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[Electrophysiological evaluation of retrograde cardioplegia--experimental study of efficacy for the right ventricle]
H Utsunomiya1, M Ikeshita, T Shoji
1Department of Thoracic and Cardiovascular Surgery, Nippon Medical School, Tokyo, Japan.
Insights
Retrograde coronary sinus cardioplegia with diltiazem offers superior right ventricular protection during coronary artery bypass grafting compared to standard antegrade methods. This technique ensures better myocardial preservation, especially in challenging multi-vessel obstruction cases.
Area of Science:
- Cardiovascular Surgery
- Myocardial Protection
- Electrophysiology
Context:
- Increasing coronary artery bypass grafting (CABG) for multi-vessel coronary obstructions.
- Limitations of antegrade cardioplegia in delivering solution beyond proximal blockages.
- Retrograde coronary sinus cardioplegia as a potential alternative.
Purpose:
- To evaluate the efficacy of retrograde coronary sinus cardioplegia for right ventricular protection.
- To compare retrograde cardioplegia (with and without diltiazem) against antegrade cardioplegia.
- To assess myocardial preservation using electrophysiological and ultrastructural methods.
Summary:
- Thirty-six dogs received retrograde cardioplegia (GIK or GIK+diltiazem) or antegrade cardioplegia (GIK).
- Retrograde cardioplegia with diltiazem (Group II) showed significantly better preservation of right ventricular electrical activity and ultrastructure compared to GIK alone (Group I) and antegrade cardioplegia (Group III).
- Unipolar peak-to-peak amplitude (UPPA) analysis indicated superior myocardial preservation in Group II.
Impact:
- Retrograde coronary sinus cardioplegia, particularly when combined with diltiazem, presents a promising strategy for enhanced right ventricular protection in CABG.
- This technique may improve outcomes for patients with complex coronary artery disease where antegrade delivery is compromised.
- Further clinical investigation is warranted to validate these findings in human subjects.
Abstract:
Recently, coronary artery bypass grafting operations for patients with total proximal multi-vessel coronary obstructions are increased. In these cases, antegrade cardioplegia through the aortic root has been applied as usual. But it seems to be difficult to deliver cardioplegic solution to myocardium uniformly beyond coronary stenosis. Retrograde coronary sinus cardioplegia in the presence of proximal coronary artery obstruction could maintain improved cardioplegic delivery and satisfactory myocardial protection. Because of the limitation of antegrade cardioplegia, retrograde cardioplegic technique has, once again, been cited as a reasonable alternative to antegrade cardioplegia. But on the other hand, retrograde cardioplegia includes the potential for relatively inadequate preservation of right ventricle based on the venous drainage communication to the coronary sinus. The object of the present work is mainly to evaluate the efficacy of retrograde coronary sinus cardioplegic technique for right ventricle by electrophysiological method. Thirty-six adult mongrel dogs divided three groups. Sixteen animals (Group I) received GIK cardioplegia through the coronary sinus, thirteen animals (Group II) received GIK added diltiazem cardioplegia through the same way, and seven animals (Group III) received GIK cardioplegia through aortic root. No large temperature gradients of myocardium between right and left ventricle in each group and also temperature gradients of right ventricle between three groups have been observed. The time duration from starting of injection of cardioplegia to disappear the electrical activity in right and left ventricle were 11.4 +/- 8.2, 3.4 +/- 1.2 minutes in group I, 2.9 +/- 1.5, 2.2 +/- 1.4 minutes in group II, and 0.9 +/- 0.4, 0.9 +/- 0.2 minutes in group III. The time duration from starting of injection of cardioplegia to reappear the electrical activity in right and left ventricle were 6.4 +/- 8.7, 13.4 +/- 7.9 minutes in group I, 20.0 +/- 3.5, 21.3 +/- 1.6 minutes in group II and 18.0 +/- 5.5, 18.7 +/- 4.5 minutes in group III. Unipolar peak-to-peak amplitude (UPPA) analysis reveals the condition of myocardial preservation during ischemic arrest and we compared preischemic UPPA with post-ischemic UPPA. In group I, UPPA declined of 44.1 +/- 29.3% in right ventricle and 72.7 +/- 27.6% in left ventricle, in group II, 78.7 +/- 28.7%, 81.9 +/- 23.6%, in group III, 71.4 +/- 18.7%, 76.7 +/- 9.89%. Analysis of ultrastructural changes in the myocardium are shown that injury was most manifest in the right ventricle of group I, but in group II, ultrastructure of right ventricle maintained nearly normal condition.(ABSTRACT TRUNCATED AT 400 WORDS)