The study was conducted at the Obafemi Awolowo University Teaching Hospitals Complex, Ile- Ife, which comprises the Ife Hospital Unit and the Wesley Guild Hospital unit, Ilesa. It serves as a tertiary care centre spanning a large catchment area.
The total bed complement of both centers is five hundred and seventy two.
STUDY DESIGN
Longitudinal Descriptive Study Design
STUDY POPULATION (INCLUSION CRITERIA)
The study population consists of adult Nigerian patients (>18 years of age) presenting to the cardiology clinic or emergency room.
100 consecutive acutely decompensated or chronic heart failure patients admitted via the emergency room and medical outpatient clinic that fulfill the Framingham criteria49 for diagnosing heart failure were recruited into the study.
50 apparently healthy volunteers (without heart failure) matched for age and sex served as controls.
PATIENT EXCLUSION CRITERIA
The following groups of patients were excluded from the study.
- Patients with chronic obstructive airway disease
- Patients with moderate renal disease (Creatinine Clearance <60ml/min)9 as determined by the Cockroft and Gault Equation 98
- Morbidly obese patients (BMI> 40Kg/M²).99
- Patients with orthopaedic or neurologic impairment (severe arthritis, stroke).
Patients diagnosed to have diabetes mellitus (DM) as defined by a fasting plasma glucose of 7.0mmol/L or those already on treatment for DM.
SAMPLE SIZE CALCULATION
The formula below was used in calculating the sample size.
N = 2 Z2PQ d2 N = minimum sample size
Z = the standard normal deviation, usually set at 1.96, which corresponds to the 95%
confidence level.
Z=1.96%
P = this is the prevalence and it is the estimated proportion of cases in the population. The prevalence of heart failure in those presenting with cardiovascular diseases is between 2.8% and 16% 100
Q =1-prevalence
d = precision which is usually set at 0.05 (adjusted with error margin of 10%) Sample size was calculated to be 51.63
A total of 150 patients were evaluated in this study STATISTICAL ANALYSIS
The results obtained were entered into a personal computer and analyzed with a statistical computer software package (SPSS version 11.0).Continuous variables were expressed as means and categorical variables as percentages. The association of the risk factors for mortality with the risk groups was determined using chi square for the categorical
variables and students t-test for the continuous variables. A value of P<0.05 was considered significant.
In order to determine the echocardiographic variable(s) predictive of the risk groups, only variables that had a univariate association with the risk groups at P < 0.05 were considered for inclusion in the multivariate binary logistic regression analysis.
Adjusted odds ratio and 95% confidence interval were calculated in order to determine the strength of association between the predicting variables and risk groups
ETHICAL CONSIDERATION
Approval of the ethics and research committee of the hospital was obtained before proceeding with the study. Fully informed consent was obtained from each study
participant.
DATA COLLECTION METHOD/INSTRUMENTS PROTOCOL 1-CLINICOLABORATORY
The patients were clerked in detail and examined. Socio-demographic information including relevant past medical history to determine the presence of co- morbidities like diabetes, anemia (PCV<30%), alcohol intake, obesity (BMI>30) 99 was obtained.
The biochemical parameters that were measured are
- Admission serum creatinine level using the standard hospital laboratory method of Jaffes reaction.
- Admission serum urea level determination using the colorimetric test (the diacyl monoxime method).
- Determination of the admission serum sodium and potassium level, using the flame emission spectrophotometer.
- The brachial artery systolic and diastolic blood pressure was determined at korotkoff phases 1 and 5 respectively cut off point using a mercury sphygmomanometer after ten minutes rest in a quiet room.
- The patient’s weight and height was taken using a functioning weighing scale and a Harpenden Stadiometer respectively. All measurements were taken with the shoes removed and in light clothing. Weights were measured to the nearest 1Kg and heights to the nearest 1cm and the body mass index was then calculated
- The urine microscopy was done to screen for casts.
- The full haemogram including the erythrocyte sedimentation rate (ESR) was done.
- Resting 12 lead electrocardiography was performed on admission using a Kenz ECG 103 model electrocardiography machine to determine the presence of the following-left bundle branch block, atrial fibrillation and ventricular premature complexes. The QT corrected interval was also calculated.
-The chest radiograph (Posterior-Anterior view) was done and the cardiothoracic ratio determined.
-The NYHA class was determined on admission. NYHA Class 1 HF patients were asymptomatic heart failure patients presenting to the cardiology clinic on account of symptoms not referable to HF. Class 2 HF patients had dyspnoea on performing activities like walking next door to a neighbor’s house. Class 3 HF patients had dyspnoea on performing activities like getting up from their bed to use the bathroom. Class 4 HF patients had dyspnoea at rest.
PROTOCOL 2 -SELF PACED EXERCISE TEST.
The 12 minute walk test was performed as described by the American Association of Cardiovascular and Pulmonary Rehabilitation in its “guidelines for pulmonary rehabilitation”101 with the exception that oxymetry, and the Borg dyspnea scale were not monitored. A demonstration was done for study participants using the 20 meters well lit rectangular corridor of the medical wards as the walking course. Patients were asked to walk at what they considered to be their comfortable walking speed. Timing was initiated once the patient is standing and ready to begin walking.
The distance was measured with a linear scale marked on the floor. Patients were allowed to rest by sitting or standing at any point during the course to allow for standardization, however rest breaks were based only on patients’ request. The patients were instructed to stop at the end of the twelve minutes. An assistant measured and recorded the time to keep the investigator blinded to distance cues and to prevent interruption of the timed walk test. No encouragement was provided during walking and patients who could not complete the test were allowed to discontinue the test. The distance walked was measured with a tape and the patient informed of this on completing the test. The pre-exercise and post exercise heart rate and blood pressure were taken in the sitting position.
PROTOCOL 3- ECHOCARDIOGRAPHY
Transthoracic Echocardiography was carried out on all the 100 patients and 50 controls. The standard transthoracic views (parasternal long axis, parasternal short axis and apical four chamber) were recorded from parasternal and apical transducer positions.
Using the electronic steering capacity of the modern two dimensional scanner, a single line of interrogation within the 90 degrees sector was selected in order to obtain an M- mode interrogation line along that sector.
Measurements were in accordance with the recommendations of the American Society of Echocardiography102 with leading edge to leading edge recordings taken.
LEFT VENTRICULAR DIASTOLIC FUNTION The following measurement were taken
1. Peak flow velocity in early diastole (PVFE) in m/s 2. Peak flow velocity in late diastole (PVFA) in m/s
3. The ratio of peak flow velocity in early diastole to peak flow velocity in late diastole (PVFE/PVFA)
4. Isovolumic relaxation time (IVRT)
5. Deceleration time LEFT VENTRICULAR SYSTOLIC FUNCTION
The following measurements were used to assess the left ventricular systolic function.
1. Fractional Shortening =LVDD-LVSD ×100 LVDD
2. Ejection Fraction = EDV-ESV × 100 EDV
3. Stroke Volume = End diastolic volume – End systolic volume.
4. Cardiac Output = Stroke volume x Heart Rate (HR)
5. Cardiac Index = Cardiac Output Body surface area
The echocardiography machine uses the Teicholz formula103 to determine the end systolic and diastolic volumes.
EDV = 7.0 × LVEDD3
2.4+LVEDD ESV = 7.0 ×LVESD3
2.4 +LVESD
OTHER ECHOCARDIOGRAPHIC DETERMINATIONS
1. Chamber dimensions, septal wall thickness (SWT) and left ventricular posterior wall thickness. (PWT)
2. A regression equation has been derived for the calculation of Left Ventricular Mass (LVM) using the measurement performed based on the recommendations of the American Society of Echocardiography104that is the leading edge to leading edge methodology.
LVM = 1.04 [(LVID +IVST +PWT)3 -(LVID)3] × 0.8 +0.6 1.04 - Specific gravity of the myocardium (g/ml)
LVID - Left Ventricular Internal Dimension (cm) PWT - Posterior Wall Thickness (cm)
IVST - Interventricular Septal Thickness (cm)
Relative wall thickness (RWT) will be derived as follows.
RWT = IVST +PWT LVDD
LVDD = Left ventricular diastolic dimension
3 Valvular abnormalities including the presence or absence of, mitral and aortic regurgitation and aortic root calcification were noted.
4 The presence of pericardial effusion was also noted.
5 The isovolumic relaxation time (IVRT) was determined from the pulsed wave Doppler image with the sample volume positioned to record mitral inflow and left ventricular outflow simultaneously. The distance between the end of the aortic flow and the beginning of the mitral flow defined the IVRT.
6 Using the mitral E wave flow velocity image, the machine automatically generated the deceleration time of early diastolic filing.
DETERMINATION OF THE AETIOLOGY OF HEART FAILURE
This was based on the history, cardiovascular examination findings and echocardiographic findings. The electrocardiogram and chest radiographs were also taken into consideration.
Hypertension was diagnosed in patients who presented with an elevated blood pressure or a normal blood pressure but with features of long standing hypertension like a fourth heart sound and a loud aortic component of the second heart sound. These patients also had an increased left ventricular posterior wall and/or an interventricular septum diastolic dimension above 1.1cm.The primary diagnostic features of dilated cardiomyopathy was left ventricular dilation (diastolic dimension above 5.7cm) and systolic dysfunction with a generalized hypokinesis of the walls of the ventricle in the absence of other causes of HF.
Rheumatic heart disease was diagnosed in patients that had mitral and/or aortic valve thickening with concomitant valve motion abnormalities or moderate to severe
regurgitation across the valves The patients diagnosed to have rheumatic heart disease fell between the ages 18-39 years. Myocardial infarction was diagnosed from the classical history of ischemic-like chest pain and elctrocardiograhic findings in keeping with an acute infarction (hyperacute ST segment elevation) .Endomyocardial fibrosis was diagnosed following the echocardiographic findings of significant pericardial effusion, increased echoes emanating from the endocardial surface, preserved systolic function and a restrictive pattern of diastolic dysfunction, dilated right and/or left atrium with tricuspid and/or mitral regurgitation. This was accompanied with some obliteration of the right ventricular apex.
Based on the presence or absence of the following three risk factors, patients were classified into three risk groups.
Risk factor 1 - admission BUN >15.35 mmol/L Risk factor 2 -admission SBP < 115 mmHg Risk factor 3- serum creatinine > 243.1 µmol/L High risk group.-All three risk factors present
Intermediate risk group-varying combinations of the three risk factors Low risk group -none of the three risk factors present
MODALITIES FOR FOLLOW UP
Patients were followed up personally in the cardiology clinic. They were given monthly appointments (or more frequently when indicated) until the completion of the study and thereafter as indicated. The patients contact details were taken which ensured home or telephone follow up where patients defaulted from clinic appointments.
CHAPTER FOUR RESULTS
CLINICAL AND DEMOGRAPHIC PARAMETERS OF STUDY PARTICIPANTS
As shown in table 1, there was no significant difference in age, body mass index (BMI) and body surface area (BSA) when the values were compared between heart failure (HF) and control groups; 54.40 15.41 yrs vs. 54.34 15.17 yrs (P>0.05), 23.49
4.99 Kg/M2 vs. 23.43 3.77 Kg/M2 (P >0.05) and 1.67 0.21 M2 vs. 1.74 0.19 M2 (P>0.05) respectively. HF patients were well matched for age and sex.
HF patients had a significantly higher erythrocyte sedimentation rate (ESR), serum urea level, serum creatinine level and cardiothoracic ratio compared to the control group;
21.46 20.79 mm/Hr vs.7.56 4.59 mm/Hr (P<0.001), 6.61 3.49 mmol/L vs. 3.97 0.94 mmo/L (P<0.001), 118.07 39.27mol/L vs. 78.52 18.32 mol/L (P<0.001) and 0.62 0.09 vs. 0.48 0.02 (P<0.001) respectively. There were significant differences in packed cell volume (PCV) and serum sodium level when the values were compared between HF and control group; 38.99 4.91% vs. 42.04 4.17% (P <0.001) and 132.86
4.36 mmol/L vs. 134.68 3.89 mmol/L (P<0.05) , respectively, though they were all within normal limits.
The QT (corrected) interval in HF patients was significantly longer than the control group however the mean QT interval in both groups were within normal limits and not absolutely prolonged; 0.42 0.03 seconds vs. 0.41 0.03 seconds (P<0.05).
Table 1: CLINICAL AND DEMOGRAPHIC PARAMETERS OF THE STUDY PARTICIPANTS
* QTc n = 92 (Heart failure)
BMI ,Body Mass Index; BSA, Body Surface Area;PCV, Packed Cell Volume;
ESR, Erythrocyte Sedimentation Rate; CTR, Cardiothoracic-ratio Parameter Heart Failure
n=100
Control n = 50
T df
P-value Sex (male/female)
Age(yrs) BMI (Kg/M2) BSA (M2) PCV (%) ESR (mm/Hr) Sodium (mmol/L) Urea (mmol/L) Creatinine (mol/L) CTR
*QTc (Seconds)
62/38 54.40 + 15.41 23.49 + 4.99 1.67 + 0.21 38.99 + 4.91 21.46 + 20.79 132.86 + 4.36 6.61 + 3.49 118.07 + 39.27 0.62 + 0.09 0.42 + 0.03
27/23 54.34 + 15.17 23.43 + 3.77 1.74 + 0.19 42.04 + 4.17 7.56 + 4.59 134.68 + 3.89 3.97 + 0.94 78.52 + 18.32 0.48 + 0.02 0.41 + 0.03
- 0.02 0.06 -1.83 -3.76 4.66 -2.49 5.25 6.76 10.48 2.24
1 148 148 148 148 148 148 148 148 148 139
0.347 0.982 0.949 0.069 0.000 0.000 0.014 0.000 0.000 0.000 0.026
CARDIOVASCULAR RESPONSES DURING EXERCISE TESTING
As shown in table 2, the ability to increase heart rate in response to exercise and the distance covered during the 12 minutes self paced exercise test was significantly reduced when HF patients were compared to the control group; 2.24 11.13 beats per minute vs.
23.08 14.25 beats per minute (P<0.001) and 461.22 215.14 meters vs. 1072.14 167.04 meters (P <0.001)
Table 2: CARDIOVASCULAR RESPONSES DURING EXERCISE TESTING
Parameter Heart Failure
n=99
Control n=50
t df
P-value Pre Exercise SBP (mmHg)
Post Exercise SBP(mmHg) Pre Exercise DBP (mmHg) Post Exercise DBP(mmHg) Heart Rate Change (bpm) Distance Covered in 12 minutes(meters)
125.10+26.11 125.27+29.91 82.22+15.08 83.15+15.67 2.24 + 11.13
461.22+215.14
118.24+8.73 132.20 + 8.31 74.80 + 5.79 76.88 + 7.05 23.08 + 14.25
1072.14 + 167.04
1.805 -1.064 3.352 2.692 - 9.8
- 17.572 147 147 147 147 147
147
0.07 0.111 0.001 0.008 0.00
0.000
ELECTROCARDIOGRAPGHIC FINDINGS IN THE STUDY PARTICIPANTS Table 3 shows that the proportion with ventricular premature complexes (VPC) , atrial fibrillation (AF) and left bundle branch block (LBBB) was significantly higher in HF compared with the control group; 29% vs. 10% (P<0.05) ,11% vs. 0% (P<0.05) and 10% vs.0% (P<0.05) , respectively.
Table 3: ELECTROCARDIOGRAPHIC FINDINGS IN STUDY PARTICIPANTS
VPC, Ventricular Premature Complexes; AF, Atrial Fibrillation; LBBB, Left Bundle Branch Block.
Parameter Heart Failure n=100
(n) (%)
Control n=50
(n) (%)
x2 df P-value
VPC Absent Present AF
Absent Present LBBB Absent Present
71 (71%) 29 (29%)
89 (89%) 11 (11%) 90 (90%) 10 (10%)
45 (90%) 5 (10%)
50 (100%) 0 (0%)
50 (100%) 0 (0%)
6.87
5.94
5.36
1
1
1
0.009
0.015
0.021
ECHOCARDIOGRAPHIC FINDINGS IN STUDY PARTICIPANTS
As shown in table 4, HF patients had significantly increased left ventricular diastolic and systolic dimensions compared to the control group. 5.65 1.22 cm vs. 4.64
0.49 cm (P <0.001) and 4.58 1.28cm vs. 3.18 0.44 cm (P<0.001),respectively.
The aortic root dimension (AOD),left atrial dimension (LAD), end systolic volume (ESV), end diastolic volume (EDV) and left ventricular mass index (LVMI) was significantly increased in HF compared to the control group; 3.04 0.53 cm vs. 2.79 0.43 cm (P<0.05), 4.28 0.84 cm vs. 3.13 0.41 cm (P<0.001), 117.94 91.52 ml vs.
33.92 13.28 ml (P<0.001), 199.18 116.76 ml vs. 102.30 31.17 ml (P<0.001) and 171.08 78.24 g/m2 vs. 91.64 24.41 g/m2 (P<0.001).
HF patients had significantly reduced fractional shortening and ejection fraction compared with the control group; 19.70 8.82% vs. 31.84 6.09% (P<0.001) and 46.57
16.65% vs. 66.95 8.13 % (P<0.001), respectively.
The stroke volume (SV), cardiac output (CO) and cardiac index (CI) of HF patients was significantly higher compared to the control group; 85.00 52.18ml vs. 68.36 21.86ml, 7.74 5.28 L/min vs. 5.09 1.56 L/min and 4.62 3.07 L/min M2 vs.2.89 0.84 L/min M2) (P<0.001), respectively.
HF patients had a significant prolongation of the isovolumic relaxation time (IVRT) compared with the control group; 102.52 34.37milliseconds vs. 87.84
17.89milliseconds (p<0.05). The deceleration time was significantly shortened in HF patients when compared with the control group; 181.22 60.00 milliseconds vs. 217.68
Table 4: ECHOCARDIOGRAPHIC FINDINGS IN STUDY PARTICIPANTS Parameter Heart Failure
n=99
Control n=50
t df
P-value LVDD [cm]
LVSD (cm) FS [ %]
EF [%]
IVSd [cm]
PWTd.[cm]
AOD[cm]
LAD[cm]
SV (ml) ESV(ml) EDV (ml) C.O (L/min) C I( L/min m2 ) I V R T (ms) DecT. (ms) RWT.
LVM index (g/m2)
5.65±1.22 4.58 ± 1.28 19.70±8.82 46.57 ± 16.65 1.19 ± 0.34 1.14 ± 0.25
3.04 ± 0.53 4.28 ± 0.84 85.00 ±52.18 117.94± 91.52 199.18 ±116.76 7.74 ± 5.28 4.62 ± 3.07 102.52 ± 34.37 181.22 ± 60.00 0.44 ± 0.17 171.08 ± 78.24
4.64 ± 0.49 3.18 ± 0.44 31.84 ± 6.09 66.95 ± + 8.13 0.98± 0.11 0.97± 0.15 2.79± 0.43 3.13± 0.41 68.36± 21.86 33.92 ± 13.28 102.30± 31.17 5.09 ± 1.56 2.89± 0.84 87.84 ± 17.89 217.68 ±56.00 0.43 ± 0.06 91.64 ± 24.41
5.65 7.47 - 8.39 8.17 4.21 4.54 2.84 9.14 2.16 6.45 5.76 3.47 3.92 -2.81 3.56 0.57 7.00
147 147 147 147 147 147 147 147 147 147 147 147 147 136 143 147 147
0.000 0.000 0.000 0.000 0.000 0.000 0.005 0.000 0.033 0.000 0.000 0.001 0.000 0.006 0.001 0.573 0.000 LVDD, left ventricular diastolic dimension; LVSD, left ventricular systolic dimension;
EF, ejection fraction; FS, fractional shortening IVS ,interventricular septum dimension in diastole; PWTd, posterior wall thickness in diastole; AOD, aortic root dimension;LAD, left atrial dimension;SV, stroke volume; ESV, end systolic volume; EDV,end diastolic volume; CO, cardiac output; CI, cardiac index; IVRT, isovolumic relaxation time; DecT, Deceleration time.
ECHOCARDIOGRAPHIC FINDINGS IN THE STUDY PARTICIPANTS (continued)
Table 5 shows that the proportion with moderate/severe mitral, aortic, tricuspid and pulmonary regurgitation was significantly higher in HF patients compared to the control group; 65% vs. 0% (P<0.001), 22% vs. 0% (P<0.001), 54% vs. 0% (P<0.001) and 44%
vs. 0% (P<0.001),respectively.
Table 5: ECHOCARDIOGRAPHIC FINDINGS IN STUDY PARTICIPANTS
MR, Mitral Regurgitation; TR, Tricuspid Regurgitation; PR, Pulmonary regurgitation;
AR ,aortic regurgitation.
Parameter
Heart Failure n=100
(n) (%)
Control n=50
(n) (%)
x2 Df P-value
MR
Absent/Mild Moderate/Severe TR
Absent/Mild Moderate/Severe PR
Absent/Mild Moderate/Severe AR
Absent/Mild Moderate/Severe
35 (35%) 65 (65%)
46 (46%) 54 (54%)
56 (56%) 44 (44%)
78 (78%) 22 (22%)
50 (100%) 0 (0%)
50 (100%) 0 (0%)
50 (100%) 0 (0%)
50 (100%) 0 (0%)
57.36
42.19
2.74
2.90
1
1
1
1
0.000
0.000
0 .098 0.000
DIASTOLIC DYSFUNCTION AMONGST STUDY PARTICIPANTS
As shown in table 6, assessment of diastolic function using the mitral valve E/A ratio was possible in only 92 HF patients. Assessment of diastolic dysfunction across the mitral valve was not possible in patients that had severe aortic regurgitation or atrial fibrillation. Impaired relaxation of the left ventricle was the commonest abnormality in HF patients occurring in 48 (52.2%) patients followed by a restrictive pattern found in 25 (27.2%) patients. The abnormality that occurred least was pseudo-normalization which was found in 13 (14.13%) patients.
Table 6: PATTERN OF DIASTOLIC DYSFUNCTION AMONGST STUDY PARTICIPANTS
Type of Diastolic Abnormality
Heart Failure (HF) n=92
(n) (%)
Control n=50
n (%) Normal
Impaired Relaxation Pseudo-normalization Restrictive
6 (6.5%) 48 (52.2%) 13 (14.1%) 25 (27.2%)
43 (86%) 7 (14%) 0 (0%) 0 (0%)
X2 =92.14 df = 3 p-value = 0.000
SYSTOLIC AND DIASTOLIC DYSFUNCTION IN HEART FAILURE PATIENTS
Ejection fraction could not be determined in one of the patients due to massive pericardial effusion, which made accurate 2-Dimensional imaging technically difficult. The various types of diastolic abnormalities of the left ventricle was determined in 92 HF patients.
Table 7 shows that all the patients that had systolic dysfunction (EF<50%) also had diastolic dysfunction. Thirty seven (37) patients had a pure diastolic failure (EF >50%).
Impaired relaxation was the commonest abnormality in the patients that had a normal EF, accounting for 67.6% of the cases. This was followed by a restrictive pattern of left ventricular filling accounting for 10.8% of the cases. Two patients (5.4%) had pseudo normalization of the E/A ratio.
Table 7: PATTERN OF DIASTOLIC ABNORMALITIES IN PATIENTS WITH BOTH SYSTOLIC AND DIASTOLIC DYSFUNCTION COMPARED WITH PATIENTS WITH NORMAL EJECTION FRACTION
Type of Diastolic Abnormality
Ejection Fraction (EF) <50%
n=55
n (%)
EF >50%
n=37 n (%)
Normal
Impaired relaxation Pseudo-normalization Restrictive
0 (0%) 23 (41.8%) 11 (20%)
21 (38.2%)
6 (16.2%) 25 (67.6%) 2 (5.4%) 4 (10.8%)
X2 = 20.407 df = 3 P-value = 0.000
CLASSIFICATION OF HF PATIENTS INTO RISK GROUPS
Forty-one patients representing 41% of the heart failure patients had a low systolic blood pressure. Six patients representing 6% of the HF had an elevated serum urea and two patients representing 2% had an elevated serum creatinine. Fifty-nine (59) out of 100 HF patients (59%) had none of the 3 risk factors most predictive of mortality and were therefore classified into the low risk group. Only 2 out of the 100 HF patients (2%) had all the 3 risk factors and these were classified into the high-risk group. The remaining 39 patients (39%) had varying combinations of the 3 risk factors and were therefore classified into the intermediate risk group..
In view of the fact that only 2 patients fell within the high risk group, the intermediate risk group and the high risk groups were merged for the purpose of a meaningful statistical analysis. This gave a total number of 41 patients (41%) in the intermediate / high risk group while 59 patients (59%) remained in the low risk group.
The two risk groups (low and intermediate/high) were compared in all subsequent analysis.
AETIOLOGY OF HEART FAILURE
As shown in table 8, the commonest cause of HF was hypertension accounting for 69%
of cases. This was followed by dilated cardiomyopathy and rheumatic heart disease accounting for 16% and 10% of cases respectively. Myocardial infarction and endomyocardial fibrosis accounted for 4% of cases (2%each).One patient had a congenital heart disease (ostium secundum type atrial septal defect).
Table 8: AETIOLOGY OF HEART FAILURE
AETIOLOGY n %
Hypertension
Dilated Cardiomyopathy Rheumatic Heart Disease Myocardial Infarction Endomyocardial fibrosis Congenital heart disease
69 16 10 2 2 1
69%
16%
10%
2%
2%
1%
TOTAL 100 100%
CLINICAL/LABORATORY PARAMETERS IN HEART FAILURE
As shown in tables 9 and 10, there was no significant difference in the proportion of males in the intermediate/high risk group compared to the low risk group; 63.4%
vs.61.0% (P>0.05).The proportion of patients that had a third heart sound, elevated jugular venous pressure (JVP), New York Heart Association (NYHA) class 3/4 and pleural effusion was significantly greater in the intermediate/high risk group compared to the low risk group; 82.9% vs. 61.0% (P<0.05), 75.6% vs.47.5% (P<0.05),78.0%
vs.42.4% (P<0.001),82.9% vs.27.1% (P<0.001) and 41.5% vs.20.3% (P<0.05) respectively.
There was no significant difference in age, packed cell volume (PCV), erythrocyte sedimentation rate (ESR) and serum sodium when the values were compared between the low risk and the intermediate/high risk groups;56.63 13.65 years vs. 51.20 17.30 years (P>0.05),39.37 4.26% vs. 38.44 5.72 % (P>0.05),18.25 21.24 mm/Hr vs. 26.07 19.47 mm/Hr (P>0.05) and 133.39 4.00mmol/L vs. 132.10 4.78mmol/L (P>0.05)respectively. Patients in the intermediate/high risk group had a significantly higher cardio-thoracic ratio and uric acid level compared to the low risk group; 0.60 0.08 vs. 0.66 0.09 (P<0.05) and 0.34 0.06 mmol/L vs. 0.39 0.06 mmol/L (P<0.001) The body mass index (BMI) was significantly higher in the low risk group compared to the intermediate/high risk group;24.39 5.11 Kg/m2 vs. 22.20 4.59 Kg/m2 (P<0.05).The intermediate /high risk group had a significantly narrower pulse pressure compared to the low risk group 33.90 15.15 mmHg vs. 52.64 11.39mmHg (P<0.001)
Table 9: CLINICAL PARAMETERS ASSESED IN HEART FAILURE Parameter Low risk group
n=59
Intermediate / High risk group n=41
x2 df P Age (years)
BMI(Kg/m2) Gender Male Female S3 Present Absent Elevated JVP Present Absent Basal
Crepitations Present Absent NYHA CLASS 1\2 3\4 Pleural Effusion Present Absent
56.63 ± 13.65 24.39 + 5.11 36 (61.0%) 23 (39.0%)
36 (61%) 23 (39%)
28 (47.5%) 31 (52.5%)
39 (66.1%) 20 (33.9%)
43 (72.9%) 16 (27.1%)
12 (20.3%) 47 (94%)
51.20 ± 17.30 22.20 + 4.59 26 (63.4%) 15 (36.6%)
34 (82.9%) 7 (17.1%)
31 (75.6%) 10 (24.4%)
33 (80.5%) 8 (19.5%)
7 (17.1) 34 (82.9%)
17 (41.5%) 24 (58.5%) - - 0.06
5.53
7.93
2.49
30.13
5.243 98 98 1
1
1
1
1
1
0.083 0.031 0.802
0.019
0.005
0.115
0.000
0.022
Table 10: LABORATORY PARAMETERS IN HEART FAILURE Parameter Low Risk group
n=59
Intermediate/High risk group
n=41
t df P-value
CTR
*QTc (secs) PCV (%) ESR (mm/Hr) Na (mmol/L) UricAcid (mmol/L) Pulse pressure
0.60 + 0.08 0.41 + 0.035 39.37 + 4.26 18.25 + 21.24 133.39 + 4.00 0.34 + 0.06 52.64 + 11.39
0.66 + 0.09 0.43 + 0.028 38.44 + 5.72 26.07 + 19.47 132.10 + 4.78 0.39 + 0.06 33.90 + 15.15
-3.59 -3.20 0.94 -1.87 1.47 -4.09 7.06
98 90 98 98 98 98 98
0.001 0.002 0.352 0.064 0.146 0.000 0.000
* QTc n = 54 for Low risk, 38 for intermediate / high risk group
CTR, Cardiothoracic-ratio; BMI, Body Mass Index; PCV, Packed Cell volume;
ESR,,erythrocyte sedimentation rate; Na, serum sodium.
ELECTROCARDIOGRAPHIC FINDINGS IN HEART FAILURE
As shown in table 11, a significant proportion of patients in the intermediate/high risk group compared with those in the low risk group had left bundle branch block (LBBB), ventricular premature complexes (VPC) and atrial fibrillation (AF); 17.1% vs.5.1%
(P<0.05), 43.9% vs.18.6% (P<0.05) and 19.5% vs. 5.1% (P<0.05) respectively.
Table 11: ELECTROCARDIOGRAPHIC FINDINGS IN HEART FAILURE
Parameter Low Risk
n=59 (n ) (%)
Intermediate/
High Risk n=41 (n) ( %)
x2 df P -value
LEFT BUNDLE BRANCH BLOCK Present
Absent
VENTRICULAR PREMATURE COMPLEXES Present Absent
ATRIAL
FIBRILLATION
Present Absent
3 (5.1%) 56 (94.9%)
11 (18.6%) 48 (81.4%)
3 (5.1%) 56 (94.9%)
7 (17.1%) 34 (82.9%)
18 (43.9%) 23 (56.1%)
8 (19.5%) 33 (80.5%)
3.863
7.495
5.143 1
1
1
0.049
0.006
0.023
ECHOCARDIOGRAPHIC FINDINGS IN HEART FAILURE
As shown in table 12, the left atrial dimension, left ventricular systolic dimension and end systolic volume was significantly higher in the intermediate/high risk group compared to the low risk group;4.12 0.80cm vs. 4.52 0.85cm (P<0.05),4.33 1.54 vs.
3.94 1.02cm (P<0.05) and 154.25 118.20ml vs. 93.32 56.86ml (P<0.05) respectively. There was no significant difference in the left ventricular mass index when the values were compared between the low risk group and the intermediate/high risk group; 158.55 53.89g/m2 vs. 189.57 102.34g/m2. The fractional shortening and ejection fraction was significantly higher in the low risk group compared to the intermediate/high risk group;21.86 7.36 vs. 16.53 9.88 (P<0.05) and 51.33 13.15%
vs.39.55 18.83% (P<0.001) respectively. There was no significant difference in stroke volume, cardiac output and cardiac index when the values were compare between the two risk groups.
The deceleration time was significantly shortened in the intermediate/high risk group compared to the low risk group; 164.8950.73 milliseconds vs.192.11
63.57milliseconds (P<0.05). The proportion of patients with moderate/severe mitral regurgitation, moderate/severe tricuspid regurgitation was significantly higher in the intermediate/high risk group compared to the low risk group; 31/40 (77.5%) vs.32/59 (54.2%) (P<0.05) and 26/40 (65.0)% vs. 26/59 (45.8%) (P<0.05) respectively.
Table 12: ECHOCARDIOGRAPHY FINDINGS IN HEART FAILURE Parameter Low Risk
group n=59
Intermediate/High Risk group
n=40
t df P- value
LAD (cm)
LVM Index(g/m2) ESV (ml)
EDV (ml) LVDD (cm) LVSD (cm) FS (%) EF (%) SV (ml) CO (L/min) CI (L/minM2) DT (ms) MR
Absent-mild / Moderate-severe TR
Absent-mild / Moderate-severe
4.12 + 0.80 158.55 + 53.89 93.32 + 56.86 184.46 + 95.56 5.51 + 1.04 4.33 + 1.02 21.86 + 7.36 51.33 + 13.15 90.00 + 50.07 7.96 + 5.26 4.71 + 3.18 192.11 + 63.57
27/32
32/27
4.52 + 0.85 189.57 + 102.34 154.25 + 118.2 220.90 + 140.53 5.85 + 1.44 3.94 + 1.54 16.53 + 9.88 39.55 + 18.83 77.62 + 54.96 7.41 + 5.36 4.50 + 2.93 164.89 + 50.73
8/31
14/26
-2.40 -1.96 -3.42 -1.53 -1.36 -2.36 3.07 3.67 1.16 0.50 0.33 2.21
-
- 97 97 97 97 97 97 97 97 97 97 97 93
1
1
0.019 0.052 0.001 0.128 0.176 0.02 0.003 0.000 0.249 0.618 0.743 0.030
0.007
0.047
LEGEND FOR TABLE 12
LAD, left atrial dimension; LVM index, left ventricular mass index; ESV, end systolic volume; EDV, end diastolic volume; LVDD, left ventricular diastolic dimension; LVSD, left ventricular systolic dimension; FS, fractional shortening; EF, ejection fraction; SV, stroke volume; CO, cardiac output; CI, cardiac index; DT, deceleration time; MR ,mitral regurgitation; TR, tricuspid regurgitation.
OUTCOME IN HEART FAILURE PATIENTS
Out of the 100 HF patients that were recruited, 6 died (6% mortality) within the 3 months study period and 5 were lost to follow up (5% attrition).Subsequently, 89 patients had a repeat echocardiogram. All 6 patients that died within the study period belonged to the intermediate/high risk group. Table 13 shows that the improvement in fractional shortening and ejection fraction was significantly greater in the low risk group compared to the intermediate/high risk group; 5.28 9.06% vs. 0.91 6.33 % and 7.86 13.83%
vs.–1.20 13.21% respectively.
Table 13: ECHOCARDIOGRAM AFTER 3 MONTHS THERAPY
Parameter Low Risk n=54
Intermediate/ High Risk
n=35
t df P-value Change in
Fractional Shortening
(%) 5.28 + 9.06 -0.91 + 6.33 3.517 87 0.001
Change in
Ejection Fraction (%) 7.86 + 13.83 -1.20 + 13.21 3.069 87 0.003 Change in Stroke
Volume (ml) -8.23 + 27.97 14.14 + 54.03 -2.564 87 0.012
As shown in table 14, the commonest diastolic abnormality that occurred in the low risk group was impaired relaxation which accounted for 68.4% of the cases. A restrictive pattern of left ventricular filling was the most common diastolic abnormality observed in the intermediate/high risk group accounting for 48.6% of the cases.
Table 14: COMPARISOM OF DIASTOLIC FUNCTIONS BETWEEN THE LOW AND INTERMEDIATE/HIGH RISK GROUPS
Type of Diastolic abnormality Low Risk
n=57 (n) (%)
Intermediate/
high Risk n=35 (n) (%)
Normal
Impaired Relaxation Pseudo-normalization Restrictive filling
3 (5.3%) 39 (68.4%) 7 (12.3%) 8 (14%)
3 (8.6%) 9 (25.7%) 6 (17.1%) 17 (48.6%)