Reciprocal Relationships: the Genetic Counselor-Patient Relationship Following a Life-Limiting Prenatal Diagnosis.

Utilizing the tenet, "Relationship is integral to the genetic counseling process" from the Reciprocal Engagement Model (REM) of genetic counseling practice, this study sought to explore the relationship between the genetic counselor and patient following a "life-limiting" prenatal diagnosis that resulted in a major loss (termination, stillbirth/miscarriage, or neonatal death). The specific aims of this study were to: 1) Understand and describe aspects of the genetic counselor-patient relationship in the context of the life-limiting prenatal diagnosis, and identify characteristics and actions of the 2) genetic counselor and 3) patient that influence the relationship. Genetic counselor (GC) participants were recruited via a web-based survey distributed by NSGC and the NSGC Prenatal SIG. Eligible GCs maintained a relationship with a patient beyond the prenatal diagnosis and had a willing patient participant. Individual 60-min audio-recorded telephone interviews were conducted with eight GC and 8 respective patients (n = 16) using parallel interview guides (n = 16). Transcriptions underwent thematic content analysis for systematic coding and identification of emergent themes. The GC-patient relationship was characterized by the evolution of communication and promoted by the supportive needs of the patient, the nature of the diagnosis, and characteristics and supportive actions of the participants. This exploratory study highlights the unique service of support offered by genetic counselors in the context of a life-limiting prenatal diagnosis.

Spatial regularization of the electrocardiographic inverse problem and its application to endocardial mapping.

Numeric regularization methods for solving the inverse problem of electrocardiography in realistic volume conductor models have been mostly limited to uniform regularization in the spatial domain. A method of spatial regularization (SR) was developed and tested in canine, where each spatial spectral component of the volume conductor model was considered separately, and a SR operator was selected based on explicit a posteriori criterion at each time instant through the heartbeat. The inverse problem was solved in the left ventricle by reconstructing endocardial surface electrograms based on cavitary electrograms measured with the use of a noncontact, multielectrode probe. The results were validated based on electrograms measured in situ at the same endocardial locations using an integrated, multielectrode basket-catheter. A probe-endocardium three-dimensional model was determined from multiplane fluoroscopic images. The boundary element method was applied to solve the boundary value problem and derive the relationship between endocardial and probe potentials. Endocardial electrograms were reconstructed during both normal and paced rhythms using SR as well as standard, uniform, zeroth-order Tikhonov (ZOT) regularization. Compared to endocardial electrograms measured by the basket, electrograms reconstructed using SR [relative error (RE) = 0.32, correlation coefficient (CC) = 0.97, activation error = 3.3 ms] were superior to electrograms reconstructed using ZOT regularization (RE = 0.59, CC = 0.79, activation error = 4.9 ms). Therefore, regularization based on spatial spectral components of the model improves the solution of the inverse problem of electrocardiography compared to uniform regularization.

Electrophysiological imaging of the right atrium using a noncontact multielectrode cavitary probe: study of normal and abnormal rhythms.

Cavitary electrograms previously were measured from multiple directions simultaneously in the canine left ventricle with the use of noncontact multielectrode probes. The objective of the present study was to measure cavitary electrograms in the canine right atrium (RA) and describe the corresponding global activation sequences during normal and abnormal atrial rhythms. A 64-electrode custom probe was inserted into the RA of six dogs. Probe position and orientation were guided by fluoroscopy. Probe unipolar electrograms were acquired simultaneously during sinus rhythm, RA pacing, and ventricular pacing. Vagally mediated atrial fibrillation (AF) was induced in four dogs. Probe electrograms were acquired during AF induced at baseline and after intravenous infusion of ibutilide (0.075 mg/kg followed by 0.075 mg/kg infusion over 10 minutes). Isochrone maps were derived from noncontact probe electrograms and were displayed on a beat-by-beat basis during normal and paced rhythms. During AF, maps were displayed for 10 consecutive 100-ms windows. Isochrone maps of normal and paced beats revealed regions of early activation that were consistent with sites of wavefront initiation. During AF, multiple varying activation wavefronts were observed. At baseline, AF cycle length was 110 +/- 15 ms and the number of wavefronts was 1.72 +/- 0.25 per 100-ms window. After ibutilide, AF cycle increased to 182 +/- 36 ms (P = 0.018) and the number of wavefronts decreased to 0.82 +/- 0.14 per 100-ms window (P = 0.009). In conclusion, global electrophysiological imaging with a noncontact multielectrode probe delineates RA anatomy. Furthermore, images of AF activation depict multiple wandering wavefronts. Ibutilide reduces the number of these wavefronts and organizes AF.

Three-dimensional electrophysiological imaging of the intact canine left ventricle using a noncontact multielectrode cavitary probe: study of sinus, paced, and spontaneous premature beats.

BACKGROUND: The feasibility of measuring cavitary electrograms using a noncontact probe and reconstructing endocardial surface electrograms and activation sequences during paced beats was previously demonstrated in the isolated canine left ventricle (LV). The objective of the present study was to develop and test a high-resolution, three-dimensional, endocardial electrophysiological imaging technique that simultaneously reconstructs endocardial surface electrograms and their corresponding activation sequences during normal and abnormal beats with the use of cavitary electrograms measured with a noncontact multielectrode probe in the intact canine LV. METHODS AND RESULTS: A 128-electrode probe was inserted into the intact canine LV. Probe unipolar electrograms were simultaneously acquired during sinus, artificially paced, and spontaneous premature beats. Representative endocardial electrograms were measured directly using eight needle electrodes (the "gold standard"). A probe-cavity realistic, three-dimensional geometric model was constructed using two-dimensional epicardial echocardiography. Boundary element methods and numeric regularization were used to compute electrograms at 194 sites on the endocardium. In eight pacing protocols, computed endocardial electrograms correlated well with directly measured electrograms (r=.88). Corresponding activation times were also in agreement with those determined from measured endocardial electrograms (activation error, 4.7 ms). The earliest region of activation was invariably in the vicinity of the pacing needle (spatial error, 9.2 mm). Subsequently, the site of origin of ischemia-induced spontaneous ventricular premature beats and the ensuing sequence of depolarization was identified. CONCLUSIONS: Noncontact mapping provides realistic, three-dimensional electrophysiological images of the endocardium, on a beat-by-beat basis, that localize the sites of origin of premature beats and reconstruct their activation sequences.