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J Leitch

Publications and source records attributed to J Leitch.

25 records · Page 2Linked to original sources
PubMed1995

QT dispersion does not predict early ventricular fibrillation after acute myocardial infarction.

Ventricular arrhythmias may be associated with increased QT dispersion (difference between maximum and minimum QT on standard 12-lead ECG). We performed a case control study to determine if QT dispersion on the admission ECG could predict early VF after acute myocardial infarction. The cases were 24 patients with acute myocardial infarction (14 inferior, 8 anterior, and 2 lateral) with VF within 12 hours of admission. There were 24 control patients without VF matched for site of infarction and ST segment score (sum of ST segment elevation). VF occurred a median of 153 minutes (interquartile range 93-245) after onset of chest pain and 33 minutes (range 7-104) after initial ECG. QT (399 +/- 37 and 394 +/- 37), QT corrected (440 +/- 38 and 429 +/- 29), and QT dispersion (68 +/- 20 and 66 +/- 27) were similar in patients and controls. By design, ST score was similar (11 +/- 9 vs 9 +/- 5 mV), although a good match could not be obtained for three patients with extreme ST elevation. Patients with VF presented to the hospital earlier after the onset of chest pain (median 95 min [range 65-188] compared to 150 min [range 80-270], P = 0.05) and had a lower serum sodium (138 +/- 2.4 vs 140 +/- 2.5, P = 0.05) than controls. Thus, QT interval and QT dispersion, measured on the presenting ECG, did not predict early VF after myocardial infarction.

Aged↗
PubMed1992

Feasibility of an implantable arrhythmia monitor.

Conventional Holter monitoring is of limited benefit in patients with infrequent symptoms suspected to be related to arrhythmia. A small recorder implanted subcutaneously might obviate many limitations of conventional monitoring. To determine the feasibility of obtaining adequate electrocardiographic signals from such a device, a prototype was temporarily implanted in 17 patients undergoing pacemaker implantation. The prototype contained four disc-shaped titanium electrodes, 0.21 inches in diameter embedded in epoxy. The four electrodes were in a square configuration spaced 0.72 inches center to center and were placed face down in a subcutaneous pocket in the left pectoral region. Bipolar recordings were made from a horizontal pair, a vertical pair, and both diagonal paris of electrodes (interelectrode distance 1.02 inches) and recorded on electromagnetic tape after filtering at 0.5-250 Hz. The mean peak-to-peak amplitude in each configuration was determined over a five-beat interval. Clear recordings were obtained from all 17 patients with recognizable P, QRS, and T waves. The amplitude of the signals obtained from the diagonal pairs of electrodes (175 +/- 51 and 170 +/- 54 microV) were greater than obtained from either the vertical pair (142 +/- 62 microV, P = 0.08 compared to diagonal electrodes) or the horizontal pair of electrodes (105 +/- 54 microV, P < 0.01). The maximum amplitude recorded from any configuration was 189 +/- 54 microV. In six patients the device was also tested with the electrodes face up in the subcutaneous pocket.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMedDate not supplied

Does acyclovir increase serum lithium levels?

A 42-year-old woman was admitted to the hospital to receive intravenous acyclovir for a herpes zoster infection. At the time she was taking lithium carbonate 450 mg twice/day. Six days after starting acyclovir she exhibited signs of lithium toxicity. When measured, the serum lithium level had increased 4-fold during acyclovir therapy. Both agents are excreted by the kidneys, raising the possibility that acyclovir at high serum concentrations may interfere with the renal excretion of lithium. A MEDLINE search did not identify any citation describing the possibility of an interaction between the drugs. This case suggests that acyclovir when given intravenously in doses of 10 mg/kg may result in increased serum lithium concentrations. Until additional data are available, if intravenous acyclovir is administered concurrently with lithium, we recommend closely monitoring patients for signs of lithium toxicity and measuring serum lithium levels every second or third day.

Acyclovir↗