Management of methomyl poisoning.

Eleven patients who suffered methomyl poisoning were admitted to the intensive care unit. All of them showed cholinergic symptoms similar to that produced by organophosphate insecticides but of lesser intensity. Plasma cholinesterase activity was normal in four patients and moderately lower in the remainder (always above 32%). All of the patients showed miosis and none presented with bradycardia. No complications were detected in the acute stage or on further examination a month later. The treatment applied was: (1) gastric lavage or washing the skin; (2) the administration of activated charcoal; (3) small doses of atropine according to symptoms (average of total dose 4.3 mg). All of the patients recovered within 24-48 h. In conclusion, we can assume that methomyl poisoning does not produce serious complications if moderate surveillance is assumed. Only small doses of atropine are required to counteract symptoms.

[Sensing anomalies with the VVI pacemaker. Clinical study by Holter]. / Anomalías de sensado en marcapasos VVI. Estudio clínico con Holter.

Defective sensing incidence is controversial. It has rarely been assessed by Holter in series of consecutive patients. Holter was used in 59 cases (84% of implants over 9 months) with a follow-up of between 7 and 19 months. The generators came from 2 manufacturers, 44 unipolar and 15 bipolar, with standard sensitivity level and in VVI with rates covering up the patient's own rythm. Results. Unipolar: all asymptomatic registration and two symptomatic in the follow-up. There were myopotential inhibitions in 31 (70%), but only in 6% lasted over 2,000 msec, there were less than 16 episodes in 94% of cases distributed along the day with an increase between 6 am and 3 pm, and absent from 4 to 6 am. In six (14%) there were inhibitions and reversion to asynchronous.+ pacing with the R on T phenomenon and non conducted artifacts in four; in one case the asynchronous stimulation occurred over sinus rhythm. Undersensing was confirmed in four (9%) but in three was caused by PVC. Bipolar: all were asymptomatic and without sensing anomalies. Conclusions. The high incidence of asymptomatic oversensing in unipolar generators limits Holter's value in the diagnosis of symptomatic cases by myopotential interference. Its routine use for detecting anomalies in sensing seems inadvisable. The reversion to asynchronic functioning is not unusual and could be a potentially provocative mechanism of ventricular arrhythmias.

[Longitudinal dissociation of the bundle of His and infra-His block]. / Disociación longitudinal del haz de His y bloqueo infrahisiano.

A case with advanced supra-His block and escape pacemaker at the proximal His block with longitudinal dissociation of the bundle of His is presented. These alterations caused a complete left bundle branch block and prolonged HV interval obtaining the normalization of the QRS after distal His extrasystole. We comment on the differential diagnosis between first degree intra-His and infra-His blocks.