Etiological Distribution of Chronic and Transient Atrial

Fibrillation in Patients at Cantonal Hospital Zenica

Enes Abdović10 yrs Prospective Study,

2940pts from June 2000 to May 2010

5 th Congress of Cardiologists and Angiologistsof Bosnia and Herzegovina

Background

• Atrial fibrillation (AF) is the most prevalent sustained cardiac arrhythmia in developed countries. 

• It is a disease of the elderly and it is common in patients (pts) with organic heart disease.

• Hypertension, diabetes mellitus, heart failure and valvular heart disease are predisposing factors to AF.

Aim

• To evaluate relationship of different types of AF (transitory/chronic) with underlying heart disease and demographic characteristics of pts as well

Godtfresen J. Atrial fibrillation: course and prognosis. A follow-up study of 1212 cases. In: Kulbertus HE, Olsson

SB, Schlepper M, eds. Atrial Fibrillation. Mölndal,

Sweden: AB Hässle; 1982:134–145.

• Godtfredsen, retrospectively analyzed the charts of 1212 patients with AF hospitalized in Slagelse, Denmark, during the years 1940 to 1967.

• Chronic AF cases represented 65% of his patients.

The ALFA Study Samuel Lévy et al. Circulation 1999

• The relative prevalences of paroxysmal, chronic, and recent onset AF were 22.1%, 51.4%, and 26.4%, respectively.

• Underlying heart disease was present in 534 patients (70.6%). An absence of underlying heart disease referred to as lone AF was observed in 29.4% of the total patient population despite the wide use of echocardiography.

• Hypertension was the most common underlying condition (39.4%), and hypertensive heart disease was found in 21.4% of the total patient population.

• Of interest is the fact that the incidence of coronary artery disease (16.6%) and myocardial diseases (15.3%) have reached or exceeded the incidence of valvular heart disease in the total cohort (15.2%).

The ALFA Study, 756 pts Samuel Lévy et al. Circulation 1999

Median age 68.6 yrs (19-95)

Male gender 57,7% (436)

Chronic AF 51,4% (389)

Hypertension 39,4% (298)

Diabetes mellitus 10.7% (81)

Thyroid gland diseases

3,1% (24)

Lone AF 29,4% (221)

• Am Heart J 2008;155:197-9

• The development of atrial fibrillation (AF) is a relatively common complication of acute myocardial infarction (AMI) present in ~10% to 15% of AMIs and generally thought to be a marker of adverse prognosis.

“Non pathologic AF”Taggar JS and Lip GYH “Risk Predictors for Atrial Fibrillation” Ed. Europace 2008

• It is estimated that in ~2 – 10% (and possibly as much as 30%) of people presenting with AF there is no identifiable aetiology and this subset of patients is often to reffered as “Lone AF(LAF)”

• LAF is more likely among younger populations. In one study, the mean age at diagnosis of LAF was 46.8 years.

Etiological distribution of pts with AF

39%

25%

15% 12% 3%

8%

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

HHD DCM CHD VHD Lone Other

Results

Median age 72 years (16-96)

Male gender 48,7% (1426)

Chronic AF 69,9% (2045)

Hypertension 71,1% (2089)

Diabetes mellitus 17.2% (503)

Thyroid gland diseases

6,1% (197)

IV block 29,1% (853)

Age Distribution of pts with AF

Sex and Age Distribution of pts with AF

0

50

100

150

200

250

16-20 21-25 26-30 31-35 36-40 41-45 46-50 51-55 56-60 61-65 66-70 71-75 76-80 81-85 86-90 91-95 96-100

Males

Females

Median age (IQ range) of pts with AF The median age was 72 years,

ranged between 16 and 96 years

Sex

• Female’s predominance in:• HA, VHD, DM,

• Male’s predominance in:• Lone FA, DCM

Transitory vs. Chronic AF

Transitory vs. Chronic AF

Transitory AF

Chronic AF

FemalesOR=1.28 95% CI=1.00-

1.64Sex

Males

Younger ptsOR=1.04 95% CI=1.02-

1.05Age

Older pts

LoneAFOR=3.85 95% CI=1.64-

9.04

Concomitant/

Underlying Disease

DCMOR=2.19 95% CI=1.20-4.01

HypertensionOR=1.47 95% CI=1.07-

2.04

VHDOR=4.27 95% CI=2.24-8.15

Chronic-transitory AF ratio distribuated by age of patients

3,40

3,87

1,69 1,78 2,09

2,94

1,50

2,50

3,50

4,50

56-60 61-65 66-70 71-75 76-80 81-85

Intraventricular Block Distribution

20%

36%

25%18%

24%

0%0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

HHD DCM CHD VHD Lone Other

Without IVB

IVB

Distribution of IVB(%)

LBBB

LBBB+LAHB

LBBB+LPHB

LAHB

LPHB

LAHB+RBBB

LPHB+RBBB

RBBB

20

10

40

1

5

10

410

Summary

Frequency Age Sex Diabetes IV block

HHDthe most common (39%)

DCMthe oldest (71±9 yrs)

males(63%)

the most common (36%)

CHDhighest(23%)

VHDthe youngest(66±11 yrs)

females(63%)

lowest(4%)

only 18%

Lone only 2.5%mostly in younger males (men 72%, average age 56±13 yrs)

A Proposed Model for the Pathogenesis of AF

Experimental and clinical studies have shown that AF is maintained by multiple reentrant wavelets within the atrial muscle.

It has been estimated that a critical number of wavelets (from 3 to 6) is necessary for perpetuation of AF...

Conclusion(1)• The classical risk factors for developing AF

include HA, diabetes mellitus, valvular disease, ischaemic cardiomyopathy, CHF and thyroid disease.

• HHD was by far the most prevalent associated medical condition.

• Chronic AF was predominant in groups with advanced cardiac remodeling such as DCM and VHD. On the contrary to transient AF, it is a disease of the elderly.

Conclusion(2)

• In order to prevent or postpone the development of AF an optimal treatment of hypertension and diabetes mellitus is necessery