Why is intracardiac echocardiography helpful? Benefits, costs, and how to learn.

Current interventional procedures in structural heart disease and cardiac arrhythmias require peri-interventional echocardiographic monitoring and guidance to become as safe, expedient, and well-tolerated for patients as possible. Intracardiac echocardiography (ICE) complements and has in part replaced transoesophageal echocardiography (TEE), including real-time three-dimensional (RT-3D) imaging. The latter is still widely accepted as a method to prepare for and to guide interventional treatments. In contrast to TEE, ICE represents a purely intraprocedural guiding and imaging tool unsuitable for diagnostic purposes. Patients tolerate ICE much better, and the method does not require general anaesthesia. Accurate imaging of the particular pathology, its anatomic features, and spatial relation to the surrounding structures is critical for catheter and wire positioning, device deployment, evaluation of the result, and for ruling out complications. This review describes the peri-interventional role of ICE, outlines current limitations, and points out future implications. Two-dimensional ICE has become a suitable guiding tool for a variety of percutaneous treatments in patients who are conscious or under monitored anaesthesia care, whereas RT-3DICE is still undergoing clinical testing. Continuous TEE monitoring under general anaesthesia remains a widely accepted alternative.

Device closure of interatrial communications: peri-interventional echocardiographic assessment.

The interventional closure of interatrial communications requires peri-interventional echocardiographic assessment and guidance to make those treatments as safe as possible. Transoesophageal echocardiography (TEE) including real-time three-dimensional (RT-3D) imaging, later complemented and in part replaced by intracardiac echocardiography (ICE), has become established as the standard approach to prepare for and to guide the interventional treatment of interatrial communications. Accurate imaging of the anatomic features of the particular communication is critical for case selection, planning, and intraprocedural guidance. Especially in the atrial septal defect (ASD) closure, which tends to be more challenging than the patent foramen ovale (PFO) closure, a certain risk of severe complications remains and may result from suboptimal device performance. Other complications may be related to discontinuous use of echocardiographic monitoring. Image fusion and RT-3D ICE are currently under clinical testing and might be suitable to facilitate spatial orientation. Nowadays, two-dimensional ICE is the method of choice for guiding percutaneous device closure, especially of ASDs and 'complex' PFOs. Uninterrupted TEE under deep sedation is an alternative. In contrast, the closure of 'simple' PFOs will often require nothing but final confirmation of the result, and therefore, short echocardiographic viewing is sufficient in many cases.

Assessment of aortic valve area in aortic stenosis using cardiac magnetic resonance tomography: comparison with echocardiography.

BACKGROUND: Cardiac magnetic resonance tomography (CMR) is a new imaging technique capable of imaging the aortic valve with high resolution. We assessed the aortic valve area (AVA) in patients with aortic stenosis (AS) using CMR and compared the results to those obtained by transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE). METHODS: Forty-two patients (36% female, 71 +/- 8 years) symptomatic for AS underwent TTE followed by TEE to determine the AVA; the continuity equation was used with TTE and the planimetry technique with TEE. In 26 of these patients, the AVA was additionally obtained by CMR planimetry. RESULTS: The mean AVA derived by TTE, TEE and CMR were 0.74 +/- 0.27, 0.87 +/- 25 and 0.97 +/- 0.30 cm(2), respectively. The mean absolute differences in AVA were 0.13 +/- 0.19 cm(2) for TTE vs. TEE, 0.21 +/- 0.25 cm(2) for TTE vs. CMR and 0.05 +/- 0.11 cm(2) for CMR vs. TEE. CONCLUSION: There is a good agreement between CMR and the echocardiographic determination of the AVA. If multicenter, large-scale studies confirm these observations, CMR could serve as a noninvasive alternative to TTE/TEE for the assessment of AVA in AS.

Assessment of coronary flow velocity reserve by noninvasive transthoracic Doppler echocardiography in patients with angiographically normal coronary arteries.

The measurement of coronary flow velocity reserve (CFVR) by transthoracic Doppler echocardiography (TTDE) with invasive intracoronary Doppler flow wire technique (ICD) was validated and the pathological factors which influence CFVR in patients with angiographically normal coronary arteries were analyzed. CFVR was determined successfully in left anterior descending artery (LAD) in 37 of 40 patients with angiographically normal coronary arteries (men 22, women 15, age 20-75 years, mean age 54 +/- 12 years). Coronary flow velocity was measured in the distal LAD by TTDE with contrast enhancement at baseline and during intravenous adenosine infusion of 140 microg/kg per min within 48 h after ICD technique. Average peak velocity at baseline (APVb), average peak velocity during hyperemia (APVh) and CFVR determined from TTDE were correlated closely with those from ICD measurements (APVb: y = 0.64x + 5.04, r = 0.86, P < 0.001; APVh: y = 0.63x + 14.36, r = 0.82, P < 0.001; CFVR: y = 0.65x + 0.92, r = 0.88, P < 0.001). For CFVR measurements, the mean differences between TTDE and ICD methods were 0.12 +/- 0.39. CFVR in patients with history of hypertension was significantly lower than that in patients without history of hypertension (P < 0.05). Intravascular ultrasound (IVUS) was performed in 34 patients. Plaque formation was found in LAD by IVUS in 17 (50%) patients. No significant difference in CFVR was found between the patients without plaque formation (3.11 +/- 0.49) and those with plaque formation (2.76 +/- 0.53, P = 0.056). It is suggested that TTDE with contrast enhancement provides reliable measurement of APV and CFVR in the distal LAD. The early stage of atherosclerosis could be detected by IVUS, which may be normal in angiography. CFVR is impaired in patients with history of hypertension compared with that in patients without history of hypertension.

Analysis of fossa ovalis membrane velocities by transesophageal Doppler tissue echocardiography: a novel approach to functional assessment of patent foramen ovale.

BACKGROUND: Recent studies have suggested that a higher mobility of the fossa ovalis membrane (FOM) may be associated with an increased risk for stroke in patients with patent foramen ovale (PFO). The current study analyzed whether Doppler tissue echocardiography is useful for quantitation of FOM motion velocities. METHODS: FOM dynamics were prospectively studied in 107 consecutive patients (average age 50.7 +/- 15.3 years, 48 men) with in sinus rhythm who underwent transesophageal echocardiography for various indications. With pulsed wave Doppler tissue echocardiography interrogation, a characteristic quadrophasic signal was recorded in all patients, consisting of a positive wave toward the left atrium (A-wave) at late diastole, followed by a negative wave (B-wave) toward the right atrium, a pronounced, again positive wave during midsystole (C-wave), and a final negative wave (D-wave). RESULTS: Peak velocities of A-wave, B-wave, C-wave, and D-wave were 0.08 +/- 0.02 m/s, 0.11 +/- 0.05 m/s, 0.17 +/- 0.07 m/s, and 0.14 +/- 0.06 m/s, respectively. In 21 of 107 (19.6%) patients, PFO was detected. Patients with PFO had significantly higher C-wave and D-wave peak velocities compared with the 86 patients without PFO (0.23 +/- 0.10 m/s vs 0.15 +/- 0.05 m/s, P < .001 and 0.16 +/- 0.07 m/s vs 0.12 +/- 0.06 m/s, P = .04, respectively). CONCLUSIONS: Assessment of FOM dynamics using Doppler tissue echocardiography is feasible. It allows definition of a characteristic quadrophasic FOM motion pattern, thereby providing new insights into the physiology of FOM mobility. Patients with PFO were found to have increased FOM mobility compared with patients without PFO.

Noninvasive assessment of microvascular function in arterial hypertension by transthoracic Doppler harmonic echocardiography.

OBJECTIVES: The present study sought to investigate the use of transthoracic Doppler harmonic echocardiography (TTDHE) to evaluate changes in coronary flow dynamics due to microvascular dysfunction. BACKGROUND: Coronary flow velocity reserve (CFVR) measurements by TTDHE are useful for assessing epicardial coronary artery stenoses. It remains unclear, however, if microvascular disease can be detected. METHODS: In 54 patients with chest pain, intracoronary Doppler (ICD) and TTDHE were used to measure average peak velocity at baseline and hyperemia. Significant coronary lesions had been ruled out by both angiography and intravascular ultrasound. Comparative measurements were performed in the distal left anterior descending coronary artery after intracoronary and intravenous administration of adenosine, and CFVR was calculated. Hypertensive patients (n = 25) were studied and compared to a control group (26 normotensive individuals). RESULTS: Three patients (5%) had to be excluded because of insufficient image quality or side effects. In both groups, TTDHE-derived CFVR data correlated closely with ICD measurements (group 1: y = 0.67x + 0.076, standard error of estimate [SEE] = 0.25, r = 0.87, p < 0.001; group 2: y = 0.64x + 1.11, SEE = 0.26, r = 0.87, p < 0.001). CFVR was lower in hypertensives than in normotensive controls (2.44 +/- 0.49 vs. 3.33 +/- 0.40, p < 0.001, cut point = 2.84). CONCLUSIONS: The newly described echocardiographic method is suitable for assessing microvascular dysfunction noninvasively and corresponds well to invasive measurements.

Non-invasive assessment of coronary flow velocity reserve: a new method using transthoracic Doppler echocardiography.

Transthoracic Doppler echocardiography (TTDE) allows noninvasive flow measurement in the distal left anterior descending artery (LAD). The feasibility of detecting coronary flow by contrast-enhanced TTDE with second harmonic technique was assessed, the coronary flow velocity reserve (CFVR) was evaluated in comparison to intracoronary Doppler flow (ICD) analysis and the CFVR after PTCA in LAD was investigated. In 77 (96%) of 80 patients, CFVR was successfully determined with intravenous adenosine infusion. Doppler signal quality was evaluated in the first 46 patients by use of intravenous Levovist infusion and second harmonic technique. The Doppler flow was not visible in 1. patient only. CFVR determined from TTDE (2.77 +/- 0.65) was correlated closely with those from ICD (2.88 +/- 0.78) measurements (y = 0.73x + 0.67, r = 0.87, P < 0.001). In conclusion, TTDE is a feasible method and provides reliable data on CFVR which can be used for follow-up after PTCA.

Evaluation of Hemodynamic Determinants of Quantitative Tissue Doppler Echocardiography in the Assessment of Left Ventricular Function.

The aim of the present study was to determine whether quantitative tissue Doppler echocardiography has a role in the assessment of left ventricular hemodynamics. Thirty patients with suspected or known heart disease, but no wall motion abnormalities, took part in the study. Quantitative tissue Doppler echocardiography was performed using new software for digital analysis of the tissue Doppler signal. Average systolic subendocardial (S1), subepicardial (S2), and transmural (S3) wall velocity data were obtained from the inferoposterior wall and compared with the hemodynamics, including high fidelity pressure readings. S1 and S3 rates were found to be most reliable, being directly related to the peak rate of left ventricular pressure rise (dP/dt(peak)) and inversely to systemic vascular resistance (SVR) and resistance index (SVRI). The best correlation was between S1, dP/dt(peak), and SVRI (multiple regression analysis: r = 0.76, P < 0.0001; simple regression analysis relating S1 to dP/dt(peak)/SVRI: r = 0.77, SEE = 0.25, P < 0.0001). Thus, wall velocity indices as defined in this study have promise to become helpful in guiding the therapeutic modulation of inotropy and afterload in patients with heart failure.