Vena cava interruption after pulmonary embolectomy.

Interruption of the inferior vena cava for thromboembolism is occasionally apppropriate following either pulmonary embolectomy or other cardiac operation performed through a median sternotomy. Experience has shown that simple extension of the sternotomy incision to the umbilicus is a quick and practical means of obtaining good exposure for caval interruption.     

Double-inlet left ventricle with rudimentary right ventricle and ventriculoarterial concordance

Seven hearts were studied that had in common the segmental combination of double-inlet left ventricle, rudimentary right ventricle and ventriculoarterial concordance. The prototype of these hearts has been described as the “Holmes heart” or “single ventricle type A1.” Five of the hearts had 2 atrioventricular valves; in 1 of these the right valve was minimally straddling. The other 2 had a common valve. In 6 of the hearts the rudimentary right ventricle was obliquely situated on the anterior surface of the dominant left ventricle. The trabecular component was anterior and right-sided with the outlet components and pulmonary trunk in left-sided position. In the final case, both trabecular and outlet components of the rudimentary right ventricle were left-sided. Conduction tissue studies were performed in 2 hearts. In 1, the connecting atrioventricular node and bundle were in anomalous anterolateral position, as expected in double-inlet left ventricle. In the other, a ring-like, posterior, nonbranching bundle connected the regular node in the atrial septum to the branching bundle positioned on the anterior interventricular septum. The anatomic findings are related to the likely modes of presentation and differential diagnosis while the conduction tissue findings are discussed in the light of options for surgical repair. Thus, the term “single ventricle” is best avoided when describing hearts that unequivocally possess 2 ventricular chambers.     

Current Status of Pacemaker Power Sources

After years during which pacers of very similar design and capabilities were provided by a small number of manufacturers, many different lithium, halogen, rechargeable, and nuclear power sources are now available. The variety of chemistries, methods of construction, and sealing techniques used in the batteries of the different manufacturers is almost unlimited. This has made it necessary for physicians who implant and follow pacers to acquire a general knowledge of the field if they are to make an informed choice of pacemaker power source for implantation and if they are to manage recalls with a minimum of patient and physician trauma. More experience is required before it can be definitely determined which of the new pacer power sources will prove superior, but when coupled with well-designed, hermetically sealed pulse generators, all are capable of providing continuous pacing for at least 5 years and the 10-year pacemaker is now a probability.     

Is potassium a necessary component of cardioplegic solutions?

Potassium-treated hearts were more completely arrested, usually did not require defibrillation, and had slightly less impairment of left ventricular contractility than those treated with hypothermia alone. There was more reactive hyperemia in non-potassium-treated hearts suggesting a greater oxygen debt. There were no significant differences however, in myocardial metabolism, as determined by myocardial lactate and ATP, myocardial lactate extraction, and electron microscopy.     

Direct Ascending Aortic Insertion of the “Percutaneous” Intraaortic Balloon Catheter in the Open Chest: Advantages and Precautions

When intraoperative balloon pump support is needed for patients who cannot be weaned from cardiopulmonary bypass and when the balloon catheter will not pass retrograde into the aorta from the femoral artery, the catheter must be inserted into the ascending aorta directly. We have found that the new Datascope “percutaneous” balloon catheter offers many advantages for direct insertion into the ascending aorta, but certain precautions are necessary to prevent cerebral emboli when the percutaneous balloon catheter is used this way.     

Effects of various periods of cold potassium cardioplegic arrest upon myocardial contractility and metabolism

A maximal “safe” period of cardioplegic arrest has not been documented. Twenty-five dogs were therefore subjected to 1, 2, and 3 hr of potassium cardioplegic arrest (Groups I, II, and III), using 200 ml at 20-min intervals of D₅ 0.2 NS with 20 mEq KCl and 6 mEq NaHCO₃/500 ml at 0–4°C. Results: Myocardial temperature decreased to 13°C after each cardioplegic infusion. Left ventricular pressure volume curves did not decrease significantly in Group I, but did in Group II, from 204 ± 20 mm Hg with 10-ml volume to 140 ± 8 (P < 0.03). Group III decreased from 117 ± 9 with 5-ml volume to 60 ± 3 (P < 0.0004), from 160 ± 11 with 10-ml volume to 108 ± 6 (P < 0.004), and from 181 ± 17 with 15-ml volume to 127 ± 9 (P < 0.03). Cardiac output was less in Group III than in Groups I and II 60 min after bypass [44 ± 10 vs 76 ± 8 ml/min/kg (P < 0.08)]. Myocardial ATP was significantly less in Group III than Group I 15 min after reperfusion and 60 min after bypass, being 2.25 ± 0.35 and 2.95 ± 0.81 vs 5.18 ± 0.85 and 5.68 ± 0.60 μmoles/g (P < 0.05). Myocardial lactate increased from 3.65 to 8.55 ± 0.81 μmoles/g at 60 min of cardioplegia, 9.36 ± 0.67 at 2 hr, and 12.01 ± 2.0 at 3 hr. Myocardial glycogen decreased through the cardioplegic period and remained depressed in Group III 30 min after bypass, being 488 ± 124 mg%, as compared to 901 ± 130 in Group I (P < 0.05). Conclusions: Hearts subjected to 1 and 2 hr of potassium cardioplegia showed relatively little hemodynamic or metabolic derangement, as compared to those subjected to 3 hr of cardioplegia.     

Measurement of ejection fraction by thermal dilution techniques

The reproducibility, accuracy, and clinical applicability of ventricular ejection fraction derived by a thermal dilution technique were assessed in 22 dogs and 18 patients. Results obtained by the thermal technique were compared to simultaneous results obtained by radionuclide angiography. Right ventricular ejection fraction, measured in 9 dogs (1014 determinations) and 8 patients (744 determinations) was reproducible ±5%. Left ventricular ejection fraction, measured in 10 patients, was reproducible ±5%. Correlation between thermal and radionuclear measurements varied from 0.86 to 0.93 (all P < 0.02). We conclude that, because of its low cost, ease of use, and accuracy, thermally derived ejection fraction determinations can be helpful in hemodynamic monitoring of critically ill patients.     

Boerhaave syndrome: Successful conservative management in three patients with late presentation

Three patients with Boerhaave syndrome were successfully managed with nonoperative treatment. The diagnosis was delayed 5 days in one patient and 10 days in the other two. None of the patients appeared septic. Their conditions had been misdiagnosed as myocardial infarction, pneumonia and pulmonary embolism. Treatment consisted of intravenous hyperalimentation and administration of antacids and antibiotics. Cimetidine was also used in one patient. Two patients were discharged 14 days after diagnosis and the third on the 20th hospital day. Follow-up barium swallows showed complete healing in 2 months in all three patients. Conservative management of spontaneous esophageal perforation is feasible when (1) the perforation is already 5 days old, (2) there are no signs of severe sepsis, (3) esophageal barium study shows a wide-mouthed cavity draining freely back into the esophagus, and (4) the pleural space is not contaminated. When the diagnosis is made promptly, surgical therapy remains the treatment of choice, and patients managed conservatively who show signs of sepsis should be operated on without hesitation. Follow-up esophageal evaluation should be performed to confirm complete healing and to evaluate underlying disease.     

Penetrating left ventricular stab wound: a method of control during resuscitation and prior to repair

A 34-year-old man with left ventricular stab wounds, suffered cardiac arrest soon after arriving in the Intensive Care Unit from the Accident and Emergency Department. He had cardiac tamponade without elevation of his central venous pressure; this was because of exsanguination into his left hemithorax. Immediate thoracotomy while still in his bed confirmed tamponade and revealed two large left ventricular stab wounds, one anterior and one posterior; the heart was in ventricular fibrillation. As he had already been anoxic for some time, no effort could be made to repair the stab wounds before resuscitating him. It was neccessary to control bleeding from two separate injuries while replacing volume, continuing with intracardiac drugs, internal cardiac massage and internal defibrillation. This was achieved by inserting a Foley catheter into each wound, inflating the balloons, clamping the catheters and having the assistant gently retracting the catheters against each other while the operator continued with the resuscitation. When the circulation was restored, pledgeted horizontal mattress sutures were inserted on either side of each Foley catheter, which was with-drawn immediately before tying the suture. The patient was discharged home 12 days later without any complications.     

Aortopulmonary Anastomosis in Patients with Levotransposition

A technique for approximating the right pulmonary artery to the aorta in levo (L) transposition is described. The anastomosis is placed high on the ascending aorta to avoid occluding the coronary circulation by the clamp during the anastomosis. It is in patients with occluded left side anastomoses or single right pulmonary arteries that the right-sided anastomoses are most useful in L-transposition.