Does P-Wave Dispersion Predict the Atrial Fibrillation Occurrence After Direct-Current Shock Therapy?

Effect of ramipril/hydrochlorothiazide and ramipril/canrenone combination on atrial fibrillation recurrence in hypertensive type 2 diabetic patients with and without cardiac autonomic neuropathy

INTRODUCTION

The aim of this study was to compare the effect of ramipril/canrenone versus ramipril/hydrochlorothiazide (HCTZ) combination on atrial fibrillation (AF) recurrence in type 2 diabetic hypertensives with and without cardiac autonomic neuropathy (CAN).

MATERIAL AND METHODS

A total of 289 hypertensive type 2 diabetic patients, 95 with CAN, in sinus rhythm but with at least two episodes of AF in the previous 6 months were randomized to ramipril 5 mg plus canrenone 50 mg (titrated to 10/100 mg) or to ramipril 5 mg plus HCTZ 12.5 mg (titrated to 10/25 mg) or to amlodipine 5 mg (titrated to 10 mg) for 1 year. Clinic blood pressure (BP) and a 24-h ECG were evaluated monthly. Patients were asked to report any episode of symptomatic AF and to perform an ECG as early as possible. Serum procollagen type I carboxy-terminal peptide (PIP) and carboxy-terminal telopeptide of collagen type I (CITP) were evaluated before and after each treatment period.

RESULTS

Blood pressure was similarly and significantly reduced by all treatments. A total of 51% of patients with amlodipine had a recurrence of AF, as did 31% of patients with ramipril/HCTZ (p < 0.05 vs. amlodipine) and 13% of patients with ramipril/canrenone (p < 0.01 vs. amlodipine and p < 0.05 vs. ramipril/HCTZ). A similar trend was found in diabetic patients with CAN. Both combinations reduced PIP and increased CITP, but the effects of ramipril/canrenone were significantly more marked.

CONCLUSIONS

These findings suggest that in type 2 diabetic hypertensives, ramipril/canrenone treatment was more effective than ramipril/HCTZ in reducing AF recurrence. This could be related to the greater improvement in cardiac fibrosis.

P-wave dispersion: What we know till now?

P-wave dispersion is defined as the difference between the maximum and the minimum P-wave duration recorded from multiple different-surface ECG leads. It has been known that increased P-wave duration and P-wave dispersion reflect prolongation of intraatrial and interatrial conduction time and the inhomogeneous propagation of sinus impulses, which are well-known electrophysiologic characteristics in patients with atrial arrhythmias and especially paroxysmal atrial fibrillation. Extensive clinical evaluation of P-wave dispersion has been performed in the assessment of the risk for atrial fibrillation in patients without apparent heart disease, in hypertensives, in patients with coronary artery disease, in patients undergoing coronary artery bypass surgery, in patients with congenital heart diseases, as well as in other groups of patients suffering from various cardiac or non-cardiac diseases. In this paper, we aimed to summarize the measurement methods, current use in different clinical situations, strengths and limitations of the of P-wave dispersion.

Effect of valsartan and ramipril on atrial fibrillation recurrence and P-wave dispersion in hypertensive patients with recurrent symptomatic lone atrial fibrillation

BACKGROUND

This study compared the effect of antihypertensive treatment with valsartan or ramipril on atrial fibrillation (AF) recurrence, on P-wave dispersion, (PWD) and on serum procollagen type I carboxy terminal peptide (PIP).

METHODS

A total of 369 mild hypertensive (systolic blood pressure (SBP) >140 and/or 90 < diastolic blood pressure (DBP) < 110 mm Hg) outpatients in sinus rhythm but with at least two episodes of AF in the previous 6 months were randomized to valsartan (n = 122), ramipril (n = 124), or amlodipine (n = 123) for 1 year. Clinic blood pressure (BP) and a 24-h electrocardiogram (ECG) were evaluated monthly. Patients were asked to report any episode of symptomatic AF and to perform an ECG as early as possible. PWD and serum PIP levels were evaluated before and after each treatment period.

RESULTS

SBP and DBP were significantly reduced by the three treatments (P < 0.001). A total of 46 (47.4%) patients treated with amlodipine had a recurrence of AF as did 26 (27.9%) patients treated with ramipril (P < 0.01 vs. amlodipine) and 16 (16.1%) patients treated with valsartan (P < 0.01 vs. amlodipine and P < 0.05 vs. ramipril). The Kaplan-Meyer analysis showed a significant reduction of AF episodes in the valsartan group (P = 0.005 log-rank test) as well as in the ramipril group (P = 0.021), even if at a lesser degree. PWD values were significantly reduced by ramipril (-4.2 ms, P < 0.05) and even more by valsartan (-11.2 ms, P < 0.01), the difference being significant (P < 0.01). Serum PIP levels were reduced by ramipril (-49.7 microg, P < 0.001) and valsartan (-49.3 microg, P < 0.001).

CONCLUSIONS

Despite similar BP lowering, valsartan and ramipril were more effective than amlodipine in preventing new episodes of AF, but the effect of valsartan was greater than that of ramipril. This could be related to the greater PWD reduction observed with valsartan.

Coronary Collateral Circulation: Any Effect on P-Wave Dispersion?

Coronary collateral circulation determines the severity of ischemic myocardial damage. Increased P-wave dispersion is an independent predictor for atrial fibrillation. Consistent evidence is little about the relation between coronary collateral circulation and arrhythmia risk. In this article, the effect of coronary collateral circulation on P-wave dispersion was evaluated. Collateral grade and P-wave dispersion were ascertained in 100 patients with ≥85% diameter stenoses in left anterior descending or right coronary arteries. Left ventricular function score was also determined in all patients. Coronary collateral circulation was absent in 32 patients, whereas 68 patients had coronary collateral circulation. Patients with collateral grade ≥1 had greater left ventricular function score than did patients with collateral grade 0 ( P = .048). However, there was no significant difference between P-wave dispersion of patients with and without coronary collateral circulation ( P = .45). The presence of coronary collateral circulation failed to exert a beneficial decreasing effect on P-wave dispersion.

Quantitative estimation of left atrial linear dimension on a transthoracic echocardiogram using an electrocardiographic formulaic assessment

A proportionate and incremental association between left atrial (LA) dilatation on a transthoracic echocardiogram (TTE) and increasing severity in abnormal atrial depolarization can be described by the regression formula: LA dimension in parasternal long-axis view (in millimeters) = 2.47 + 0.29 [P-wave duration (in milliseconds)]. However, prospective testing of this formula for LA quantification with comparison to other TTE indexes is lacking. We prospectively obtained 12-lead electrocardiograms for 72 consecutive patients before individual, nonemergent TTE assessment. P waves were assessed independently to the nearest 10 ms for application of the formula with a Bland-Altman plot. P-wave durations were obtained specifically from lead II and also from any lead that yielded the widest measurement. There was a strong formulaic correlation with LA measurement by TTE (p <0.00000001; r = 0.662), irrespective of electrocardiographic lead used. However, as the measurement difference increased between that in any lead and lead II, correlation strength increased. Correlation was not significantly affected by commonly measured electrocardiographic and TTE indexes, such as, PR interval, QRS complex, and left ventricular end-diastolic as well as systolic dimensions, after adjustment for these variables. Moreover, when the P-wave axis remained within the normal range, the correlation strength increased. The Bland-Altman plot also showed good agreement of LA dimension assessment between formulaic estimation and TTE measurement. In conclusion, there is good agreement and correlation between formulaic estimation and that of TTE for measurement of LA linear dimension. The LA regression formula is an indirect asset that could perhaps supplement LA quantification on TTE in certain circumstances.

Predictors of early recurrence and delayed cure after segmental pulmonary vein isolation for paroxysmal atrial fibrillation without structural heart disease

BACKGROUND

Early recurrence of atrial fibrillation (ERAF) and delayed cure are commonly observed after atrial fibrillation (AF) ablation. The purpose of this study was to determine the predictors of ERAF and delayed cure after a single pulmonary vein isolation (PVI) performed in paroxysmal AF patients without structural heart disease.

METHODS AND RESULTS

In 108 consecutive patients (93 men, 15 women; mean age 51 +/- 8 years) with paroxysmal AF and no structural heart disease, segmental PVI guided by a Lasso catheter was performed. Forty-one percent (44/108) AF patients had ERAF after a single PVI. Univariate analysis revealed that left atrial diameter (p = 0.004), age (p = 0.024) and P-wave dispersion (p = 0.045) were significantly related to ERAF. Logistic regression analysis revealed that left atrial enlargement was the only independent predictor of ERAF (odds ratio [OR] 1.17; 95% confidence interval [CI] 1.04-1.30, p = 0.006). Delayed cure occurred in 32% (14/44) patients with ERAF. P-wave dispersion (p = 0.001), left atrial diameter (p = 0.008) were significantly related to delayed cure. P-wave dispersion was the only independent predictive factor of delayed cure (OR 0.91; 95% CI 0.85-0.97, p = 0.004).

CONCLUSIONS

Elderly patients with left atrial enlargement and a high dispersion of P wave are susceptible to ERAF after a single PVI. Left atrial enlargement is the only independent predictor of ERAF. Among patients with ERAF, those with less P-wave dispersion and less left atrial diameter have a higher probability of delayed cure. P-wave dispersion can independently predict delayed cure.