Biomedical subjects

N Kerin

Publications and source records attributed to N Kerin.

5 recordsLinked to original sources

PubMed1978

Concealed atrial bigeminy and trigeminy.

Patterns indicative of concealed atrial extrasystoles were observed in two patients with frequent premature atrial depolarizations. In the first patient, the predominant pattern was such that most of the numbers (S) of sinus P waves between atrial extrasystoles satisfied the equation S = 3n-1, where n is any positive integer. This pattern is characteristic of concealed trigeminy. Over a sequence of 49 interectopic intervals, this patient vacillated between concealed atrial trigeminy and bigeminy. A second patient displayed a pattern characteristic of the "even number" variant of concealed bigeminy. The numbers of sinus P waves in consecutive interectopic intervals were predominantly even. These various patterns of concealed atrial extrasystoles closely resemble previously reported patterns of concealed ventricular extrasystoles.

Aged↗

PubMed1978

Coronary involvement after a single myocardial infarction. Coronary angiography study.

Coronary angiography was performed in 95 patients 3 months to 3 years after a single myocardial infarction. The patients were categorized into 4 groups according to coronary angiography findings: group I with three or four vessels diseased; group II with two vessels diseased; group III with one vessel diseased, and group IV with normal arteries. Vessel disease was considered present if 50% of the lumen was narrowed. The patient population was almost equally distributed among group I (26), group II (26), group II (33) and group III (34). Group IV included only 3 patients in this retrospective study.

Adult↗

PubMed1977

Two variants of concealed trigeminy.

Long rhythm strips were analyzed from three patients with frequent unifocal ventricular extrasystoles. The predominant rhythm in each patient was concealed trigeminy; i.w., the number of conducted sinus beats, S, between extrasystoles satisfied the equation S = 3n --1, where n is any positive integer. In one of these patients, about one-fourth of the values of S did not satisfy this equation; however, all such exceptional values of S satisfied the equation S = 3n. In the other two patients, very few of the exceptional values of S fit the equation S = 3n, but they did conform to the equation S = 3n --2. It is proposed that in all forms of concealed trigeminy, there is a characteristic 3:1 block in the re-entry loop that is responsible for the extrasystoles. Furthermore, it is postulated that immediately after each manifest extrasystole, the 3:1 block is converted transiently to a 4:1 or 2:1 block in the "3n" and "3n--2" variants, respectively. After the first penetration of the block site after a manifest extrasystole, if the re-entrant impulse is concealed, the 3:1 ratio is resumed in both variants until the next manifest extrasystole appears.

Adult↗

PubMed1977

A subvariant of concealed bigeminy.

A subvariant of the "even variant" of concealed bigeminy was studied in two patients. The typical pattern consisted of two types of sequences of conducted sinus beats between extrasystoles. One pattern was bigeminal, i.e., alternating sinus beats and extrasystoles. Between bigeminal sequences were intervals in which there were more than one conducted sinus beat between extrasystoles. In such longer sequences, the numbers of sinus beats were almost invariably even. In the bigeminal sequences, the coupling intervals progressively diminished for each successive extrasystole in the sequence. The proposed explanation for the subvariant was based on a reentry loop in which there were three sites of block: proximal, intermediate, and distal. Block was postulated to take place at the proximal site after those extrasystoles with the shortest coupling intervals, at the intermediate site after odd-numbered conducted sinus beats in the non-bigeminal sequences, and at the distal site ("concealment") after the even-numbered sinus beats in these longer sequences.

Aged↗

PubMed1975

Ventricular quadrigeminy as a manifestation of concealed bigeminy.

Long rhythm strips were analyzed from five patients with frequent ventricular extrasystoles. The predominant pattern was quadrigeminal; i.e., three sinus beats between extrasystoles. However, about 20% of the interectopic intervals contained numbers of sinus beats (S) greater than three. Analysis of the distribution of such values of S greater than 3 revealed that there were many more odd than even values (P less than 0.001). Also, carotid sinus pressure yielded only odd values of S greater than 3. This predominance of odd values strongly suggested the existence of concealed extrasystoles. Therefore, all odd values of S greater than 3 were analyzed to determine whether they satisfied the criterion for concealed bigeminy (S = 2n - 1) or for concealed quadrigeminy (S = 4n - 1). The distribution was found to satisfy the criterion for concealed bigeminy, suggesting that the quadrigeminal pattern was a manifestation of a 2:1 rather than a 4:1 block in a re-entry loop. Stable quadrigeminy occurs often in concealed bigeminy, because the re-entrant impulse finds the myocardium excitable after a normal R-R interval but refractory after a compensatory pause.

Adult↗