Comparable long-term results of the extracardiac conduit total cavopulmonary connection in heterotaxy to non-heterotaxy patients.

BACKGROUND: Fontan operation in heterotaxy patients has been associated with high mortality. We studied whether adoption of the extracardiac conduit (EC) total cavopulmonary connection (TCPC) in heterotaxy demonstrated comparable results to non-heterotaxy population. METHODS: A retrospective medical record review of 35 consecutive patients with heterotaxy and 70 consecutive patients without heterotaxy syndrome who underwent EC TCPC between 2000 and 2018 was performed. RESULTS: In the 35 heterotaxy patients, 30 were right and 5 were left atrial isomerism. Anomalies of venous return included bilateral superior vena cava in 20 (57.1%), separated hepatic vein in 8 (22.9%), interrupted inferior vena cava in 3 (8.6%), total anomalous pulmonary venous return in 7 (20%), and partial in 2 patients (5.7%). All patients underwent EC TCPC under beating-heart cardiopulmonary bypass except in four patients (11.4%) cardioplegic arrest was needed for cardiac repair. The surgical mortality rate was lower in heterotaxy patients (0% vs. 5.7%; p = 0.299) but statistically not significant. The follow-up ranged from 2 months to 17.8 years (mean 9.4 ± 5.6 years). At 15 years, there was no significant difference between the heterotaxy and non-heterotaxy patients regarding the long-term survival (70% vs. 78.6%; p = 0.443), freedom from reoperation (81.9% vs. 96.5%; p = 0.057), and postoperative arrhythmia (17.1% vs. 7.1%; p = 0.174). CONCLUSIONS: EC TCPC can be performed in heterotaxy patients with comparable early and late results to the non-heterotaxy population. However, the late morbidities regarding the Fontan circulation needs careful follow-up.

Idi1 and Hmgcs2 Are Affected by Stretch in HL-1 Atrial Myocytes.

BACKGROUND: Lipid expression is increased in the atrial myocytes of mitral regurgitation (MR) patients. This study aimed to investigate key regulatory genes and mechanisms of atrial lipotoxic myopathy in MR. METHODS: The HL-1 atrial myocytes were subjected to uniaxial cyclic stretching for eight hours. Fatty acid metabolism, lipoprotein signaling, and cholesterol metabolism were analyzed by PCR assay (168 genes). RESULTS: The stretched myocytes had significantly larger cell size and higher lipid expression than non-stretched myocytes (all p < 0.001). Fatty acid metabolism, lipoprotein signaling, and cholesterol metabolism in the myocytes were analyzed by PCR assay (168 genes). In comparison with their counterparts in non-stretched myocytes, seven genes in stretched monocytes (Idi1, Olr1, Nr1h4, Fabp2, Prkag3, Slc27a5, Fabp6) revealed differential upregulation with an altered fold change >1.5. Nine genes in stretched monocytes (Apoa4, Hmgcs2, Apol8, Srebf1, Acsm4, Fabp1, Acox2, Acsl6, Gk) revealed differential downregulation with an altered fold change <0.67. Canonical pathway analysis, using Ingenuity Pathway Analysis software, revealed that the only genes in the "superpathway of cholesterol biosynthesis" were Idi1 (upregulated) and Hmgcs2 (downregulated). The fraction of stretched myocytes expressing Nile red was significantly decreased by RNA interference of Idi1 (p < 0.05) and was significantly decreased by plasmid transfection of Hmgcs2 (p = 0.004). CONCLUSIONS: The Idi1 and Hmgcs2 genes have regulatory roles in atrial lipotoxic myopathy associated with atrial enlargement.

Deciphering the gene expression profile of peroxisome proliferator-activated receptor signaling pathway in the left atria of patients with mitral regurgitation.

BACKGROUND: Differentially expressed genes in the left atria of mitral regurgitation (MR) pigs have been linked to peroxisome proliferator-activated receptor (PPAR) signaling pathway in the KEGG pathway. However, specific genes of the PPAR signaling pathway in the left atria of MR patients have never been explored. METHODS: This study enrolled 15 MR patients with heart failure, 7 patients with aortic valve disease and heart failure, and 6 normal controls. We used PCR assay (84 genes) for PPAR pathway and quantitative RT-PCR to study specific genes of the PPAR pathway in the left atria. RESULTS: Gene expression profiling analysis through PCR assay identified 23 genes to be differentially expressed in the left atria of MR patients compared to normal controls. The expressions of APOA1, ACADM, FABP3, ETFDH, ECH1, CPT1B, CPT2, SLC27A6, ACAA2, SMARCD3, SORBS1, EHHADH, SLC27A1, PPARGC1B, PPARA and CPT1A were significantly up-regulated, whereas the expression of PLTP was significantly down-regulated in the MR patients compared to normal controls. The expressions of HMGCS2, ACADM, FABP3, MLYCD, ECH1, ACAA2, EHHADH, CPT1A and PLTP were significantly up-regulated in the MR patients compared to patients with aortic valve disease. Notably, only ACADM, FABP3, ECH1, ACAA2, EHHADH, CPT1A and PLTP of the PPAR pathway were significantly differentially expressed in the MR patients compared to patients with aortic valve disease and normal controls. CONCLUSIONS: Differentially expressed genes of the PPAR pathway have been identified in the left atria of MR patients compared with patients with aortic valve disease and normal controls.

Early and intermediate-term results of the extracardiac conduit total cavopulmonary connection for functional single-ventricle hearts.

BACKGROUND/PURPOSE: Fontan operation has evolved from atriopulmonary connection to total cavopulmonary connection (TCPC) due to its advantages in terms of hemodynamics and reduction of atrium-related complications. We analyzed the early and intermediate-term results of extracardiac conduit TCPC (EC-TCPC) procedure in patients with functional single ventricle to investigate the risk factors of surgical mortality and intermediate failure. METHODS: Retrospective review of the medical records of 88 consecutive patients with functional single ventricle who underwent EC-TCPC from 2000 to 2013 was conducted. RESULTS: The follow-up was 100% complete, ranging from 3 months to 13 years (mean 7.0 ± 3.8 years). There were two (2.3%) hospital and 18 (20.4%) late deaths. The estimated event-free survival rates at 1 year, 5 years, and 10 years were 90.6%, 89.3%, and 77.2%, respectively. On univariate analysis, fenestration was the only risk factor for surgical mortality (p = 0.027). On multivariate analysis, the significant atrioventricular valve regurgitation was the only risk factor for intermediate failure (p = 0.017). CONCLUSION: The clinical results of EC-TCPC in patients with functional single ventricle were satisfactory. The patients who needed fenestration during operation had higher risk of surgical mortality. Significant atrioventricular valve regurgitation had negative impact on intermediate survival.

Fontan Operation in a Patient with Severe Hypoplastic Right Pulmonary Artery, Single Ventricle, and Heterotaxy Syndrome.

Assessment of the pulmonary circulation status including pressure, resistance, size, and absence of anatomical distortion, is crucial to the successful Fontan operation. Most patients are found to have acceptable pulmonary arteries after previous palliation, although some degree of distortion is not uncommon. However, in rare instances, some patients have only one functioning lung with another pulmonary artery seriously hypoplastic or atretic. For theses patients, completion of a Fontan operation will be challenging. We reported a 17-year-old girl with a single ventricle and heterotaxy syndrome and only her left lung functioning, who underwent one-lung Fontan operation with a satisfactory result.

Mitochondrial apoptotic pathway activation in the atria of heart failure patients due to mitral and tricuspid regurgitation.

Apoptosis occurs in atrial cardiomyocytes in mitral and tricuspid valve disease. The purpose of this study was to examine the respective roles of the mitochondrial and tumor necrosis factor-α receptor associated death domain (TRADD)-mediated death receptor pathways for apoptosis in the atrial cardiomyocytes of heart failure patients due to severe mitral and moderate-to-severe tricuspid regurgitation. This study comprised eighteen patients (7 patients with persistent atrial fibrillation and 11 in sinus rhythm). Atrial appendage tissues were obtained during surgery. Three purchased normal human left atrial tissues served as normal controls. Moderately-to-severely myolytic cardiomyocytes comprised 59.7±22.1% of the cardiomyocytes in the right atria and 52.4±12.9% of the cardiomyocytes in the left atria of mitral and tricuspid regurgitation patients with atrial fibrillation group and comprised 58.4±24.8% of the cardiomyocytes in the right atria of mitral and tricuspid regurgitation patients with sinus rhythm. In contrast, no myolysis was observed in the normal human adult left atrial tissue samples. Immunohistochemical analysis showed expression of cleaved caspase-9, an effector of the mitochondrial pathways, in the majority of right atrial cardiomyocytes (87.3±10.0%) of mitral and tricuspid regurgitation patients with sinus rhythm, and right atrial cardiomyocytes (90.6±31.4%) and left atrial cardiomyocytes (70.7±22.0%) of mitral and tricuspid regurgitation patients with atrial fibrillation. In contrast, only 5.7% of cardiomyocytes of the normal left atrial tissues showed strongly positive expression of cleaved caspase-9. Of note, none of the atrial cardiomyocytes in right atrial tissue in sinus rhythm and in the fibrillating right and left atria of mitral and tricuspid regurgitation patients, and in the normal human adult left atrial tissue samples showed cleaved caspase-8 expression, which is a downstream effector of TRADD of the death receptor pathway. Immunoblotting of atrial extracts showed that there was enhanced expression of cytosolic cytochrome c, an effector of the mitochondrial pathways, but no expression of membrane TRADD and cytosolic caspase-8 in the right atrial tissue of mitral and tricuspid regurgitation patients with sinus rhythm, and right atrial and left atrial tissues of mitral and tricuspid regurgitation patients with atrial fibrillation. Taken together, this study showed that mitochondrial pathway for apoptosis was activated in the right atria in sinus rhythm and in the left and right atria in atrial fibrillation of heart failure patients due to mitral and tricuspid regurgitation, and this mitochondrial pathway activation may contribute to atrial contractile dysfunction and enlargement in this clinical setting.

Enhanced expression of ROCK in left atrial myocytes of mitral regurgitation: a potential mechanism of myolysis.

BACKGROUND: Severe mitral regurgitation (MR) may cause myolysis in the left atrial myocytes. Myolysis may contribute to atrial enlargement. However, the relationship between Rho-associated kinase (ROCK) and myolysis in the left atrial myocytes of MR patients remain unclear. METHODS: This study comprised 22 patients with severe MR [12 with atrial fibrillation (AF) and ten in sinus rhythm]. Left atrial appendage tissues were obtained during surgery. Normal left atrial tissues were purchased. Immunofluorescence histochemical and immunoblotting studies were performed. RESULTS: The expression of ROCK2 in the myolytic left atrial myocytes of MR AF patients (p = 0.009) and MR sinus patients (p = 0.011) were significantly higher than that of the normal subjects. Similarly, the expression of ROCK1 in the myolytic left atrial myocytes of MR AF patients was significantly higher than that of the normal subjects (p = 0.010), and the expression of ROCK1 in the myolytic left atrial myocytes of MR sinus patients was higher than that of the normal subjects (p = 0.091). Immunofluorescence study revealed significant co-localization and juxtaposition of ROCK2 and cleaved caspase-3 in the left atrial myocytes both in the MR AF group (Pearson's coefficient = 0.74 ± 0.03) and the MR sinus group (Pearson's coefficient = 0.73 ± 0.02). Similarly, immunofluorescence study revealed significant co-localization and juxtaposition of ROCK1 and cleaved caspase-3 in the left atrial myocytes both in the MR AF group (Pearson's coefficient = 0.65 ± 0.03) and the MR sinus group (Pearson's coefficient = 0.65 ± 0.03). Correlation analysis demonstrated that there was a significant direct relationship between the expression of ROCK2 in the myolytic left atrial myocytes and left atrial diameter in the MR patients (p = 0.041; r = 0.440). Moreover, the ratio of phosphorylated myosin-binding subunit of myosin light chain phosphatase (pMBS)/total MBS of left atrial tissues was significantly higher in the MR AF group (p < 0.04) and the MR sinus group (p < 0.04) compared with the normal control group. CONCLUSIONS: The enhanced expression of ROCKs might be involved in the myolysis of the left atrial myocytes of MR patients.

Thymectomy for myasthenia gravis: video-assisted versus transsternal.

BACKGROUND/PURPOSE: Thymectomy may benefit patients with generalized myasthenia gravis (MG) or myasthenia with thymomas. Currently, video-assisted (VA) thoracic surgery is popular and plays an important role in thymectomy. We compared the clinical outcomes of VA thymectomy with conventional transsternal (TS) approach to investigate the effectiveness of VA technology in the current era. METHODS: A retrospective review of our thymectomy results for patients with MG from 1998 to 2011 was conducted. A total of 83 consecutive patients were enrolled. According to the surgeons' and patients' preference, 39 patients received conventional TS thymectomy and 44 were operated on in a VA fashion. The results were categorized and analyzed according to the Myasthenia Gravis Foundation of America (MGFA) postintervention statuses with some modification. RESULTS: No obvious difference between conventional TS thymectomy and VA thymectomy was noted regarding the remission statuses and the clinical outcomes by the modified MGFA score. However, the patients who received VA thymectomy showed shorter intensive care unit (ICU) stays (4.2 ± 3.3 days vs. 2.3 ± 1.5 days, p = 0.001). CONCLUSION: Compared with the conventional TS thymectomy, the VA approach is similarly effective with shorter ICU stays.

Huge mediastinal ancient schwannoma causing acute respiratory failure: a case report.

Benign mediastinal tumor is usually asymptomatic and exhibits uncomplicated clinical course. Posterior mediastinal schwannoma is common, but a huge benign tumor causing acute respiratory failure due to mass effect is unusual. We present a patient who suffered from acute respiratory failure due to huge mediastinal mass effect and improved after en bloc surgical resection. A 56-year-old woman had no history of systemic disease, but experienced general discomfort and malaise for several months. She was referred to our emergency department after developing sudden respiratory failure. Intubation was performed with ventilator support and she was admitted to the intensive care unit. Chest radiograph and computed tomography showed a huge mass over the left pleural cavity causing left lung, heart, and mediastinal compression. After en bloc resection, she was weaned off the ventilator successfully and was discharged at 24 days after the operation. Postoperative outpatient follow-up showed no symptoms. Mediastinal ancient schwannoma is a rare posterior mediastinal benign tumor. However, mass effect might lead to lethal complications. En bloc resection is necessary for curative treatment.

Comparative of clinical performance between next-generation sequencing and standard blood culture diagnostic method in patients suffering from sepsis.

BACKGROUND: Next-generation sequencing (NGS) is a massively unbiased sequencing technology. The objective of this study was to evaluate the performance of NGS-based approach in the detection of microorganisms from septic patients and compare with results of blood culture (BC). METHODS: The observational and non-interventional study was conducted from April 2019 to August 2019. RESULTS: A total of 96 sets of BC and 48 NGS results obtained from 48 septic patients were analyzed in this study. Thirty-two microorganisms (27 bacteria, 3 fungi and 2 viral) were detected by NGS in 23 (47.9%) patients; and 18 bacteria in 18 (37.5%) patients by BC. Exclusion of skin commensals, the positivity of NGS and BC was 62.5% and 14.5%, respectively (P < 0.001). Microorganisms identified by NGS demonstrated positive agreement with BC in 12 (25%) patients, including concordant results in 11 (22.9%) cases, and discrepancy results in 1 (2%). Of 11 patients with concordant results, 4 had additional microorganisms detected by NGS. NGS-positive but BC-negative was found in 9 (18.7%) patients. Using NGS, difficult-to-culture micro-organisms such as Pneumocystic jirovecii was identified in 2 patients, and Leptospira interrogans in one. Six (12.5%) patients with BC-positive but NGS-negative, whereas skin commensals were isolated in 4 (66.6%) cases. The number of patients that were positive by BC only increase from 29% to 47.9% when combining NGS and BC analyses (P = 0.033). CONCLUSIONS: Our study support the advantage of NGS for the diagnosis of infecting microorganisms in sepsis, especially for microorganisms that are currently difficult or impossible to culture.

Autophagy as a mechanism for myolysis of cardiomyocytes in mitral regurgitation.

BACKGROUND: Myolysis of atrial cardiomyocytes occurs in patients with severe mitral and tricuspid regurgitation. This morphological remodelling may involve autophagy. METHODS: This study comprised 20 patients (10 with long-standing persistent atrial fibrillation and 10 with sinus rhythm) with severe mitral and tricuspid regurgitation. Atrial appendageal tissues were obtained during surgery. The appearance of autophagosomes (LC3B) in myocytes can reflect autophagy induction. Complement 9 is used as a reliable marker of oncosis. RESULTS: In the fibrillating right atria, 68·4 ± 18·9% of total myocytes showed moderate-to-severe myolysis, while 64·2 ± 15·8% of total myocytes comprised these cells in right atrial myocardium with sinus rhythm. Immunohistochemical study revealed LC3B-positive myocytes in 8·0% of myocytes without myolysis, 11·9% of myocytes with mild myolysis and 49·4% of myocytes with moderate-to-severe myolysis in right atrial myocardium with sinus rhythm (P < 0·0001). Similarly, in the fibrillating right atria, LC3B-positive myocytes were observed in 5·9% of myocytes without myolysis, 12·2% of myocytes with mild myolysis and 50·7% of myocytes with moderate-to-severe myolysis (P < 0·0001). Moreover, in the fibrillating left atria, LC3B-positive myocytes were observed in 4·9% of myocytes without myolysis, 12·6% of myocytes with mild myolysis and 52·0% of myocytes with moderate-to-severe myolysis (P < 0·0001). None of the atrial myocytes displayed intracellular deposition of complement 9. CONCLUSIONS: Induction of autophagy, but not oncosis, occurs in most cases of atrial cardiomyocytes with severe mitral and tricuspid regurgitation, even those without atrial fibrillation, and is closely associated with the development of myolysis in this disease.

Slit stent technique for ensuring the correct length of artificial chordae in mitral repair.

Excellent long-term results have been described for replacement of diseased mitral valve chordae with polytetrafluoroethylene sutures. Tying the knot at the intended length of the artificial chordae is technically demanding. Herein, a simple and reproducible method, using a slit plastic tube for stenting the artificial chordae at the intended length is described. With this technique, the knot of the premeasured artificial chordae can be tied surely without change in the length.

Absent pulmonary valve syndrome with ascending aortic aneurysm.

Absent pulmonary valve syndrome is rare. We report the case of a child with absent pulmonary valve syndrome noted after birth. Progressive dilatation of the main pulmonary artery and ascending aorta were noted by echocardiography and confirmed by heart computed tomography. He underwent ascending aorta graft replacement and pulmonary artery reduction angioplasty at the age of 6. Good outcome was achieved at 18-month follow-up where subsequent computed tomography revealed a normal size ascending aorta and main pulmonary artery.

Increased inflammatory cell infiltration in the atrial myocardium of patients with atrial fibrillation.

Atrial fibrillation (AF) may be caused by structural and electrophysiological changes in the atria induced by inflammation. This study analyzed 35 adult patients with symptomatic severe mitral valve disease and moderate-to-severe tricuspid valve disease and without coronary artery disease who underwent valve operations for congestive heart failure; 18 patients had persistent AF and 17 patients had no history or electrocardiogram examination of AF before surgery. Atrial appendageal tissues obtained during surgery were evaluated for histopathological changes. The number of inflammatory cells identified as CD45-positive cells in the right atrial myocardium in the AF group (7.5 +/- 7.5 cells per high power field) was significantly higher than that of normal controls (2.7 +/- 1.5 cells per high power field, p = 0.0018). The number of inflammatory cells in the right atrial myocardium did not differ between the sinus group and normal controls (2.7 +/- 1.5 vs 2.6 +/- 2.2 cells per high power field, p >0.05). Additionally, the number of inflammatory cells in the atrial myocardium did not differ between the right and left atria in patients with AF (7.5 +/- 7.5 cells per high power field for right atria vs 7.1 +/- 4.2 cells per high power field for left atria, p = 0.7563). Moreover, correlation analysis revealed a significant association between the number of inflammatory cells in the right atrial myocardium and the number of inflammatory cells in the left atrial myocardium in patients with AF (r = 0.6145, p = 0.0067). In conclusion, inflammatory cell infiltration increases in the atrial myocardium of patients with AF.

Dedifferentiation of atrial cardiomyocytes in cardiac valve disease: unrelated to atrial fibrillation.

BACKGROUND: Valvular heart disease has become an important public health concern. The increased wall stress and underlying disease entity associated with mitral valve disease provide unfavorable circumstances for atrial cardiomyocytes. The expression of the alpha-smooth muscle actin isoform is considered characteristic of cardiomyocyte dedifferentiation (embryonic cardiomyocyte), and cardiomyocyte dedifferentiation may indicate an adaptive state, enabling cardiomyocytes to survive despite unfavorable circumstances. METHODS: This study comprised 20 adult patients with symptomatic severe mitral valve disease and moderate to severe tricuspid valve disease and without coronary artery disease undergoing valve operations for congestive heart failure. Ten patients had persistent atrial fibrillation and 10 patients had never been in atrial fibrillation by history and electrocardiograms before surgery. Atrial tissues of the right atrial appendage were obtained during surgery. RESULTS: Immunohistochemical study demonstrated that alpha-smooth muscle actin protein expression was not altered by atrial fibrillation, and alpha-smooth muscle actin protein expression in atrial tissues was higher in patients with sinus rhythm than in those with atrial fibrillation (the percentage of cells that were alpha-smooth muscle actin-positive was 51.5+/-34.9% for right atria from patients in sinus rhythm vs. 16.2+/-15.0% for right atria from patients with atrial fibrillation) (P<.03). Semiquantitation of alpha-smooth muscle actin by immunoblotting of extracts from atrial tissues showed similar findings as in the immunohistochemical observations: that is, atrial fibrillation did not influence the expression of alpha-smooth muscle actin protein. Interstitial fibrosis represented 43.2+/-13.9% of the right atrial tissue in the sinus group, whereas interstitial fibrosis comprised 49.8+/-8.2% of the right atrial tissue in the atrial fibrillation group (P=.320). CONCLUSIONS: Dedifferentiation of atrial cardiomyocytes occurs in patients with cardiac valve disease, even without atrial fibrillation.

Optimal initial treatment and clinical outcome of type A aortic intramural hematoma: a clinical review.

Intramural hematoma (IMH) of the aorta is a well-known variant of aortic dissection; however, the optimal initial treatment strategy for type A IMH remains controversial. An English language search of Medline for manuscripts on the treatments and outcomes of IMH with the keywords 'intramural hematoma', 'ascending aorta or type A', 'aortic disease' with cross-references was performed for articles dating from January 1986 to September 2006. Primary outcomes of interest were initial treatment strategies as well as the early and overall mortality rates. Earlier publications studying overlapping patient groups from the same institutions were excluded. Case reports and small series of less than 10 patients were not enrolled. Data from 328 reported cases in 12 studies were extracted. Initial surgery and medical treatment were performed for 168 (51.2%) and 160 (48.8%) patients, respectively. Nine out of 12 studies (75%) came from Asia. The early mortality rate was 10.1% (17/168) and 14.4% (23/160) in patients who received initial surgery and medical treatment, respectively (p=0.37). The optimal initial treatment strategy for type A IMH may still be individualized. Initial medical treatment and timed surgical therapy seems to be associated with higher early mortality rates in patients with type A IMH, even in a primarily Asian cohort. The impact of either initial treatment strategy on long-term survival must be evaluated in further study.

Intramedullary reinforcement of sternal fixation with autologous xiphoid tenon.

Minimally invasive cardiac surgery through a partial sternotomy or a ministernotomy is popular. However, the transverse nonunion of the sternum will be a potential complication. Valid and valuable techniques have been introduced for securing the sternotomy fixation. Most of them are focused on the materials or methods for extrinsic reinforcement. A new concept, focused on the intramedullary reinforcement of the sternal fixation, was designed by incarcerating a cancellous portion of the autologous xiphoid in the marrow space of the inter-segmental junction of the partial sternotomy. This autologous xiphoid tenon method is simple, reliable, and reproducible without additional requirement of device implantation or an iliac incision for the bone grafting.

Successful repair of neonatal tricuspid regurgitation due to chordae rupture.

Neonatal rupture of the chordae of tricuspid valve with severe regurgitation is rare and disastrous. We report on a full-term female neonate presented with cyanosis caused by severe tricuspid regurgitation (TR) due to anterior leaflet chordal rupture. After initial stabilization by prostaglandin E1 infusion, successful early repair was achieved with artificial chordae implantation. The unique pathophysiology and the therapeutic strategy of this situation will be described.

Differential Gene Expression Profile of Renin-Angiotensin System in the Left Atrium in Mitral Regurgitation Patients.

BACKGROUND: Left atrial enlargement is a mortality and heart failure risk factor in primary mitral regurgitation (MR) patients. Pig models of MR have shown differential expression of genes linked to the renin-angiotensin system. Therefore, the aim of this study was to investigate the key genes of the renin-angiotensin that are expressed differentially in the left atrial myocardium in MR patients. METHODS: Quantitative RT-PCR was used to compare gene expression in the renin-angiotensin system in the left atrium in MR patients, aortic valve disease patients, and normal subjects. RESULTS: Plasma angiotensin II concentrations did not significantly differ between MR patients and aortic valve disease patients (P = 0.582). Compared to normal controls, however, MR patients had significantly downregulated expressions of angiotensin-converting enzyme, angiotensin I converting enzyme 2, type 1 angiotensin II receptor, glutamyl aminopeptidase, angiotensinogen, cathepsin A (CTSA), thimet oligopeptidase 1, neurolysin, alanyl aminopeptidase, cathepsin G, leucyl/cystinyl aminopeptidase (LNPEP), neprilysin, and carboxypeptidase A3 in the left atrium. The MR patients also had significantly upregulated expressions of MAS1 oncogene (MAS1) and mineralocorticoid receptor compared to normal controls. Additionally, in comparison with aortic valve disease patients, MR patients had significantly downregulated CTSA and LNPEP expression and significantly upregulated MAS1 expression in the left atrium. CONCLUSIONS: Expressions of genes in the renin-angiotensin system, especially CTSA, LNPEP, and MAS1, in the left atrium in MR patients significantly differed from expressions of these genes in aortic valve disease patients and normal controls. Notably, differences in expression were independent of circulating angiotensin II levels. The results of this study provide a rationale for pharmacological therapies or posttranslational regulation therapies targeting genes expressed differentially in the renin-angiotensin system to remedy structural remodeling associated with atrial enlargement and heart failure progression in patients with MR.