High potassium solution for elective cardioplegia associated with hypothermia has been shown to be effective for electromechanical arrest and myocardial preservation. The extracellular space (ECS), intracellular potassium, percentage of water change, and ventricular compliance were measured after 1 how of reperfusion following 1 hour of high (35 mEq/liter) and low (5 mEq/liter) potassium (K+) cardioplegia employing normothermia and hypothermia in the isolated perfused hypertrophied heart. The ECS measured with 3H inulin in the hypertrophied control group was 27.80 ± 0.1% with total water content of 81.1 ± 0.4%, both of which were higher than the previously measured normal myocardium (P < 0.05). High potassium hypothermic arrest and reperfusion showed no change in ECS or intracellular K+ in normal hearts but produced an increase in ECS (35.2 ±3.0) (P < 0.001) and intracellular potassium in the hypertrophied group. Low potassium hypothermic arrest and reperfusion showed no change in ECS and increase in intracellular K+ in normal hearts but produced increased ECS (45.0 ± 3.3%) and intercellular K+ in hypertrophied hearts (P < 0.05). High potassium normothermic arrest and reperfusion showed increased ECS and intracellular potassium in both normal hearts, ECS = 27.8 ± 0.1% (four dogs) (P < 0.05) and hypertrophied hearts, ECS = 55.7 ± 1.2% (P < 0.05). Compliance measurements in hypertrophied hearts showed no change with hypothermic high and low potassium arrest but decreased compliance (P < 0.05) when normothermic high K+ arrest was employed. Postperfusion shifts of potassium in the reperfusion period suggest decreased potassium efflux and increased fluid shifts in all groups except the normal myocardium protected with hypothermic high K+ solution. Although different from controls, hypertrophied hearts protected with hypothermic high K+ solution showed less fluid shifts and potassium efflux than did the hypertrophied hypothermic low K+ or hypertrophied normothermic high K+ groups. The hypertrophied heart is more susceptible to fluid and potassium shifts after potassium arrest than is the normal heart with high K+ hypothermic arrest producing the least amount of changes.
|Original language||English (US)|
|Number of pages||9|
|State||Published - Jun 1979|
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