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Summary The NCTs represent a spectrum of diverse electrophysiologic and clinical arrhythmias originating anywhere from the SA node to the ventricular septum. They are due to re-entry circuits or areas of enhanced focal automaticity. Clinical history, electrocardiography, and hemodynamic data are all important contributors to the accurate diagnosis and treatment of these arrhythmias. Verapamil is effective in treating many NCTs, although digitalis, beta blockers, procainamide, or cardioversion may be required.

The effect of pH-adjustment of three per cent 2-chloroprocaine (2-CP, Nesacaine MPF) on the onset, duration, and spread of epidural analgesia and anaesthesia was studied in patients undergoing lower extremity surgery. Forty ASA physical status I and II patients were randomized to two groups. In a double-blinded fashion, patients in both groups received an epidural injection of 15 ml of local anaesthetic (LA) solution via a Tuohy needle at the L3-4 interspace. Local anaesthesia for Group I was prepared by adding 3 mEq NaHCO3 to 27 ml three per cent 2-CP and for Group II was prepared by adding 3 ml 0.9 per cent NaCl to 27 ml three per cent 2-CP. Both solutions contained epinephrine (1:200,000). The pH of commercially prepared Nesacaine MPF was 3.19 +/- 0.02. The pH of the solutions used for Group I and Group II patients were 7.32 +/- 0.01 and 3.27 +/- 0.02, respectively. Times to analgesia and anaesthesia at the L2 dermatome were significantly decreased in Group I patients by 2.5 and 6.6 minutes, respectively. Likewise, pH-adjustment accelerated the attainment of maximum level of block by 2.8 min. No statistical differences were found between groups in the maximum level of epidural block, or in time to 2-segment regression. No precipitation of LA was observed in pH-adjusted solutions of 2-CP after 24 hours. We recommend the use of pH-adjusted three per cent 2-CP (Nesacaine MPF) to accelerate the onset of epidural block.