Real Time Three-Dimensional Echocardiography in Assessment of Left Ventricular Dyssynchrony and Cardiac Resynchronization Therapy

Echocardiography for the management of patients with biventricular pacing: Possible roles in cardiac resynchronization therapy implementation

Cardiac resynchronization therapy (CRT) is an established therapeutic option for the subset of patients with heart failure (HF), reduced ejection fraction (EF), and dyssynchrony evidenced by electrocardiography. Benefit from CRT has been proven in many clinical trials, yet a sizeable proportion of these patients with wide QRS do not respond to this intervention, despite the updated practice guidelines. Several echocardiographic indices, targeting mechanical rather than electrical dyssynchrony, have been suggested to address this issue, but research so far has not succeeded in providing a single and simple measurement with adequate sensitivity and specificity for identification of responders. While there is still ongoing research in this field, echocardiography proves helpful in other aspects of CRT implementation, such as site selection for left ventricular (LV) lead pacing and optimization of pacing parameters during follow-up visits.

Assessment of left ventricular function in chronic alcoholics by real-time three-dimensional echocardiography

Chronic alcohol consumption may lead to progressive cardiac dysfunction. The aim of this study was to evaluate the feasibility of using real-time 3-dimensional echocardiography (3DE) on assessing left ventricular (LV) function in chronic alcoholics.We classified 92 male alcoholics into mild, moderate, and severe groups; 30 age-matched controls were also recruited. LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), LV ejection fraction (LVEF), LV mass (LVM), LV mass index (LVMI), and systolic dyssynchrony index (SDI) were measured by 3DE and 2-dimensional echocardiography (2DE).Compared to the control group, LV volume and mass were higher in the moderate and severe alcoholic groups (P < 0.05). The severe alcoholic (symptomatic) group demonstrated decreased LVEF and increased SDI (detected by 3DE) (P < 0.05).Real-time 3DE can detect the increases of LV volumes and mass in asymptomatic alcoholics, and the changes of LVEF and systolic synchrony index in symptomatic alcoholics.

A pilot study of systolic dyssynchrony index by real-time three-dimensional echocardiography predicting clinical outcomes to surgical ventricular reconstruction in patients with left ventricular aneurysm

OBJECTIVES

The aim of the study was to detect whether the systolic dyssynchrony index (SDI) assessed by real-time 3D echocardiography (RT3DE) could predict clinical outcomes of patients with ventricular aneurysm in response to surgical ventricular reconstruction (SVR).

METHODS

In total, 120 individuals underwent RT3DE, including 30 healthy volunteers and 90 patients with ventricular aneurysm. All patients underwent clinical and echocardiographic assessments at baseline and at 12 months after SVR. The SDI was defined as the SD of time to minimum systolic volume of the 16 left ventricular (LV) segments, expressed in percent RR duration. SVR responder was defined as a >15% decrease in LV end-systolic volume, reduction in NYHA functional class or 20% relative increase in the LV ejection fraction (LVEF).

RESULTS

The SDI was significantly higher in patients with aneurysm, at 14.3% compared with 2.0% in healthy volunteers (P <0.047). The SDI was negatively correlated with the LVEF. After SVR, 86 patients were responders. In this patient subgroup, the SDI exhibited an immediate significant decrease (to 7.7%; P <0.034) and a progressive decrease during 12 months of follow-up (to 4.9%; P <0.044). The SDI can discriminate SVR responders. Receiver-operating characteristic curve analysis yielded cut-off values of SDI 14.3% best associated with SVR response; area under the curve was 0.79 with reduction in NYHA class, 0.86 with increase in EF and 0.66 with decrease in the end-systolic volume.

CONCLUSIONS

RT3DE can be used to assess LV mechanical dyssynchrony in patients with aneurysm. SVR produces a mechanical intraventricular resynchronization and SDI can predict improvement following SVR.

Three-dimensional echocardiography and cardiac magnetic resonance imaging in the screening of long-term survivors of childhood cancer after cardiotoxic therapy

The left ventricular (LV) volumes, ejection fraction (EF), and dyssynchrony indexes for the 16 and 12 cardiac segments (Tmsv16-SD and Tmsv12-SD, respectively) were analyzed among nonadult, anthracycline-exposed long-term survivors of childhood cancer and compared with those of healthy controls using conventional and real-time 3-dimensional echocardiography (RT-3DE) with cardiac magnetic resonance (CMR) imaging in a prospective, cross-sectional, single tertiary center setting. Seventy-one survivors and gender-, body surface area-, and age-matched healthy controls were studied by conventional echocardiography and RT-3DE. Fifty-eight of the 71 survivors underwent also CMR. The survivors were evaluated in 2 groups. Group I consisted of 63 exposed to anthracyclines and group II consisted of 8 also exposed to cardiac irradiation. By RT-3DE, the group I survivors had a lower LVEF (57% vs 60%, respectively, p = 0.003) and larger body surface area-indexed LV end-systolic volume (31 vs 28 ml/m(2), respectively, p = 0.001) than controls. The Tmsv16-SD was higher in group II than in I (1.93% vs 1.39%, respectively, p = 0.003). None of the survivors had an abnormal fractional shortening (<28%), but 10% had an LVEF <50% by RT-3DE. An LVEF <55% was detected in 45 of 58 (78%) of those imaged with CMR. In conclusion, RT-3DE seems to detect more abnormalities in cardiac function than conventional echocardiography following childhood cancer therapy. The LV dyssynchrony indexes derived from RT-3DE appear potentially useful in assessing the early signs of cardiotoxicity between anthracycline and cardiac irradiation exposed long-term survivors of childhood cancer.

Echocardiography in patients with complications related to pacemakers and cardiac defibrillators

The evolving indications and uses for implantable cardiac devices have led to a significant increase in the number of implanted devices each year. Implantation of endocardial leads for permanent pacemakers and cardiac defibrillators can cause many delayed complications. Complications may be mechanical and related to the interaction of the device leads with the valves and endomyocardium, e.g., perforation, infection, and thrombosis, or due to the electrical pacing of the myocardium and conduction abnormalities, e.g., left ventricular dyssynchrony. Tricuspid regurgitation, another delayed complication in these patients, may be secondary to both mechanical and pacing effects of the device leads. Echocardiography plays an important role in the diagnosis of these device-related complications. Both two-dimensional transthoracic echocardiography and transesophageal echocardiography provide useful diagnostic information. Real time three-dimensional echocardiography is a novel technique that can further enhance the detection of lead-related complications.

Distribution of dyssynchrony in subjects with no known cardiac disease and comparison of velocity vector imaging to color-coded tissue Doppler imaging

Data on the distribution of dyssynchrony in subjects with normal ejection fraction (EF) and normal QRS are scarce. We studied 100 subjects with no known cardiac disease (52% male, mean age 60 ± 17 years) using velocity vector imaging (VVI). Seventeen percent had septal to lateral (S-L) wall longitudinal delay >75 msec, 63% of subjects had S-L wall radial delay >75 msec, and 25% had a circumferential opposing wall delay >100 msec. Those with circumferential opposing wall delay of >100 msec had a lower EF (57 ± 5% vs. 62 ± 5%, P < 0.05). In an additional group of 33 patients, we compared the longitudinal dyssynchrony parameters as assessed by VVI and tissue Doppler imaging (TDI) and found them to be comparable. In conclusion, we find significant variation in time to peak velocities in subjects with no known cardiac disease, who had a normal left ventricular ejection fraction and QRS duration. VVI is comparable to TDI.