Differences In Left Atrial Size Research Articles

Electrocardiographic P wave changes after thoracoscopic pulmonary vein isolation for atrial fibrillation

Changes in P wave duration (PWD) and P wave area (PWA) have been described following catheter ablation for atrial fibrillation (AF). We hypothesize that video-assisted thoracoscopic pulmonary vein isolation (VATS-PVI) for AF results in decrease of PWD, PWA and P wave dispersion, which may resemble reverse electrical remodeling of the atrium after restoration of sinus rhythm. VATS-PVI consisted of PVI and ganglionic plexus ablation in 29 patients (mean age, 59 ± 7years; 23 males; 17 paroxysmal AF) and additional left atrial lesions in patients with persistent AF. PWD and PWA were measured in ECG lead II, aVF and V2 of ECGs during sinus rhythm before, directly after, and 6months postprocedure. P wave dispersion was derived from the 12 lead ECG. Prior to VATS-PVI, PWD did not correlate with left atrial size and no difference in left atrial size was found between patients with paroxysmal or persistent AF (p = 0.27). Following VATS-PVI, PWD initially prolonged in all patients from 115 ± 4.6ms to 131 ± 3.6ms (p < 0.01) but shortened to 99 ± 3.2ms after 6months (p < 0.01). PWA was 5.60 ± 0.32mV*ms at baseline, 6.44 ± 0.32mV*ms post-VATS-PVI (P = NS), and 5.40 ± 0.28mV*ms after 6months (p = NS vs. baseline, p < 0.05 vs. post-VATS-PVI). P wave dispersion decreased in the persistent AF group from baseline 67 ± 3.3 to 64 ± 2.5ms post-VATS-PVI (p = 0.30) and to 61 ± 3.4ms after 6months (p < 0.05). PWD increases significantly directly after successful VATS-PVI in both groups. There was significant decrease in PWD after 6months. Similarly, P wave dispersion decreased in the persistent group. These changes suggest an immediate procedure related effect, but the later changes may represent reverse electrical atrial remodeling following cessation of AF.

How to achieve durable pulmonary vein isolation: Use the force

How to achieve durable pulmonary vein isolation: Use the force

Pulmonary Vein Isolation for the Treatment of Drug-Refractory Atrial Fibrillation in Adults with Congenital Heart Disease

Atrial fibrillation (AF) is a common arrhythmia in adults with congenital heart disease (CHD). Long-term antiarrhythmic therapy (AAT) in these patients has significant shortcomings. The safety and efficacy of pulmonary vein antrum isolation (PVAI) for the treatment of AF in CHD is presently unknown. We hypothesized that PVAI for AF in patients with CHD is effective and safe. We reviewed a prospective cohort of 4315 patients (age ≥ 18) undergoing PVAI for drug refractory AF at a single institution and identified 36 consecutive patients with CHD (single ventricle physiology, tetralogy of Fallot, coarctation of the aorta, ventricular septal defects, atrial septal defects (ASD) and cardiomyopathy resulting from anomalous origin of the left main coronary from the pulmonary artery). A second cohort of 355 consecutive patients with noncongenital structural heart disease (NSHD) (coronary artery disease, valvular heart disease, ejection fraction <50%, or prior noncongenital cardiac surgery) undergoing PVAI during the same time period was used as a control. Success was defined as freedom from AF starting two months after PVAI in the absence AAT until the end of follow-up. Partial success was defined as freedom from AF in the presence of AAT until the end of follow-up. Combined success was defined as the sum of success and partial success. We compared the outcomes with the use of propensity-score matching in the overall cohort. Patients with NSHD were older and had higher prevalence of hypertension (P < .01), diabetes (P < .01) and hyperlipidemia (P < .01). The most common CHD lesion was ASD (61%) and the most common NSHD lesion was valvular heart disease (57%). After one PVAI, success was achieved in 42% and 53% at 300 days in the CHD and NSHD groups respectively. Four-year success was achieved in 27% and 36% in the CHD and NSHD groups, respectively. There were no significant differences in the success rates between patients groups (P= .46), nor were there any differences in left atrial size or changes in ejection fraction after one or two PVAI in the respective groups. Complication rates between the CHD and NSHD groups were similar (15% vs. 11%, P= .42) except for a higher risk of vascular site complications in patients with CHD (8% vs. 1%, P < .05). PVAI is an attractive treatment modality in drug refractory AF in CHD, with combined success rates in excess of 60%. The maintenance of sinus rhythm after PVAI in CHD appears similar to that of NSHD and warrants prospective validation.

The Electrical Substrate of Vagal Atrial Fibrillation as Assessed by the Signal‐Averaged Electrocardiogram of the P Wave

The autonomic nervous system is thought to be involved in the initiation of atrial fibrillation (AF). However, there is a distinct entity of vagal AF characterized by episodes occurring at rest, postprandially, or during sleep. The purpose of this study was to compare intraatrial conduction in patients with vagally mediated AF to those with nonvagal AF, using the signal-averaged electrocardiogram (SAECG) of P wave. SAECG of P wave was performed in 58 patients with AF using the Marquette Medical System, and the mean filtered P-wave duration (SAPW) was measured. Nine patients were categorized as having pure vagal AF (Group I), and 42 patients as having nonvagal AF (Group II); the remaining seven patients were excluded from analysis because of incomplete data. The patients in Group I were significantly younger and more likely to have paroxysmal lone AF, as compared to those in Group II. There was no significant difference in left atrial size and left ventricular function in the two groups. The mean SAPW was significantly shorter in Group I when compared to Group II (118 +/- 5 ms vs 149 +/- 39 ms, P < 0.001). Whereas all patients in Group I had a normal SAPW, 79% of patients in Group II had an abnormal SAPW (P < 0.001). A normal SAPW was significantly predictive of vagal AF independent of other co-variables. (1) Patients with vagal AF are younger, and invariably have paroxysmal lone AF. (2) SAPW is normal and significantly shorter in vagal AF when compared to patients with nonvagal AF. (3) This suggests that those in the vagal AF population have normal intraatrial conduction, which has implications for AF ablation in these patients.

Long-Term Effects of the Maze Procedure on Atrial Size and Mechanical Function

The Maze procedure is effective in restoring sinus rhythm, but the extensive procedure may have negative effects on atrial mechanical function. Decreased atrial contractility has been observed early after the Maze procedure. The purpose of this study was to determine the long-term effect of the Maze procedure on atrial size and mechanical function. Fifty-two patients with symptomatic atrial fibrillation, without structural heart or valvular disease, underwent the Cox Maze III procedure. Atrial size and mechanical function were assessed by echocardiographic examination at baseline and postoperatively at a mean +/- SD of 6 +/- 1 and 56 +/- 12 months. The left atrial area was decreased 6 months after the procedure compared with baseline (mean, 15.4 +/- 3.3 vs 17.6 +/- 3.2 cm2, p < 0.01). By 56 months, however, the left atrial area had increased compared with the 6-month follow-up (19.5 +/- 3.9 vs 15.4 +/- 3.3 cm2, p < 0.001), resulting in no difference in left atrial size compared with the baseline values. The left atrial contractility, measured as fractional area change, was significantly reduced at 6 and 56 months of follow-up (0.20 +/- 0.09 and 0.19 +/- 0.07 vs baseline 0.36 +/- 0.09), as was the transmitral A-wave velocity (30 +/- 12 and 28 +/- 8 cm/s vs baseline 40 +/- 15). The same pattern was seen for the right atrium. This study shows that the Maze procedure results in a sustained decrease in atrial contractility. The initial reduction in atrial size is later reversed. These findings contradict late improvements in atrial mechanical function after Maze surgery and may have important implications for the risk of thromboembolic complications.

Assessment of Left Atrial Function and Remodeling in Patients With Atrial Fibrillation by Performing Strain Echocardiography: A Prospective Study to Assess the Influence of Renin-Angiotensin System Inhibitors on Atrial Fibrillation

Background and Objectives: Renin-angiotensin system (RAS) inhibitors are likely to reduce the development of atrial fibrillation (AF) by preventing atrial fibrosis. We attempted to assess the relevance of strain echocardiography for quantitative assessment of the left atrial (LA) status in AF, its modification by RAS inhibitors and changes of biochemical markers during cardiac remodeling in AF. Subjects and Methods: Strain echocardiography is performed 2 times (baseline and 12 month) in 60 patients with AF (RAS inhibitors-used group: 30, nonused group: 30). In an apical 4-chamber view, the regional analysis consisted of placing the region of interest cursor at the basal segments of the septal and lateral wall of LA. Mean peak systolic and early diastolic strain/rate are measured with LA end-systolic antero-posterior, longitudinal and transverse dimensions. Results: Six patients of RAS inhibitors-used group (group A, 20%) and three patients of non-used group (group B, 10%) were converted to normal sinus rhythm during the study. LA size, E wave velocity, E/E’, strain parameters showed no significant differences between groups at the baseline. There were no significant differences in LA size and E wave velocity between groups at the 12 months, however, peak systolic strain/rate were significantly higher in group A (36.71±13.63% and 2.98±0.59s 1

Is there an anatomical substrate for idiopathic paroxysmal atrial fibrillation? A case–control echocardiographic study

Idiopathic paroxysmal atrial fibrillation (AF) occurs in patients with apparently normal heart. Its mechanisms may be complex and are poorly understood. The aim of the study was to evaluate whether patients with idiopathic AF have any structural abnormality that may explain the occurrence of AF. A case-control study was undertaken including 60 consecutive patients (mean age 48 +/- 12 years; 75% men) with idiopathic AF admitted to the emergency department. Sixty sex- and age-matched healthy volunteers made up the control group. An echocardiogram was performed in all patients and volunteers to assess the left atrial (LA) and ventricular (LV) dimensions and valvular function. LV diastolic function was also evaluated by analysis of the LV inflow and pulmonary vein flow velocity patterns and tissue Doppler imaging of the mitral annulus. All AF patients showed normal echocardiographic studies with similar LV dimensions, ejection fraction, and diastolic function when compared with normal controls. However, patients with AF had larger LA dimensions (27 +/- 3 vs. 24 +/- 3 mm/m(2)), LA area (10 +/- 2 vs. 8 +/- 2 mm(2)/m(2)), and LA volume (27 +/- 9 vs. 19 +/- 6 mL/m(2)) (P < 0.05 for all). Among patients with AF, there were no differences in LA size between patients with a first episode or recurrent paroxysmal episodes. Patients with idiopathic AF showed larger left atria when compared with controls, there being no differences between patients with a first episode or a recurrence. This suggests the presence of an enhanced substrate to develop idiopathic lone AF.

Severity of diastolic dysfunction as a determinant of left atrial size

Background: Left ventricular diastolic dysfunction (LV DD) increases cardiac morbidity. High left atrial (LA) pressure results from LV DD, leading to LA enlargement. We conducted a study to determine if LV DD severity is correlated to increased LA size. Methods: We reviewed 367 patients with echocardiographic evaluations over 36 months. Severity of LV DD and LA diameter were determined in apical views. The onset of AF following the initial echo was recorded. LA diameter was calculated for normal patients (NP) and those with LV DD. The odds ratio (OR) of developing AF and time to event for each class of LV DD was determined. The OR for AF was calculated for congestive heart failure (CHF), LV hypertrophy (LVH), coronary disease (CAD), diabetes (DM), and hypertension (HTN). Results: LA diameter in NP=43.6±8.28 mm (95% C.I.=42.4–44.8 mm). LA diameter for grade I LV DD=43.5±6.26 mm (95% C.I.=41.6–45.3 mm); grades II+III LV DD= 47.5±7.34 mm (95% C.I.=45.5–49.5 mm). LA diameter in grades II and III LV DD was increased (P<0.05) compared to NP and grade I. There was no difference in LA size between NP and grade I LV DD, nor was there between grade II and III LV DD. Overall, the risk of AF was not increased in patients with LV DD as compared to NP (OR=1.03, 95% C.I.=0.61–1.73, P=NS). Patients with grades II+III LV DD trended toward a shorter time to onset of AF (763.8±586.6 days vs. 1090.9±758.3 and 1085.4±711.8 days, respectively, P=NS) compared to NP and grade I LV DD. CHF was associated with a risk for AF (OR 2.39, 95% C.I.=1.41–4.07, P<0.005). LVH, CAD, DM, and HTN had no increased risk for AF. Conclusions: Our study demonstrates an association between abnormal LV DD and increased LA diameter. LV DD did not increase the risk of AF, however, the presence of heart failure was a strong predictor for AF development.

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P-wave signal averaging is used in an attempt to detect patients at risk of atrial arrhythmias, particularly atrial fibrillation. Although many studies utilized this method, data on the relationship between clinical and echocardiographic variables and signal averaged P-wave parameters are sparse. Thus, we performed a prospective study to evaluate the influence of important clinical and echocardiographic variables on P-wave parameters. The study included 100 probands without demonstrable cardiac disease. P-wave signal averaging was performed after echocardiographic examination in all subjects. Overall P-wave duration averaged 122±16 ms and correlated significantly with age, left atrial and left ventricular end-diastolic diameter on univariate analysis (r=0.287, 0.393 and 0.375; p=0.004, ;0.0001 and ;0.0001, respectively). On multivariate analysis, however, age was the only independent factor affecting signal averaged P-wave duration (p=0.02). There were statistically significant differences in left atrial size and P-wave duration if probands were grouped according to their age. Conclusion There is a significant relationship between signal averaged P-wave duration and age. This may be due to increased atrial fibrosis in elderly subjects. These data should be considered when signal-averaged P wave duration is used as a risk stratifier in patients prone to atrial fibrillation.

Surgical left atrial appendage ligation is frequently incomplete: a transesophageal echocardiographic study

OBJECTIVESThis study sought to determine the incidence of incomplete ligation of the left atrial appendage (LAA) during mitral valve surgery.BACKGROUNDLigation of the LAA to prevent future thromboembolic events is commonly performed during mitral surgery. However, success in completely excluding the appendage from the circulation has never been systematically assessed.METHODSUsing transesophageal Doppler echocardiography, we studied 50 patients who underwent mitral valve surgery and ligation of the LAA. Thirty patients were studied immediately postoperative, and 20 patients were studied 6 days to 13 years after surgery. Incomplete ligation was detected by demonstrating a color jet traversing the separation between the left atrial body and appendage.RESULTSTransesophageal echocardiography detected incomplete LAA ligation in 18 of 50 (36%) patients. The incidence of incomplete ligation was not significantly different between patients studied immediately postoperative and patients studied at various times after surgery. Type of mitral surgery (repair vs. replacement), operative approach (sternotomy vs. port access), left atrial size or degree of mitral regurgitation did not significantly correlate with the incidence of incomplete appendage ligation. However, the power to detect a significant difference in left atrial size was only 64%. Spontaneous echo contrast or thrombus was identified within appendages in 9 of 18 (50%) patients with incomplete ligation, while 4 of these 18 (22%) patients had thromboembolic events.CONCLUSIONSSurgical LAA ligation is frequently incomplete. The similar incidence of incomplete ligation detected immediately postoperative and at various times thereafter suggest that this results from an intraoperative phenomenon rather than from gradual dehiscence of sutures over years. The incidence of incomplete left atrial ligation was unrelated to type of surgery, surgical approach, left atrial size or degree of mitral regurgitation. Residual communication between the incompletely ligated appendage and the left atrial body may produce a milieu of stagnant blood flow within the appendage and be a potential mechanism for embolic events.

Restoration of atrial mechanical function after maze operation in patients with structural heart disease

Background The maze operation is effective for the restoration of sinus rhythm; however, restoration of atrial mechanical function has not been demonstrated in all patients. Methods Maze operations were performed in 32 patients (13 men, 19 women; mean age 47.1 ± 9.0 years) combined with valvular surgery ( n = 25), coronary artery bypass graft (CABG) ( n = 3), and others ( n = 4). At 1 week, 3 months, 6 months, and 1 year after the operation, prospective serial Doppler echocardiographic examination was carried out to determine the presence of atrial mechanical function. Results Sinus rhythm was restored and maintained during the follow-up period in 26 (81%) patients; in 22 patients this was due solely to the operation, whereas in four patients an antiarrhythmic agent was needed to maintain sinus rhythm. Another four patients showed paroxysmal atrial fibrillation (AF) despite treatment with an antiarrhythmic agent. Right atrial mechanical function was restored in all 30 patients with sinus rhythm or paroxysmal AF; in 19 (63%) of these, left atrial mechanical function was restored. In patients with restored left atrial mechanical function, peak A velocity (A) and A/E ratio (A/E) of mitral inflow were significantly lower than in the 16 postoperative control patients (A: 0.46 ± 0.14 m/sec vs 0.75 ± 0.29 m/sec, p < 0.01; A/E: 0.40 vs 0.80, p < 0.01). In patients with left atrial mechanical function, the duration of AF was significantly shorter than in patients without left atrial mechanical function (1.9 ± 2.9 years vs 7.1 ± 3.0 years, p < 0.01), but there were no significant differences in left atrial size and volume. Conclusions The maze operation could be safely added to standard open heart surgery for the correction of underlying structural heart disease. The rate of conversion to sinus rhythm resulting solely from the operation might be lower than the rates previously reported with only the duration of AF adversely affecting the restoration of left atrial mechanical function. Considering the fact that not all patients converted to sinus rhythm show atrial mechanical function, the role of the maze operation in the prevention of systemic embolism, with subsequent improvement in survival, requires further study. (Am Heart J 1998;136:1070-4.)

A prospective study of atrial fibrillation and stroke.

In a prospective study of 72 patients with stroke and atrial fibrillation, we classified strokes as cardioembolic or noncardioembolic based on arterial assessment using Doppler sonography and angiography. We analyzed and cross-tabulated 18 clinical characteristics and found four to be significantly associated with a cardioembolic mechanism: stroke with onset during activity and peak deficit at onset (p less than 0.008), previous infarct in a different vascular territory (p less than 0.01), previous transient ischemic attack in a different vascular territory (p less than 0.01), and transient ischemic attack lasting greater than 1 hour (p less than 0.02). Starting with these four characteristics, we used a step-down procedure to select variables for a logistic regression model. Only previous infarct in a different vascular territory (odds ratio = 7.38) and transient ischemic attack lasting greater than 1 hour (odds ratio = 7.89) were selected by the model. Using M-mode and two-dimensional echocardiography, we compared left atrial size in 46 patients with that in 78 controls who had atrial fibrillation without stroke. Left atrial size in patients and controls with mitral valvulopathy was significantly larger than that in patients and controls without mitral valve disease. There was, however, no difference in left atrial size between patients with nonvalvular atrial fibrillation and cardioembolic stroke and controls or patients with nonvalvular atrial fibrillation and noncardioembolic stroke. We concluded that some clinical characteristics are closely related to cardioembolic stroke and that left atrial enlargement reflects underlying cardiopathy rather than atrial emboli-forming capability.

Doppler echocardiographic study of the frequency and severity of aortic regurgitation in hypertrophic cardiomyopathy

Aortic rergurgitation (AR) has been reported sporadically in hypertrophic cardiomyopathy (HC) but neither its frequency nor severity has been determined. Thirty-one consecutive patients with HC were evaluated by Doppler echocardiography over a 2-year period. Twenty-nine had echocardiographically normal aortic cusps and participated in the study; 2 had calcified aortic valves and were excluded. AR of grade I to grade II severity was demonstrated in 9 of 29 (31%) patients. Patients were divided into 2 groups: group 1 (n = 9) with AR and group 2 (n = 20) without AR. Group 1 patients were significantly older than group 2 patients (73 ± 7 vs 60 ± 17 years, p < 0.05) and had larger end-diastolic (4.5 ± 0.5 vs 4.0 ± 0.7 cm, p < 0.01) and end-systolic (2.7 ± 0.4 vs 2.3 ± 0.4, p < 0.02) left ventricular dimensions. Left ventricular wall thickness, degree of asymmetric septal hypertrophy and left ventricular fractional shortening were similar in the 2 groups. Mitral rergurgitation was more common in group 1 (100% vs 35%, p < 0.005), although there were no differences in left atrial size between the 2 groups. The HC patients were compared with a control group of 23 normal subjects of similar age. There was no mitral rergurgitation or AR in the normal subjects. Thus, nearly one-third of patients with HC had mild AR by Doppler. The AR most probably results from high-velocity systolic blood flow causing microscopic damage to the valve cusps.