Download Left atrium size and incidence of new

DECLARATION OF CONFLICT OF INTEREST
Left atrium size and incidence of
new-onset atrial fibrillation in
essential hypertensives. A 6 years
prospective study
D.TSIACHRIS, C.TSIOUFIS, A.KASIAKOGIAS,
M.POULAKIS, M.ALMYROUDI, D.ARAGIANNIS,
K.KINTIS, I.ANDRIKOU, I.ANASTASOPOULOS,
C.STEFANADIS
First Cardiology Clinic, University of Athens
Hippokration Hospital, Athens, Greece
Epidemiology
 Atrial fibrillation (AF) is the most common
sustained cardiac arrhythmia, occurring in
1–2% of the general population.
 The prevalence of AF increases with age,
from <0.5% at 40–50 years, to 5–15% at 80
years
Heart 2001;86:516–521
JAMA 2001;285:2370–2375
Clinical events (outcomes) affected by AF
ESC Guidelines 2010
The annual cost per patient is close to €3000
 AF is an extremely costly public
health problem, with
 hospitalizations as the primary cost driver (52%),
 followed by drugs (23%),
 consultations (9%),
 further investigations (8%),
 loss of work (6%), and
 paramedical procedures (2%)
Am Heart J. 2004;147:121– 6
Heart. 2004;90:286–92
Anatomical and Electrophysiological
Substrates Promoting AF
Diseases
Anatomical
Cellular
EP
Hypertension
Atrial
dilatation
Myolysis
Conduction
abnormalities
Heart Failure
PV dilatation
Apoptosis
ERP dispersion
Coronary
artery disease
Fibrosis
Channel
expression
changes
Ectopic activity
Valvular
disease
Left atrium (LA) and CV risk
 Increased LA size is closely
related to
 atrial fibrillation
Henry WL, et al. Circulation.
1976;
 stroke, once atrial fibrillation is
manifested
Cabin HS, et al. Am J Cardiol.
1990;
Index of future adverse
cardiovascular events
LA volume or diameter?
 2-D derived LA volume provides a
more accurate measure of the true size of
the LA than LA diameter, although both
LA size parameters have been shown to be
markers of CV risk
Lester SJ, Am J Cardiol 1999
LA size and SR?
 LA volume is a more robust marker of CV
events than LA area or diameter in subjects
with sinus rhythm
In patients with AF, the predictive utility of LA size seems unsatisfactory
Tsang et al, JACC 2006
LA size and diastolic function
 Atrial size as assessed by LAVI has been correlated
with the severity of Diastolic Dysfunction, and this
association was still apparent after controlling for
pertinent covariates
Pritchett et al, JACC 2006
Positive association of LAVI with BNP in untreated
essential hypertensives
Tsioufis et al, J Hypertens 2006
Study purpose
 The aim of our study was to compare
the
predictive
role
of
LA
size,
as
determined either by LA diameter or by
LA volume index, for the incidence of
new-onset AF.
Study population
 We prospectively
followed up for a median
period
 of 6 years (IQ 5-6.6 years)
 782 uncomplicated hypertensives
 without history of AF episodes
 aged 58.1±10 years
Study design
 All subjects had at least one visit
annually
and
at
entry
underwent
complete echocardiographic study.
Cardiac ultrasound
LV mass was calculated with the method of
Devereux et al and normalized either for body
surface area (BSA) or for height2.7 to obtain LV
mass index
Relative
Wall Thickness (RWT) was
calculated at end diastole according to the
following equation: RWT = (interventricular
septum thickness + posterior wall thickness) /
(LV end-diastolic diameter)
LA
diameter
LA diameter was measured by 2Dguided M-mode echocardiography
obtained in the parasternal shortaxis view at the base of the heart
LAV = π/6 (SA1 x SA2 x LX)
SA1 : M-mode LA diameter
SA2 and LX : short- and
long-axis in the apical 4chamber view at ventricular
end-systole 
LA volume was indexed for
body surface area to estimate
LA volume index (LAVI)
 LAVI = LAV / BSA
Laboratory parameters
 Metabolic profile, serum creatinine levels
(sCr) and estimated creatinine clearance
(CrCl) (according to Cockroft-Gault formula)
were assessed from a morning blood sample.
 CKD was defined based on estimated CrCl
between 15 and 59 ml/min.
The incidence of new-onset AF over the whole followup period was 5% (22 patients with paroxysmal AF
and 17 patients with permanent AF).
new onset AF
Free of AF
Clinical characteristics
Patients
with AF
(n=39)
Patients
without AF
(n=743)
p
Age (years)
66.7±8
57.6±10
<0.001
Males (%)
59
47
0.14
28.7±3.6
28.6±4.1
0.84
99.9±8
97±11
0.048
15
10
0.37
Office SBP (mmHg)
144.3±15
142.2±16
0.46
Office DBP (mmHg)
84.7±9
90.0±10
0.002
Office PP (mmHg)
59.6±13
52.2±14
0.002
BMI (Kg/m2)
Waist (cm)
Diabetics (%)
Cardiac ultrasound characteristics
Patients with
AF (n=39)
Patients without
AF (n=743)
p
LVMI-BSA (g/m2)
121.5±29
107.6±27
0.002
LVMI-height
(g/m2.7)
49.4±12
44.0±11
0.003
0.46±0.08
0.43±0.07
0.018
LAD (mm)
42.5±5.3
38.0±4.7
<0.001
LAVI (ml/m2)
26.8±8.3
22.7±6.7
0.001
E (cm/s)
0.82±0.26
0.75±0.17
0.02
E/A
1.03±0.37
0.97±0.26
0.13
Em
7.0±2.7
7.9±2.8
0.07
Em/Am
0.90±0.4
0.83±0.4
0.35
E to Em
13±6.3
10.6±4.6
0.004
RWT
Laboratory parameters
Patients
with AF
(n=39)
Patients
without AF
(n=743)
p
Glucose (years)
102.8±19
102±20
0.80
Serum creatinine
(mg/dl)
1.04±0.24
0.97±0.3
0.19
76.6±25
90.2±29
0.006
27.7
12.7
0.1
5.62±1.6
5.16±1.5
0.07
Creatinine
clearance (ml/min)
CKD (%)
Uric acid (mg/dl)
Predictive role of LA diameter
 In successive multivariate Cox regression models
 age (HR 1.076, p<0.001),
 left ventricular mass index (HR 1.015, p=0.013)
 LA diameter (HR 1.201, p<0.001)
o instead of LAVI (HR 1.042, p=0.07)
turned out to be independent predictors of
new-onset AF.
Regression model including LAD





Variables in the Equation
Wald Sig. Exp(B)
95,0% CI
LowerUpper
Age
14,814 0,000 1,076 1,037 1,118
Off PP 0,872 0,350 1,011 ,988 1,034
LVMI
6,214 0,013 1,015 1,003 1,026
LAD 31,709 0,000 1,201
1,127 1,280
Regression model including LAVI





Variables in the Equation
B Wald Sig. Exp(B)
95,0% CI
Lower
Upper
Age
0,021 8,772 0,003 1,065
1,110
Off PP 0,013 1,109 0,292 1,014
,988
LVMI
0,007 2,054 0,152
1,009
1,023
LAVI
0,023 3,362 0,067 1,042
,997
1,021
1,039
,997
1,089
Limitations
Other
formulas
Simpson’s
Area-length
Volume is
more difficult
to measure?
No data for
inter or intra
observer
variability
 LA size assessed either by its diameter or by
its volume is closely related to LV mass index
irrespective from LV geometric pattern in the
early stages of essential hypertension.
LA diameter: easier and better
 Uncomplicated hypertensives with new-onset AF
are characterized by significantly increased LA
diameter and LA volume indexed for body surface
area.
 Although LAVI has been generally considered a
more accurate estimate of LA size, LA diameter
turned out to be a more powerful predictor of newonset AF in the setting of essential hypertension.