Frank Grothues

Coronary Artery Imaging in Grown Up Congenital Heart Disease Complementary Role of Magnetic Resonance and X-Ray Coronary Angiography

BACKGROUND There is a high incidence of anomalous coronary arteries in subjects with congenital heart disease. These abnormalities can be responsible for myocardial ischemia and sudden death or be damaged during surgical intervention. It can be difficult to define the proximal course of anomalous coronary arteries with the use of conventional x-ray coronary angiography. Magnetic resonance coronary angiography (MRCA) has been shown to be useful in the assessment of the 3-dimensional relationship between the coronary arteries and the great vessels in subjects with normal cardiac morphology but has not been used in patients with congenital heart disease. METHODS AND RESULTS Twenty-five adults with various congenital heart abnormalities were studied. X-ray coronary angiography and respiratory-gated MRCA were performed in all subjects. Coronary artery origin and proximal course were assessed for each imaging modality by separate, blinded investigators. Images were then compared, and a consensus diagnosis was reached. With the consensus readings for both magnetic resonance and x-ray coronary angiography, it was possible to identify the origin and course of the proximal coronary arteries in all 25 subjects: 16 with coronary anomalies and 9 with normal coronary arteries. Respiratory-gated MRCA had an accuracy of 92%, a sensitivity of 88%, and a specificity of 100% for the detection of abnormal coronary arteries. The MRCA results were more likely to agree with the consensus for definition of the proximal course of the coronary arteries (P<0.02). CONCLUSIONS For the assessment of anomalous coronary artery anatomy in patients with congenital heart disease, the use of the combination of MRCA with x-ray coronary angiography improves the definition of the proximal coronary artery course. MRCA provides correct spatial relationships, whereas x-ray angiography provides a view of the entire coronary length and its peripheral run-off. Furthermore, respiratory-gated MRCA can be performed without breath holding and with only limited subject cooperation.

Integrated visualization of morphologic and perfusion data for the analysis of coronary artery disease

We present static and dynamic techniques to visualize perfusion data and to relate perfusion data to morphologic image data. In particular, we describe the integrated analysis of MRI myocardial perfusion data with CT coronary angiographies depicting the morphology. We refined the Bulls-Eye Plot, a wide-spread and accepted analysis tool in cardiac diagnosis, to show aggregated information of perfusion data at rest and under stress. The correlation between regions of the myocard with reduced perfusion and 3d renditions of the coronary vessels can be explored within a synchronized visualization of both. With our research, we attempt to improve the diagnosis of early stage coronary artery disease.

Left Atrial Appendage Flow in Nonrheumatic Atrial Fibrillation: Relationship With Pulmonary Venous Flow and ECG Fibrillatory Wave Amplitude

OBJECTIVE This study was conducted (1) to examine the relationship between left atrial appendage (LAA) flow velocity and pulmonary venous flow (PVF) variables during nonrheumatic atrial fibrillation (AF), and (2) to determine whether a reduction in LAA flow is reflected by the fibrillatory wave amplitude on the surface ECG. BACKGROUND Although LAA Doppler echocardiographic signals provide information regarding the velocity and direction of flow only for a localized narrow sample, systolic PVF represents in part the global left atrial function, mainly relaxation. Controversy exists about whether the amplitude of fibrillatory waves recorded on the surface ECG correlates with LAA flow velocity during AF. MEASUREMENTS AND RESULTS Thirty-three patients (20 men, 13 women; mean [+/- SD] age, 61 +/- 11 years) with nonrheumatic AF undergoing transthoracic and transesophageal echocardiography were studied. A correlation between LAA flow velocity and systolic PVF variables (peak systolic velocity, R: = 0.450, p = 0.009; velocity-time integral of systolic flow, R = 0.491, p = 0.004; systolic fraction of PVF, R: = 0.627, p < 0.0001) was observed. Patients with a low LAA flow profile (< 25 cm/s) had a reduced systolic PVF. Longer AF duration and the occurrence of moderate mitral regurgitation were related to reduced LAA flow. AF was subdivided into coarse (peak-to-peak fibrillatory amplitude > or = 1 mm) or fine (< 1 mm) in standard ECG lead V1. There was no association between the coarseness of AF and the LAA flow profile. CONCLUSION In patients with nonrheumatic AF, a reduction in LAA flow velocity correlates with a reduction in systolic PVF. These hemodynamic changes are not reflected by the ECG fibrillatory wave amplitude.

Noncontact Mapping of Ventricular Tachycardia in a Closed‐Chest Animal Model of Chronic Myocardial Infarction

Treatment of ventricular tachyarrhythmias in the setting of chronic myocardial infarction requires accurate characterization of the arrhythmia substrate. New mapping technologies have been developed that facilitate identification and ablation of critical areas even in rapid, hemodynamically unstable ventricular tachycardia.

Left Atrial Appendage Function and Pulmonary Venous Flow in Patients with Nonrheumatic Atrial Fibrillation and Their Relation to Spontaneous Echo Contrast

This study analyzed the relation between frequency of left atrial appendage (LAA) contractions, pulmonary venous flow (PVF) parameters, and spontaneous echo contrast (SEC). Thirty‐six patients (22 male, 14 female, mean age 61 ± 11 years) with nonrheumatic atrial fibrillation undergoing transesophageal echocardiography were studied. Doppler flow was obtained from both the LAA and the left upper pulmonary vein. Fourier analysis was applied to the LAA signal that exhibited the frequency of LAA contractions. LAA emptying velocity and PVF parameters were determined. There was no relation between velocity and frequency of LAA flow (r = 0.256, P = ns). Among LAA and PVF parameters, patients with left atrial SEC (n = 17) had a lower LAA velocity (16.8 ± 10.8 cm/sec vs 35.6 ± 13.2 cm/sec, P < 0.001), a larger LAA area (4.8 ± 2.2 cm2 vs 3.0 ± 1.3 cm2, P = 0.008), and a reduced systolic velocity time integral of PVF (3.4 ± 2.2 cm vs 5.4 ± 2.2 cm, P = 0.017) when compared with patients without SEC. Frequency of LAA contractions was similar between both groups (6.8 ± 0.4 Hz vs 6.8 ± 1.0 Hz, P = ns). In conclusion, the rate of LAA contraction does not correlate with LAA flow velocity and SEC. A low left atrial flow expressed by low LAA flow velocity and a reduction in systolic PVF is a major hemodynamic determinant for the occurrence of SEC.

Clinical InvestigationsCardiologyLeft Atrial Appendage Flow in Nonrheumatic Atrial Fibrillation: Relationship With Pulmonary Venous Flow and ECG Fibrillatory Wave Amplitude

OBJECTIVE This study was conducted (1) to examine the relationship between left atrial appendage (LAA) flow velocity and pulmonary venous flow (PVF) variables during nonrheumatic atrial fibrillation (AF), and (2) to determine whether a reduction in LAA flow is reflected by the fibrillatory wave amplitude on the surface ECG. BACKGROUND Although LAA Doppler echocardiographic signals provide information regarding the velocity and direction of flow only for a localized narrow sample, systolic PVF represents in part the global left atrial function, mainly relaxation. Controversy exists about whether the amplitude of fibrillatory waves recorded on the surface ECG correlates with LAA flow velocity during AF. MEASUREMENTS AND RESULTS Thirty-three patients (20 men, 13 women; mean [+/- SD] age, 61 +/- 11 years) with nonrheumatic AF undergoing transthoracic and transesophageal echocardiography were studied. A correlation between LAA flow velocity and systolic PVF variables (peak systolic velocity, R: = 0.450, p = 0.009; velocity-time integral of systolic flow, R = 0.491, p = 0.004; systolic fraction of PVF, R: = 0.627, p < 0.0001) was observed. Patients with a low LAA flow profile (< 25 cm/s) had a reduced systolic PVF. Longer AF duration and the occurrence of moderate mitral regurgitation were related to reduced LAA flow. AF was subdivided into coarse (peak-to-peak fibrillatory amplitude > or = 1 mm) or fine (< 1 mm) in standard ECG lead V1. There was no association between the coarseness of AF and the LAA flow profile. CONCLUSION In patients with nonrheumatic AF, a reduction in LAA flow velocity correlates with a reduction in systolic PVF. These hemodynamic changes are not reflected by the ECG fibrillatory wave amplitude.

Serial Assessment of Ventricular Morphology and Function

Cardiovascular magnetic resonance (CMR) is an accurate, reproducible and well-validated imaging technique for the measurement of left ventricular and right ventricular volumes, function, and mass. In patients who have heart failure, CMR is ideally suited both for the initial assessment of fundamental parameters of cardiac function and longitudinal follow-up. Because of its accuracy, the decision to implement therapeutic measures based on cutoff values for ventricular ejection fraction can be made with confidence. Because the above-mentioned parameters correlate with morbidity and mortality, CMR can be used to estimate the prognosis of an individual patient and to obtain surrogate parameters in clinical trials. The process of ventricular remodeling after cardiac injury and reverse remodeling using medical and interventional therapy can be assessed using relatively small sample sizes, which puts CMR in the forefront of imaging techniques in remodeling research.

Safety of gadoversetamide in patients with acute and chronic myocardial infarction

To assess the safety data from two large, multicenter, phase 2 trials on the use of gadoversetamide (OptiMARK, Tyco Healthcare/Mallinckrodt, St. Louis, MO) as a contrast agent in delayed hyperenhancement magnetic resonance imaging (DE‐MRI) in patients with acute and chronic myocardial infarction (MI).

Balanced steady-state free precession vs. segmented fast low-angle shot for the evaluation of ventricular volumes, mass, and function at 3 Tesla

To compare balanced steady‐state free precession (SSFP) and segmented fast low angle shot (FLASH) for quantification of left and right ventricular volumes and function and for left ventricular mass at high field (3 Tesla).

Electrocardiographic Characteristics in Patients with Nonrheumatic Atrial Fibrillation and Their Relation to Echocardiographic Parameters

BOLLMANN, A., et al.: Electrocardiographic Characteristics in Patients with Nonrheumatic Atrial Fibrillation and their Relation to Echocardiographic Parameters. The aim of this study was to determine the relation between (1) ECG fibrillatory wave amplitude and left atrial diameter and left atrial appendage (LAA) flow velocity using different ECG recording techniques, and (2) ECG fibrillatory frequency and frequency of LAA contractions in patients with nonrheumatic AF. In 36 patients (22 men, 14 women, mean age 61 ± 11 years) with persistent AF, ECG recordings were performed using a standard 12‐lead ECG and an orthogonal ECG lead system using a high gain, high resolution ECG. AF was classified as coarse (fibrillatory amplitude ≥ 1 mm) or fine (fibrillatory amplitude < 1 mm) in leads I, aVF, V1 and corresponding leads X, Y, and Z. Fibrillatory frequency from the ECG was determined by subtracting averaged QRST complexes and applying a Fourier analysis to the resulting signal. Doppler flow was obtained from LAA during transesophageal echocardiography and LAA emptying velocity was determined. Fourier analysis was also applied to the Doppler signal generating the frequency of LAA contractions. Coarse AF was observed in 0, 9, and 18 patients in leads I, aVF, and V, respectively. It was more often (P < 0.05) detected in corresponding leads X (n = 13), Y (n = 31), and Z (n = 23). Fine AF in lead X was associated with a reduced LAA velocity (33 ± 16 cm/s in coarse AF vs 22 ± 13 cm/s in fine AF, P = 0.05). There was neither a relation between AF coarseness in any other ECG lead and LAA flow velocity, left atrial diameter, or echo contrast. In 25 patients with an active LAA flow, the mean frequency of LAA contractions was 6.8 ± 0.8 Hz. The corresponding mean frequency obtained from the ECG was 6.7 ± 0.7 Hz (r = 0.85, P < 0.001). The mean difference between these two measures was 0.04 Hz, and the 95% confidence limits were 0.90 and – 0.82 Hz using the Bland‐Altman method. In conclusion, AF coarseness and its relation to LAA flow velocity depend on the ECG recording technique used. LAA contractions represent one mechanical correlate of the electrical fibrillatory activity in AF.