RESUMO
OBJECTIVE: To highlight the use of procainamide as a potential alternative treatment modality in cases of ventricular tachycardia that are refractory to lidocaine and magnesium sulfate. ANIMAL: 1 adult horse weighing 380 kg. CLINICAL PRESENTATION, PROGRESSION, AND PROCEDURES: A 25-year-old Arabian gelding presented with severe colic signs. Due to persistent pain, it was elected to carry out an exploratory laparotomy. During the procedure a diagnosis of severe, unstable ventricular tachycardia was made based on the ECG findings, with an initial heart rate of 195 beats per minute and severe hypotension. TREATMENT AND OUTCOME: Initial treatment consisted of discontinuing dobutamine and the administration of a 2 mg/kg IV lidocaine bolus followed by a continuous rate infusion at 50 µg/kg/min. Twenty grams magnesium sulfate (5 mg/kg) was administered IV in 1 L of lactated Ringer solution as a slow bolus over 30 minutes. Ventricular tachycardia persisted with poor peripheral pulses, a severely dampened arterial waveform, and a MAP of 30 to 45 mm Hg. Two milligrams/kg IV procainamide was administered over 3 minutes, 3 separate times, at 5-minute intervals. Immediately following the third dose sinus rhythm was detected on the ECG, the arterial waveform improved, and MAP increased to 85 mm Hg. CLINICAL RELEVANCE: Ventricular tachycardia is a rare but potentially life-threatening complication in horses undergoing general anesthesia. The potential of this arrhythmia to progress to ventricular fibrillation is of grave concern, as the option to attempt to externally defibrillate horses back to normal sinus rhythm does not exist. This case highlights procainamide as a potential option for cases of ventricular tachycardia that are refractory to more standard treatment modalities.
RESUMO
OBJECTIVE: To describe a 3-wire method with endoscopic guidance for extensive nasal septum resection. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Thirteen horses with nasal septum diseases. METHODS: In anesthetized horses in left lateral recumbency, endoscopic guidance was used to place obstetrical wires for the ventral and caudal incisions in the nasal septum and a trephine opening was used to place the dorsal wire. The rostral aspect of the septum was incised with a scalpel, followed by incisions with the preplaced wires, and the nasal passages were packed with gauze. Horses were recovered with a temporary tracheotomy. RESULTS: Conversion to intraoral placement of wires was required in two horses, one to correct entangled wires and the other because hemorrhage obscured the endoscopic view. Exercise tolerance was improved postoperatively, abnormal respiratory noise was decreased or eliminated by surgery in all horses, and all owners were satisfied. One Thoroughbred racehorse performed with modest success. CONCLUSIONS: Modification of the 3-wire method was effective and safe for extensive nasal septum removal. Technical complications of the procedure include entangling of wires and intraoperative hemorrhage. CLINICAL SIGNIFICANCE: Endoscopic guidance can be used to place obstetrical wires for nasal septum resection in small horses and precludes use of a large tracheotomy for anesthetic delivery. Reasons for athletic failures were difficult to establish retrospectively, although assessment of postoperative noise at speed might be more relevant to recovery of athletic potential than assessment at slower gaits.
