Factors determining ventricular fibrillation after induced cardiac arrest

One single dose of histidine-tryptophan-ketoglutarate solution gives equally good myocardial protection in elective mitral valve surgery as repetitive cold blood cardioplegia: a prospective randomized study

OBJECTIVES

Histidine-tryptophan-ketoglutarate (HTK-Custodiol) cardioplegic solution is administered as one single dose for more than 2 hours of ischemia. No prospective randomized clinical study has compared the effects of HTK and cold blood cardioplegia on myocardial damage in elective mitral valve surgery. Thus, the main aim of the present study was to examine whether one single dose of cold antegrade HTK gives as good myocardial protection as repetitive antegrade cold blood cardioplegia in mitral valve surgery.

METHODS

Eighty consecutive patients undergoing elective isolated mitral valve surgery for mitral regurgitation, with or without ablation for atrial fibrillation, were included in the study and randomized to HTK or blood cardioplegia. Markers of myocardial injury (troponin-T and creatine kinase MB) were analyzed at baseline and 7 hours, 1 day, 2 days, and 3 days after surgery.

RESULTS

No significant difference in creatine kinase MB and troponin-T between HTK and blood cardioplegia groups was found at any time point. There was a significant correlation between ischemic time and markers of myocardial injury in the HTK group only and significantly more spontaneous ventricular fibrillation after release of crossclamping in the HTK group.

CONCLUSIONS

One single dose of antegrade cold HTK cardioplegic solution in elective mitral valve surgery protects the myocardium equally well as repetitive antegrade cold blood cardioplegia.

Elective cardiac surgery using Celsior or St. Thomas No. 2 solution: a prospective, single-center, randomized pilot study

OBJECTIVE

Celsior is a crystalloid solution specifically designed for solid-organ transplantation. Due to its advanced combination of solutes, we wanted to evaluate its safety, efficacy, and possible benefits when used as blood cardioplegia in elective cardiac surgery in a single-center, randomized, controlled clinical trial, comparing its performance with a well-established cardioplegic solution.

METHODS

Patients programmed for aortic valve replacement were randomized to receive either St. Thomas No. 2 or Celsior as blood cardioplegia with the same administration protocol. Intraoperative and postoperative variables concerning myocardial protection were registered and compared.

RESULTS

A total of 60 patients were enrolled and randomized (Celsior, 30; St. Thomas, 30). There were no significant differences in baseline and preoperative variables. Volume of cardioplegic solution, number of administrations needed and the amount of potassium added were similar in both groups. Patients in the Celsior group showed a higher incidence of spontaneous sinus rhythm after myocardial ischemia (77% vs 40%, p=0.004) and fewer patients required defibrillation (17% vs 43%, p=0.024) for ventricular reperfusion arrhythmias. Postoperatively, there were no significant differences in troponin I release, inotropic and vasopressor drug support, ICU stay, and postoperative evolution. There were no deaths in the study.

CONCLUSIONS

Celsior solution used as blood cardioplegia is effective and seems to be safe in elective aortic valve replacement when compared in this pilot study with a standard cardioplegic solution used worldwide. Fast return to sinus rhythm and lower incidence of reperfusion arrhythmias in the Celsior group may reflect a better myocardial protection during cardioplegic arrest. More investigation is needed to elucidate its performance in elective surgery.

Arrest duration influences postcardioplegia electrophysiologic recovery and reperfusion arrhythmias

BACKGROUND

This study tests the hypothesis that postcardioplegia electrophysiologic recovery is influenced by the duration of cardioplegic arrest.

METHODS

Pigs were randomized to various durations of cardioplegic arrest (group I, 15 minutes; group II, 60 minutes; group III, 120 minutes). Electrophysiologic data included limb lead, atrial and ventricular epicardial, and ventricular endocardial electrocardiograms. Variables included times for earliest electrical activity and sinus rhythm; number of defibrillations; mechanism for reperfusion ventricular fibrillation; and time until last ventricular fibrillation.

RESULTS

Time to last ventricular fibrillation was 73+/-8, 134+/-23, and 238+/-23 seconds for groups I, II, and III (mean+/-standard error of the mean; p < 0.05 between group III versus groups I and II). The number of defibrillations was 1.0+/-0.3, 5.8+/-1.2, and 10.5+/-1.1 for groups I, II, and III (p < 0.05 between groups). The time to sinus rhythm was 66+/-8, 192+/-27, and 249+/-23 seconds for groups I, II, and III (p < 0.05 group I versus groups II and III). The most common mechanism for reperfusion arrhythmias was an accelerating ventricular tachycardia that initiated fibrillation (79 of 167 episodes). However, in many instances postdefibrillation amplifier saturation masked the initiation of reperfusion arrhythmias.

CONCLUSIONS

Electrophysiologic recovery after cardioplegic arrest is influenced by the duration of cardioplegic arrest.

Catecholamines during cardiopulmonary resuscitation for cardiac arrest

Serum catecholamines were measured during continued prolonged cardiopulmonary resuscitation and after 10 mg increments of intravenous epinephrine. This was part of an ongoing trial of 10 mg epinephrine versus placebo. Eight patients were in the placebo arm and seven in the epinephrine arm and the rhythms were two ventricular fibrillation, nine asystole and four electromechanical dissociation. Data were analysed by time from onset of the cardiac arrest and samples were analysed for levels of DHPG (dihydroxyphenylglycol) nor-epinephrine, epinephrine, DOPA (dihydroxyphenylalanine) and DOPAC (dihydroxyphenyl acetic acid). There was a significant (P < 0.001) difference between arterial and venous samples of epinephrine but not the other catecholamines. High levels of catecholamines were maintained in all time phases except for nor-epinephrine where significant (P < 0.0003) reduction occurred progressively after 20 min. Non-steady state kinetics were suggested between epinephrine and nor-epinephrine and DHPG and nor-epinephrine for the first 20 min. Very large increases in epinephrine were achieved with administered 10 mg epinephrine and this resulted in high DHPG levels supporting the experimental belief that exogenously administered epinephrine induces myocardial release of nor-epinephrine. This data supports the known effects of CPR on catecholamine release. It provides data on the other neurotransmitter hormones and supports the relationships shown in other animal and human data. It is suggested that supplementation with epinephrine during CPR may be unnecessary and the levels reached may be deleterious. Nor-adrenaline supplementation may be necessary after prolonged CPR.