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Year : 2017  |  Volume : 31  |  Issue : 2  |  Page : 119-122

Profile of acute ST-elevation myocardial infarction patients with hyponatremia

Department of Medicine, RIMS, Imphal, Manipur, India

Date of Web Publication20-Apr-2017

Correspondence Address:
Konsam Biona Devi
Department of Medicine, RIMS, Imphal, Manipur
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jms.jms_83_15

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Context: In acute ST-elevation myocardial infarction (STEMI), hyponatremia occurs due to neurohormonal activation. Magnitude of this neurohormonal change is related to the severity of myocardial damage. Aims: This study aimed to document the profile of STEMI with hyponatremia and to evaluate the correlation of hyponatremia with Killip class, creatine kinase-muscle brain (CK-MB) level, and degree of ST-elevation. Settings and Design: A longitudinal study was conducted in a tertiary care teaching hospital, Imphal. Patients and Methods: The study included 100 patients with STEMI. Killip class was ascertained on admission. Serum sodium level was estimated on admission, after 24 h, 48 h, and 72 h. CK-MB level was estimated, and the degree of ST-elevation was measured. Statistical Analysis: Statistical Package for the Social Sciences (SPSS 16.0 version) and Student's t-test, Chi-square test, and Fisher's exact test were used for statistical analysis. P < 0.05 was considered statistically significant. Results: Hyponatremia was observed in 44% of the patients. There was no significant relation of hyponatremia with comorbidities such as hypertension, diabetes mellitus, and dyslipidemia. Hyponatremia was associated with Killip III and IV (P = 0.00), higher CK-MB level (P = 0.010), and higher degree of ST-elevation (P = 0.002). Out of six in-hospital deaths, four had hyponatremia. Conclusion: Since hyponatremia was found to be associated with higher Killip class, elevated CK-MB level, and greater degree of ST-segment elevation, it can be speculated that hyponatremia in STEMI patients can be a predictor of poor outcome. Therefore, serum sodium levels can serve as a simple marker to identify patients at high risk.

Keywords: Hyponatremia, Killip class, neurohormonal activation, ST-elevation myocardial infarction

How to cite this article:
Devi KB, Chanu KJ, Ram R, Narayanaswamy G, Singh KB, Chongtham DS. Profile of acute ST-elevation myocardial infarction patients with hyponatremia. J Med Soc 2017;31:119-22

How to cite this URL:
Devi KB, Chanu KJ, Ram R, Narayanaswamy G, Singh KB, Chongtham DS. Profile of acute ST-elevation myocardial infarction patients with hyponatremia. J Med Soc [serial online] 2017 [cited 2023 Jun 8];31:119-22. Available from:

  Introduction Top

ST-segment elevation myocardial infarction (STEMI) is one of the presentations of acute coronary syndromes.[1] STEMI continues to be a major health problem in the industrialized world and is becoming an increasingly important problem in developing countries.[2]

Due to neurohormonal activation in STEMI, there is release of hormones such as vasopressin, renin, and norepinephrine.[3],[4],[5] Hyponatremia is a reflection of these hormonal changes. It has been identified as an independent predictor of short-term mortality, long-term mortality, and rehospitalization for heart failure.[6],[7],[8] Therefore, the study was undertaken to assess the profile of STEMI patients with hyponatremia.

  Patients and Methods Top

The present study was conducted in 100 patients with STEMI admitted in the Department of Medicine, Tertiary Care Teaching Hospital, Imphal, over a period of 24 months from October 2013 to September 2015. Patients with 18 years and above diagnosed as having acute STEMI according to the WHO Criteria [9] and the joint ESC/ACCF/AHA/WHF committee guidelines [10] were included in the study. Hyponatremia was defined as a serum sodium level of <135 mEq/L.[11]

A detailed history and Killip classes were ascertained for all the patients at the time of presentation. Serum sodium level was estimated on admission, after 24 h, 48 h, and 72 h. In each patient's electrocardiogram, highest ST segment elevation was measured in terms of millimeter. Creatine kinase-muscle brain (CK-MB) isoenzyme was estimated. Patients underwent routine investigations such as random blood sugar and kidney function test, lipid profile, and echocardiography. STEMI patients with hyponatremia were correlated with killip class, CK-MB, and degree of ST-elevation.

Ethical approval was obtained from the Institutional Ethics Committee, before conducting the study. Written informed consent was given by all the patients included in the study. Privacy and confidentiality of the patients were maintained.

All statistical calculations were performed with the Statistical Package for Social Sciences (SPSS Inc., Chicago, IL, USA) Windows based version 16. Descriptive analysis was expressed in percentage. Chi-square/Fisher's exact test was used for comparison analysis.

  Results Top

The present study included 100 patients of acute STEMI. Hyponatremia was observed in 44% of the patients. Hyponatremia was most commonly associated among patients with age more than 70 years when compared to other age groups (P = 0.13) as shown in [Table 1]. The number of male patients was 65 out of 100. Hyponatremia was present in 45.7% of female and 43.1% of male patients (P = 0.79). Out of 100 patients, hypertension and diabetes were present in 33 and 15 patients, respectively. Hyponatremia was present in 42.4% of hypertensive (P = 0.824) and 53.3% of diabetic STEMI patients (P = 0.430). Only 27.3% of patients with hyponatremia were found to have high total cholesterol level (P = 0.957). Low high-density lipoprotein was found in half of the patients with hyponatremia (P = 0.859) and high low-density lipoprotein level was found in 56.8% of patients with hyponatremia (P = 0.054). Patients who smoked were 56 in number and hyponatremia was present in 53.6% of the patients (P = 0.03).
Table 1: Relation between age and hyponatremia

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[Table 2] shows that hyponatremia was commonly associated with anterolateral wall (75%), anteroseptal (100%), and extensive anterior wall (56.2%), when compared with the other sites of STEMI. Patients who presented with or developed hyponatremia more often had lower left ventricular ejection fraction (58.88 ± 8.31 vs. 63.15 ± 6.89, P= 0.007) though data were not available for two patients [Table 3] and [Figure 1].
Table 2: Relation between site of myocardial infarction and presence of hyponatremia

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Table 3: Comparison of variables with hyponatremia

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Figure 1: Comparison of left ventricular ejection fraction and hyponatremia

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Killip class III and IV were more common in patients with hyponatremia than other class as shown in [Table 4] and [Figure 2]. Patients with hyponatremia had higher CK-MB level (115.09 ± 89.39 vs. 69.93 ± 81.56, P= 0.01) as shown in [Table 3] and [Figure 3]. STEMI patients with hyponatremia had significantly higher ST-elevation (mean 4.8 ± 2.4 vs. 3.5 ± 1.8) than MI patients with normal sodium level (P = 0.002) [Table 5]. Of the six patients who expired, four had hyponatremia (P = 0.08) [Table 6].
Figure 2: Relation between Killip classification and hyponatremia

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Figure 3: Comparison of creatine kinase-muscle brain and hyponatremia

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Table 4: Relation between Killip classification and hyponatremia

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Table 5: Relation between ST-elevation and hyponatremia

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Table 6: Relation between mortality and hyponatremia

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  Discussion Top

In the present study, hyponatremia was present in 44% of the patients. Similarly, in the study done by Mati et al., hyponatremia was observed in 43% of the MI patients.[12] It was found to be most commonly associated among patients with age more than 70 years though the result was not significant. This insignificant result may be due to the small sample size taken in the study, which is well supported by a similar study done by Hasoor et al. where the sample size was comparable.[13] In a similar study done by Hasoor et al., hyponatremia was more commonly observed in elderly patients.

The study did not show any significant relation of hyponatremia with co-morbidities like hypertension, diabetes and dyslipidemia. There was no sex predilection for hyponatremia in STEMI patients. These finding are in accordance to the study done by Klopotowski et al. and Hasoor et al.[7],[13] Hyponatremia was more common in smokers as observed in the study done by Goldberg et al.[6]

Patients with hyponatremia more often had anterior wall MI, lower ejection fraction, higher Killip class, or higher CK-MB level. Moreover, magnitude of ST elevation was more in patients with hyponatremia. These are in concordance to the study conducted by McAlpine HM et al. and Goldberg et al., where similar results were observed.[5],[6]

Large sample size studies conducted by Goldberg et al., Klopotowski et al., and Tang and Hua showed a significant association between mortality and hyponatremia.[6],[7],[14] In our study, out of six in-hospital deaths, four had hyponatremia but the finding was not considered significant. This may be because of small sample size of the study.

  Conclusion Top

Various studies had shown that higher Killip class, elevated CK-MB level, and greater degree of ST-segment elevation were associated with unfavorable clinical outcomes such as cardiac arrest, congestive cardiac failure, arrhythmias, atrioventricular block, and death. Since hyponatremia was found to be associated with them, it can be concluded that hyponatremia in patients with STEMI can be a predictor of poor outcome. Therefore, serum sodium levels can serve as simple biochemical marker to identify patients at higher risk of developing unfavorable outcomes.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Cannon CP, Braunwald E. Non-ST-segment elevation acute coronary syndrome (non-ST-segment elevation myocardial infarction and unstable angina). In: Kasper DL, Fauci AS, Hauser SL, Longo DL, Jameson JL, Loscalzo J, editors. Harrison's Principle of Internal Medicine. 19th ed. New York: McGraw Hill; 2015. p. 1593-8.  Back to cited text no. 1
Scirica BM, Morrow DA. ST-elevation myocardial infarction: Pathology, pathophysiology, and clinical features. In: Mann DL, Zipes DP, Libby P, Bonow RO, Braunwald E, editors. Braunwald's Heart Disease: A Textbook of Cardiovascular Disease. 10th ed. Philadelphia: Elsevier Saunders; 2014. p. 1068-94.  Back to cited text no. 2
Adrogué HJ, Madias NE. Hyponatremia. N Engl J Med 2000;342:1581-9.  Back to cited text no. 3
Rowe JW, Shelton RL, Helderman JH, Vestal RE, Robertson GL. Influence of the emetic reflex on vasopressin release in man. Kidney Int 1979;16:729-35.  Back to cited text no. 4
McAlpine HM, Morton JJ, Leckie B, Rumley A, Gillen G, Dargie HJ. Neuroendocrine activation after acute myocardial infarction. Br Heart J 1988;60:117-24.  Back to cited text no. 5
Goldberg A, Hammerman H, Petcherski S, Zdorovyak A, Yalonetsky S, Kapeliovich M, et al. Prognostic importance of hyponatremia in acute ST-elevation myocardial infarction. Am J Med 2004;117:242-8.  Back to cited text no. 6
Klopotowski M, Kruk M, Przyluski J, Kalinczuk L, Pregowski J, Bekta P, et al. Sodium level on admission and in-hospital outcomes of STEMI patients treated with primary angioplasty: The ANIN Myocardial Infarction registry. Med Sci Monit 2009;15:CR477-83.  Back to cited text no. 7
Goldberg A, Hammerman H, Petcherski S, Nassar M, Zdorovyak A, Yalonetsky S, et al. Hyponatremia and long-term mortality in survivors of acute ST-elevation myocardial infarction. Arch Intern Med 2006;166:781-6.  Back to cited text no. 8
Tunstall-Pedoe H, Kuulasmaa K, Amouyel P, Arveiler D, Rajakangas AM, Pajak A. Myocardial infarction and coronary deaths in the World Health Organization MONICA project. Registration procedures, event rates, and case-fatality rates in 38 populations from 21 countries in four continents. Circulation 1994;90:583-612.  Back to cited text no. 9
Thygesen K, Alpert JS, Jaffe AS, Simoons ML, Chaitman BR, White HD; Joint ESC/ACCF/AHA/WHF Task Force for the Universal Definition of Myocardial Infarction, et al. Third universal definition of myocardial infarction. Circulation 2012;126:2020-35.  Back to cited text no. 10
Goh KP. Management of hyponatremia. Am Fam Physician 2004;69:2387-94.  Back to cited text no. 11
Mati E, Krishnamurthy N, Ashakiran S, Sumathi ME, Prasad R.Dyselectrolytemia in acute myocardial infarction – A retrospective study. J Clin Biomed Sci 2012;2:167-74.  Back to cited text no. 12
Hasoor S, Kinagi A, Afiya S. A prospective study of in hospital outcome of acute phase of STEMI with hyponatremia. J Evol Med Dent Sci 2014;3:14483-92.  Back to cited text no. 13
Tang Q, Hua Q. Relationship between hyponatremia and in-hospital outcomes in Chinese patients with ST-elevation myocardial infarction. Intern Med 2011;50:969-74.  Back to cited text no. 14


  [Figure 1], [Figure 2], [Figure 3]

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

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