Relationship between ECG QRS voltage and left ventricular functions in patients with heart failure attending federal Medical Centre Nguru, Northeastern Nigeria

Musa Mohammed Baba; Faruk Buba; Mohammed Abdullahi Talle; Hayatu Umar; Habu Abdul

doi:10.4103/njc.njc_22_19

ORIGINAL ARTICLE

Year : 2020 | Volume : 17 | Issue : 1 | Page : 55-60

Relationship between ECG QRS voltage and left ventricular functions in patients with heart failure attending federal Medical Centre Nguru, Northeastern Nigeria

Musa Mohammed Baba¹, Faruk Buba², Mohammed Abdullahi Talle², Hayatu Umar³, Habu Abdul¹
¹ Department of Internal Medicine, Federal Medical Centre Nguru, Yobe State, Nigeria
² Department of Medicine, College of Medical Sciences, University of Maiduguri, Maiduguri, Borno State, Nigeria
³ Department of Internal Medicine, Usman Danfodio University, Sokoto, Nigeria

Date of Submission	30-Sep-2019
Date of Decision	13-Dec-2019
Date of Acceptance	09-Jan-2020
Date of Web Publication	30-Jun-2020

Correspondence Address:
Dr. Musa Mohammed Baba
Department of Internal Medicine, Federal Medical Centre, P. M. B 02, Nguru, Yobe State
Nigeria

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/njc.njc_22_19

Abstract

Introduction: Heart failure (HF) is a clinical syndrome characterized by typical symptoms (e.g., breathlessness, ankle swelling, and fatigue) that may be accompanied by signs (e.g. elevated jugular venous pressure, pulmonary crackles, and peripheral edema) caused by a structural and/or functional cardiac abnormality, resulting in a reduced cardiac output and/or elevated intracardiac pressures at rest or during stress. Electrocardiogram (ECG) is a widely available tool; it is relatively inexpensive and simple to perform; and it yields an instant result. A normal ECG makes systolic dysfunction unlikely and is rare in patients with suspected heart failure. Low ECG voltage has been reported as a marker of the severity of HF and is a risk factor for adverse outcomes in patients with systolic HF at 1 year. However, the relationship between ECG QRS voltage and left ventricular function in patients with heart failure has not been evaluated. Therefore, the objective of this study is to determine the relationship between electrocardiographic QRS voltage and left ventricular function.
Methodology: This was a prospective cross-sectional study conducted among inpatients with HF in the medical ward of the hospital.
Results: Three hundred and sixty patients were recruited for the study, of which 19 had incomplete data and were excluded in the analysis. The remaining 341 subjects were analyzed comprising 215 female and 126 male with a mean age of 47.54 ± 18.85 years. Majority of patients with normal or high QRS voltage had HF with preserved ejection fraction (HFpEF), while those with low QRS voltage had HF with reduced ejection fraction (HFrEF). On the other hand, patients with high QRS voltage had impaired relaxation pattern of diastolic dysfunction, while those with low QRS voltage had a restrictive pattern of diastolic dysfunction. There was a positive and significant correlation between the QRS voltage and ejection fraction, fractional shortening, isovolumic left ventricular relaxation time, and left ventricular deceleration time, while a negative but not significant correlation was observed between electrocardiographic QRS voltage and transmitral E/A ratio. Majority of patients with normal QRS voltage had normal left ventricular geometry, while those with high QRS voltage predominantly had concentric left ventricular hypertrophy and those with low QRS voltage had eccentric left ventricular hypertrophy. Patients with concentric left ventricular hypertrophy had predominantly HFpEF and impaired relaxation pattern of diastolic dysfunction, while those with eccentric left ventricular hypertrophy had HFrEF and restrictive pattern of diastolic dysfunction.
Conclusion: HF patients with high QRS voltage had preserved left ventricular systolic function, impaired relaxation pattern of left ventricular diastolic dysfunction, and concentric left ventricular hypertrophy. While those with low QRS voltage predominantly had reduced left ventricular systolic function, restrictive pattern of left ventricular diastolic dysfunction, and eccentric left ventricular hypertrophy.

Keywords: ECG, left ventricular function, QRS voltage

How to cite this article:
Baba MM, Buba F, Talle MA, Umar H, Abdul H. Relationship between ECG QRS voltage and left ventricular functions in patients with heart failure attending federal Medical Centre Nguru, Northeastern Nigeria. Nig J Cardiol 2020;17:55-60

How to cite this URL:
Baba MM, Buba F, Talle MA, Umar H, Abdul H. Relationship between ECG QRS voltage and left ventricular functions in patients with heart failure attending federal Medical Centre Nguru, Northeastern Nigeria. Nig J Cardiol [serial online] 2020 [cited 2023 May 29];17:55-60. Available from: https://www.nigjcardiol.org/text.asp?2020/17/1/55/288646

Introduction

Heart failure (HF) is a clinical syndrome characterized by typical symptoms (e.g., breathlessness, ankle swelling, and fatigue) that may be accompanied by signs (e.g., elevated jugular venous pressure, pulmonary crackles, and peripheral edema) caused by a structural and/or functional cardiac abnormality, resulting in a reduced cardiac output and/or elevated intracardiac pressures at rest or during stress.^[1] The American College of Cardiology and American Heart Association guidelines on HF classified the progression of heart disease into four stages as follows: Stage A – patients are at high risk for HF but have no structural heart disease or symptoms of HF, Stage B – patients have structural heart disease but have no symptoms of HF, Stage C – patients have structural heart disease and have symptoms of HF, and Stage D – patients have refractory HF requiring specialized interventions.^[2] Similarly, the New York Heart Association classified HF into four functional classes based on the relationship between dyspnea and the amount of effort required to provoke this symptom as follows: Class I patients have no limitation of physical activity, Class II patients have slight limitation of physical activity, Class III patients have marked limitation of physical activity, and Class IV patients have symptoms even at rest and are unable to carry on any physical activity without discomfort.^[3] HF has also been classified according to the ejection fraction, natriuretic peptide levels, and the presence of structural heart disease and diastolic dysfunction into three subtypes, namely HF with reduced ejection fraction (HFrEF) with left ventricular ejection fraction of <40%, HF with preserved ejection fraction (HFpEF) with left ventricular ejection fraction of >50%, and HF mid-range ejection fraction (HFmrEF) with left ventricular ejection fraction of 40–49.^[1] HF has emerged as the most common primary diagnosis for patients admitted to hospital with suspected cardiac disease in Africa.^[4]

Electrocardiogram (ECG) is a widely available tool; it is relatively inexpensive and simple to perform, and it yields an instant result. A normal ECG makes systolic dysfunction unlikely and is rare in patients with suspected HF.^[5] Low ECG voltage has been reported as a marker of the severity of HF and is a risk factor for adverse outcomes in patients with systolic HF at 1 year.^[6] The mechanism of the ECG QRS voltage attenuation in HF is thought to be a combination of reduced ability of the myocardium to generate force that will transmit to the surface and impact of peripheral edema, with different proportions of these two influences in different patients depending on the extent of changes in the heart and the peripheral edema.^{[7],[8],[9],[10]} However, the relationship between ECG QRS voltage and left ventricular function in patients with HF has not been evaluated. Therefore, the objective of this study is to determine the relationship between electrocardiographic QRS voltage and left ventricular function.

Methodology

This was a prospective cross-sectional study conducted among in patients with HF in the medical ward of the hospital after obtaining an ethical approval from the Ethics and Research Committee of the hospital as well as verbal consent from the patients or their relatives.

Inclusion criteria

The inclusion criteria for the study were adults with HF symptoms that met the Framingham diagnostic criteria.^[11]

Exclusion criteria

Patients excluded from the study were those with HF symptoms that did not meet the Framingham diagnostic criteria or patient with HF symptoms <18 years. Other exclusion criteria included patients with hypothyroidism, pericardial effusion, pleural effusion, chronic obstructive airway disease, pneumothorax, hypothermia, and morbidly obsessed patients.

All patients had detailed medical history and examination; the diagnosis of HF was based on the Framingham diagnostic criteria.^[11] Serum electrolytes, fasting blood glucose, lipid profile, electrocardiography, and echocardiography were done to all patients. Electrocardiographic diagnosis of high QRS voltage is based on the Sokolow–Lyon criteria for the diagnosis left ventricular hypertrophy,^[12] while low QRS voltage is defined as nadir-to-peak QRS complex voltage <0.5 mV (<5 mm) in all limb leads and <1.0 mV (<<<<10 mm) in all precordial leads.^[13] Echocardiographic measurements were done according to the standard guidelines.^[14],[15] Left ventricular mass index (LVMI) and left ventricular relative wall thickness (RWT) were used to define the left ventricular geometry. The normal LVMI and RWT vary for age and sex; for females, normal LVMI and RWT are 43–95 g/m² and 0.22–0.42, respectively. While for males, normal LVMI and RWT are 49–115 g/m² and 0.24–0.42, respectively. Normal left ventricular geometry is defined as normal LVMI and normal RWT. Concentric hypertrophy is defined as increased LVMI and RWT. Eccentric left ventricular hypertrophy is defined as increased LVMI with normal RWT, and concentric remodeling is defined as normal LVMI with increased RWT.^[14],[15] All patients were placed on the same anti-heart failure regiments except otherwise contraindicated (angiotensin-converting enzyme inhibitor or angiotensin receptor blocker, aldosterone antagonist, carvedilol, and loop diuretics either furosemide or Torsemide. Digoxin was added to patients with arrhythmias or those with poor systolic function. Amiodarone was however prescribed to patients with refractory atrial fibrillation). Antiplatelet (aspirin or clopidogrel) and warfarin were prescribed to patients with dilated cardiac chamber with hypokinesia and those with rheumatic heart disease in atrial fibrillation, respectively, as part of HF management protocol.^[1]

Data analysis

Statistical analysis was done using SPSS version 21.0 (SPSS, IBM). Chicago, Illinoi. Data were presented as mean ± standard deviation for continuous variables, while categorical variables were expressed as frequencies and proportion. Student's t-test was used to compare mean values of continuous variables, while Fisher's exact or Chi-square tests were used where necessary to compare categorical variables. Spearman correlation coefficient was used to determine the relationship between continuous variable, and P < 0.05 was considered statistically significant.

Results

Three hundred and sixty patients were recruited for the study, out of which 19 had incomplete data and were excluded in the analysis. The remaining 341 patients were analyzed comprising 215 females and 126 males with a mean age of 47.54 ± 18.85 years. [Table 1] shows the demographic and clinical characteristics of the study population. The mean body mass index and heart rate of the studied population were 26.27 ± 4.73 kg/m² and 104.43 ± 18.09 beats/min, respectively, and their mean systolic and diastolic blood pressure were 128.03 ± 24.95 mmHg and 79.05 ± 14.30 mmHg, respectively, while their mean QRS voltage was 29.78 ± 9.98. Three hundred and twenty (93.84%) patients had normal QRS voltage duration, while 15 (6.16%) had prolonged QRS voltage duration. One hundred and thirty-one (38.4%) had progressive hypertensive heart disease, 62 (18.2%) were hypertensive diabetics, 80 (23.5%) had peripartum cardiomyopathy, 39 (11.4%) had idiopathic dilated cardiomyopathy, 24 (7.0%) had rheumatic heart disease, while 5 (1.5%) had a myocardial infarction. [Table 2] shows the mean QRS voltage of patients with various categories of left ventricular systolic function. The analysis of QRS voltage revealed that 127 patients had normal QRS voltage, of these 64 (50.4%) had HFpEF, 54 (42.5%) had HFrEF, and 9 (7.1%) had HFmrEF. High QRS voltage was observed in 134 patients, among these, 110 (82.1%) had HFpEF, 18 (13.4%) had HFrEF, and 6 (4.5%) had HFmrEF. Eighty patients had low QRS voltage, of these 12 (15.0%) had HFpEF, 62 (77.5%) had HFrEF, and 6 (7.5%) had HFmrEF. [Table 3] shows the QRS voltage distribution among patients with various categories of HF.

Table 1: Demographic and clinical characteristics of the study population

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Table 2: Mean QRS voltage among patients with various categories of heart failure

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Table 3: QRS voltage distribution among patients with various categories of heart failure

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Among the 127 patients with normal QRS voltage, 27 (21.3%) had normal left ventricular diastolic function, 40 (31.5%) had impaired relaxation pattern of left ventricular diastolic dysfunction, and 60 (47.2%) had a restrictive pattern of left ventricular diastolic dysfunction. Among the 134 patients with high QRS voltage, 14 (10.4%) had a normal left ventricular diastolic function, 114 (85.1%) had impaired relaxation pattern of left ventricular diastolic dysfunction, and 6 (4.5%) had a restrictive pattern of left ventricular diastolic dysfunction. Of the eighty patients with low QRS voltage, 7 (8.7%) had a normal left ventricular diastolic function, 3 (3.8%) had impaired relaxation pattern of left ventricular diastolic dysfunction, and 70 (87.5%) had restrictive pattern of left ventricular diastolic dysfunction. [Table 4] shows the distribution of QRS voltage among patients with various categories of left ventricular diastolic functions.

Table 4: QRS voltage distribution among patients with various categories of left ventricular diastolic functions

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There was a positive and significant correlation between electrocardiographic QRS voltage and parameters of left ventricular systolic function, i.e. ejection fraction and fractional shortening (r = 0.484, P ≤ 0.001 and r = 0.452, P ≤ 001, respectively). On the other hand, there was a significant but negative correlation between left ventricular internal diameter and electrocardiographic QRS voltage (r = −0.308, P ≤ 0.001). Similarly, there was a positive and significant correlation between electrocardiographic QRS voltage and parameters of left ventricular diastolic function, i.e. isovolumic relaxation time (IVRT) and left ventricular deceleration time (DCT) (r = 0.626, P ≤ 0.001 and r = 0.360, P ≤ 0.001, respectively). However, a negative but not significant correlation was observed between electrocardiographic QRS voltage and transmitral E/A ratio (r = −0.064, P = 0.242). [Table 5] shows the correlation between electrocardiographic QRS voltage and left ventricular internal diameter, left ventricular ejection fraction, left ventricular fractional shortening, left ventricular isovolumic relaxation time, left ventricular DCT, and the ratio of early transmitral left ventricular filling flow velocity to late atrial contraction of left ventricular filling flow velocity (E/A ratio). [Table 6] shows the mean QRS voltage of patients with various categories of left ventricular geometry. Majority of patients with normal QRS voltage (77, 60.6%) had normal left ventricular geometry, while those with high QRS voltage predominantly had concentric left ventricular hypertrophy (118, 88.0%) and those with low QRS voltage (73, 91.3%) had eccentric left ventricular hypertrophy. [Table 7] shows the QRS voltage distribution among patients with various categories of left ventricular geometry.

Table 5: Correlation between electrocardiographic QRS voltage and left ventricular internal diameter in diastole, ejection fraction, fractional shortening, isovolumic relaxation time, deceleration time, and mitral E/A ratio

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Table 6: Mean QRS voltage among patients with various categories of left ventricular geometry

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Table 7: QRS voltage distribution among patients with various categories of left ventricular geometry

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Eighty-six patients had normal left ventricular geometry, of which 45 (52.3%) had HFpEF, 32 (37.2%) had HF with reduced ejection fraction, and 9 (10.5%) had HFmrEF. One hundred and forty two-patients had concentric left ventricular hypertrophy, of these 112 (78.9%) had HFpEF, 23 (16.2%) had HF with reduced ejection fraction, and 7 (4.9%) had HFmrEF. Similarly, 104 had eccentric left ventricular hypertrophy, of these 23 (22.1%) had HFpEF, 77 (74.0%) had HF with reduced ejection fraction, and 4 (3.8%) HFmrEF. [Table 8] shows the distribution of left ventricular systolic function among patients with various categories of left ventricular geometry. Among the patients with normal left ventricular geometry, 16 (18.6%) had a normal left ventricular diastolic function, 21 (24.4%) had impaired relaxation patterns of diastolic dysfunction, and 49 (57.0%) had a restrictive pattern of diastolic dysfunction. Concentric left ventricular hypertrophy was observed in 142 patients. Among the patients with concentric left ventricular geometry, 20 (14.1%) had a normal left ventricular diastolic function, 115 (81.0%) had impaired relaxation pattern of left ventricular diastolic dysfunction, and 7 (4.9%) had a restrictive pattern of diastolic dysfunction. While among those with eccentric left ventricular hypertrophy, 12 (11.5%) had a normal left ventricular diastolic function, 13 (12.5%) had impaired relaxation pattern of left ventricular diastolic dysfunction, and 79 (76.0%) had a restrictive pattern of left ventricular diastolic dysfunction. [Table 9] shows the distribution of diastolic dysfunction in patients with various categories of left ventricular geometry.

Table 8: Distribution of left ventricular systolic function among patients with various categories of left ventricular geometry

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Table 9: Distribution of diastolic functions among patients with various categories of left ventricular geometry

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Discussion

HF is a major public health problem worldwide. Available data suggest that the morbidity due to HF is significant in many parts of the world. In this cross-sectional study, female subjects constitute a substantial proportion of patients admitted with HF; this perhaps may be due to peripartum cardiomyopathy among the female subjects as it a purely disease of women. Progressive hypertensive heart disease was the most common cause of HF, while cardiomyopathies were the second particularly peripartum type. Rheumatic heart disease and myocardial infarction were the third and fourth causes of HF. These suggest that hypertension remained the major cause of HF among our patients.

High QRS voltage was observed predominantly among patients with progressive hypertensive heart disease and hypertensive diabetics compared to those with peripartum cardiomyopathy and idiopathic dilated cardiomyopathy, suggesting that hypertension and/or diabetes could be responsible for the left ventricular hypertrophy, as it was previously described.^{[16],[17],[18]} In this study, we found that patients with high QRS voltage predominantly had HFpEF and impaired relaxation pattern of diastolic dysfunction. On the other hand, those with low QRS voltage had HF with reduced ejection fraction and restrictive pattern of diastolic dysfunction. We also observed a positive and significant correlation between QRS voltage and left ventricular ejection fraction, fractional shortening, IVRT and DCT and negative correlation between QRS voltage and trans-mitral flow (E/A ratio). These findings suggest that myocardial hypertrophy enhances contractility, increases QRS voltage and impaired ventricular compliance during diastole often occurs as a compensatory phenomenon that eventually becomes maladaptive, and evolves toward progressive left ventricular dysfunction and HF similar to what was previously described by other researchers.^{[7],[8],[9],[10],[19]}

In this study, we found that peripartum cardiomyopathy and idiopathic dilated cardiomyopathy were associated with chamber dilatation, reduced myocardial contractility, reduced left ventricular systolic function, and low QRS voltage, a finding previously described by Pearson et al.^[20] We also found that the majority of patients with concentric left ventricular hypertrophy had HFpEF, impaired relaxation pattern of left ventricular diastolic dysfunction, and high QRS voltage, similar to the previous report by Gupta et al.^[21] Eccentric left ventricular hypertrophy results from the combination of volume and pressure overload.^[22] While on the other hand, restrictive diastolic dysfunction is associated with chamber dilatation and increased left ventricular end-diastolic pressure.^[23] In this study, we observed that patients with eccentric left ventricular hypertrophy had heart failure with reduced ejection fraction, restrictive pattern of diastolic dysfunction, and low QRS voltage findings in keeping with previous studies.^[22],[23]

Conclusion

Our findings is this study revealed that HF patients with high QRS voltage had predominantly preserved left ventricular systolic function, impaired relaxation pattern of left ventricular diastolic dysfunction, and concentric left ventricular hypertrophy, while those with low QRS voltage predominantly had reduced left ventricular systolic function, restrictive pattern of left ventricular diastolic dysfunction, and eccentric left ventricular hypertrophy.

Limitation of this study

Lack of tissue Doppler study to isolate those with Grade 2 (pseudonormalized) diastolic dysfunction
Lack of pulmonary venous flow study of left atrial filling to isolate those patients with Grade 2 (pseudonormalized) diastolic dysfunction.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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