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Systemic embolization is a potential complication in patients with thrombi situated in the left atrium and particularly, in the left atrial appendage (LAA). Reduced LAA contraction velocities, determined by the transesophageal echocardiography (TEE), are associated with increased risk of LAA spontaneous echocontrast and thrombus formation, and a history of systemic embolism. However, TEE remains a semi-invasive procedure, limiting its serial application as a screening tool. Therefore, it is desirable to obtain information regarding LAA function by transthoracic echocardiography in patients having cardioembolic stroke. The present study was designed to investigate various echocardiographic variables for patients with stroke to predict LAA dysfunction, reflected as reduced LAA contraction velocity. We studied a total of 61 patients with newly diagnosed acute embolic stroke (42 patients) and transient ischemic attack (19 patients). Computerized tomographic scanning was performed for the diagnosis of embolic stroke. Left atrial functional parameters determined by transthoracic echocardiography, such as left atrial active emptying fraction and acceleration slope of mitral inflow A wave, had significant correlations with the LAA contraction velocity (r = 0.57, p < 0.001; r = 0.54, p < 0.001, respectively). Left atrial volume index, left atrial active emptying volume and left atrial fractional shortening were also correlated with LAA contraction velocity (r = -0.44, p < 0.001; r = 0.38, p = 0.003; r = 0.37, p = 0.004, respectively). In conclusion, transthoracic echocardiography can provide valuable and reliable information about the LAA contraction velocity in stroke patients with sinus rhythm. This finding gives new insights for the appropriate strategy in the evaluation of an acute ischemic stroke.
We assessed total body water (TBW) content and cardiac function in 25 normotensive (N) and 22 gestational hypertensive (GH) women matched for age, gestational age, and prepregnancy body mass index (BMI) during the third trimester of gestation. Patients underwent maternal echocardiography, bioelectrical impedance analysis (BIA), and hematocrit (Hct %) evaluation. The TBW:Hct ratio (water balance index, WBI) was calculated. Hct was significantly lower in N vs. GH women (31.9+/-2.2% vs. 36.2+/-2.5; p<0.001). There was no difference in TBW between the two groups. WBI was higher in N vs. GH women (1.35+/-0.20 l.kg(-1) x m(-2) vs. 1.19+/-0.18; p<0.001). N subjects showed a higher stroke volume than GH patients (78.0+/-9.7 ml vs. 67.9+/-10.2; p=0.001). Atrial function was higher in N vs. GH women (left atrial fractional area change 57.4+/-5.1% vs. 42.5+/-7.5; p<0.001). A correlation was found between stroke volume and WBI ( r=0.93, p<0.0001). Maternal cardiac function and WBI are strongly related and might help in understanding the mechanisms of adaptation in normal and hypertensive pregnancy.
OBJECTIVE: Left heart atrial and ventricular epicardial pacing through a left lateral thoracotomy is an alternative approach for lead insertion in children, avoiding venous access complications and right ventricular stimulation, without compromising sporting or musical activities. We analyzed the survival and performance of left atrial and left ventricular epicardial pacing leads, and present mid-term follow-up data. METHODS: Seventy-five bipolar steroid eluting pacing leads (Medtronic CapSure Epi 4968) were implanted in 41 children, aged 8.6+5.1 years. Pacing systems included 34 DDDR and 7 VVIR. Pacing leads were inserted through a muscle-sparing left lateral thoracotomy, and sutured to the left atrial appendage or atrium, and to the left ventricle. The generators were buried behind the abdominal muscles or between the thoracic muscle layers. Congenital heart disease with previous cardiac surgery was present in 25 children. Indications for pacing were post-operative heart block (n=14), sinus node disease (n=13), congenital heart block (n=9), and various (n=5). Threshold values and measured data were obtained at 6-month intervals. The mean follow-up was 3.8+2.9 years. RESULTS: There was no mortality or major morbidity, with excellent functional and cosmetic results. Lead survival was 94 and 86% for atrial leads, and 97 and 86% for ventricular leads, at 1 and 5 years, respectively. There were five reoperations for lead fracture (n=2), insulation break (n=1), oversensing (n=1), and infection (n=1). Device reprogramming was required in three instances. In the absence of acute lead failure, mid-term follow-up shows very satisfactory and stable lead performance. CONCLUSIONS: Left heart atrial and ventricular epicardial pacing leads inserted through a left lateral thoracotomy demonstrate a high probability of survival, with favorable pacing characteristics, and optimal sensing thresholds at mid-term follow-up. Epicardial left heart pacing is reliable, and easy access can be achieved through a cosmetic and functional muscle-sparing left lateral thoracotomy.
An excellent correlation exists between the change in the left atrial (LA) angiographic area and posterior aortic wall motion. The aim of the study was to define the role of posterior aortic wall motion, indicating LA volume change, during the left ventricular (LV) phase for the assessment of LV diastolic function. A total of 155 patients underwent echocardiography after cardiac catheterization. Study patients were classified into four groups according to the ratio of early-to-late transmitral flow velocity (E/A ratio) and/or LV end-diastolic pressure (EDP): 42 patients with LVEDP < 15 mmHg and E/A ratio > 1 (normal filling); 46 patients with E/A < 1 (impaired relaxation); 46 patients with LVEDP > or = 15 mmHg and E/A > 1 and < 2 (pseudonormal filling); 21 patients with E/A > 2, E > or = 70 cm/s, and E-wave deceleration time < or = 160 ms (restrictive filling). The slopes of early and late (slopes E and A) diastolic motion of LA wall were derived from M-mode analysis, together with the LV isovolumic time constant Tau from cardiac catheterization. Values of slope E/A decreased in restrictive filling, pseudonormal filling, and impaired relaxation as compared with normal filling (0.41 +/- 0.14, 0.69 +/- 0.15, and 0.56 +/- 0.23 vs 1.25 +/- 0.26, P < 0.001, respectively) and correlated inversely with the isovolumic time constant Tau (r = 0.79, P < 0.001). In cases for which a value of slope E/A < 1 was obtained, indicating a relaxation abnormality, the M-mode derived pattern of LA wall motion identified the underlying abnormal LV diastolic function with a sensitivity of 98.3%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 95.2%. Analysis of the slope of LA wall motion, indicating LA volume change rate, during LV diastolic phase is useful in evaluating LV diastolic function. It provides a new noninvasive index that correlates well with invasive index of LV relaxation.
Advanced or second-degree atrioventricular (AV) heart block pre-existing or developing during atrial pacing (AP) at low heart rates of smaller than 130 per minute, limits the value of AP to stress the left ventricle. When Wenkebach type AV block is present, the heart rate can be increased by administration of atropine before atrial pacing or by right ventricular pacing. Atropine, however, occasionally may cause serious supraventricular or ventricular arrhythmias, and high rate right ventricular pacing is not tolerated by many patients with left ventricular dysfunction because of the absence of the atrial contribution. Twenty-eight out of 101 patients with angina pectoris (27.7 percent) developed second degree AV heart block during atrial pacing studies performed for evaluation of left ventricular function. In 8 of the 28 patients, sequential AV pacing (SP) was performed successfully, with the heart rate being increased to 150-167 per minute. In 4 of the 8 patients, left ventricular dysnfunction was demonstrated during and immediately after SP. Typical angina pectoris developed in two of the four patients during SP, one of whom proved to have normal coronary arteriogram. Sequential AV pacing is an alternative method to increase the heart rate for the purpose of stressing the left ventricle when advanced degree or second-degree AV heart block pre-exists or develops during right atrial pacing. In some patients the method of SP might be preferable to administration of atropine or to ventricular pacing.
BACKGROUND: The myocardial length-tension and the force-frequency relations are important mechanisms that regulate the contractile strength of the heart. AIMS: To evaluate in humans the effect on left ventricular function of the interaction between the myocardial length-tension and force-frequency relations. METHODS AND RESULTS: Eight patients with dilated cardiomyopathy (DCM) and 6 control subjects underwent radionuclide monitoring of left ventricular function during atrial pacing, saline loading and atrial pacing at the end of saline loading. In controls, atrial pacing reduced left ventricular end-diastolic (P < 0.001) and end-systolic volumes (P < 0.001) with no change in ejection fraction whereas after volume expansion end-diastolic volume (P < 0.001) and ejection fraction (P < 0.001) increased. Atrial pacing after volume expansion increased ejection fraction (P < 0.05). In patients with DCM, ejection fraction was reduced during atrial pacing (P < 0.001) and volume expansion (P < 0.05) due to an increase in left ventricular end-systolic volume (P < 0.001). Pacing tachycardia after volume expansion further increased end-systolic volume and reduced ejection fraction with a significant 'pacing by load' interaction (P < 0.001). Peak filling rate increased at each step in controls while it remained unchanged in patients with DCM. CONCLUSION: The heart rate increase during left ventricular distension improves ventricular function in normals and has detrimental effects in patients with DCM.
One hundred twenty-four consecutive patients (85%) with paroxysmal atrial fibrillation (AF) and 21 (15%) with atrial flutter (AFI) were studied immediately after pharmacologic or electrical cardioversion to sinus rhythm. Mean age was 59 +/- 13 years (range 23 to 79). Patients with reduced left ventricular function were excluded from the study. After restoration to sinus rhythm, the clinical course of all patients was followed for the first recurrence of paroxysmal AF or AFI irrespective of the therapeutic approach. Mean follow-up was 23 +/- 16 months. After 12 months of follow-up, 50% of all patients remained in sinus rhythm. Univariate analysis indicated that coronary artery disease (relative risk 1.9; 95% confidence interval 0.9-3.9), history of paroxysmal AF or AFI (2.3; 1.1-5.0), female sex (2.3; 1.1-4.6), pulmonary disease (3.9; 1.9-7.6) and valvular heart disease (4.4; 2.2-8.8) were associated with an increased risk for recurrent or frequent episodes of paroxysmal AF or AFI. No predictors were found to be associated with a decrease in length of the recurrence-free period after successful conversion to sinus rhythm. Multivariate analysis identified history of AF or AFI (odds ratio 2.5; 95% confidence interval 0.9-6.4), coronary artery disease (3.1; 1.1-8.2) and female sex (3.4; 1.3-8.9) as independent predictors for recurrent or frequent episodes of paroxysmal AF or AFI. The presence of these risk factors should be taken into account when prophylactic therapy with antiarrhythmic drugs is being considered in the treatment of paroxysmal AF or AFI.
Motion of the left ventricular [left ventricle (LV)] atrioventricular (AV) plane has been used to assess systolic LV function. The method has not been used properly to assess diastolic function, especially after a first myocardial infarction (MI). The diastolic function was assessed in 47 previously healthy patients with a first MI assessed by echocardiographic diastolic motion of the LV AV plane. The motion of the AV plane was recorded at four different LV sites, that is, at the septal, anterior, lateral, and inferior walls. Two distinct phases of motion were noticed during diastole at all the sites: one at the early diastole caused by rapid filling of the LV and the other at late diastole during the atrial contraction. The contribution of left atrial contraction to LV filling at different LV sites was calculated by relating the magnitude of the motion caused by atrial contraction to the total diastolic AV plane motion at the respective sites. These left atrial contributions were regarded as the regional diastolic function of the respective LV sites. The global LV diastolic function was determined from the left atrial contribution to total AV plane motion from the above four sites. Patients with anterior MI had a significantly lower ejection fraction than those with inferior MI (41% and 49%, respectively; P < 0.01). Compared with age-matched healthy subjects, the regional atrial contribution to diastolic filling was significantly higher at the anterior wall in anterior MI (38% and 52%, respectively; P < 0.001) and at the inferior wall in inferior MI (43% and 53%, respectively; P < 0.01). The atrial contribution to global LV filling was increased in anterior MI (48% compared with 42% in healthy subjects; P < 0.05) but not in inferior MI. These findings suggest that the diastolic AV plane displacement (AVPD) may be used to assess both the regional and the global diastolic function in patients following an MI.
OBJECTIVES: We prospectively studied the recovery of atrial function after atrial compartment operation and mitral valve surgery in patients with chronic atrial fibrillation caused by mitral valve disease. BACKGROUND: Chronic atrial fibrillation is the most common arrhythmia in mitral valve disease. This arrhythmia is associated with excessive morbidity and mortality. Mitral valve surgery alone rarely eliminates it. METHODS: Twenty-two patients underwent mitral valve surgery and a new surgical method, atrial compartment operation. Doppler echocardiography was performed in all patients before operation and at 1 week and 2 and 6 months after operation in the successful cardioversion group. Peak early diastolic (E) and atrial (A) filling velocities, peak A/E velocity ratio and A/E integral ratio of the mitral and tricuspid valves were measured. RESULTS: Sinus rhythm was restored immediately after operation in 91% of patients and was maintained for > 1 week in 15 (68%) of 22 patients and > 6 months in 14 (64%) of 22. Eleven of 15 patients had left atrial paralysis (A/E integral ratio 0) at 1 week and 6 of 14 patients at 2 months. Nine of 15 patients had right atrial paralysis (A/E integral ratio 0) at 1 week and 1 of 14 patients at 2 months. Both left and right atrial contractile function (presence of an A wave on Doppler findings) was detected at 6 months in 14 patients. Mean (+/- SD) peak atrial filling velocity of the mitral valve was 15 +/- 26 cm/s at 1 week, 38 +/- 39 cm/s at 2 months and 93 +/- 32 cm/s at 6 months (p < 0.001). Mean peak atrial filling velocity of the tricuspid valve was 14 +/- 19 cm/s at 1 week, 33 +/- 19 cm/s at 2 months and 50 +/- 19 cm/s at 6 months (p < 0.001). Peak early diastolic and atrial filling velocities, peak A/E velocity ratio and A/E integral ratio of the mitral and tricuspid valves increased significantly from 1 week to 6 months. CONCLUSIONS: Chronic atrial fibrillation in mitral valve disease can often be eliminated by atrial compartment operation. No surgical mortality or significant complications were encountered. Both left and right atrial function, as manifested by Doppler findings, recover after compartment operation and improve over time. The mechanical function of the right atrium recovers earlier than that of the left.
Echocardiographic measurements were obtained in 20 patients before cardioversion immediately after and two, four and six hours after cardioversion to normal sinus rhythm. At six hours after cardioversion there was no significant change in heart rate, left atrial diameters (LAD), left ventricular end-diastolic diameters (LVEDD) or left ventricular end-systolic diameters (LVESD). On follow-up one month to nine months after cardioversion, 14 of the 20 patients (70%) remained in normal sinus rhythm. Neither LAD, LVEDD, or LVESD, nor the presence or amplitude of the A-wave on the mitral valve echogram correlated with the persistence or normal sinus rhythm.
Effects of changes in atrioventricular interval on left ventricular diastolic filling were studied using pulsed Doppler echocardiography in 14 patients with programmable dual chamber pacemakers. Peak early diastolic filling velocity (E) and peak atrial filling velocity (A) were measured from the transmitral flow velocity pattern at three different atrioventricular intervals under the same pacing rate of 80 beats.min-1 in each patient. When the atrioventricular interval was switched from intermediate [148(SD10) ms] to short [68(11) ms], stroke volume did not change significantly [60(14) to 58(13) ml], but E increased from 39(12) to 44(11) cm.s-1 (p less than 0.05), and A decreased from 48(8) to 38(9) cm.s-1 (p less than 0.05). At the short atrioventricular interval, incomplete atrial emptying by the atrial contraction seemed to cause a reciprocal increase in the early diastolic filling. When the atrioventricular interval was switched from intermediate to long [234(16) ms], stroke volume, E and A did not change significantly [57(14) ml, 37(13) cm.s-1, 51(8) cm.s-1 respectively]. At the short and long atrioventricular intervals, atrial filling always changed in the direction opposite to that of early diastolic filling. Changes in stroke volume as well as peak early diastolic filling velocity caused by altering atrioventricular interval were pronounced in aged patients and patients with decreased early diastolic filling. In conclusion, left ventricular diastolic filling patterns can be affected by atrioventricular interval even without any concomitant pathological changes in the left atrial or ventricular function. These effects should not be taken lightly, especially in patients with decreased left ventricular early diastolic filling.
The primary aim of this study is to investigate the factors related to the recurrence of atrial fibrillation (AF) after a successful ablation of atrioventricular accessory pathway. Thirty-seven patients with spontaneous AF (study group) were selected from 401 consecutive patients who underwent radiofrequency catheter ablation of atrioventricular accessory pathway. A multivariate regression analysis was used in order to evaluate the relationships between AF recurrence and patients' age, sex, atrial size, left ventricular function, location of accessory pathways, heart rate during atrioventricular re-entrant tachycardia and atrial vulnerability (induction of sustained AF) after a successful ablation. Atrioventricular accessory pathway was abolished in 36 of the study group patients and 351 of the control group patients. During the follow-up of 36 +/- 11 months, four patients (11.1%) from the study group experienced sustained AF. Multivariate regression analysis showed that, in patients with pre-ablation AF, older age and post-ablation atrial vulnerability were the only independent predictive factors for AF recurrence. We concluded that radiofrequency catheter ablation of atrioventricular accessory pathway greatly reduces the risk of AF in patients who had a history of symptomatic AF. Older patients and patients with inducible AF after accessory pathway ablation are at an increased risk of AF recurrence. These patients should be closely monitored after successful ablation of atrioventricular accessory pathways.
This study aims at evaluating the effect of a small spherical balloon functioning during acute mitral regurgitation. Acute mitral regurgitation was produced in 11 mongrel dogs with a specially designed curved blade introduced through the left ventricular apex. Left atrial pressure, electrocardiogram, left ventricular pressure (in 8 dogs) and aortic flow (in 7 dogs) were monitored. The mean left atrial pressure increased by 9.45 +/- 2.44 mmHg (p less than 0.01) and the v wave by 14.09 +/- 2.94 mmHg (p less than 0.001). The systolic left ventricular pressure and the aortic flow decreased. The heart remained in sinus rhythm & the rate did not change significantly. After the production of mitral regurgitation, a small spherical balloon (9 to 16 cc capacity) mounted on a catheter was introduced to the left ventricle through the apex and positioned in the mitral ring. The balloon was inflated by means of a pump during systole and deflated during diastole. During its function the mean left atrial pressure decreased by 4.37 +/- 0.84 mmHg (p less than 0.001) and the v wave by 8.64 +/- 1.23 mm Hg (p less than 0.001). The systolic left ventricular pressure and the aortic flow increased. The peak systolic gradient across the mitral valve increased by 20.5 +/- 3.86 mmHg (p less than 0.01). The heart rate did not change. It is suggested that in acute mitral regurgitation the function of a small balloon could improve the hemodynamic condition by acting as a valve at the mitral ring for reduction of regurgitation and possibly by improving systolic function in severe heart failure.
BACKGROUND AND AIM: N-terminal pro-B-type natriuretic peptide (NT-proBNP) has diagnostic and prognostic value in patients with heart failure. The present prospective study was designed to assess whether changes in NT-proBNP levels after surgical mitral valve repair reflect changes in heart failure symptoms and changes in left atrial size, left ventricular size and left ventricular function. METHODS: The study population consisted of 22 patients (mean age: 62.8 +/- 14.2 years, 68% male) undergoing surgical mitral valve repair. Serial NT-proBNP measurements, transthoracic echocardiography and New York Heart Association (NYHA) class assessment were performed before and 6 months after surgery. RESULTS: All patients underwent successful mitral valve repair and no patients died during follow-up. The decrease in NT-proBNP level was associated with the reduction in left atrial dimension (r = 0.72, P < 0.001), left ventricular end-systolic dimension (r = 0.63, P = 0.002), left ventricular end-diastolic dimension (r = 0.46, P = 0.031), and the increase in fractional shortening (r = - 0.63, P = 0.002). Finally, patients with decreasing NT-proBNP levels revealed a significant improvement in heart failure symptoms (NYHA class). CONCLUSION: Changes in NT-proBNP after surgical mitral valve repair reflect changes in heart failure symptoms and changes in left atrial and ventricular dimensions and function.
In order to determine if an increase in heart rate is associated with an increase of left ventricular contractile function during the neonatal period we recorded phasic and mean aortic blood pressure, left atrial mean or left ventricular end diastolic pressure, phasic left ventricular blood pressure, aortic blood flow velocity and the instantaneous first derivatives of left ventricular blood pressure (dP/dt) and aortic blood flow velocity (dV/dt) during pacing-induced tachycardia in conscious newborn and adult sheep. There was a significant positive linear correlation between heart rate and both indices of contractility (dP/dt and dV/dt) in both age groups. Left ventricular end diastolic pressure was unchanged except for a decrease at the most rapid heart rate in the newborns. There was no change in aortic mean blood pressure during the study. Our data demonstrate that an increase of heart rate is associated with an increase of left ventricular contractile function in conscious neonatal and adult sheep. Investigations of the effects of potential inotropic agents on left ventricular contractile performance in newborns and adults must evaluate the independent effect of any simultaneously occurring increase in heart rate.
AIM: To assess whether left ventricular function shows circadian variation in healthy people. SUBJECTS AND METHODS: 10 healthy men (7) and women (3) aged 35-50 underwent M mode echocardiography of the left ventricle and Doppler velocimetry of transmitral flow at 4 h intervals over 24 h. The participants were in hospital over the study period and their diet, meal times, and sleeping hours were standardised as far as possible. MEASUREMENTS: Heart rate, blood pressure, left ventricular and atrial diameters, fractional shortening, peak early and late transmitral velocities, time from the second heart sound to the early diastolic velocity peak (relaxation time), isovolumic relaxation period, acceleration and deceleration of the early transmitral flow, atrial filling fraction. RESULTS: A circadian rhythm was observed in heart rate and blood pressure, but neither the left ventricular diameters and systolic function nor the left atrial size showed statistically significant diurnal trends. The relaxation time (mean (SD)) measured 144 (16) ms at 2 pm, 144 (21) ms at 6 pm, 149 (22) ms at 10 pm, 168 (23) ms at 2 am, 174 (28) ms at 6 am, and 151 (21) ms at 10 am (P = 0.009). Diurnal rhythms were seen also in the isovolumic relaxation period (P = 0.003) and in the acceleration of the early diastolic transmitral flow (P = 0.037); the lowest and highest values of flow acceleration were observed during the nocturnal and daytime hours, respectively. CONCLUSIONS: The Doppler indices of left ventricular filling in healthy people show diurnal changes suggestive of a circadian rhythm in the rate of left ventricular relaxation. The most likely underlying mechanism is the day-night cycle in sympathoadrenal activity.