RESUMO
@#Objective To compare the outcomes following emergency surgery or conservative treatment for patients with acute type A aortic intramural hematoma (IMH). Methods Clinical data of consecutive patients diagnosed with acute type A aortic IMH in our hospital from September 2014 to December 2018 were retrospectively analyzed. The patients who met our surgical indications received surgery (an operation group) and other patients received strict conservative treatment (a conservative treatment group). Results Finally 127 patients were enrolled, including 112 males and 15 females with an average age of 53.6±13.0 years. Of 127 patients, 85 (66.9%) patients accepted emergency surgery and 42 (33.1%) patients accepted strict conservative treatment. There was no difference between the two groups in early mortality or complications (P>0.05). The 5-year survival rate was 90.4% in the operation group and 74.3% in the conservative treatment group (P=0.010). A maximum aortic diameter in the ascending aorta and aortic arch≥45 mm and maximum thickness of IMH in the same section≥8 mm were risk factors for IMH-related death in patients undergoing conservative treatment (P<0.001). Conclusion The mortality associated with emergency surgery for patients with acute type A aortic IMH is satisfactory. In clinical centers with well-established surgical techniques and postoperative management, emergency surgical treatment may provide a better outcome than conservative treatment for patients with acute type A aortic IMH.
RESUMO
Objective:To identify the causative genes of sporadic thoracic aortic aneurysm or dissection (TAAD) and their correlation with clinical phenotype in the southern Chinese.Methods:We analyzed 11 core genes of TAAD probands without specific family history of 226 cases by next-generation sequencing technology, and performed sanger sequencing for their close relatives. Clinical data of each patient, including age of onset, syndromic phenotypes, involvement of aortic root, aortic maximum diameter and D-dimer were collected. And statistical software SPSS was used to evaluate the correlation between clinical phenotypes and gene mutations.Results:A total of 106 variants were detected in 226 probands with gene-positive frequency of 44.69%, consist of 16 pathogenic (P) variants, 18 likely pathogenic (LP) variants and 71 variants of uncertain significance (VUS). More than half of the mutations were from the non-syndromic TAAD, in which the FBN1 still was the most common causative gene. Earlier age of onset, an increase of women, larger diameter of aorta, Stanford B dissection and severe aortic regurgitation were likely to occur on carriers of P/LP, while thoracic aortic aneurysm occurs on carriers of VUS. Phenotype of both syndrome and dissection with aneurysm could increase the likelihood of carrying gene mutation, but D-dimer and involvement of aortic root couldn’t.Conclusion:Patients with sporadic aortic diseases in southern China have significant genetic heterogeneity and specific correlation between their clinical phenotype and gene mutation, especially in non-syndromic population. Earlier age of onset in carriers of FBN1 or ACTA2 genes, and larger maximum diameters of aorta in carrier of P/LP.
RESUMO
Objective:To investigate the preoperative ascending aorta diameter in patients with acute type A aortic dissection in the Chinese population, compares and analyze the differences in preoperative blood biomarkers, and evaluate the impact of the preoperative ascending aorta diameter in this part of patients on the short-term prognosis of patients.Methods:A collection of 641 patients with acute type A aortic dissection who were enrolled in the " Acute Aortic Syndrome High-Risk Early Warning and Intervention Study" project from January 2018 to January 2020 were collected. Divide the patients into two groups (group Ⅰ<55 mm, group Ⅱ≥55 mm) according to the preventive intervention value of ascending aorta diameter recommended by the guideline for studying preoperative ascending aorta diameter difference in blood biomarkers and the influence of ascending aorta diameter on the short-term prognosis of patients. All patients had CT scans to assess the diameter of the ascending aorta before operation.Results:In this study, all patients with acute type A aortic dissection had a mean preoperative ascending aorta diameter of (46.9±9.7)mm. The preoperative ascending aorta diameter of all patients was less than 55 mm, accounted for 84.1%. Male patients were more likely to have aortic dissection than females; most patients' age was less than 60 years old. The preoperative blood inflammatory index counts were higher in the ascending aorta diameter ≥55 mm group. However, the long-term prognosis of patients with different ascending aorta diameters before surgery was not apparent in this study. The preoperative survival rate and short-term survival rate of patients with ascending aorta diameter <55 mm were higher than those of other groups, but the difference was not statistically significant.Conclusion:In patients with acute type A aortic dissection, the diameter of the ascending aorta is usually less than 55 mm. Moreover, the blood inflammatory index counts are high in the preoperative ascending aorta diameter ≥55 mm group. Meanwhile, patients with smaller ascending aorta diameter have better survival rate and short-term prognosis.
RESUMO
Aortic esophageal fistula(AEF) is a rare, acute and fatal aortic disease.CT and gastroesophageal microscopy have limitations in their diagnosis. Thoracic endovascular aortic repair is considered a bridging treatment for subsequent radical open repair surgery, but a refined surgical plan remains inconclusive . As the etiology, diagnosis, and treatment of AEF remain controversial, this article reviews the current status of AEF treatment.
RESUMO
Assessment of the risk of in-hospital mortality in an acute Stanford type A aortic dissection is helpful for clinical decision making. In recent years, there are three in-hospital mortality risk assessment models for acute Stanford type A aortic dissection: IRAD model, LH model, and Fuwai model. In this review, we highlight the construction of these models and compare their pros and cons. At present, the performance of the LH model in Europe and the United States has been validated, but still needs to be verified in China. The performance of the Fuwai model is currently the most comprehensive. It is necessary to establish a simple and stable acute Stanford type A aortic dissection death risk assessment system suitable for domestic needs.
RESUMO
Objective:To evaluate the effects of supra-arch branches bypass on cerebral oxygen saturation and hemodynamics in patients with Stanford type B aortic dissection.Methods:From January to December 2018, consecutive 27 patients with Stanford type B aortic dissection were enrolled in the study. All patients received hybrid treatment, including supra-arch branches bypass(right axillary artery-left common carotid artery-left subclavian artery) and thoracic endovascular aortic repaire(TEVAR). All the operations were performed by the same surgical team. The left and right cerebral oxygen saturation were measured after anesthesia(T1), left carotid artery occlusion(T2) and after operation(T3); peak systolic velocity(PSV) and resistance index(RI) of left and right carotid arteries were measured before(t1) and after operation(t2).Results:The left cerebral oxygen saturation was 0.62 ±0.01, 0.54±0.01 and 0.62±0.01 at T1, T2 and T3, respectively. There was significant difference between T2 and T1 and T3( P=0.002, P=0.001), but there was no significant difference between T1 and T3. The PSV of left carotid artery at t1 and t2 were(0.91±0.11)m/s and(0.76±0.09)m/s respectively, with no significant difference( P= 0.191). The RI of left carotid artery at t1 and t2 were 0.83±0.06 and 0.93±0.13 respectively, with no significant difference( P= 0.575). Conclusion:If one side of carotid artery was blocked for a short time during supra-arch branches bypass, the cerebral oxygen saturation would be decreased temporarily, but the changes of cerebral oxygen metabolism could be completely restored after operation. However, the hemodynamics of carotid artery would not change significantly. In the hybrid treatment strategy for the patients with aortic dissection Stanford type B, blocking bilateral carotid arteries can be avoided. Making the right axillary artery-left common carotid artery-left subclavian artery shunt is a safe and effective choice.
RESUMO
OBJECTIVE@#To explore genetic mutation types and their correlation with clinical phenotypes in Uighur patients with aortic disease in Kashgar (Xinjiang Uighur Autonomous Region, China).@*METHODS@#We examined 37 pathogenic genes in 19 Uighur families with aortic diseases including Marfan syndrome from Kashgar using next generation sequencing, and the results were confirmed by Sanger sequence in the first relatives.@*RESULTS@#This study included 19 families with aortic diseases, in whom a total of 23 variants were identified, and 11 (57.89%) probands had one or more variants. Among them, definite pathogenic mutation was detected in one patient (5.26%), variants of uncertain significance (VUS) were found in 8 (42.11%), and benign/likely benign variants were detected in 7 (36.84%). The 23 variants identified included one (5.26%) pathogenic variant, 14 (60.87%) VUS, and 8 (34.78%) benign/likely benign variants. The 14 VUS were analyzed by prediction with SIFT and Polyphen2 HDIV, which identified 6 (42.86%) variants as deleterious/possibly damaging; all the 8 benign/likely benign variants were predicted to be deleterious/possibly damaging.@*CONCLUSIONS@#We detected 23 genetic variants in the 19 Uighur families with aortic diseases, and 22 of these variants remain to be verified by more patient data in future studies.
Assuntos
Humanos , Doenças da Aorta , China , Predisposição Genética para Doença/genética , Sequenciamento de Nucleotídeos em Larga Escala , Mutação , FenótipoRESUMO
Objective To detect 14 genes including fibrillin-1(FBN1) and so on mutations in 17 patients with Marfan syndrome(MFS) and family members of 2 patients and to investigate the correlation between FBN1 gene mutation and MFS.Methods Genomic DNAs were extracted from whole blood sample of 17 patients and 43 family members.After DNA samples were amplified by polymerase chain raction(PCR), we used capture panels to get target genes which would be sequenced by Illumina HiSeq2500 Analyzers(Illumina, SanDiego, USA).The target genes included ACTA2、CBS、FBN1、FBN2、MYH11、COL3A1、SMAD3、TGFBR1、TGFBR2、MYLK、MSTN、COLA2、TGFB2 and SLC2A10.The results of sequencing would be compared with multiple databases, including NCBI dbSNP, HapMap, 1000 human genome dataset and database of 100 Chinese healthy adults, to find gene mutation.Finally, these mutations would be validated using conventional Sanger sequencing methods.Results A total of 10 FBN1 mutations and 1 actin alpha2(ACTA2) mutation in 17 patients were identified, of which 8 FBN1 mutations and 1 ACTA2 mutation were novel.One FBN1 mutation was underwent family investigation and we found in this family, all patients had this mutation and others did not have it.Conclusion Missense mutation of c.7280G>A in the 59th exon of FBN1 gene is new pathogenic mutation for MFS.The other 8 novel mutations may be the pathogenic factors of MFS.
RESUMO
Objective:To clarify whether nutritional risk screening 2002 could be used as a basis for nutritional support for liver surgery patients.Methods:Among the 243 hospitalized patients,61 patients had ≥ 3 NRS 2002 scores,and 41 of them were given nutrition support.The remaining 182 patients scored < 3,and 73 of them were administrated with nutrition support.Results:The incidence of nutritional risk of hospitalized patients in liver surgery was 25 %.Among the patients at nutritional risk group,67% were given nutrition support.And the rates of infection related complication were nutritional supported patients significantly lower than that in the no nutrition support group (P < 0.05).Conclusion:Accurate application of NRS 2002 and necessary nutrition support in liver surgery patients could improve nutritional status and clinical outcome.
RESUMO
@#Objective To summarize the experiences of the surgical management for adult patients with aortic coarctation. Methods Clinical data of 40 adult patients diagnosed with aortic coarctation undergoing surgical repair in our center between July 2004 and March 2015 were retrospectively analyzed. There were 28 males and 15 females with a mean age of 26.3±11.0 years (ranging 16-57 years). We evaluated the effect of surgery by the change of pressure gradient between upper limb and lower limb, mechanical ventilation time, and length of ICU stay and hospital stay. Results Forty surgeries were finished successfully. One patient died after surgery. The follow-up ranged from 12 to 36 months. The mean pressure gradient reduced significantly after surgery. There were 6 patients suffering blood hypertension at their discharge, and all of them still need antihypertensive drugs. Conclusion Surgical repair is an effective treatment for adult with aortic coarctation. Extra-anatomic ascending-to-descending aortic bypass and concomitant repair of intracardiac anomalies is safe and effective.
RESUMO
Objective To summarize the effect of supra-arch branches bypass combined with endovascular aortic repair for aortic diseases.Methods From January 2012 to August 2015,120 cases of thoracic aortic diseases (aortic dissection 103,aortic aneurysm 16,penetrating aortic ulcer 1) received hybrid operation in Guangdong Cardiovascular Institute.Vascular bypass was established among the brachiocephalic arteries,followed by endovascular repair through femoral artery either one-stage or two-stage.Patients were followed up for 3-24 months.Results Technical success was achieved among all the patients.Five patients died after the operation(one patient had retrograde aortic dissection,2 patients had pericardial tamponade,one patient had apnea,and one patient had respiratory and cardiac arrest.The death rate is 4.1%),4 patients had stroke,among them,symptoms were relieved in three patients,one patient was not cured.Total 92 patients were followed-up and had no symptoms of up-limb ischemia or dizziness.CT scan showed bypass graft and endovascular stent patency.6 patients had endoleak (type Ⅰ b 2 cases,type Ⅱ 3 cases,and type Ⅲ 1 case),distal aortic dissection occurred in one patient,three patients had mild contrast agent leakage around the distal endovascular stent,type A aortic dissection occurred in one patient,there were no late stage death.Conclusion Supraarch branches bypass combined with endovascular aortic repair for treating aortic disease is minimally invasive,safe,and can reduce the incidence of postoperative complications.
RESUMO
Objective To evaluate the prevalence and impact of coronary artery disease (CAD) in aged patients with Stanford type B aortic dissection(AD).Methods From January 2008 to December 2011,CAG was routinely performed before aortography and thoracic aortic repair(TEVAR) to determine the prevalence of concomitant CAD in 200 consecutive Stanford type B AD patients who were older than 50 years.All patients received 1 year follow-up.Adverse events were compared between patients with and without concomitant CAD.Data analysis by SPSS 17.0 statistical software,using Student t test,Chi-square test and Fisher exact test.Results CAG showed 53 patients (26.5%) had CAD.Multivariate logistic regression analysis showed that male gender(OR =4.415,95% CI:1.131-17.237,P =0.033) and age (OR =1.061,95% CI:1.017-1.108,P =0.006) were independent predictors of Stanford type BAD coexisted with CAD.Age was also independent predictor of multi-vessel disease(MVD) and/or left main disease(LMD) (OR =1.096,95% CI:1.009-1.191,P =0.023).At 30-day follow-up,there was no difference in the incidence of adverse events between patients with and without concomitant CAD.Patients with concomitant CAD showed higher incidence of myocardial infarction[3 (5.66%) vs.0(0),P =0.018] and stroke [4 (7.55 %) vs.1 (0.68 %),P =0.018].Conclusion The prevalence of CAD in aged patients with Stanford type BAD is relatively high.Concomitant CAD is associated with higher risk of cardio-cerebrovascular ischemic events while dose not increase the risk of adverse aorta related events.
RESUMO
Objective To analyze the risk factors of postoperative acute renal injury (AKI) for acute Stanford type A aortic dissection in 137 cases.Methods From January 2010 to December 2011,137 patients with acute Stanford type A aortic dissection were received surgical operations in our hospital.There were 106 males and 31 females with their mean age of(46.8 ± 13.1)years and mean weight of (69.9 ± 18.0) kg.The postoperative acute renal injury diagnosis was according to AKIN diagnosis standard of acute kidney injury network working group in 2005.All patients were received surgical repair with cardiopulmonary bypass,including 120 patients with deep hypothermic circulatory arrest and selective cerebral perfusion.Among them,there were 54 cases with total arch replacement and 66 with right half arch replacement.The postoperative managements were include control the patients' mean arterial blood pressure at 80 to 90 mmHg (1 mmHg =0.133 kPa),supplement the blood volume timely,and correction of hypoxia and hypoproteinemia.The patients were received renal replacement therapy if still oliguria after medical treatments,or their blood creatinine raising continually more than 500 μmol/L.Results A total of 12 patients died in hospitalization with a total in-hospital mortality of 8.74% (12/137).76 cases had AKI in the first day after operations,including 38 cases (27.7%) with stage Ⅰ and 21 cases (15.3%) with stage Ⅱ and 17 cases (12.4%) with stage Ⅲ.There were 36 patients have acute renal failure (ARF) with morbility of 26.3% (36/137),and 34 patients among them were received renal replacement therapy.Single factor analysis showed that preoperative creatinine,total arch replacement,cardiopulmonary bypasstime,intraoperative day transfusion of concentrated red cells are risk factors of ARF.Logistic regression was used for multivariate analysis showed that total arch replacement and preoperative creatinine abnormalities are independent risk factors for postoperative AFR.Conclusion Total arch replacement and preoperative creatinine abnormalities were independent risk factors of AFR for acute type A dissection after operation.
RESUMO
Objective: To analyze the risk factors on acute respiratory dysfunction caused death in patients after type A aortic dissection surgery. Methods: A total of 223 patients who received aorta replacement surgery in our hospital from 2010-01 to 2012-12 were retrospectively studied. 80 patients suffered from post-operative acute respiratory dysfunction including 61 male and 19 female with the mean age of (49.2 ± 11.6) years. Those patients were divided into 2 groups as Death group, n=18 and Survival group, n=62. We analyzed the most relevant risk factors for death, such as gender, age, histories of smoking, diabetes, hypertension, Marfan syndrome;pre-operative acute or chronic dissection, hypoxemia, mal-perfusion, LVEDD and LVEF;CPB time, aortic-clamping time;post-operative ICU retention time, mechanical ventilation time, permanent neurologic dysfunction, pulmonary infection, MACE, renal failure, hypohepatia, septicemia and wound mal-healing, et al. Results: The early post-operative ( Conclusion: The occurrence and mortality were high in patients after type A aortic dissection surgery especially in those with female gender and post-operative renal failure.
RESUMO
<p><b>BACKGROUND</b>Thoracic endovascular aortic repair (TEVAR) is an emerging treatment modality, which has been rapidly embraced by clinicians treating thoracic aortic disease. However, the clinical manifestations of systemic inflammatory response after TEVAR as post-implantation syndrome (PIS) resemble the perioperative infection. This study aimed to evaluate changes and diagnostic value of procalcitonin (PCT) and other traditional inflammatory markers for infections after TEVAR.</p><p><b>METHODS</b>We conducted a prospective clinical study that enrolled 162 consecutive aortic dissection cases, who underwent TEVAR in our institution between July 2011 and November 2012. The PCT, C-response protein (CRP), erythrocyte sedimentation rate (ESR) and blood routine examination were monitored before the operation and on days 1, 2, 3 and 5 after the operation. The diagnosis of infection was confirmed by the infection control committee with reference to Hospital Acquired Infection Diagnostic Criteria Assessment, released by the Ministry of Health of the People's Republic of China.</p><p><b>RESULTS</b>Post endovascular repair of thoracic aorta, PCT changes significantly at different time points (χ(2) = 13.225, P = 0.021), without significant difference between the PIS group and the control group (0.24 ± 0.04 vs.0.26 ± 0.10, P = 0.804). PCT values were significantly higher in the first day after TEVAR than the preoperative levels (0.18 ± 0.03 vs. 0.11 ± 0.02, P < 0.001). Compared with PIS patients, the level of PCT, CRP, White blood cell (WBC) and neutrophil (NEU) in the infection patients elevated significantly (relatively χ(2) = 6.062, P = 0.048; χ(2) = 6.081, P = 0.048; χ(2) = 11.030, P = 0.004; χ(2) = 14.632, P = 0.001). According to the ROC analysis, the PCT levels in the first day after TEVAR (AUC = 0.785, P = 0.012) had better predictive values of infection than WBC, NEU CRP and ESR (AUC = 0.720, P = 0.040; AUC = 0.715, P = 0.045; AUC = 0.663, P = 0.274; AUC = 0.502, P = 0.991). The best predictive index was the changes of PCT between preoperative and postoperative (PCT), which possess AUC as 0.803 (P = 0.014). And PCT = 0.055 could be considered as an infection diagnosis cutoff value with a sensitivity of 83.3% and specificity 69.0%.</p><p><b>CONCLUSIONS</b>PCT provides better diagnostic value of infection compared with other inflammatory markers. The potential applications of PCT in differential diagnosis of PIS and infection after percutaneous TEVAR deserve further studies.</p>
Assuntos
Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Sedimentação Sanguínea , Proteína C-Reativa , Metabolismo , Calcitonina , Metabolismo , Peptídeo Relacionado com Gene de Calcitonina , Diagnóstico Diferencial , Estudos Prospectivos , Precursores de Proteínas , Metabolismo , Procedimentos Cirúrgicos VascularesRESUMO
BACKGROUND:The mechanical valves used in the adult Luo-Ye pump have a large size and great destruction to blood, which are not suitable for infant ventricular assist pump. Therefore, designing and producing a high molecular valve with smal size and low incidence of thrombosis is a research hotspot. OBJECTIVE:To design and produce a valve of 20 mL infant Luo-Ye pump, and to test its basic functions and fatigue properties. METHODS:The size and shape of valve was designed with MASTERCAM software, polyurethane valve was obtained through producing the valve model and plastic injection;the static leakage, pressure drop and fatigue resistance of polyurethane valve were tested according to the ISO5840 requirements. RESULTS AND CONCLUSION:The polyurethane trefoil valve was produced, but the failure rate of plastic injection was high;the basic function of the trefoil valve met the ISO5840 requirements bascial y;after continuously operated 1.0×107 times, stroke volume of 20 mL Luo-Ye pump was changed 5.2%, and two polyurethane valves and valve leaflets did not change and damage. Polyurethane trefoil valve was designed and produced successful y;polyurethane valves could meet the needs of 20 mL Luo-Ye pump, which already have the ability to clinical trials.
RESUMO
Objective To retrospectively analyze the surgical methods and efficacy in 70 cases of type A aortic dissection patients over 65 years old.Methods From January 2005 to May 2012,70 type A aortic dissection patients over 65 years old received surgical treatment.Among them,there were 47 males aged 65 to 78 years old with mean 71,23 females,aged 65 to 72 years old with mean 68.55 cases were acute onset,while 15 cases were chronically onset.Different surgical methods were selected depend on patients' situations.We followed up all patients after discharged from hospital to continue to observe their health situation and evaluate the therapeutic effects.Results After surgery,eight patients died in the hospital,62 patients were recovered and discharged from the hospital.The mortality rate is 11.4%.During the follow up period from 3 to 72 months,there were no dead,aneurysm rupture and others severe complications.9 cases received endovascular graft exclusion within 6 months after discharged from hospital.The survival patients were satisfactory healed with their daily living activity resumed.Conclusion For over 65 years old patients with aortic dissection,the accurate and rapid selection of surgical method could improve the survival rate and the quality of life with a lower occurrence rate of complications.
RESUMO
Objective: To evaluate the mitral, aortic and tricuspid valve replacement for rheumatic heart disease. Methods: From June 1990 to June 2001, 941 patients underwent valve replacement. Among them, 24 patients underwent simultaneously mitral, aortic and tricuspid valve replacement. There were 17 females and 7 males, with mean age of 36 years (ranged from 18 to 59 years). Eight patients had previous closed mitral valvotomy. Eleven patients complicated with left atrium thrombus, 16 with hapotomeglia, and 8 with ascites. The X ray results showed that the C/T ratio was 0.66 to 0.91. The heart function (NYHA) was class III in 9, and class IV in 15. All patients had combined mitral, aortic valve lesions associated with severe tricuspid valve regurgitation. Results: One patient died postoperatively with an operative mortality of 4.2%. 23 patients followed up from 20 to 36 months (mean, 26.4 months). There was no thrombolism and anticoagulant related hemorrhage. The echocardiography demonstrated the diameter of left atrium right ventricle, and LVDd significantly decreased after operation. The heart function was also significantly improved. Conclusion: The combination of mitral, aortic and tricuspid valve replacement could achieve a satisfactory result with low mortality and better recovery of heart function.
RESUMO
Electrocardiac signal is one of the most important signals which is used to trigger ventricular assist device (VAD), and the delay time of VAD assistance is very important to get a satisfied result. Proper delay will give VAD relatively enough time to assist, avoiding left heart failure caused by the collision of the heart and VAD during systolic phase. This becomes much more important when the left atrium drainage is insufficient. The aim of our study is to set up an equation to calculate the delay time by RR interval. We try to set up an equation about RR and R-Ao like: R-Ao = A x (RR)n + B(A and B are constant). RR represents the RR interval and R-Ao represents the duration of the period between the peak point of QRS and the point of aortic valve closing; First, calculate RR according to weighting average method, and then, calculate the anticipant R-Ao according to the before-mentioned equation. After adjustment, R-Ao will be used as assistance delay time. R-R interval was measured in 457 selected pediatric patients who were undergiong left heart catheterization and who did not have arrhythmias. From the ECG recording during catheterization, R-R interval was measured while R-Ao was obtained from aortic pressure wave chart; Plot graphs with R-Ao as dependent variable and (RR)n as independent variable; find out correlating model and calculate the arguments A and B of R-Ao = A x (RR)n + B. The results showed that the relation between (RR)1/3 and R-Ao is the most significant, the relation coefficient is 0.733, the regress coefficient is -0.182 (P < 0.001) and the interception is 1.070. This means that R-Ao = (-0.182) (RR) 1/3 + 1.070. The likelyhood degrees of different sections differ markedly. When heart rate is less than 120 beats per min. The relation argument is about 0.733 while 0.45 when heart rate is more than 120 beats per min, Therefore, we can use the equation R-Ao = (-0.182) (RR)1/3 + 1.070 to calculate R-Ao when heart rate is less than 120 beats per min.