Atrial fibrillation in congestive cardiomyopathy: echocardiographic and hemodynamic correlates

Left atrial size changes in patients with paroxysmal lone atrial fibrillation. An echocardiographic follow-up

Left atrial enlargement has been demonstrated to occur as a consequence of the arrhythmia in patients with chronic atrial fibrillation (AF) in the absence of organic heart disease, whereas contrasting results have been reported in patients with paroxysmal lone AF. In the present investigation the behavior of left atrial size was followed up for an average period of 30.3 months in 20 patients with paroxysmal lone AF since their first arrhythmic episode. No significant changes in left atrial size were found at the end of the follow-up period. In 65% of patients the arrhythmia recurred at least once yearly. Left atrial size at enrollment was not significantly different in these patients from those without recurrences and did not change in either group during follow-up. The results suggest that in patients with lone AF left atrial dilatation occurs only after the arrhythmia becomes chronic. Early restoration of sinus rhythm may interrupt the vicious circle leading to atrial enlargement.

Radiofrequency ablation of a supraventricular tachycardia due to interatrial conduction from the recipient to donor atria in an orthotopic heart transplant recipient

Interatrial conduction of recipient atrial tachycardia to the donor atria of an orthotopic heart transplant recipient resulted in a unique cause of supraventricular tachycardia. An electrophysiologic study was performed, and the recipient atria was found to be in an atrial tachycardia, cycle length of 210 msec, with periods of both 2:1 and 1:1 conduction to the donor atria resulting in a donor atrial cycle length of 420 msec and 210 msec, respectively. The site of interatrial conduction was mapped to the right atrial suture line, along the atrial free wall, and was successfully disrupted with radiofrequency energy. Arrhythmias of a similar mechanism may also be observed in other postsurgical patients.

Echocardiographic predictors of nonrheumatic atrial fibrillation. The Framingham Heart Study

BACKGROUND

Although structural heart disease is often present in patients with nonrheumatic atrial fibrillation, the echocardiographic precursors of atrial fibrillation have not been reported previously. In this elderly, population-based cohort, our objective was to examine prospectively the echocardiographic predictors of nonrheumatic atrial fibrillation.

METHODS AND RESULTS

Subjects in the Framingham Heart Study were routinely evaluated with M-mode echocardiography; 1924 subjects, ranging in age from 59 to 90 years, comprised the population at risk. Cox proportional hazards modeling was used to analyze the association of selected echocardiographic features with atrial fibrillation risk after adjustment for age, sex, hypertension, coronary heart disease, congestive heart failure, diabetes, and valvular heart disease. During a mean follow-up interval of 7.2 years, 154 subjects (8.0%) developed atrial fibrillation. Multivariable stepwise analysis identified left atrial size (hazard ratio [HR] per 5-mm increment, 1.39; 95% confidence interval [CI], 1.14 to 1.68), left ventricular fractional shortening (HR per 5% decrement, 1.34; 95% CI, 1.08 to 1.66), and sum of septal and left ventricular posterior wall thickness (HR per 4-mm increment, 1.28; 95% CI, 1.03 to 1.60) as independent echocardiographic predictors of atrial fibrillation. For each of the echocardiographic predictors, risk increased progressively over successive quartiles. Moreover, risk increased markedly when highest-risk-quartile measurements for these features were present in combination; the cumulative 8-year age-adjusted atrial fibrillation rates were 7.3% and 17.0%, respectively, when one and two or more highest-risk-quartile features were present, compared with 3.7% when none was present.

CONCLUSIONS

In this elderly, population-based sample, left atrial enlargement, increased left ventricular wall thickness, and reduced left ventricular fractional shortening were predictive of risk for nonrheumatic atrial fibrillation. These echocardiographic precursors offer prognostic information beyond that provided by traditional clinical atrial fibrillation risk factors.

Mitral anulus motion. Relation to pulmonary venous and transmitral flows in normal subjects and in patients with dilated cardiomyopathy

The dynamics between mitral anulus motion, and, thus, motion of the base of the heart, and filling of the left atrium and ventricle were studied by Doppler echocardiography in 12 normal subjects and 28 patients with dilated cardiomyopathy. The normal motion of the mitral anulus is associated with two phases of inflow from the pulmonary veins. The first phase (J) of pulmonary venous inflow occurs during ventricular systole, concomitant with the descent of the mitral anulus toward the ventricular apex, the extent of which is 12.8 +/- 1.4 mm. The end of the descent of the anulus occurs at the cessation of aortic ejection. About 100 msec later, a rapid recoil of the mitral anulus toward the atrium coincides with the onset of transmitral filling. This rapid recoil contributes to the displacement of blood from the atria into the ventricles in early diastole. The second phase (K) of pulmonary venous flow begins in early diastole, with its peak occurring about 50 msec after the peak of transmitral flow. During atrial contraction, the mitral anulus moves slightly (2.4 +/- 0.7 mm) toward the atrium and then returns toward its initial position within 120 msec. This motion coincides with the A wave of transmitral flow. In patients with dilated cardiomyopathy, pulmonary venous flow and mitral anulus motion are markedly altered in comparison with normal subjects. In all patients, motion of the mitral anulus is either reduced or absent.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial fibrillation and atrial enlargement in patients with mitral stenosis

The present study was designed to assess the relative contribution of atrial fibrillation and left atrial pressure to changes in the size of the left and right atria in patients with mitral stenosis. The study included 155 subjects, 102 of whom underwent prospective echocardiography and Doppler cardiography, and 69 of whom underwent cardiac catheterization. The size of the atria was determined by two-dimensional echocardiography. There were no significant hemodynamic differences between patients with mitral stenosis who were in either sinus rhythm or atrial fibrillation. The left atrium was larger (p less than 0.001) in patients with mitral stenosis and atrial fibrillation (37.6 +/- 10.8 cm2) than in patients in sinus rhythm (27.8 +/- 7.7 cm2) or normal subjects (15 +/- 3.3 cm2). The size of the right atrium was larger (p less than 0.001) in patients with mitral stenosis and atrial fibrillation (21.7 +/- 5.2 cm2) than in patients in sinus rhythm (13.4 +/- 3.9 cm2) or normal subjects (13.8 +/- 3.7 cm2). Multiple regression analysis showed that the severity of mitral stenosis accounted for 38%, age for 7%, and atrial fibrillation for 11% of the change in the size of the left atrium. Atrial fibrillation accounted for 24%, age for 11, and mitral valve area for 3% of the change in the size of the right atrium. The analysis suggests that the onset of left atrial dilatation in mitral stenosis is the result of an early increase in left atrial pressure. Atrial fibrillation, which develops irrespective of the severity of the mitral stenosis, contributes to a further enlargement of the left and right atria.