Jae Kwan Song

Comparison of Ventricular Dyssynchrony According to the Position of Right Ventricular Pacing Electrode: A Multi-Center Prospective Echocardiographic Study

Background Conventional pacemaker implantation induces left ventricular (LV) dyssynchrony, which might affect the LV function. We sought to evaluate the impact of different right ventricular (RV) pacing sites on the LV dyssynchrony and performance. Methods Comprehensive echocardiographic evaluation including the atrio-ventricular, inter- and intra-ventricular dyssynchrony based on M-mode, conventional Doppler and tissue Doppler imaging (TDI) was done before and immediately after (< 7 days) pacemaker implantation. For the LV performance, LV ejection fraction, longitudinal peak systolic velocity at the mitral annulus (S) annular or mean longitudinal velocity of the 6 basal segments (Sm) were used. These results were compared with those of 15 age matched controls. Results A total of 79 patients (48 females, mean age 63 ± 12 years) underwent RV pacing at the apex (n = 45, group I) or the septum (n = 34, group II). After pacemaker implantation, the QRS duration was significantly increased in both groups, but the change was greater in group I (57.1 ± 28.3 versus 32.8 ± 40.5 msec). Both the S and Sm were lower in pacing groups than those in controls and Sm was significantly higher in group II (4.2 ± 1.0 versus 4.9 ± 1.3 m/sec) than group I despite a similar LV ejection fraction. The aortic pre-ejection time and septal to posterior wall motion delay in patients with pacemaker were longer compared to normal controls, but there were no significant differences. Both the TDI velocity and strain analysis showed no difference of the dyssynchrony indices between the two groups, despite a higher tendency of Doppler strain dyssynchrony indices in the RV apical pacing group compared to those of the control. Conclusion Despite the marked increase of the QRS duration after pacing, M-mode, Doppler and TDI failed to demonstrate any difference according to the pacing sites. The long-term effect of the longitudinal contraction being less affected and a smaller increase of the QRS duration in the RV septal pacing group needs to be confirmed in a longitudinal follow-up study.

A case of carbon monoxide poisoning with thrombus in right atrium.

Carbon monoxide is a nonirritant, odorless, colorless gas. Its effects are prominent in organs most sensitive to oxygen deprivation, such as the heart, brain, and kidney. Although less frequently, an association between thromboembolic events and carbon monoxide poisoning has been shown in the literatures. In this case, we report a case of atrial thrombus associated with carbon monoxide poisoning.

A Case of Loeffler's Endocarditis Associated with Churg-Strauss Syndrome

Loefflers endocarditis is generally caused by hypereosinophilic syndrome. It is a restrictive cardiomyopathy characterized with eosinophilia and eosionophilic penetration leading to the fibrous thickening of endocardium of both ventricles, apical obliteration and heart failure. We report a case of a 23-year-old male with Loefflers endocarditis caused by Churg-Strauss syndrome. The echocardiogram showed that biventricular failure with large thrombus in left ventricle. His symptoms and typical echocardiographic findings markedly improved within 2 months after treatment for Churg-Strauss syndrome.

Comparison of Myocardial Contrast Echocardiography Versus Rest Sestamibi Myocardial Perfusion Imaging in the Early Diagnosis of Acute Coronary Syndrome

BACKGROUNDnIt remains unclear whether myocardial contrast echocardiography (MCE) is as accurate as myocardial perfusion imaging with technetium-99m sestamibi (MPI) for the diagnosis of acute coronary syndrome (ACS). We sought to directly compare the diagnostic accuracy of MCE with resting MPI in a head-to-head fashion.nnnMETHODSnWe prospectively enrolled 98 consecutive patients (mean age; 59+/-9 years, 68 males) who presented to the emergency department with chest pain suggestive of acute myocardial ischemia. Early MCE was performed by using continuous infusion of perfluorocarbon-exposed sonicated dextrose albumin (PESDA) during intermittent power Doppler harmonic imaging. Myocardial perfusion defects observed in at least one coronary territory were considered positive. Sestamibi was injected immediately after MCE and MPI was obtained within 6 hours of tracer injection.nnnRESULTSnACS was confirmed in 67 patients. There were 32 patients with acute myocardial infarction (AMI) and 35 patients with unstable angina requiring urgent revascularization. The sensitivities of MCE and MPI for the diagnosis of ACS were 72% and 61%, respectively, which were significantly higher than those of ST segment change (24%, p<0.001 vs. MCE and vs. MPI) and troponin I (27%, p<0.001 vs. MCE and vs. MPI), with similar specificities of 90% to 100%. On a receiveroperating characteristics curve demonstrating diagnostic accuracy for ACS, the area under the curve of MCE was significantly larger than that of MPI (0.86 vs. 0.77, respectively; p=0.019).nnnCONCLUSIONnMCE and MPI overcome the low sensitivity of routine triage tests for detecting ACS, and MCE is more accurate than MPI for the diagnosis of ACS in the emergency department.

Restoration of Atrial Mechanical Function after Successful Radio - Frequency Catheter Ablation of Atrial Flutter

Background: Atrial mechanical dysfunction and its recovery time course after successful radiofrequency ablation of chronic atrial flutter (AFL) has been largely unknown. We serially evaluated left atrial function by echocardiography after successful ablation of chronic atrial flutter. Methods: In 13 patients with chronic AFL, mitral E wave A wave, and the ratio of A/E velocity were measured at 1 day, 1 month, 3 months and 6–12 months after successful radiofrequency (RF) ablation. Doppler tissue imaging (DTI) technique was also used to avoid load-dependent variation in the flow velocity pattern. Results: Left atrial mechanical function, assessed by A wave velocity and the annular motion, was depressed at 1 day, but improved significantly at 1 month and maintained through 6–12 months after the ablation. Left atrial size did not change significantly. Conclusion: Left atrial mechanical function was depressed immediately after successful RF ablation of chronic AFL, but it improved significantly after 1 month and was maintained over one year.

Association between flow skewness and aortic dilatation in patients with aortic stenosis

We investigated association between hemodynamic characteristics and aortic dilatation in patients with severe aortic stenosis (AS). Eighty patients with severe AS (mean age, 67.2u2009±u200912.5xa0years) who underwent multi-detector computed tomography and phase-contrast magnetic resonance imaging at the ascending aorta were retrospectively analyzed. Patients with an ascending aorta diameter >4xa0cm had a significantly higher forward flow rate at systole (28.5u2009±u20096.0xa0vs. 36.2u2009±u20098.6xa0Lxa0min, Pu2009<u20090.001), and retrograde flow rate at systole (11.3u2009±u20094.2xa0vs. 18.8u2009±u20095.8xa0Lxa0min, Pu2009<u20090.001), fractional reverse ratio (a ratio of retrograde flow rate to forward flow rate; 34.1u2009±u200911.9% vs. 43.5u2009±u200918.0%, Pu2009=u20090.014), flow skewness Rskewness (a ratio of sum of forward and retrograde systole flow to net systole flow rate; 2.4u2009±u20090.7 vs. 3.2u2009±u20091.0, Pu2009<u20090.001). The presence of bicuspid aortic valve (BAV; odds ratio [OR] 72.01, 95% confidence interval [CI] 10.57–490.46, Pu2009<u20090.001), Left ventricular mass index (LVMI; OR 1.02 /g/m2; CI 1.00–1.04, Pu2009=u20090.043) and Rskewness (OR 5.6 per 1, 95% CI 1.8–17.1, Pu2009=u20090.001) were associated with aortic dilatation. BAV, LVMI, and increased Rskewness in the ascending aorta are associated with aortic dilatation in patients with AS.

Differential Diagnosis of a Left Atrial Mass after Surgical Excision of Myxoma: a Remnant or a Thrombus?

Echocardiographic diagnosis of atrial myxoma may not always be straightforward, and the distinction between myxoma and thrombi is not easy, especially when we observe a mass after successful surgery. Our report describes a 72-year-old woman who presented with right upper limb hemiparesis and was subsequently diagnosed as having transient ischemic attack due to a left atrial myxoma. One month after successful surgical resection of the tumor, the patient developed left-sided weakness. Echocardiography revealed a left atrial mass attached to the interatrial septum. Intravenous heparin was administered as a therapeutic trial for postoperative thrombi, which resulted in a decrease in mass size within a week. Anticoagulation with warfarin was continued, and complete resolution was demonstrated on a 4-month follow-up transesophageal echocardiography. This case highlights the fact that thrombus formation at the surgical site should be considered an unusual but potential complication after surgical resection of left atrial myxomas.

DIFFERENT PATTERNS OF LEAFLET ELONGATION IN NON–PROLAPSING MITRAL SEGMENT IN PATIENTS WITH SINGLE SEGMENT PROLAPSE: IN VIVO MITRAL LEAFLET GEOMETRY ANALYSIS USING 3D FULL VOLUME DATA

To determine in vivo geometric factors associated with lealet elongation and adaptation patterns in both prolapsing and non-prolapsing segment, 3D full volume data were obtained during transesophageal echocardiography in 20 healthy subjects and 60 patients with severe mitral regurgitation due to myxomatous degeneration (MD) conined to a single scallop either in anterior (n=14, group A) or posterior lealet (n=46, group B). A customized software was used to evaluate mitral lealet surface area (MLSA) and annular area (AA). Compared to controls, patients with MD showed larger total MLSA(12.9±2.3 vs 18.6±3.9 cm2, p<0.01) and AA (8.7±1.3 vs. 11.9±2.5 cm2, p<0.01). In controls, the ratio between anterior to posterior MLSA was 1.4±0.2, which decreased signiicantly in patients with MD (1.2±0.4, p<0.01). Both anterior (r=0.62, p<0.001) and posterior MLSA (r=0.77, p<0.01) showed a strong positive association with AA in patients with MD. In group B, there was a stronger association (p=0.012) between posterior MLSA and AA (r=0.832, p<0.001) than anterior MLSA and AA (r=0.602, p<0.01). However, in group A, there was no difference in association (p=0.369) between posterior MLSA and AA (r=0.62, p=0.017) than anterior MLSA and AA (r=0.79, p=0.001).