Left Ventricular Mass Index as a Diagnostic Predictor for Hypertrophy of the Left Ventricle in Hypertensive Patients

Background: Patient suffering from hypertension are at increased incidence of suffering from increase in size of left ventricular mass (hypertrophy) due to associated risk factor like male sex, advanced age, males including addiction to smoking and alcohol. Measurement of left ventricular mass index helps in detecting the increase in size of left ventricular mass (hypertrophy). Objectives: To evaluate increase in size of left ventricular mass (hypertrophy) in relation to ventricular mass index of left ventricle in hypertensive patients. Method: A total 100 patients were grouped into 2 groups and named as Group I who served as Normal-Left ventricular mass index-N-LVMI) and Group II who served as Increased Left ventricular mass index-I-LVMI (More than 118g/m2 in males and 109 g/m2 in females. All patients were evaluated for past history and related cardiovascular parameters. About 67 patients among 100 had normal LVMI and 33 patients as per Penn’s convention formula had increased LVMI. Body surface area was calculated by using formula 0.20247 x Height (m) 0.725 x Weight (Kg) 0.425 according to DuBois and DuBois formula. LVMI for males is 118gm/m 2 and 109 gm/m 2 in females as per normal Indian population and a value above suggests increase in size of left ventricular mass (hypertrophy). Statistics: Chi-square test. Results: Mean with ± standard deviation in age (in years) was 50 ± 10.3 and 58± 9.8 in patients without LVH and un patients with LVH respectively. Lateral shift of the apex was seen more in Group II (24.2%) when compared to Group I which showed 4.6%. Apical impulse was found to be 33.3% in Group II as compared to Group I. Chest X ray showed 27.2% in Group II compared to Group I which was 15% for Group I in-terms of cardiac enlargement. Patients having LVH were 51.5% in Group II as compared to 17.9% in Group I for SOKOLOV LYON INDEX and in terms of ROMHILT ESTES, Group II with 42.4% and Group II with 8.9% patients. Patient having concentric LVH as per results of 2 D ECHO patients in Group II was 78.8% compared to patients in Group I which was 11.9%. Conclusion: There was a substantial and positive association that shows a strong association between LVMI and increase in size of left ventricular mass (hypertrophy) in hypertensive patients as evident from our study.


Introduction
A maladaptive response due to long term blood pressure along with risk factors like atrial fibrillation, systolic and or diastolic heart failure is the major etiological factor for pathogenesis of LVH and sudden cardiac arrest in patients suffering from hypertension 1 .Hypertension leads to increase in afterload and LV wall Corresponding Author: Satheesh Balakrishnan Assistant professor, Department of Nephrology, Pushpagiri Medical College, Thiruvalla Mob No.: 9497634957 e-mail: drsatheesh1978@gmail.com stress followed by stimulation of myocyte leading to increase in size of left ventricular mass (hypertrophy), collagen formation and fibroblasts which is the main etiology for cardiac remodeling and deposition of fibrous tissue disproportionate fashion.This leads to decrease in LV compliance thus reducing diastolic function.Coronary blood flow reserve gets greatly affected as a consequence of structural changes in coronary arteries including fibrosis of myocardial interstitial cells and in myocardial mass possibly with myocardial ischemia causing transient diastolic dysfunction 2 .American Society of Echocardiography stated reference ranges for LV mass and LV mass indexed (LVMI) to body surface area (BSA) using M-mode and two-dimensional (2D) echocardiography recently looks different, because the value may vary significantly in Indian population [3][4][5] .A predictor in disguise for cardiovascular complications is increased LVM in general population and in hypertensive patients is strongly correlated apart from advancing age is and reduction in LVH proved to be important in prognosis 6 .Keeping this view in mind, we have tried to study of increase in size of left ventricular mass (hypertrophy) with special reference to left ventricular mass index in patients suffering from hypertension.

Patients having diabetes mellitus.
All the cardiovascular parameters were evaluated Following clinical data were obtained from all patients.
1. Age and sex of the patients.

History of stroke or recurrent transient ischemic attacks
6. Standard cuff blood pressure in right upper limbs was taken twice, mean value was taken as the blood pressure.
8. Ophthalmic examination for any evidence of hypertensive retinopathy.
9. Routine blood and urine investigations 10.Chest X-ray: To measure exact cardio thoracic ratio 11.ECG was obtained from all patients.ECG criteria which was used in our study was Sokolov-Lyon index and Romhilt-Estes score system.In Sokolov-Lyon index, S in V1 + R in V5/V6>35 mm was regarded as increase in size of left ventricular mass (hypertrophy).In Romhilt-Estes score system, total score is 12. Score of 5 or more was regarded as increase in size of left ventricular mass (hypertrophy).
12. Echocardiographic Method-with Combined M mode and also included 2-dimensional echocardiographic studies were performed in all patients.
Penn's convention formula is LVM-1.04(LVIDd + PWT + IVST 3 )-LVIDd 3 -14gm for LVMI The DuBois and DuBois formula is 0.20247 x Height (m) 0.725 x Weight (Kg) 0.425 LVMI = LVM /BSA.Males with118gm/m 2 and 109 gm/m 2 in females is the normal LVMI for Indian population.A value over and above this is clear suggestive of increase in size of left ventricular mass (hypertrophy).
Statistical Analysis: Chi-square test was used.p value was calculated and we found statistically significant relation between increase in size of left ventricular mass (hypertrophy) and ischemic heart disease and stroke.

Results
Our entire study samples were divided in to 2 groups.Group I was considered as Normal LVMI and Group II with Increased LVMI which was more than 118g/m 2 in males and 109 g/m 2 in females.

Demographic features:
In our study, we found that males 76 and females were 24 among 100 samples.About 33 subjects had I-LVMI and 67 patients had N-LVMI.Among males 50 had N-LVMI and 26 had I-LVMI.Among females, 7 had I-LVMI and 17 had N-LVMI.50± 10.3 and 58± 9.8 is the mean age in years in patients without LVH and in patients with LVH respectively.Mean BSA in group I is1.7±0.1 and in group II is 1.72±0.1 (Table 1).

Duration of hypertension:
Mean duration of hypertension in Group I was 6 ± 3.2 compared in Group II which was to 7.7 ± 3.
In patients with hypertension with less than 5 years of duration, about 72% of the subjects were in Group I.In patients with hypertension with more than 10 years' duration, about 78% subjects were in Group II (Table 2).

Treatment history and Clinical features
See Table 2 Investigations: Chest x ray showed cardiac enlargement in more patients 2 (27.2%) in Group 2 than in Group I (15%).About 51.5% patients in Group 2 had LVH compared to 17.9% patients in Group I as per SOKOLOV LYON INDEX.In terms of 2 D ECHO, 78.8% patients were found in Group II and 11.9% patients were found in Group I (Table 3).

Target organ involvement and damage
See Table 4 & 5

Discusssion
Two prospective studies demonstrated that in patients with primary hypertension with concentric LVH develop a higher incidence of cardiovascular events than those with eccentric LVH 7,8 .
Physicians are aware bout the morbidity that is linked to increase in size of left ventricular mass (hypertrophy).Echocardiography invention has made the detection of increase in size of left ventricular mass (hypertrophy) easy and simple and hence is most common diagnostic test.As per Penn's formula and echocardiographic method, a study with 2 independent correlation using sex specific criteria showed high sensitivity of 97% and specificity 96% indicating the importance of echocardiography measurements.
Although the 12 lead ECG is the standard method used in detecting increase in size of left ventricular mass (hypertrophy), it has significant limitations in sensitivity and specificity, and little value in estimating the quantitative extent increase in size of left ventricular mass (hypertrophy).
In a previous study, the LVMI for Indian population was studied as 118g/m 2 in males and 109/m 2 in females.These values were taken as the reference values in this study and used as gold standard for increase in size of left ventricular mass (hypertrophy) 10 .

Demographic Features
Sex: Males were more in our study compared to female with increase in size of left ventricular mass (hypertrophy).
Age: As age proceeds the incidence of increase in size of left ventricular mass (hypertrophy) also increases especially if patient already suffering from hypertension as evident from our study.

Duration of hypertension:
Chronicity of hypertension plays a significant role in the development of increase in size of left ventricular mass (hypertrophy) which is similar study Ross et al 11 .
Blood pressure: The mean systolic and diastolic BP were more in our study especiallt in patients suffering from increased LVH.
Treatment: Patients on regular treatment showed decreased incidence of increase in size of left ventricular mass (hypertrophy) compared with the patients with no treatment or irregular treatment.
Clinical correlations: Our study showed positive correlation with the long standing duration of hypertension and increase in size of left ventricular mass (hypertrophy) and reduced ventricular compliance which is similar to other studies [11][12][13] .
Target organ involvement and damage: In our study, the relation between the LVH and incidence of coronary artery disease and stroke was statistically significant which is similar to Framingham heart study and Eurostroke studies [17][18][19][20] .

Conclusion
Our study has strongly showed positive co-relation that exists between LVMI which serves as a predictor in disguise for disguise for left ventricular ` in hypertensive patients.

Table 1 Demographic Features
The mean systolic blood pressure in mm of Hg is 134±12 in Group I and 158± 14 in Group II.The mean diastolic BP in mm of Hg is 82 ± 6 in Group I and 98 ± 8 in Group II ( N-LVMI = Normal Left ventricular mass index, INC-LVMI=Increased Left ventricular mass indexBlood pressure changes:

Table 2 ). Table 2 Blood Pressure Changes
N-LVMI = Normal Left ventricular mass index, INC-LVMI=Increased Left ventricular mass index

Table 4 : Target Organ Involvement
N-LVMI = Normal Left ventricular mass index, INC-LVMI=Increased Left ventricular mass index