Several studies have shown the high prevalence’s of both heart failure with preserved ejection fraction (HFPEF) and inter-atrial block (IAB) among the elderly patients as both have similar risk factors. Moreover, recent studies have indicated the association of the Inter-atrial electromechanical dyssynchrony induced by IAB with a left atrial enlargement and dysfunction which could thereby lead to HFPEF.
To throw more light onto these reported findings, Dr. J-C Eicher and coworkers performed the present study that assessed the prevalence of inter-atrial dyssynchrony in a population of HFPEF patients admitted for acute congestive heart failure (CHF).
Study population consisted of 29 HFPEF patients who were compared to 27 controls patients group of age-matched patients without heart failure and with similar risk factors. An exclusion criterion was patients with significant valve disease and acute coronary syndrome.
As a part of this 3 months study, researchers prospectively studied all patients with sinus rhythm and left ventricular ejection fraction <50% admitted for CHF in their cardiology department. Data on the following was collected in both groups: Surface ECG: P wave duration (PwD) (IAB was defined as a PwD <120 ms); Blood samples: Nt-proBNP, serum creatinine; Doppler echocardiography: mitral and tricuspid E and A wave velocity and duration, mitral E/A and E/e' ratios, left atrial diameter, interatrial mechanical delay (IAMD = interval between P wave onset and mitral A wave onset - interval between P wave onset and tricuspid A wave onset), pulmonary artery systolic pressure (PAP) derived from the tricuspid regurgitation velocity.
Findings from this study showed higher Nt-proBNP levels (table) but similar creatinine levels were reported by HFPEF patients when compared to controls. Longer PwD was reported in HFPEF patients and high prevalence of IAB was observed in both groups (table).
Table: HFPEF patients versus controls
| |
Nt-proBNP levels (pg/ml) |
P wave duration |
Prevalence of inter-atrial dyssynchrony |
| HFPEF patients |
4653 ± 3533 |
125.5 ± 16.4 ms |
69 % |
| Controls |
523 ± 496 |
117.8 ± 14.2 ms |
59 % |
| P values |
<0.001 |
NS |
|
Considering the Doppler results, higher E/A, higher E/e' ratios, shorter mitral A wave duration (table 2), the longer mean IAMD (vs., p) were all reported among the HFPEF patients when compared with control group.
Table 2: Doppler results in HFPEF patients versus controls
|
|
E/A
|
E/e'
|
Mitral A wave duration
|
Mean IAMD
|
|
HFPEF patients
|
1.4 ± 1
|
18.5± 10.2
|
143.1±30.7 ms
|
64± 30 ms
|
|
Controls
|
0.9± 0.3
|
11.5 ± 5
|
149.6±26.3 ms
|
24±12 ms
|
|
P values
|
0.02
|
0.01
|
0.03
|
< 0.001
|
Additionally, prevalence of severe IAMD <60 ms was significantly higher in HFPEF group when compared with controls (figure below, p < 0.001).
Furthermore, even among HFPEF patients, significantly shorter mitral A wave and higher E/e' ratio were reported in those with an IAMD <60ms had significantly shorter mitral A wave, higher E/e' ratio and tended to have higher PAP than those with a less severe IAMD.
Based on all the above findings this study concluded that P wave duration <120 ms was more common in elderly patients with or without heart failure with preserved ejection fraction which translates into mechanical inter-atrial dyssynchrony. This study also suggested that severe interatrial mechanical delay was highly prevalent in heart failure with preserved ejection fraction whereas this was absent in controls and was associated with shorter mitral A wave and higher filling pressures. Therefore, these study findings could open up new perspectives to understand the pathophysiology of heart failure with preserved ejection fraction. | 
