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ORIGINAL ARTICLE
Year : 2022  |  Volume : 20  |  Issue : 2  |  Page : 63-68

Acute anterior wall myocardial infarction: The importance of ST-Segment change in lead aVR


1 Consultant, Interventional Cardiologist, Galaxy Hospital Varanasi, Uttar Pradesh, India
2 Consultant, Department of Cardiology, Super Speciality Hospital, Associated Hospital of Government Medical College, Srinagar, Jammu and Kashmir, India
3 Consultant Cardiologist, Batra Hospital and Medical Research Centre, New Delhi, India

Date of Submission26-Jan-2022
Date of Decision18-Mar-2022
Date of Acceptance22-Mar-2022
Date of Web Publication07-May-2022

Correspondence Address:
Dr. Sheikh Mohamad Tahir
Department of Cardiology, Super Speciality Hospital, Associated Hospital of Government Medical College, Srinagar, Jammu and Kashmir
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/cmi.cmi_15_22

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  Abstract 


Background: According to recent research, examining the ST-segment shift in lead aVR provides valuable information on coronary angiographic anatomy and risk categorization. In acute anterior wall myocardial infarction (MI), lead aVR has diagnostic and prognostic relevance. The purpose of this study is to look at the relationship between presenting clinical status and coronary artery disease risk factors and ST-segment deviation in lead aVR. Methods: This prospective observational hospital-based study was carried out in the Department of Cardiology at Batra Hospital and Medical Research Centre in New Delhi. Patients with acute anterior wall ST-elevation MI who presented within 24 h of symptoms were included in the study. Continuous data were expressed as mean standard deviation and categorical variables as the number or percentage of patients. Results: The study involved 73 individuals who met the inclusion and exclusion criteria and had acute anterior wall ST-elevation MI. Thirty of the 73 patients (41%) had ST-segment elevation in lead aVR larger than 0.5 mm. In two groups, the distribution of various cardiovascular risk factors was examined. In all of the cases, the left anterior descending artery was affected. Patients with double- and triple-vessel disease were seen in more significant numbers in Group A than in Group B. Cardiogenic shock occurred in 6 of 30 patients in Group A and 3 of 43 patients in Group B. Conclusions: ST-elevation in lead aVR has predictive value. Patients with higher ST-segment elevation in aVR are more likely to suffer angina, CHF, and cardiogenic shock complications. Providing these patients with percutaneous or surgical revascularization therapy as soon as possible can reduce mortality.

Keywords: Coronary artery circulation, heart rupture, myocardial infarct, necrosis, postinfarction


How to cite this article:
Gupta V, Tahir SM, Yadav R D. Acute anterior wall myocardial infarction: The importance of ST-Segment change in lead aVR. Curr Med Issues 2022;20:63-8

How to cite this URL:
Gupta V, Tahir SM, Yadav R D. Acute anterior wall myocardial infarction: The importance of ST-Segment change in lead aVR. Curr Med Issues [serial online] 2022 [cited 2022 May 21];20:63-8. Available from: https://www.cmijournal.org/text.asp?2022/20/2/63/344930




  Introduction Top


The 12-lead electrocardiogram (ECG) is a critical tool for diagnosing and risk-stratifying acute coronary syndrome (ACS).[1] The right upper heart, encompassing the outflow tract of the right ventricle and the basal portion of the interventricular septum, was studied using lead aVR, an augmented and unipolar limb lead.[2] Unlike the other 11 leads, lead aVR had been overlooked for a long time. In ACS, however, a recent study found that evaluating ST-segment shift in lead aVR provided helpful information on coronary angiographic anatomy and risk stratification.[2],[3] ST-elevation in aVR can also be caused by global submyocardial ischemia caused by left main coronary artery (LMCA) disease or triple vascular disease. In lead aVR, transmural ischemia in the inferolateral and apical regions, on the other hand, can cause ST-segment depression.[2]

The ACS can be identified by ST-segment elevation, depression, or isoelectric ST segment in lead aVR.[4] Depression and ST-segment elevation is associated with a poor prognosis and increased mortality. AVR ST elevation of <1 mm in inferior and anterior infarction has been related to higher 30-day mortality.[5] A study also discovered that ST-segment elevation in lead aVR was associated with increasing age and more risk factors such as diabetes, hypertension, smoking, and a family history of ischemic heart disease, as well as a higher risk of complications such as shock, heart failure, arrhythmia, postmyocardial infarction (MI) angina, and a higher rate of mortality.[6]

Furthermore, ST-segment shift in lead aVR has been found in trials to determine the location of a coronary occlusion in ACS.[7] Lead aVR can help detect a blockage in the LMCA. Ischemia of the basal section of the interventricular septum is the electrocardiographic explanation for the presence of ST-segment elevation in this lead.[8] Lead aVR can also help differentiate LMCA from proximal left anterior descending artery (LAD) disease. ST elevation in aVR implies LMCA disease more than in V1, and vice versa, proximal LAD illness.[9] In distal blockage of the LAD that does not involve the proximal septal region, there is no ST elevation but rather a depression in lead aVR.[10]

According to the literature, lead aVR has diagnostic and prognostic value in acute anterior wall MI (AWMI). Keeping this in mind, we designed this study with the following goals in mind.

  • To investigate the predictive importance and clinical outcome of ST-segment deviation in lead aVR patients with acute anterior wall ST-elevation MI
  • To investigate the angiographic link with ST-segment deviation in lead aVR patients with acute anterior wall ST-elevation MI
  • To investigate the relationship between presenting clinical status and coronary artery disease risk factors and ST-segment deviation in lead aVR in individuals with acute anterior wall ST-elevation MI.



  Methods Top


Study site

The study was conducted in the Department of Cardiology at Batra Hospital and Medical Research Centre, Delhi.

Study population

Study population included patients of acute anterior wall ST-elevation MI, presenting within 24 h of the onset of symptoms.

Study design

This study is a prospective observational clinical study.

Sample size

A sample size of 50 was calculated using formula n = Zα/2 2 p (1 − p)/s2 where n = sample size, p = prevalence, s = margin of error, Zα/2 = 1.96 at α = 5%, and α = level of significance. As there are no data available regarding the prevalence of acute anterior wall myocardial infarction (AWMI), the prevalence of coronary artery disease was taken as a guiding tool. However, we continued to recruit patients throughout the study period to make the study more significant. A total of 73 patients could be included in the study after applying the exclusion criteria.

Time frame of the study

The study was conducted from July 2015 to May 2016.

Inclusion criteria

Patients with acute anterior wall ST-elevation MI were included in the study.

Exclusion criteria

The following patients were excluded from the study: patients having a prior anterior MI, patients presenting after 24 h of the onset of symptoms, patients with bundle branch block conduction disturbances, patients not undergoing coronary angiography on an emergent basis, and patients with prior percutaneous transluminal coronary angioplasty or coronary artery bypass grafting (CABG). Subsequent patients with a diagnosis of acute AWMI, based on clinical symptoms (onset less than 24 hours), ECG criteria -new ST elevation at the J point in at least two contiguous leads of 2 mm (0.2 mV) in men or 1.5 mm (0.15 mV) in women in leads V2–V3 and/or of 1 mm (0.1mV) in other contiguous chest leads12 and, cardiac biomarkers (if required) were selected. Patients were divided into two groups based on the ST-segment deviation in lead aVR Group A – ST-segment elevation of >0.5 mm in lead aVR and Group B – ST-segment elevation of ≤0.5 mm in lead aVR.

ST-segment shift was measured at 20 ms after J point in case of ST-elevation and 80 ms after J point in case of ST-segment depression using the preceding TP segment as a baseline. Informed written consent was obtained from all patients. Initial clinical data at presentation were recorded. In addition, demographic data, risk factors for CAD, and data from the physical examination were collected.

Patients were first stabilized and then subjected to coronary angiography, and records of coronary anatomy were noted. Those who did not undergo coronary angiography because of any reason and were treated medically with thrombolytic therapy were excluded from the study. A stenosis >50% in diameter of the LMCA or a stenosis >70% in one or more of the major epicardial vessels or their main branches was considered significant. Patients were then subjected to definitive interventional management, either percutaneous coronary intervention (PCI) or surgical revascularization as needed. Patients were then followed up in coronary care unit (CCU) and inward for any major inhospital adverse event such as death, angina, heart failure, or cardiogenic shock. Echocardiographic findings before discharge and the total duration of hospital stay were also recorded.

Statistical analysis

MS Office Excel worksheet 2007 was used to tabulate the data. Continuous data were expressed as mean standard deviation and categorical variables as the number or percentage of patients. For the comparison of constant data, an unpaired t-test was used. For categorical data comparison, Fisher's exact test was used. All statistical analyses were carried out using the Statistical Package for the Social Sciences (SPSS) version 26.0.

Forms of informed consent

Each participant completed a patient information document following the description of the protocol and its requirements. It was interpreted, explained, and signed in their vernacular if the patient could not read English. Again, the patient's confidentiality was fully respected.


  Results Top


The study involved 73 individuals who met the inclusion and exclusion criteria and had acute anterior wall ST-elevation MI. They were separated into two groups based on the ST-segment deviation in the lead aVR. Thirty of the 73 patients (41%) had ST-segment elevation in lead aVR larger than 0.5 mm.

  • Group A: 30 patients with ST-segment elevation in lead aVR more than 0.5 mm
  • Group B: 43 individuals were included with ST-segment elevation in lead aVR <0.5 mm.


Ten of the thirty patients in Group A showed ST-segment elevation in lead aVR >1 mm, whereas only 5 of the 43 patients in Group B had ST-segment depression in lead aVR 0 mm. As a result, most patients (58 of 73, or 79.5%) had 0–1 mm ST-segment elevation in lead aVR.

Patients in both the groups were age matched. The mean value of clinical presentation parameters such as heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) was more remarkable in Group A patients; however, only the heart rate (HR) at presentation showed a statistically significant difference between the two groups. The mean HR followed in Group A patients was 93.93 compared to 84.11 in Group B patients, with P = 0.047. SBP was higher in Group A (14,038.86) than in Group B (13,330.82) (P = 0.396). DBP was similarly higher in Group A patients (8724.8) compared to Group B patients (8117.53), although the difference was not statistically significant (P = 0.261).

The percentage of patients in Killip class >1 was higher in Group A (8 of 30, 26.67%) than in Group B (8 of 43, 18%), although this was not statistically significant [Table 1].
Table 1: Baseline characteristics of the study participants

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Distribution of risk factors

In two groups, the distribution of various cardiovascular risk factors was examined. Patients in Group A had a higher percentage of hypertension, smoking, and a family history of hypertension than patients in Group B. About 50% of the patients in Group A were hypertensive, compared to 34.9% in Group B (P = 0.023), and 83.3% in Group A were smokers, compared to 62.8% in Group B (P = 0.069). In Group A, 33.33% of patients had a family history of cardiovascular disease, whereas 23.35% in Group B (P = 0.43). Diabetes was diagnosed in 30% of the patients in Group A versus 32.55% in Group B (P = 1.0). In Group A, 56.67% of the patients had dyslipidemia compared to 55.81% in Group B (P = 1.0). However, no significant difference in risk factors was found between the two groups [Table 2].
Table 2: Risk factor distribution among the study participants

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Characteristics of angiogram

Coronary angiography revealed that 17 of 30 (56.67%) patients in Group A had multivessel disease, compared to 13 of 43 (30.23%) in Group B. Thus, patients in Group A outnumbered patients in Group B in terms of multivessel disease, and the difference was statistically significant (P = 0.03). In addition, patients with double- and triple-vessel illnesses were seen in more significant numbers in Group A than in Group B.

The LAD artery was affected in all of the patients. In both groups, the lesion site was about equally proximal (66.67% in Group A vs. 65.11% in Group B). The remaining patients all had a mid-LAD lesion. There were no lesions in the distal LAD in any of the patients [Table 3].
Table 3: Angiographic characteristics and relationship among the study participants

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Management in two groups

Percutaneous revascularization was performed on all 43 patients in Group B, while surgical revascularization was performed on 4 of 30 patients in Group A, with the remainder undergoing PCI. As a result, all patients had a definitive treatment, either PCI or CABG. Intra-aortic balloon pump was required in 9 of 30 patients in Group A versus one in Group B (P = 0.001). Adverse incidents in two groups are shown in [Table 4].
Table 4: Management done among the two groups based on the diagnosis (study participants)

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Complications were more common in participants in Group A than in patients in Group B. Patients in Group A experienced angina at a rate of 10 of 30 (33.33%) compared to only 4 of 43 (9.3%), a statistically significant difference (P = 0.15). The cardiogenic shock occurred in 6 of 30 patients in Group A versus 3 of 43 patients in Group B (P = 0.147). Congestive Heart Failure (CHF) was found in 7 of 30 patients in Group A versus 6 of 43 individuals in Group B (P = 0.359). Group A had a higher percentage, but the difference was not statistically significant [Table 5].
Table 5: Adverse events found among the two groups (study participants)

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Hospital stay duration and death

The duration of hospital stay was longer in Group A patients than in Group B patients. The average length of stay for patients in Group A was 5.2 days, compared to 4.2 days for patients in Group B; the difference was statistically significant (P = 0.028).

Three of 30 (10%) patients in Group A died, compared to 1 of 43 (2.3%) patients in Group B (P = 0.299). The death rate was more significant in Group A, although the difference was not statistically significant [Table 6].
Table 6: Duration of hospital stay and mortality among the two groups (study participants)

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  Discussion Top


Several investigations have found that ST-segment deviation in lead aVR has predictive value in acute anterior wall MI. Therefore, the goal of this study was to investigate these patients' clinical status when they arrived at the hospital, their angiographic profile, and inhospital adverse events and mortality related to ST-segment changes in lead aVR.

Our study differed from prior studies in that it only included patients who had emergency coronary angiography, and all patients had interventional treatment, either percutaneous or surgical revascularization. Those who had previously had delayed CAG or thrombolytic treatment were ineligible. As a result, the set of outcomes became more homogeneous. Patients in previous research got either thrombolytic therapy or a combination of invasive and noninvasive treatments. Our data demonstrate that angina, cardiogenic shock, and CHF are more common in patients with ST-segment elevation in aVR >0.5 mm. However, the percentage of patients who acquired these problems was much lower than in the earlier study by Abbase and Aljubawii[6] with only the prevalence of angina showing a statistically significant difference.

Thirty-three percent of 30 patients with aVR STE >0.5 mm had postprocedure angina, compared to 9.3% of 43 patients in the other group (P = 0.015). Cardiogenic shock and CHF developed in 20% and 23.3% of the patients in the aVR ST elevation >0.5 mm group, compared to 6.9% (P = 0.147) and 20% (P = 0.359) in the other group, respectively. In a similar study, Abbase and Aljubawii[6] discovered a considerably higher occurrence of all sequelae such as angina (58% vs. 35%), cardiogenic shock (30% vs. 10.5%), and CHF (44% vs. 21%) in a group with aVR STE >0.5 mm. However, thrombolytic treatment was administered to all patients in their study. Our investigation found no statistically significant difference in inhospital mortality between the two groups. Total mortality in the aVR STE >0.5 mm group was 10% (3 of 30 patients), compared to 2.3% (one out of 43) in the other. Abbase and Aljubawii[6] discovered a substantial difference in mortality, with 30% and 12% in the different groups. Inhospital mortality was 19% in the aVR STE >0.5 mm group and 5% in the other group, according to Aygul et al.[11] They cited aVR positivity as a separate predictor of inhospital death. Thirty-day mortality was similarly higher in patients with STE in aVR substudy of the HERO-2 trial. According to Wong et al.,[5] aVR ST elevation of 1 mm was linked with increased 30-day mortality for both low (22.5% for 1.5 mm and 13.2% for 1 mm) and anterior infarction (23.5% for 1.5 mm and 11.5% for 1 mm). As a result, we found reduced mortality in both groups than in these trials, and the difference was not statistically significant. We attribute this to the patient's receiving standard, Level 1 recommended treatment in the hospital, which resulted in a better outcome, and thus earlier definitive interventional management would be beneficial in both reducing adverse events as well as mortality, even in patients with elevated ST segment in aVR in acute MI, who have a known poorer prognosis.

The duration of hospitalization was longer in the group with STE in the aVR > 0.5 mm group. This group's average stay was 5.2 days, compared to 4.2 days in another group (P = 0.028). This was due to two factors. The first was that the aVR-positive group had more adverse events. The second was that fewer patients were taken for surgical revascularization, increasing the average hospital stay. Several studies have found a link between ST-segment elevation in aVR and multivessel disease.[8],[12] In our investigation, we found a similar effect. The difference was statistically significant, with 56.67% of the patients in the aVR positive group having multivessel disease compared to 30.23% of the patients with STE in aVR 0.5 mm. Furthermore, a more significant number of double vessel disease (DVD) and triple vessel disease (TVD) were found in aVR STE patients. The percentage of patients with proximal LAD disease was nearly identical in both groups (66.67% in the aVR STE group vs. 65.11% in the other), which contradicted the findings of a previous study by Kotoku et al.[13] who discovered a higher number of proximal LAD diseases in patients with STE in aVR. Patients with isoelectric and depressed ST segments had a more mid and distal illness. Due tomultivessel conditions, surgical revascularization was explored in 4 of the 30 patients, while the percutaneous intervention was used in all other groups.

Except for the HR, 93.9 compared to 84 (P = 0.047) in patients with ST-segment elevation >0.5 mm in lead aVR, baseline clinical parameters were not substantially different in patients with ST-segment elevation >0.5 mm in lead aVR. The SBP and DBP and the Killip class at presentation were not substantially different between the two groups. Wong et al.[5] discovered a significantly higher HR (82 vs. 80) in individuals with aVR ST elevation of more than 1 mm but no difference in SBP or DBP. In addition, they discovered a considerably more significant percentage of patients with Killip class >1 in the aVR ST elevation group (30.7% vs. 23.6%, P = 0.001); however, these comparisons were made in aVR ST elevation 1 mm and 1 mm. Aygul et al.[11] discovered a comparable finding in HR. However, those with aVR positive (>0.5 mm) had lower SBP and a worse Killip class.

The aVR ST elevation >0.5 mm group had more patients with hypertension (50% vs. 34.9%, P = 0.23) and smoking history (83.3% vs. 62.8%, P = 0.069), but the difference was not statistically significant. Diabetes and dyslipidemia were distributed practically identically in the two groups. This contrasted with the findings of Abbase and Aljubawii.[6] who discovered that a considerably more significant proportion of individuals with ST-segment elevation in lead aVR had risk factors such as diabetes, hypertension, smoking, and a family history of ischemic heart disease. Wong et al.[5] discovered a higher number of smokers and hypertensive patients in the aVR STE group, but no significant difference in the number of diabetic patients was reported.

Study limitation

Our study had a small number of patients and was conducted in a single hospital setting. ST-segment elevation of >1 mm or greater in lead aVR has been linked to a worse prognosis in studies. However, a connection between graded ST elevation or even ST depression in aVR and adverse events and mortality could not be examined because of the small number of patients. Clinical implications of ST-segment depression in lead aVR in a larger cohort of consecutive patients with anterior AMI need to be investigated which we could not do due to the small sample size.

Recommendations

To lessen the considerable morbidity and mortality associated with acute anterior wall ST-elevation MI, patients should be offered percutaneous or surgical revascularization.


  Conclusions Top


In acute anterior wall ST-elevation MI, ST-segment elevation in lead aVR has predictive importance and needs to be taken for primary PCI within 12 h of developing chest pain. Patients with higher ST-segment elevation in aVR are more likely to suffer angina, CHF, and cardiogenic shock complications. Providing these patients with percutaneous or surgical revascularization therapy as soon as possible can reduce mortality and morbidity. Patients with more significant ST-segment elevation in lead aVR have a worse clinical condition at presentation than those with less or no ST elevation. Multivessel coronary artery disease is more likely in patients with anterior wall MI who had ST-segment elevation in aVR >0.5 mm. There is no statistically significant difference in the cardiovascular risk profile when ST-segment elevation is present in lead aVR.

Research quality and ethics statement

The Institutional Ethics Committee at our institute reviewed this study design, data collection instruments, consent forms, and patient information sheets as part of the procedure required in all research requiring human participation. The research proposal was approved on December 23, 2014, through IRB no BH/2017/Proposal/2275-H.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

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Achar SA, Kundu S, Norcross WA. Diagnosis of acute coronary syndrome. Am Fam Physician 2005;72:119-26.  Back to cited text no. 1
    
2.
Tamura A. Significance of lead aVR in acute coronary syndrome. World J Cardiol 2014;6:630-7.  Back to cited text no. 2
    
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Adar A, Onalan O, Cakan F. Relationship between ST-segment shifts in lead aVR and coronary complexity in patients with acute coronary syndrome. Acta Cardiol Sin 2019;35:11-9.  Back to cited text no. 3
    
4.
Coppola G, Carità P, Corrado E, Borrelli A, Rotolo A, Guglielmo M, et al. ST segment elevations: Always a marker of acute myocardial infarction? Indian Heart J 2013;65:412-23.  Back to cited text no. 4
    
5.
Wong CK, Gao W, Stewart RA, Benatar J, French JK, Aylward PE, et al. aVR ST elevation: An important but neglected sign in ST elevation acute myocardial infarction. Eur Heart J 2010;31:1845-53.  Back to cited text no. 5
    
6.
Abbase AH, Aljubawii AA. The significance of ST segment elevation in lead aVR in acute anterior myocardial infarction. Med J Babylon 2011;8:490-6.  Back to cited text no. 6
    
7.
Barrabés JA, Figueras J, Moure C, Cortadellas J, Soler-Soler J. Prognostic value of lead aVR in patients with a first non-ST-segment elevation acute myocardial infarction. Circulation 2003;108:814-9.  Back to cited text no. 7
    
8.
Yamaji H, Iwasaki K, Kusachi S, Murakami T, Hirami R, Hamamoto H, et al. Prediction of acute left main coronary artery obstruction by 12-lead electrocardiography. ST segment elevation in lead aVR with less ST segment elevation in lead V (1). J Am Coll Cardiol 2001;38:1348-54.  Back to cited text no. 8
    
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Uthamalingam S, Zheng H, Leavitt M, Pomerantsev E, Ahmado I, Gurm GS, et al. Exercise-induced ST-segment elevation in ECG lead aVR is a useful indicator of significant left main or ostial LAD coronary artery stenosis. JACC Cardiovasc Imaging 2011;4:176-86.  Back to cited text no. 9
    
10.
Gorgels AP, Engelen DJ, Wellens HJ. The electrocardiogram in acute myocardial infarction. In: Fuster V, Alexander RW, O'Rourke RA, editors. Hurst's the Heart. 10th ed. New York: McGraw-Hill; 2000. p. 1361-71.  Back to cited text no. 10
    
11.
Aygul N, Ozdemir K, Tokac M, Aygul MU, Duzenli MA, Abaci A, et al. Value of lead aVR in predicting acute occlusion of proximal left anterior descending coronary artery and in-hospital outcome in ST-elevation myocardial infarction: An electrocardiographic predictor of poor prognosis. J Electrocardiol 2008;41:335-41.  Back to cited text no. 11
    
12.
Ji ZG. TCTAP A-006 clinical significance of ST-segment changes in lead aVR for patients with acute coronary syndrome. J Am Coll Cardiol 2015;65:S3-4.  Back to cited text no. 12
    
13.
Kotoku M, Tamura A, Abe Y, Kadota J. Determinants of ST-segment level in lead aVR in anterior wall acute myocardial infarction with ST-segment elevation. J Electrocardiol 2009;42:112-7.  Back to cited text no. 13
    



 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]



 

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