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“Torsade de pointes” tachycardia: Re-entry or focal activity?
Abstracts
bundle studies in three of the patients with bidirectional tachycardia confirmed the infranodal origin of this arrhythmia. Thus, properly administered lidocaine was shown to be effective in abolishing bidirectional tachycardia in patients and in abolishing atria1 tachycardia with block in patients with digoxin toxicity. [Marc J. Gorayeb, MD] Editor’s Note: It is interesting how less frequently we are seeing digitalis toxicity. This may relate to the wide spread use of digoxin as opposed to longer acting preparations and more attention to prevention of hypokalmia. It is useful to know that lidocaine will be effective in abolishing paroxysmal atria1 tachycardia with block.
?“ ?TORSADE DE POINTES” TACHYCARDIA: RE-ENTRY OR FOCAL ACTIVITY? D’Alnoncourt CN, Zierhut W, Luderitz B. Br Heart J 1982; 48:213-216. Desertenne in 1966 suggested that torsade de pointes tachycardia might be due to the interaction of two foci of ectopy at separate locations in the heart. This hypothesis was tested under specific conditions in the present study. Isolated perfused pig hearts were paced by two separate electrodes in the right and left ventricles. The QRS recorded from the area of the LAD coronary artery was positive with right ventricular pacing, and negative with left ventricular pacing. Stimulating the right ventricle at a constant rate and varying the firing rate of the left ventricular electrode caused corresponding variations in the QRS direction and amplitude. Continuous prolongation of the coupling interval of the second stimulus caused a gradual decrease in the R wave amplitude, its disappearance, followed by the appearance of a predominantly negative QRS with gradually increasing amplitude. The reverse occurred with continuous shortening of the coupling interval. In four hearts the LAD coronary artery was occluded, with the development of a stable ventricular tachycardia. With this rhythm the “torsade de pointes” pattern was generated by simply stimulating the right ventricle with gradually increasing and decreasing stimulation intervals. These results suggest that a bifocal or multifocal ectopic ventricular rhythm can be manifested as a torsade de pointes tachy[Marc J. Gorayeb, MD] cardia. Editor’s Note: This article does not comment on the prolonged QT interval often associated
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with the clinical presentation of torsade de pointes but does suggest an explanation for the success of pace making overdrive or lidocaine therapy.
?? HIGH PRESSURE INJECTION INJURIES TO THE HAND. Hayes CW, Pan HC. South Med J 1982; 75:1491-1516. Sudden discharge from grease, paint, and spray guns or from disconnected hydraulic lines may result in significant hand injuries. Pressure of 10,000 to 12,000 psi of material may be injected from such devices. Fourteen high-pressure injection injuries to the hand were seen between 1970 to 1982. Volume of material and injected pressure are of import in determining dispersion of the injected material. Injection of automobile grease, diesel oil, or hydraulic fluid appear to be less damaging to tissue than material used in commercial paint, especially solvents. The study revealed that 7 of the 14 patients were injured with a paint or spray gun and all amputations occured in this group. Injuries with paint, paint thinners, and solvents produced an amputation rate of more than 60%) whereas the amputation rate with hydraulic fluid was less than 10%. Injection into a digit or tendon sheath results in a poorer prognosis than an injury to the hand, probably because of the greater anatomic distensibility of the hand. No statistically valid data confirms or refutes the use of steroids in such injuries. In their study steroids were empirically used in the most severe injuries. Infection was not a significant factor in the prognosis of the injuries except as a secondary factor, possibly because of the bacteriostatic or bactericidal properties of the injected materials. The authors recommend early surgical debridement, decompression, adequate antibiotics given before, during, and two days after surgery. Steroids are reserved for digital injuries or injuries related to paint or solvents. [Esequiel C. Guevara, MD] Editor’s Note: Despite the author’s own observations that infection was not a problem, and steroids were used only for the most severe injuries without benefit, they recommend both modalities. What is apparent from their data is that emergency physicians and their surgical consultants frequently underestimate the seriousness of these injuries and the need for early surgery. It is also not known whether work gloves would prevent these catastrophies.
bundle studies in three of the patients with bidirectional tachycardia confirmed the infranodal origin of this arrhythmia. Thus, properly administered lidocaine was shown to be effective in abolishing bidirectional tachycardia in patients and in abolishing atria1 tachycardia with block in patients with digoxin toxicity. [Marc J. Gorayeb, MD] Editor’s Note: It is interesting how less frequently we are seeing digitalis toxicity. This may relate to the wide spread use of digoxin as opposed to longer acting preparations and more attention to prevention of hypokalmia. It is useful to know that lidocaine will be effective in abolishing paroxysmal atria1 tachycardia with block.
?“ ?TORSADE DE POINTES” TACHYCARDIA: RE-ENTRY OR FOCAL ACTIVITY? D’Alnoncourt CN, Zierhut W, Luderitz B. Br Heart J 1982; 48:213-216. Desertenne in 1966 suggested that torsade de pointes tachycardia might be due to the interaction of two foci of ectopy at separate locations in the heart. This hypothesis was tested under specific conditions in the present study. Isolated perfused pig hearts were paced by two separate electrodes in the right and left ventricles. The QRS recorded from the area of the LAD coronary artery was positive with right ventricular pacing, and negative with left ventricular pacing. Stimulating the right ventricle at a constant rate and varying the firing rate of the left ventricular electrode caused corresponding variations in the QRS direction and amplitude. Continuous prolongation of the coupling interval of the second stimulus caused a gradual decrease in the R wave amplitude, its disappearance, followed by the appearance of a predominantly negative QRS with gradually increasing amplitude. The reverse occurred with continuous shortening of the coupling interval. In four hearts the LAD coronary artery was occluded, with the development of a stable ventricular tachycardia. With this rhythm the “torsade de pointes” pattern was generated by simply stimulating the right ventricle with gradually increasing and decreasing stimulation intervals. These results suggest that a bifocal or multifocal ectopic ventricular rhythm can be manifested as a torsade de pointes tachy[Marc J. Gorayeb, MD] cardia. Editor’s Note: This article does not comment on the prolonged QT interval often associated
183
with the clinical presentation of torsade de pointes but does suggest an explanation for the success of pace making overdrive or lidocaine therapy.
?? HIGH PRESSURE INJECTION INJURIES TO THE HAND. Hayes CW, Pan HC. South Med J 1982; 75:1491-1516. Sudden discharge from grease, paint, and spray guns or from disconnected hydraulic lines may result in significant hand injuries. Pressure of 10,000 to 12,000 psi of material may be injected from such devices. Fourteen high-pressure injection injuries to the hand were seen between 1970 to 1982. Volume of material and injected pressure are of import in determining dispersion of the injected material. Injection of automobile grease, diesel oil, or hydraulic fluid appear to be less damaging to tissue than material used in commercial paint, especially solvents. The study revealed that 7 of the 14 patients were injured with a paint or spray gun and all amputations occured in this group. Injuries with paint, paint thinners, and solvents produced an amputation rate of more than 60%) whereas the amputation rate with hydraulic fluid was less than 10%. Injection into a digit or tendon sheath results in a poorer prognosis than an injury to the hand, probably because of the greater anatomic distensibility of the hand. No statistically valid data confirms or refutes the use of steroids in such injuries. In their study steroids were empirically used in the most severe injuries. Infection was not a significant factor in the prognosis of the injuries except as a secondary factor, possibly because of the bacteriostatic or bactericidal properties of the injected materials. The authors recommend early surgical debridement, decompression, adequate antibiotics given before, during, and two days after surgery. Steroids are reserved for digital injuries or injuries related to paint or solvents. [Esequiel C. Guevara, MD] Editor’s Note: Despite the author’s own observations that infection was not a problem, and steroids were used only for the most severe injuries without benefit, they recommend both modalities. What is apparent from their data is that emergency physicians and their surgical consultants frequently underestimate the seriousness of these injuries and the need for early surgery. It is also not known whether work gloves would prevent these catastrophies.