Biomedical subjects

R B Krol

Publications and source records attributed to R B Krol.

56 records · Page 4Linked to original sources

PubMed1985

Rate-dependent effects of intravenous lidocaine, procainamide and amiodarone on intraventricular conduction.

In this study, the duration of the QRS complex during ventricular pacing was used as an index of intraventricular conduction to quantitate the rate-dependent effects of intravenous lidocaine, procainamide and amiodarone. Right ventricular apical pacing (15 to 20 beats) was performed at cycle lengths of 600, 500, 400, 350, 300, 275 and 250 ms, before and 5 minutes after the intravenous administration of lidocaine in 11 patients (serum level 3.2 +/- 0.8 micrograms/ml [mean +/- SD] ), procainamide in 14 patients (serum level 8.2 +/- 1.9 micrograms/ml) and amiodarone in 12 patients (serum level 3.9 +/- 1.2 micrograms/ml). Electrocardiographic recordings were made at a paper speed of 150 mm/s. QRS duration was measured in a blinded fashion, with reproducibility within 5%. In the control state, QRS duration was the same at all paced cycle lengths. After lidocaine, procainamide and amiodarone administration, the shortest paced cycle length with complete ventricular capture was 250 +/- 0, 275 +/- 38 and 264 +/- 20 ms, respectively. At a paced cycle length of 600 ms, the increase in QRS duration compared with the control state was 1 +/- 2% with lidocaine (p greater than 0.05), 21 +/- 7% with procainamide (p less than 0.001) and 6 +/- 6% with amiodarone (p less than 0.05). At the shortest paced cycle length with complete capture, the increase in QRS duration compared with the control state was 20 +/- 6% with lidocaine (p less than 0.001), 42 +/- 11% with procainamide (p less than 0.001) and 26 +/- 4% with amiodarone (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1985

Coexistent posteroseptal and right-sided atrioventricular bypass tracts.

Twelve patients with a posteroseptal accessory pathway underwent complete electrophysiologic studies, and four were found to have a second atrioventricular (AV) bypass tract that was right anterior, right anteromedial or right anterolateral in location. In two of these four patients, the presence of the right-sided AV bypass tract was confirmed by intraoperative epicardial mapping or after catheter-induced abolition of retrograde conduction through the posteroseptal bypass tract. In three of the four patients with a dual AV bypass tract, the delta wave pattern was clearly atypical of the pattern seen with an isolated posteroseptal accessory pathway. Instead of a transition from an isoelectric or slightly positive delta wave in lead V1 to markedly positive delta waves in leads V2 to V6, the delta waves were negative or only slightly positive in leads V2 to V5. However, in a fourth patient with dual AV bypass tracts, the only atypical electrocardiographic finding was an intermittently positive delta wave in lead II; at times this patient's electrocardiogram was consistent with an isolated posteroseptal bypass tract, with negative delta waves in the inferior leads. There appears to be an association between posteroseptal and right-sided accessory pathways. In patients with a posteroseptal accessory pathway who are candidates for catheter or surgical bypass tract ablation, a complete mapping study of the tricuspid anulus is mandatory, even when the electrocardiogram is typical of an isolated posteroseptal bypass tract.

Adolescent↗