The influence of anesthesia on cardiac repolarization.

The drugs and techniques used in contemporary anaesthesia may provoke numerous side effects, including cardiac rhythm disturbances. The prolongation of the repolarization time, reflected by the QT interval in a surface electrocardiogram, is one of the mechanisms that lead to the occurrence of arrhythmias. In the paper, we present the primary mechanism that is responsible for QT interval prolongation and subsequent torsade de pointes ventricular tachycardia. The influence of anesthetics, regional anesthesia and perioperative supportive therapy on cardiac repolarization is described.

Total spinal anaesthesia as a complication of local anaesthetic test-dose administration through an epidural catheter.

We describe a case of total spinal anaesthesia, which occurred after a 3-ml lignocaine (20 mg ml(-1)) test dose was administered through an epidural catheter in a 79-year-old patient scheduled for gastrectomy under combined general and epidural anaesthesia. The surgery was postponed, and the patient required admission to the intensive therapy unit. Spinal MRI from the total spinal cord did not reveal any pathology. During the next 24 h the patient recovered and after 11 days was successfully operated on under general anaesthesia. No late complications followed. We presume that during placement, the epidural catheter had migrated to the spinal canal as a result of technical difficulties. Although controversial, we consider that administering a standard test dose of local anaesthetic via an epidural catheter is recommended, especially in high-risk patients and when epidural space identification or catheter placement poses technical difficulties. A test dose of local anaesthetic does not fully prevent complications.

Two cases of postpartum cardiomyopathy initially misdiagnosed for pulmonary embolism.

PURPOSE: To underline the crucial role of urgent echocardiography in the differential diagnosis of acute respiratory and/or circulatory failure in the postpartum period. CLINICAL FEATURES: A 24-yr-old woman was admitted to the intensive care unit (ICU) with a preliminary diagnosis of pulmonary embolism (PE) one week after Cesarean section. Neither computerized tomography nor Doppler sonography showed any signs of deep venous thrombosis or PE. In the ICU she required intubation and ventilatory support for acute respiratory and circulatory failure. Bedside echocardiography revealed features of left ventricular failure. A diagnosis of postpartum cardiomyopathy (PPCM) was made, appropriate treatment instituted and the patient soon improved. A 29-yr-old, previously healthy primipara presented at the Maternity Clinic on the fourth postpartum day complaining of increasing dyspnea and fatigue. Within eight hours she required intubation, ventilatory support and subsequent defibrillation due to cardiac arrest. She was transferred to the ICU with a preliminary diagnosis of PE. She developed pulmonary edema followed by cardiac arrest with successful resuscitation. Bedside echocardiography revealed a left ventricular ejection fraction below 30% with an increased systolic diameter of the left ventricle, restrictive diastolic abnormalities and no signs of pulmonary hypertension. Peripartum cardiomyopathy was diagnosed and supportive treatment for heart failure was instituted. CONCLUSION: It is possible to misdiagnose postpartum cardiomyopathy for PE. An error in diagnosis is life-threatening for the patient. Echocardiography is a valuable tool in the differential diagnosis. As a noninvasive procedure, it should be performed at the bedside as soon as possible to institute proper treatment and to avoid potentially fatal errors.