Left atrial function and ventricular filling in hypertensive patients with paroxysmal atrial fibrillation

Effects of aging on left atrial reservoir, conduit, and booster pump function: a multi-institution acoustic quantification study

OBJECTIVE

To assess the feasibility of measuring left atrial (LA) function with acoustic quantification (AQ) and then assess the effects of age and sex on LA reservoir, conduit, and booster pump function.

PATIENTS AND SETTING

165 subjects without cardiovascular disease, 3-79 years old, were enrolled by six tertiary hospital centres.

INTERVENTIONS

Continuous LA AQ area data were acquired and signal averaged to form composite waveforms which were analysed off-line.

MAIN OUTCOME MEASURES

Parameters of LA performance according to age and sex.

RESULTS

Signal averaged LA waveforms were sufficiently stable and detailed to allow automated analysis in all cases. An age related increase in LA area was noted. LA reservoir function did not vary with age or sex. All parameters of LA passive and active emptying revealed a significant age dependency. Overall, the passive emptying phase accounted for 66% of total LA emptying ranging from 76% in the youngest to 44% in the oldest decade. LA contraction accounted for 34% of atrial emptying in all subjects combined with the older subjects being more dependent on atrial booster pump function. When adjusted for atrial size, there were no sex related differences in LA function.

CONCLUSIONS

LA reservoir, conduit, and booster pump function can be assessed with automated analysis of signal averaged LA area waveforms. As LA performance varies with age, establishment of normal values should enhance the evaluation of pathologic states in which LA function is important.

Left ventricular diastolic dysfunction in lone atrial fibrillation determined by Doppler tissue imaging of mitral annular motion

In this study, we sought evidence for an underlying atrial or ventricular myopathy in patients with paroxysmal lone atrial fibrillation using standard echocardiographic parameters in addition to Doppler tissue imaging of mitral annular motion. No impairment in atrial contractile function was found, but there was evidence for impaired diastolic function in these patients.

P wave dispersion in hypertensive patients with paroxysmal atrial fibrillation

It is important to assess the risk of developing paroxysmal atrial fibrillation (PAF) in hypertensive patients since hypertension is a common disorder predisposing to PAF. We sought to determine if patients with hypertension at risk of PAF can be identified while in sinus rhythm by measurements of P wave dispersion. Twelve-lead surface electrocardiograms were recorded in 44 hypertensive patients with history of PAF (group I, mean age = 60) and in 50 hypertensive patients without history of AF (group II, mean age = 57). The maximum P wave duration, the minimum P wave duration, and P wave dispersion (Pd = Pmax - Pmin) were calculated from 12-lead surface ECGs. Left atrial dimension (LAD) and left ventricular ejection fraction (LVEF) were measured by echocardiography. P wave dispersion was significantly greater in group I than group II (50 +/- 12 vs 38 +/- 8 ms, P = 0.001). P minimum (75 +/- 13 vs 87 +/- 11 ms, P = 0.001) and LVEF (0.63 +/- 0.05 vs 0.67 +/- 0.04, P = 0.03) were significantly lower in group I than group II. However P maximum and LAD were not significantly different in group I than group II (P > 0.05). In univariate analysis, P minimum, P wave dispersion, and LVEF were significant predictors of PAF, whereas only P wave dispersion remained a significant independent predictor of PAF in a multivariate analysis. Measurement of P wave dispersion in sinus rhythm may be a useful noninvasive clinical tool to identify patients with hypertension at risk of developing atrial electrical instability and atrial fibrillation.

Significance and prevalence of inducible atrial tachyarrhythmias in patients undergoing electrophysiologic study for presyncope or syncope

The purpose of the study was to report the prevalence of inducible supraventricular tachyarrhythmias (SVTA) in 827 consecutive patients aged 17 to 90 years who did not have spontaneous documented SVTA and who had unexplained presyncope and/or syncope. The electrophysiologic study (EPS) included programmed atrial and ventricular stimulation up to two extrastimuli at three cycle lengths, and the study of sino-atrial and AV conduction. The results were as follows. EPS was normal in 386 patients. Inducible junctional tachycardia or atrial flutter and fibrillation was the only finding in 187 patients (23%). In the remaining patients we found ventricular tachycardia in 103 (12%), heart block in 67 (8%), sick sinus syndrome in 56 (7%) and increased vagal tone in 28 (3%). The presence of an underlying heart disease (47%) and salvos of atrial premature beats on Holter monitoring (39%) were significantly correlated with the induction of SVTA. However, the comparison with similar groups without syncope indicates that only the induction of SVTA in patients with hypertrophic cardiomyopathy and mitral valve prolapse was significantly correlated with the history of syncope. In patients without heart disease or with prior myocardial infarction or decreased left ventricular function, the induction of SVTA, which is not associated with hypotension in the supine position, could require an induction after head-up tilting, because of the lack of specificity of programmed stimulation in these patients. Programmed atrial stimulation should be systematically performed in patients with unexplained syncope, in particular in those with hypertropic cardiomyopathy and mitral valve prolapse, who require a specific treatment, if a SVTA is induced. In other patients the results of programmed atrial stimulation should be interpreted cautiously.