Medicine Poster Session
Abstract
Introduction
Materials & Methods
Results
Discussion & Conclusion
References
Discussion Board

Determinants Of Exercise Capacity In Patients With Left Ventricular Dysfunction As Assessed By SixMinute Walk Test
Contact Person: Nikolay P Nikitin (nimed@silk.org)
Results
Clinical, hemodynamic and echocardiographic characteristics of the patients are given in Table 1. Twenty eight patients were in NYHA functional class I, 44 patients in class II and 44 patients in class III. The study patients were taking a variety of medications, including angiotensinconverting enzyme inhibitors, diuretics, digitalis, betablockers, nitrates and aspirin.
Table 1. Characteristics of the study patients 
Age (years) 
55+/11 
Weight (kg) 
76+/13 
Heart Rate (beats/min) 
82+/12 
Systolic Arterial Pressure (mm Hg) 
130+/21 
Diastolic Arterial Pressure (mm Hg) 
82+/12 
NYHA class 
2.14+/0.78 
Left Atrial Size (mm) 
45+/7 
LV Mass Index (g/m^{2}) 
140+/43 
LV EndSystolic Volume Index (ml/m^{2}) 
77+/36 
LV EndDiastolic Volume Index (ml/m^{2}) 
120+/38 
LV Ejection Fraction (%) 
34+/6 
Isovolumic Relaxation Time (ms) 
79+/25 
Peak Velocity of Early Filling (m/s) 
0.54+/0.13 
Peak Velocity of Atrial Filling (m/s) 
0.42+/0.14 
PE/PA ratio 
1.47+/0.64 
Deceleration Time of Early Filling (ms) 
140+/29 
Data are expressed as mean value +/ SD. NYHA, New York Heart Association; LV, left ventricular; PE/PA ratio, ratio of early wave to atrial wave peak velocity.
Only one patient was unable to perform the 6 MW test, 9 patients completed the walk with breaks in continuity. The mean distance walked was 277+/114 m. Hemodynamic, echocardiographic and Dopplerderived variables correlated with 6 MW test distance on univariate analysis are listed in Table 2. A significant inverse correlation also existed between NYHA functional class and 6 MW test distance (r=0.435, p=0.000).
Table 2. Correlations between sixminute walk test distance and hemodynamic, echocardiographic, and Dopplerderived parameters 
Parameter 
r 
Regression equation 
p Value 
SEE 
HR 
0.362 
y=552.563.35 x 
0.000 
107.14 
SAP 
0.255 
y=100.37+1.36 x 
0.006 
111.15 
DAP 
0.219 
y=108.13+2.06 x 
0.019 
112.15 
LA size 
0.378 
y=540.965.82 x 
0.000 
106.43 
LVM index 
0.436 
y=438.261.15 x 
0.000 
103.46 
LVESV index 
0,549 
y=411.521.74 x 
0.000 
96.04 
LVEDV index 
0.512 
y=464.111.56 x 
0.000 
98.76 
LVEF 
0.509 
y=35.82+9.25 x 
0.000 
98.93 
IVRT 
0.580 
y=70.32+2.62 x 
0.000 
93.61 
PE 
0.413 
y=469.85358.00 x 
0.000 
104.66 
PA 
0.802 
y=3.81+658.98 x 
0.000 
68.72 
PE/PA ratio 
0.778 
y=481.30138.50 x 
0.000 
72.23 
DT 
0.618 
y=64.36+2.44 x 
0.000 
90.37 
r, correlation coefficient; SEE, standard error of the estimate; HR, heart rate; SAP, systolic arterial pressure; DAP, diastolic arterial pressure; LA, left atrial; LVM, left ventricular mass; LVESV, left ventricular endsystolic volume; LVEDV, left ventricular enddiastolic volume; LVEF, left ventricular ejection fraction; IVRT, isovolumic relaxation time; PE, peak velocity of early filling; PA, peak velocity of atrial filling; PE/PA ratio, ratio of early wave to atrial wave peak velocity; DT, deceleration time of early filling; y, sixminute walk test distance; x, respective parameter.
The strongest univariate determinants of 6 MW test distance were Dopplerderived indices of LV diastolic filling. When the multivariate regression analysis was performed, only PA wave velocity (F to enter 192.71, multiple R = 0.79), PE/PA ratio (F to enter 115.22, multiple R = 0.37), and heart rate (F to enter 80.98, multiple R = 0.12) emerged as independent determinants of 6 MW test distance.
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