Inter-atrial conduction time shortens after blood pressure control in hypertensive patients with left ventricular hypertrophy

Cilostazol decreases total atrial conduction time in patients with peripheral artery disease

Objective:

Total atrial conduction time (TACT) is the most important parameter in predicting the development of new-onset atrial fibrillation. We investigated the effect of cilostazol therapy on TACT in patients with peripheral artery disease.

Methods:

Thirty patients with peripheral artery disease were treated with cilostazol (200 mg/day) for 6 months. The baseline echocardiographic total atrial conduction time parameter was compared with the 6-month follow-up.

Results:

The TACT duration was decreased in all patients compared with the baseline after therapy (121.8 ± 19.3 vs. 109.1 ± 15.9 milliseconds, p<0.001). However, left atrial (LA) diameter was not changed with the therapy. The reduction of TACT duration was correlated with the increase in mitral E wave velocity/mitral A wave velocity ratio (r=-0.48, p<0.003).

Conclusion:

Our results showed that 200 mg cilostazol treatment decreased TACT duration in patients with peripheral artery disease, which may also prevent the development and/or recurrence of atrial fibrillation (AF).

Extent of left ventricular hypertrophy is related to interatrial conduction delay in hypertensive patients

The aim of this study was to investigate the relationship between left ventricular mass (LVM) and interatrial conduction delay (CD) measured by tissue Doppler echocardiography. In enrolled 66 hypertensive patients, positive correlation between interatrial CD and LVM index (r = 0.32) was detected. Meanwhile, intra-atrial CD was correlated to early diastolic tissue Doppler mitral annular velocity measured from septum (r = 0.34), tricuspid annular velocity (r = 0.29), and left atrial volume index (r = 0.26). By using stepwise linear regression analysis, LVM index was determined as an independent predictor of interatrial CD.

Variable interatrial conduction illustrated in a hypertrophic cardiomyopathy population

BACKGROUND

Patients with hypertrophic cardiomyopathy (HCM) have a high incidence of atrial fibrillation. They also have a longer P-wave duration than healthy controls, indicating conduction alterations. Previous studies have demonstrated orthogonal P-wave morphology alterations in patients with paroxysmal atrial fibrillation. In the present study, the P-wave morphology of patients with HCM was compared with that of matched controls in order to explore the nature of the atrial conduction alterations.

METHODS AND RESULTS

A total of 65 patients (45 men, mean age 49 +/- 15) with HCM were included. The control population (n = 65) was age and gender matched (45 men, mean age 49 +/- 15). Five minutes of 12-lead ECG was recorded. The data were subsequently transformed to orthogonal lead data, and unfiltered signal-averaged P-wave analysis was performed. The P-wave duration was longer in the HCM patients compared to the controls (149 +/- 22 vs 130 +/- 16 ms, P < 0.0001). Examination of the P-wave morphology demonstrated changes in conduction patterns compatible with interatrial conduction block of varying severity in both groups, but a higher degree of interatrial block seen in the HCM population. These changes were most prominent in the Leads Y and Z.

CONCLUSION

The present study suggests that the longer P-wave duration observed in HCM patients may be explained by a higher prevalence of block in one or more of the interatrial conduction routes.

Effects of Cilazapril on atrial electrical, structural and functional remodeling in atrial fibrillation dogs

BACKGROUND AND PURPOSE

The effects of angiotensin-converting enzyme inhibitor on long-term atrial electrophysiologic and structural remodeling are still unclear. The purpose of this study is to investigate the effects of Cilazapril on atrial electrical, structural, and functional remodeling in atrial fibrillation (AF) dogs induced by chronic rapid atrial pacing.

METHODS

Twenty dogs were randomly divided into sham-operated group (n = 6), control group (n = 7), and Cilazapril group (n = 7). One thin silicon plaque containing 4 pairs of electrodes was sutured to each atrium. A pacemaker was implanted in a subcutaneous pocket and attached to a screw-in epicardial lead in the right atrial appendage. The dogs in control group and Cilazapril group were paced at 400 beats per minute for 6 weeks. The dogs in Cilazapril group received Cilazapril (0.5 mg x kg(-1) x d(-1)) 1 week before rapid atrial pacing until pacing stop. Before and after 6-week rapid atrial pacing, atrial effective refractory period (AERP) at 8 sites, AERP dispersion, intraatrium conduction time, inducibility, and duration of AF were measured. Transthoracic and transesophageal echocardiographic examinations included left atrium (LA) maximal volume, LA minimal volume, LA ejection fraction, left atrial appendage (LAA) maximal volume, LAA minimal volume, LAA ejection fraction, LAA maximal forward flow velocity, and LAA minimal backward flow velocity were performed. Atrial collagen volume fraction was analyzed by Masson staining.

RESULTS

After 6-week rapid atrial pacing, although there was no significant difference in AERP shortening and AERP rate adaptation reduction between the control group and the Cilazapril group, the inducibility and duration of AF were found to be dramatically lower in the Cilazapril group than those in the control group (AF inducibility, 65.7% vs 95.7%, P < .05; AF duration, 531.5 +/- 301.2 vs 1432.2 +/- 526.5 s, P < .01). The post-tachycardia intraatrium conduction times after 6 weeks with Cilazapril were significantly shorter than those in the control group. Cliazapril could partially prevent AERP dispersion increase induced by chronic rapid atrial pacing. Compared with the control group, the LA and LAA volumes were significantly smaller; LA ejection fraction, LAA ejection fraction, LAA maximal forward flow velocity, and LAA minimal backward flow velocity were dramatically higher in the Cilazapril group. The Cilazapril group had a significantly lower percentage of interstitial fibrosis than the control group.

CONCLUSIONS

Cilazapril can suppress structural and functional remodeling and prevent the induction and promotion of AF in chronic rapid atrial pacing dogs.