied regions (> or =10 mm), was patchy with multiple foci, and predominantly involved the middle third of the ventricular wall. All 17 patients had scarring at the junction of the interventricular septum and the right ventricular (RV) free wall. On a regional basis, the extent of scarring correlated positively with wall thickness (r = 0.36, p < 0.0001), and inversely with wall thickening (r = -0.21, p < 0.0001). On a per patient basis, the extent of scarring (mean, 8 +/- 9% of LV mass) was minimally related to maximum wall thickness (r = 0.40, p = 0.07) and LV mass (r = 0.33, p = 0.15), and correlated inversely with ejection fraction (r = -0.46, p = 0.04).

CONCLUSIONS

Myocardial scarring is common in asymptomatic or mildly symptomatic HCM patients who have not suffered sudden death. When present, scarring occurs in hypertrophied regions, is consistently localized to the junctions of the septum and RV free wall, and correlates positively with regional hypertrophy and inversely with regional contraction.

Morphology and significance of the left ventricular collagen network in young patients with hypertrophic cardiomyopathy and sudden cardiac death

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is a primary cardiac disease with a diverse clinical spectrum, in which many of the abnormal structural and pathophysiologic features are consequences of inappropriate left ventricular hypertrophy.

METHODS

We analyzed the amount, distribution and structure of the cardiac collagen network in transmural sections of the ventricular septum (thickness 17 to 40 mm, mean 25 mm) in 16 previously asymptomatic children and young adults with HCM (11 to 31 years of age, mean 20 years) who died suddenly. The morphologic appearance and volume fractions of interstitial (matrix) and perivascular (adventitial) collagen were analyzed with polarization microscopy and computerized videodensitometry in picrosirius red-stained sections. Findings were compared with 16 structurally normal hearts, 5 with systemic hypertension and 6 infants who died of HCM.

RESULTS

Adults and young children with HCM had an eightfold greater amount of matrix collagen compared with normal controls (14.1 +/- 8.8% vs. 1.8 +/- 1% of the tissue section; p < 0.0001), and a threefold increase compared with patients with systemic hypertension (4.5 +/- 1.3%; p < 0.001) and infants with HCM (4.0 +/- 2.4%; p < 0.001). Compared with normal controls and hypertensives, adults and young children (and infants) with HCM showed increased numbers and thickness of each collagen fiber component of the matrix (perimysial coils, pericellular weaves and struts), which were often arranged in disorganized patterns. In HCM patients, the amount of collagen was not a consequence of other clinical, demographic and morphologic disease variables.

CONCLUSIONS

Left ventricular collagen matrix in young, previously asymptomatic patients with HCM who died suddenly is morphologically abnormal and substantially increased in size. The enlarged matrix collagen compartment is present in HCM at an early age, further expands during growth, is partially responsible for increased ventricular septal thickness and likely represents a primary morphologic abnormality in this disease. These findings support the view that the complex HCM disease process is not confined to sarcomere protein abnormalities, but also involves connective tissue elements.

Differential effects of angiotensin II on cardiac cell proliferation and intramyocardial perivascular fibrosis in vivo

BACKGROUND

Growth effects of angiotensin II (Ang II) contribute to cardiac remodeling. Remodeling, in turn, may be influenced by proliferation of nonmyocytes. The aims of this study were to determine in vivo which cardiac cell types proliferate in response to Ang II, to evaluate whether proliferation is mediated by the Ang II AT1 receptor, and to establish whether blood pressure affects cell proliferation by comparing proliferation in the normotensive right atrium and ventricle and pressure-overloaded left ventricle.

METHODS AND RESULTS

Groups of 8 Wistar rats were implanted with miniosmotic pumps releasing 5-bromo-2'-deoxyuridine (BrdU) as a cell proliferation marker for 2 weeks. Two groups received Ang II infusions via a second minipump and drinking water+/-losartan. Two groups received vehicle+/-losartan. Cell proliferation was assessed as the percentage of nuclei that incorporated BrdU. Ang II increased proliferation within medial vascular smooth muscle cells (VSMCs) and in associated adventitial/interstitial fibroblasts of intramyocardial coronary arterioles but decreased proliferation of myoendothelial cells. Despite increased blood pressure, proliferation in atria and ventricles was similar. Aldosterone levels were not significantly elevated, suggesting direct proliferative effects of Ang II. Losartan reduced Ang II-induced VSMC and adventitial fibroblast proliferation but had no effect on myoendothelial cell proliferation.

CONCLUSIONS

These results indicate direct, differential effects of Ang II on proliferation of atrial and ventricular nonmyocytes. VSMC and fibroblast proliferation is AT1 receptor-dependent, whereas myoendothelial cells are controlled by an AT1-independent mechanism. The effects are independent of aldosterone and blood pressure and have important implications in renin-dependent hypertension and chronic cardiac failure when circulating Ang II is elevated.

Quantitative evaluation of the rate of myocardial interstitial fibrosis using a personal computer

We investigated the reliability and reproducibility of an image-analyzing system run on a personal computer for measurement of myocardial interstitial fibrosis. Measurements of myocardial interstitial fibrosis in right ventricular endomyocardial biopsies obtained from patients with hypertrophic cardiomyopathy determined by this image-analyzing system were compared with measurements determined by the point-counting method. We also investigated the correlation between measurements of interstitial fibrosis obtained by image analysis and biochemical measurements of myocardial levels of hydroxyproline in normal and cardiomyopathic hamsters. The intra- and interobserver variability were significantly lower for measurements obtained by the image-analyzing system than for measurements obtained by the point-counting system. Reproducibility was superior with the image-analyzing method. The rate of myocardial interstitial fibrosis determined by the computer image-analyzing method was positively correlated with the hydroxyproline measurement (r = 0.89). Our results suggest that an image-analyzing system using a personal computer provides reproducible results with a high level of reliability.

Clinical and histologic features of alcohol drinkers with congestive heart failure

To clarify the difference between alcoholic cardiomyopathy and dilated cardiomyopathy and to investigate the characteristics of alcoholic cardiomyopathy, right ventricular endomyocardial biopsy was performed, and the two diseases were compared clinically and histologically. Changes in the cardiothoracic ratio, cardiac index, and systolic blood pressure/end-systolic volume index were greater after treatment in patients with alcoholic cardiomyopathy than in patients with dilated cardiomyopathy. Histologically, myocytic hypertrophy, fibrosis, and nuclear change were less significant in the former than in the latter. Among patients with alcoholic cardiomyopathy, the cardiac index in those with less fibrosis was greater than in those with more fibrosis. Thus patients with alcoholic cardiomyopathy had more preserved and reversible cardiac function and fewer histologic changes than the patients with dilated cardiomyopathy. Reversibility of cardiac function in patients with alcoholic cardiomyopathy correlated inversely with the severity of histologic changes.

Asymmetrical septal hypertrophy in patients with hypertension: a type of hypertensive left ventricular hypertrophy or hypertrophic cardiomyopathy combined with hypertension?

To determine whether asymmetrical septal hypertrophy (ASH) in patients with essential hypertension (HT) is a type of hypertensive left ventricular (LV) hypertrophy or hypertrophic cardiomyopathy (HCM) combined with HT, we investigated a group of 7 hypertensive patients with ASH compared with 12 HCM patients and 10 healthy controls using radionuclide angiography and right ventricular endomyocardial biopsy. The LV time-volume curve and its first and second derivative curves were constructed from cardiac output and time-activity curves constructed by combined forward and reverse-gating from the R wave. The LV wall thickness and ejection fraction were significantly greater in both the HT and HCM groups than in the control group, whereas there were no differences in these indices between the HT and HCM groups. Rapid filling volume index and rapid filling fraction showed significantly lower values in the HCM group than in the control group (p < 0.005). In contrast to the HCM group, these indices in the HT group did not differ from those in the control group. The time to peak filling rate was prolonged in the control, hypertension, and HCM groups in increasing order. Histopathological study revealed a higher incidence of myocardial cell disarray in the HCM than in the HT group. The above results suggest that ASH in hypertensive patients is a type of hypertensive LV hypertrophy.

Collagen remodelling in myocardia of patients with diabetes

AIMS

To investigate collagen remodelling in the interstitium of the heart in patients with diabetes.

METHODS

Immunohistochemical study of the biopsied myocardium using type specific anticollagen antibodies (I, III, IV, V, VI) was performed in 12 patients with non-insulin dependent diabetes mellitus and six non-diabetic patients. There was no history of hypertension or coronary artery stenosis in any of the patients.

RESULTS

Noticeable accumulations of collagen types I, III, and VI in the myocardial interstitium were recognised in both groups, but little accumulation of types IV or V was found. Types I and III mainly stained in the perimysium and perivascular region, while type VI predominantly stained in the endomysium. There was no disease specific accumulation of collagen in diabetes mellitus. The percentage of total interstitial fibrosis in the myocardium was significantly higher in the diabetic group than in the control group (p < 0.05). Although the percentages of collagen types I and VI did not differ between the two groups, the percentage type of III was significantly higher in the diabetic group than in the controls (p < 0.01).

CONCLUSIONS

Collagen remodelling mainly as a result of an increase in collagen type III in the perimysium and perivascular region, occurs in the hearts of patients with diabetes.

Cardiac characteristics and postoperative courses in Cushing's syndrome

To assess the cardiac characteristics and postoperative courses in patients with Cushing's syndrome, electrocardiography and echocardiography were performed to study 12 consecutive, unselected patients, and results were compared with those of essential hypertension and primary aldosteronism. Eleven patients had hypertension and 7 had diabetes mellitus. Before adrenalectomy, common electrocardiographic abnormalities consisted of high-voltage QRS complexes (10 patients) and negative T waves (7 patients). Echocardiograms showed left ventricular hypertrophy in 9 patients, and all the patients had evidence of asymmetric septal hypertrophy. In patients with left ventricular hypertrophy, the thickness of the interventricular septum ranged from 16 to 32 mm, whereas the ratio of the thickness of interventricular septum to that of the posterior wall ranged from 1.33 to 2.67. The interventricular septum in Cushing's syndrome was extremely thicker and asymmetric septal hypertrophy occurred more often than essential hypertension and primary aldosteronism. Nine patients could be followed up after operation. In these patients abnormal electrocardiographic findings had normalized, the thickness of interventricular septum had decreased and asymmetric septal hypertrophy had disappeared except in 1 patient. The reason why left ventricular hypertrophy in Cushing's syndrome is severe is still unknown. Because left ventricular hypertrophy is more severe and the frequency of asymmetric septal hypertrophy much greater in Cushing's syndrome than in essential and other secondary hypertension, it is thought that not only increased aortic pressure but excessive plasma cortisol may be etiologic factors in the progression of left ventricular hypertrophy in Cushing's syndrome.