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Biomedical subjects

H A Killam

Publications and source records attributed to H A Killam.

10 recordsLinked to original sources
PubMed1990

Patterns of body surface potential and ventriculograms specific to occlusion of subdivisions of the coronary arteries.

The thoracic activation map patterns, the distribution of occlusions, and the ventriculograms obtained at cardiac catheterization were examined in 166 patients with multivessel coronary disease without conduction defects or prior coronary intervention. The mean potential and ventriculographic configurations were determined for 15 groups, each formed on the basis of significant luminal occlusion (less than or equal to 90%) of an individual coronary arterial subdivision. We mathematically extracted distinctive map and wall motion patterns specific for isolated occlusion of each of the 15 major subdivisions. For these prototypes we found the following: 1) Definitive change in electrical pattern (less than 2 SD from the normal mean) occurred frequently outside the electrode sites of the standard electrocardiogram. 2) Focal akinesis systematically followed lesion site down the arterial courses; early electrical activation patterns corresponded to identifiable anatomic loss. 3) Certain paradoxes arose, for example, similar wall motion change but quite dissimilar electrical patterns from posterior descending artery occlusion of right coronary versus left circumflex origin. This technique unmasks component surface electrical patterns and ventriculographic deformities otherwise unrecognized in multisite, multivessel disease.

Adult↗
PubMed1989

Relation between the ventriculographic silhouette and topography of thoracic potential in coronary artery disease.

The body surface potential map obtained within 30 days of cardiac catheterization was examined in 180 patients with coronary artery disease. Radii to the systolic and diastolic boundaries of the right anterior oblique ventriculogram were measured at 18 degrees intervals; isointegral voltages were tabulated for early and late halves of the QRS complex at 35 definitive electrode sites. Multivariate analysis showed all ray lengths depended on all 70 voltage values. Linear transformation matrices to predict ray length from voltage distribution were calculated for a training set which was successively expanded from 80 to 160 at increments of 20 patients. Training set expansion led to a progressive decrease in the error of reproduction of the ray lengths for patients outside the training set. There is a strong relation between ventriculographic contours in patients with coronary artery disease and body surface potential values during early and late QRS complexes. Even in simplified linear formulation, the relation is detectable throughout a large population despite interindividual variations in anatomic geometry.

Adult↗
PubMed1989

Use of body surface maps to identify vessel site of coronary occlusion.

Body surface mapping is more sensitive than conventional electrocardiography for various cardiac regions. In this pilot study, the authors used isoarea maps of early (the first 40 msec), late (the next 40 msec), and total (early and late, or 80 msec) QRS complex to determine the site of coronary occlusion in patients with known coronary artery disease. In the absence of conduction abnormalities or axis deviation in the 12-lead electrocardiogram, isoarea body surface map data of single-vessel disease were unremarkable; however, isoarea departure maps (ie, the average isoarea map of normal population extracted from the study group) were characteristic. Early departure isoarea maps were revealing in all three coronary artery disease groups, with a large negative potential noted over the anterior thorax, midline for the right coronary artery, left anterior in the left anterior descending artery, and further laterally for the left circumflex artery groups. The late isoarea departure map was distinct in the left circumflex artery group with positive potentials leftward, anterolaterally. Discriminant function analysis revealed a high predictive accuracy for the left anterior descending artery group. Thus, isoarea departure maps hold promise for predicting the site of coronary occlusion in this training set of patients.

Adult↗
PubMed1989

A basis for determining body surface potential patterns attributable to single-site coronary arterial occlusion.

The authors focus on computational separation of the individual patterns of occlusion of the major segments of the right coronary artery. The raw patterns of occlusion throughout 15 standard subdivisions of the coronary arterial tree and body surface isoarea maps for 8 consecutive 10-msec intervals of QRS were examined in 200 patients with known coronary artery disease. Mean patterns of occlusion and of potential distribution were formed into 15 groups according to which patients showed greater than or equal to 90% occlusion of the respective segments. By diagonalization of the occlusion matrix, individual potential map patterns were obtained to represent the effect of isolated occlusion of each segment. While these patterns appeared consistent with the known anatomy of ventricular myocardial perfusion, further correlative study will be needed. The authors suggest that the use of such prototypical patterns of single-site obstruction may be helpful in forming and assessing recognition patterns in the clinical setting of multiple-site, multiple-vessel disease.

Coronary Disease↗
PubMed1988

Tamponade due to hemopericardium after streptokinase therapy for pulmonary embolism.

A 67-year-old man was given intravenous heparin and then streptokinase for an acute severe pulmonary embolism. The next day a large pericardial effusion developed, with tamponade. Aspiration of blood (500 ml) from the pericardial sac produced prompt relief. The possibility of hemopericardium causing tamponade should be considered on unexplained worsening of cardiac status in a patient who has recently received streptokinase for pulmonary embolism or myocardial infarction.

Aged↗
PubMed1976

Permanent cardiac pacemakers: twelve-year experience with 287 patients.

Our total pacemaker experience was evaluated to determine survival, complications, effectiveness of follow-up techniques, and future goals for surveillance. A retrospective review of 287 patients with 570 pulse generators revealed 164 alive and 104 dead; 3 recovered normal conduction, 14 transferred care, and 2 have been lost to follow-up. Average age at initial implantation was 67 years. Overall mean generator life has been 22 months. The one-, three-, five-, and ten-year survival is 84, 71, 60, and 39%, respectively. The 738 operations performed averaged 2.6 procedures per patient. Of the total survivors, 108 (66%) had no complications; 56 (34%) have had at least one complication, 70% during the first year of the initial implantation. Fifty episodes of premature interruption of pacing service were detected. Ninety-one patients (32% of the group) have required an operative procedure on their pacemaker system more frequently than every two years. Of the replacements, 89 (29%) were for reasons other than end of generator life; 66 (63%) of the deaths occurred before replacement of the first generator. Mortality in the first two years was 23%. Once survival exceeded two years the average annual death rate was 3.7% (expected, 3.2%). Survival in our series compares favorably with that of other groups who report by the actuarial method. These data suggest that some deaths, reduced patient productivity, and the high cost to health care providers may be due in part to inadequate follow-up after the first pacemaker implantation. If follow-up observation is done frequently during the first year after initial implantation and once minimum generator longevity has passed, the goals of pacemaker therapy may be achieved.

Adolescent↗