Reduced incidence of atrial fibrillation with minimally invasive direct coronary artery bypass

BACKGROUND

Atrial fibrillation (AF) is a frequent complication after coronary artery bypass graft (CABG) surgery. The purpose of this study was to determine the incidence of postoperative AF after minimally invasive direct coronary artery bypass (MIDCAB) in comparison with CABG.

METHODS

Between November 1995 and May 1997, 96 MIDCAB procedures were performed. During the same period, 42 patients underwent traditional single CABG using the left internal mammary artery graft (S-CABG). The incidence of in-hospital AF, defined as a sustained episode requiring treatment, was compared between the two groups.

RESULTS

There was no difference in age, ejection fraction, or preoperative risk score between the groups. The use of beta-blockers before or after surgery was not different. The incidence of postoperative AF in the first 6 weeks after surgery was 4% (4 of 96) for MIDCAB and 28% (12 of 42) for S-CABG (p = 0.003). Patients with postoperati

Characterization of signal properties in atherosclerotic plaque components by intravascular MRI

Magnetic resonance imaging (MRI) is capable of distinguishing between atherosclerotic plaque components solely on the basis of biochemical differences. However, to date, the majority of plaque characterization has been performed by using high-field strength units or special coils, which are not clinically applicable. Thus, the purpose of the present study was to evaluate MRI properties in histologically verified plaque components in excised human carotid endarterectomy specimens with the use of a 5F catheter-based imaging coil, standard acquisition software, and a clinical scanner operating at 0.5 T. Human carotid endarterectomy specimens from 17 patients were imaged at 37 degrees C by use of an opposed solenoid intravascular radiofrequency coil integrated into a 5F double-lumen catheter interfaced to a 0.5-T General Electric interventional scanner. Cross-sectional intravascular MRI (156x250 microm in-plane resolution) that used different imaging parameters permitted the calculation of absolute T1and T2, the magnetization transfer contrast ratio, the magnitude of regional signal loss associated with an inversion recovery sequence (inversion ratio), and regional signal loss in gradient echo (gradient echo-to-spin echo ratio) in plaque components. Histological staining included hematoxylin and eosin, Masson's trichrome, Kossa, oil red O, and Gomori's iron stain. X-ray micrographs were also used to identify regions of calcium. Seven plaque components were evaluated: fibrous cap, smooth muscle cells, organizing thrombus, fresh thrombus, lipid, edema, and calcium. The magnetization transfer contrast ratio was significantly less in the fibrous cap (0.62+/-13) than in all other components (P<0.05) The inversion ratio was greater in lipid (0.91+/-0.09) than all other components (P<0.05). Calcium was best distinguished by using the gradient echo-to-spin echo ratio, which was lower in calcium (0.36+/-0.2) than in all plaque components, except for the organizing thrombus (P<0.04). Absolute T1 (range 300+/-140 ms for lipid to 630+/-321 ms for calcium) and T2 (range 40+/-12 ms for fresh thrombus to 59+/-21 ms for smooth muscle cells) were not significantly different between groups. In vitro intravascular MRI with catheter-based coils and standard software permits sufficient spatial resolution to visualize major plaque components. Pulse sequences that take advantage of differences in biochemical structure of individual plaque components show quantitative differences in signal properties between fibrous cap, lipid, and calcium. Therefore, catheter-based imaging coils may have the potential to identify and characterize those intraplaque components associated with plaque stability by use of existing whole-body scanners.

Partial versus full sternotomy for aortic valve replacement

BACKGROUND

Recent trends suggest that smaller incisions reduce postoperative morbidity. This study tests the hypothesis that a partial upper sternotomy improves patient outcome for aortic valve replacement.

METHODS

A group of 50 patients who underwent aortic valve surgery through a partial upper sternotomy (group I) were compared to 50 patients who underwent aortic valve replacement through a median sternotomy during the same time period (group II). The mean age (60+/-2 versus 63+/-2 years; mean +/- SEM) and preoperative ejection fractions (53+/-2 versus 54+/-2) were similar. Operations were performed with central cannulation, and antegrade/retrograde blood cardioplegia.

RESULTS

There was one death in each group. No differences were found in aortic occlusion time, mediastinal drainage, transfusion incidence, narcotic requirement, length of stay, or cost. The incidence of pleural and pericardial effusions was increased (18.4% versus 3.9%, p < 0.03), and the need for postoperative inotropic support was higher (38.7% versus 19.6%, p < 0.03) in the partial sternotomy group.

CONCLUSIONS

Aortic valve replacement can be performed through a partial sternotomy with results comparable to full sternotomy. The partial sternotomy offers a cosmetic benefit, but does not significantly reduce postoperative pain, length of stay, or cost.

Recent clinical experience with left heart bypass using a centrifugal pump for repair of traumatic aortic transection

OBJECTIVE

To analyze the indications, results, and limitations of using left atrial to femoral artery (LA-FA) bypass to provide distal perfusion during repair of traumatic aortic injuries.

SUMMARY BACKGROUND DATA

There is no consensus about the best method for repair of traumatic aortic transection. Distal aortic perfusion with LA-FA bypass and a centrifugal pump has been the authors' preferred technique for injuries to the aortic isthmus and descending thoracic aorta.

METHODS

From 1988 to 1998, the authors operated on 30 patients with traumatic aortic transection using LA-FA bypass. The mean age of the group was 36+/-2 years. The mechanism of injury was from a motor vehicle accident in 97% of the cases. Distal aortic perfusion was maintained at 50 to 75 mm Hg with flow rates of 1.5 and 3 L/min. The mean aortic cross-clamp time was 38+/-2 minutes, and the mean bypass time was 49+/-2 minutes.

RESULTS

No complications related to cannulation, arterial thromboembolism, renal failure, mesenteric ischemia, or hepatic insufficiency occurred. There were no cases of postoperative paraplegia and no deaths.

CONCLUSION

Left atrial to femoral artery bypass is a safe, simple, and effective adjunct to the repair of traumatic injuries to the thoracic aorta. Active distal aortic perfusion preserves spinal cord, mesenteric, and renal blood flow and eliminates the potential catastrophic consequence of spinal cord ischemia from an unexpectedly prolonged aortic cross-clamp time.

Morbidity, cost, and six-month outcome of minimally invasive direct coronary artery bypass grafting

BACKGROUND

Minimally invasive direct coronary artery bypass grafting (MIDCABG) promises to reduce the morbidity of coronary bypass, but this has not been proved.

METHODS

This retrospective study compares the morbidity, mortality, cost, and 6-month outcome of patients less than 80 years old undergoing elective left internal mammary artery to left anterior descending artery bypass grafting via MIDCABG (n = 60) or sternotomy (n = 55) between January 1995 and December 1996. There were no differences between the groups in mean age, sex distribution, or preoperative risk level. The left internal mammary artery was mobilized from the fifth costal cartilage to the subclavian artery in all patients. The anastomoses were done with a beating heart in the MIDCABG group and with cardioplegic arrest in the sternotomy group.

RESULTS

There were no operative deaths in either group. The MIDCABG patients had a lower transfusion incidence (10/60 [17%] versus 22/55 [40%]; p< or =0.02) and a shorter postoperative intubation time (2.1+/-4.2 versus 12.6+/-9 hours; p< or =0.0001). One patient in each group was reexplored for bleeding. Three sternotomy patients (3/55, 5%) required ventilatory support for greater than 48 hours, but no MIDCABG patient was ventilated for more than 24 hours. Median postoperative length of stay was 4 days for MIDCABG and 7 days for sternotomy. Estimated hospital costs were $11,200+/-3100 for MIDCABG and $15,600+/-4200 for CABG (p < 0.001). The reduced morbidity and cost of MIDCABG was found mostly in high-risk patients. At 6-month follow-up, 5 MIDCABG patients (5/60, 8%) had evidence of recurrent ischemia involving the left anterior descending artery, primarily the result of anastomotic stricture.

CONCLUSIONS

This analysis shows that MIDCABG reduces the initial morbidity and cost of coronary bypass, but some patients require subsequent reintervention. Long-term follow-up is needed before MIDCABG can be judged better than traditional bypass, but the initial results are promising, especially in high-risk patients.

A model that predicts morbidity and mortality after coronary artery bypass graft surgery

OBJECTIVES

This study was performed to develop a method for identifying patients at increased risk for morbidity or mortality after coronary artery bypass graft surgery.

BACKGROUND

Postoperative morbidity is more common than mortality and is important because of its relation to cost.

METHODS

Univariate and forward stepwise logistic regression analysis was used to retrospectively analyze a group of 1,567 consecutive patients who underwent bypass surgery between July 1991 and December 1992. We developed a model that predicted postoperative morbidity or mortality, or both, which was then prospectively validated in a group of 1,235 consecutive patients operated on between January 1993 and April 1994. A clinical risk score was derived from the model to simplify utilization of the data.

RESULTS

The following factors, listed in decreasing order of significance, were found to be significant independent predictors: cardiogenic shock, emergency operation, catheterization-induced coronary artery closure, severe left ventricular dysfunction, increasing age, cardiomegaly, peripheral vascular disease, chronic renal insufficiency, diabetes mellitus, low body mass index, female gender, reoperation, anemia, cerebrovascular disease, chronic obstructive pulmonary disease, renal dysfunction, low albumin, elevated blood urea nitrogen, congestive heart failure and atrial arrhythmias. Observed morbidity and mortality for the validation group fell within the 95% confidence interval of that predicted by the model. Costs were closely related to the incidence of postoperative morbidity.

CONCLUSIONS

Analysis of preoperative patient variables can predict patients at increased risk for morbidity or mortality, or both, after bypass surgery. Increased morbidity results in higher costs. Different strategies for high and low risk patients should be used in cost reduction efforts.

"Keyhole" coronary artery bypass surgery

OBJECTIVE

The objective of this study was to identify the utility of "keyhole" thoracotomy approaches to single vessel coronary artery bypass surgery.

SUMMARY BACKGROUND DATA

Although minimally invasive surgery is efficacious in a wide variety of surgical disciplines, it has been slow to emerge in cardiac surgery. Among 49 selected patients, the authors have used a left anterior keyhole thoracotomy (6 cm in length) combined with complete dissection of the eternal mammary artery (IMA) pedicle under thoracoscopic guidance or directly through the keyhole incision to accomplish IMA coronary artery bypass grafting (CABG) to the left anterior descending (LAD) coronary artery circulation or to the right coronary artery (RCA).

METHODS

Keyhole CABG was accomplished in 46 of 49 patients in which this approach was attempted. All patients had significant (> 70%) obstruction of a dominant coronary artery that had failed or that was inappropriate for endovascular catheter treatment (percutaneous transluminal coronary angioplasty or stenting). Forty-four of the 49 patients had proximal LAD and 5 had proximal RCA stenoses. The mean age of the patients (35 men and 14 women) was 61 years, and their median New York Heart Association anginal class was III. The mean left ventricular ejection fraction was 42%. Femoral cardiopulmonary bypass support was used in 9 (19%) of 46 patients successfully managed with the keyhole procedure. Short-acting beta-blockade was used in the majority of patients (38 of 46) to reduce heart rate and the vigor of cardiac contraction.

RESULTS

As 49 patients have survived operation, which averaged 248 minutes in duration. Median, postoperative endotracheal intubation time for keyhole patients was 6 hours with 25 of 46 patients being extubated before leaving the operating room. The median hospital stay was 4.3 days. Conversion to sternotomy was required in three patients to accomplish bypass because of inadequate internal mammary conduits or acute cardiovascular decompensation during an attempted off-bypass keyhole procedure Postoperative complications were limited to respiratory difficulty in three patients and the development of a deep wound infection in one patient. Nine (19%) of 46 patients received postoperative transfusion. There have been no intraoperative or postoperative infarctions, and angina has been controlled in all but one patient who subsequently had an IMA-RCA anastomotic stenosis managed successfully with percutaneous transluminal coronary angioplasty.

CONCLUSIONS

These early results with keyhole CABG are encouraging. As experience broadens, keyhole CABG may become a reasonable alternative to repeated endovascular interventions or sternotomy approaches to recalcitrant single-vessel coronary arterial disease involving the proximal LAD or RCA.

Intermittent hypoxia due to right atrial compression by an ascending aortic aneurysm

Two cases are described wherein right atrial compression from a dilated and elongated ascending aorta caused intermittent positional hypoxia. Extrinsic compression of the right atrium caused shunting though a patent foramen ovale.

A model for predicting transfusion after coronary artery bypass grafting

BACKGROUND

Blood conservation has become an important issue in cardiac surgery. This study was undertaken to determine if the need of blood transfusion could be predicted from preoperative patient variables.

METHODS

From January 1, 1992, to December 31, 1993, 2,033 patients having isolated coronary artery bypass grafting procedures were studied; 1,446 (71%) were male and 587 (29%), female. The mean age was 65.1 +/- 9.9 years (range, 31 to 88 years). Emergency operation, urgent operation, and reoperations were done in 78 (4%), 188 (9%), and 189 (9%) patients, respectively. In the entire group, 1,245 (61%) received transfusion during hospitalization, and 788 (39%) did not. Logistic regression analysis was used to construct a model that predicted the need of transfusion of packed red blood cells after coronary artery bypass grafting. A transfusion risk score was constructed by assigning points to independent predictive factors on the basis of the logistic regression coefficient and the odds ratio. Preoperative predictors of transfusion were emergency operation, urgent operation, cardiogenic shock, catheterization-induced coronary occlusion, low body mass index, left ventricular ejection fraction lower than 0.30, age greater than 74 years, female sex, low red cell mass, peripheral vascular disease, insulin-dependent diabetes, creatinine level greater than 1.8 mg/dL, albumin value lower than 4 g/dL, and redo operation.

RESULTS

The mean transfusion risk score for patients receiving 0, 1 to 4, and greater than 4 units of packed red blood cells was 2.3 +/- 0.9, 5.2 +/- 3.0, and 9.6 +/- 3.5, respectively (p = 0.001). Patients with a score higher than 6 had a 95% transfusion incidence. The predictive model was validated on 422 patients having coronary artery bypass grafting from January 1 to May 31, 1994. The observed rates of the validation group fell within the 95% confidence intervals of the predicted rates.

CONCLUSIONS

These data demonstrate that readily available patient variables can predict patients at risk for transfusion. Routine use of aprotinin and other adjustments of cardiopulmonary bypass should be considered to reduce transfusion in high-risk patients.

Extracorporeal membrane oxygenation: preliminary results in patients with postcardiotomy cardiogenic shock

Long-term survival at our institution for postcardiotomy cardiogenic shock patients supported with the BioPump is 36% (29/80 patients). A heparin-coated extracorporeal membrane oxygenator (ECMO), first introduced in 1991, may reduce organ injury associated with cardiopulmonary bypass. The device can be employed rapidly because it connects directly to the cardiopulmonary bypass cannula. In an effort to improve our results in the treatment of postcardiotomy cardiogenic shock, we used ECMO in 21 patients with this syndrome and accompanying complications. The patients were divided into three groups: group 1, ECMO after coronary artery bypass grafting; group 2, ECMO after mitral valve operation; and group 3, ECMO after open heart operation with prolonged cardiac arrest. Survival in group 1 was 80% with 12 of 14 patients discharged to home. All three deaths were caused by cardiac failure. Bleeding complications in this group were moderate. There was no evidence of disseminated intravascular coagulation, and levels of fibrin split products remained within the normal range. Postoperative complications included stroke (2), renal failure (1), mediastinitis (1), and prolonged respiratory failure (6). Mortality in group 2 was 100%. The major problem limiting recovery was left ventricular distention secondary to inadequate left ventricular decompression. Mortality in group 3 was 100%; all 4 died of brain death. Extracorporeal membrane oxygenation without left ventricular drainage clearly is not effective in patients undergoing mitral valve operations as it does not effectively decompress the left ventricle, but it was highly effective in treating postcardiotomy cardiogenic shock in our coronary artery bypass grafting patients. Extracorporeal membrane oxygenation also proved to be safe as the patient-related complications of stroke, renal failure, and mediastinitis were low. Our preliminary success with heparin-coated ECMO now needs to be confirmed by studies from other centers with larger groups of patients.

Operation for congestive heart failure: transplantation, coronary artery bypass, and cardiomyoplasty

Transplantation is effective therapy for congestive heart failure (CHF), but few donors are available and many patients are not candidates. We have therefore developed a surgical approach to CHF that offers several options. Patients with no medical or psychosocial contraindications are listed for heart transplantation (HT). Patients with ischemia on thallium scan and operable vessels have coronary artery bypass grafting (CABG). Patients who are not candidates for either of these options are evaluated for cardiomyoplasty (CMP). One hundred nineteen patients have now had operation for CHF: 61 had HT, 27 had CABG, and 31 had CMP. The mean ages of the three groups were 51 +/- 1 years, 59 +/- 3 years, and 56 +/- 2 years, respectively. Preoperative pulmonary capillary wedge pressure was 22 +/- 1.1 mm Hg in the HT group, 20 +/- 2.9 mm Hg in the CABG group, and 19 +/- 1.9 mm Hg in the CMP group. Left ventricular ejection fraction improved in operative survivors in each group: 0.23 +/- 0.01 to 0.69 +/- 0.01 for the HT group, 0.31 +/- 0.01 to 0.39 +/- 0.02 for the CABG group, and 0.26 +/- 0.01 to 0.33 +/- 0.03 for the CMP group (p < 0.01). The operative mortality rate was 7% for the HT patients, 4% for the CABG patients, and 16% for the CMP patients, and 1-year survival rates for those discharged were 94%, 91%, and 65%, respectively. Long-term survivors of CMP and CABG are functionally improved but still require medical therapy for CHF. Survivors of HT do not have CHF but suffer the consequences of immunosuppression.(ABSTRACT TRUNCATED AT 250 WORDS)

Extracorporeal membrane oxygenation for adult post cardiotomy cardiogenic shock using a heparin bonded system

Extracorporeal membrane oxygenation (ECMO) for adult post cardiotomy cardiogenic shock has had limited success. The efficacy of a heparin bonded ECMO system was tested in 11 patients (eight men, three women; mean age: 63 +/- 8 years), all of whom were in post cardiotomy shock refractory to inotropes and intra-aortic balloon pumping (IABP). The system consisted of a right atrial-to-aortic loop using a hollow fiber oxygenator driven by a vortex pump. All blood contact surfaces were heparin bonded. Mean duration of support was 47.9 hr (range: 22-92.5 hr). Mean prothrombin time, activated partial thromboplastin time, and activated clotting time during full support were 17 +/- 8, 57.5 +/- 38, and 152 +/- 59 sec, respectively. Mean transfusion requirements for packed red blood cells, fresh frozen plasma, and platelets were 24 +/- 9, 19 +/- 9, and 38 +/- 15 units, respectively. Complications included acute renal failure (1 patient), sepsis (3 patients), elevation of hepatic enzymes (7 patients), and myocardial infarction (11 patients). Oxygenator failure occurred in 4 patients, and 10 patients had plasma hemoglobin levels exceeding 30 mg/L. No patient experienced focal neurologic deficit. Eight (73%) patients were weaned from ECMO. Five (45.4%) of these are alive and have been discharged home with a mean follow-up of 317 +/- 76 days (range: 179-416 days). This heparin-free ECMO system allows rapid and simple deployment and provides effective short-term cardiopulmonary support.

Repeated dose administration of desmopressin acetate in uncomplicated cardiac surgery: a prospective, blinded, randomized study

The effects of single or repeated doses of desmopressin on blood loss were examined in uncomplicated cardiac surgery, while assessing the potential for thrombogenic side effects. Seventy patients undergoing elective coronary artery bypass grafting (CABG) were studied. Patients were randomized into three blinded groups: Group I received DDAVP (0.3 micrograms/kg), IV, after cardiopulmonary bypass (CPB) and 12 hours later in the Intensive Care Unit (ICU); Group II, DDAVP (0.3 micrograms/kg), IV, after termination of CPB and saline (placebo) 12 hours later in the ICU; Group III, saline (placebo) IV after CPB and 12 hours later in the ICU. Blood loss and bleeding time decreased for Group I at 24 hours (P < 0.04) when compared to Group III; however, blood product replacement, as well as intraoperative and total blood loss at 36 hours, were not different among treatment and control groups. There were four myocardial infarctions recorded in Group I, two in Group II, and one in Group III. These differences were not found to be statistically significant. It is concluded that in routine CABG the prophylactic use of single or repeat dose DDAVP does not effectively decrease blood loss or blood product replacement.

Recent experience with major sternal wound complications

During a recent 1-year period, 31 patients sustained a major sternal wound infection and sternal dehiscence developed in 6 patients. Multiple potential risk factors were tabulated in these patients and in a control group selected from 1,521 patients undergoing sternotomy during the same time period. The overall infection rate was 2.1%, and the mortality rate in the patients with sternal infection or dehiscence was 16.2%. Chronic obstructive pulmonary disease, prolonged intensive care unit stay, respiratory failure, connective tissue disease, and male sex were significantly higher in the group with sternal infection or dehiscence (p less than 0.05). Advanced age and low cardiac output episodes were more frequent in this group, but only approached statistical significance. Although several risk factors may have been interrelated, male sex and the presence of pulmonary disease were statistically independent predictors of sternal wound infection. Risk factors may be helpful in identifying high-risk patients for additional prophylactic measures.

Traumatic aortic transection: repair using left atrial to femoral bypass

Traumatic aortic transection is a life-threatening surgical emergency. Therapy must be directed at rapid repair and prevention of postoperative complications, the most serious being paraplegia. Controversy over the optimal method of repair exists-specifically whether the use of a shunt modifies the outcome. Our series of 17 patients using left atrial to femoral bypass with the Biomedicus pump will be discussed. Preoperative preparation and operative technique will be outlined. Mortality in this series was 18%, the incidence of paraplegia was 0.

Paced skeletal muscle for dynamic cardiomyoplasty

Four patients, each with a history of myocardial infarction and diffuse coronary artery disease, underwent application of left latissimus dorsi (LD) muscle with intact neurovascular bundle to the anterolateral wall of the left ventricle. The muscle was conditioned over a six-week period subsequent to operation in 3 patients and was conditioned preoperatively with a burst stimulus in the fourth. Biopsy specimens confirm the experimental data that human skeletal muscle can be electrically conditioned over a six- to ten-week period to contain mainly fatigue-resistant type I fibers. All patients survived the procedure, and 3 showed improvement secondary to aneurysmectomy. In Patient 1, a modified resection was performed, and at 28 months after operation, at the 75-W level of exercise, the ejection fraction was 54% paced versus 45% nonpaced. In Patient 2, at 12 months, the ejection fraction at rest was 44% paced versus 30% nonpaced. Doppler echo studies confirmed the presence of the flap and its function in the paced and nonpaced mode. The third patient died of a sudden ventricular arrhythmia 2 months following operation. An infected, nonfunctioning, degenerated flap was found at autopsy. Patient 4 did not have an aneurysm. She received a bypass graft to the right coronary artery and underwent cardiomyopexy in an attempt to relieve medically refractory incapacitating chronic congestive heart failure. Ten months postoperatively, ejection fraction at rest was 33% paced versus 25% nonpaced. Constrictive myopathy has not been encountered in any of these patients.

Recovery of the failing canine heart with biventricular support in a previously fatal experimental model

Prolonged normothermic ischemia in the canine model is generally fatal with standard resuscitative techniques. To determine whether such myocardial injury is recoverable with biventricular support, we subjected 10 dogs to 45 minutes of ischemia at 37 degrees C. After ischemia, the animals were supported for 24 hours with biventricular assist with the centrifugal pump. During early reperfusion, none of the hearts could sustain a stable rhythm or blood pressure. Myocardial adenosine triphosphate concentration, expressed as micromoles per gram of heart protein, was dramatically reduced from a control of 31.5 +/- 2.4 to 14.6 +/- 2.9 (p less than 0.01 versus control), a 54% reduction. Ultrastructural analysis did not reveal the explosive cell swelling of irreversible cell injury. After 12 hours of biventricular assist, developed pressure partially recovered to 60.0 +/- 10 mm Hg (p less than 0.01 versus control) and maximal positive dP/dt measured 2,649 +/- 412 mm Hg/sec (p less than 0.01 versus control). Adenosine triphosphate concentration increased to 25.2 +/- 5.5 (p less than 0.01 versus control). Electron microscopic examination showed less chromatin clumping, no further mitochondrial distortion, and more abundant glycogen. After 24 hours of biventricular assist, cardiac output in the seven dogs successfully weaned from biventricular assist measured 3.6 +/- 0.6 L/min, developed pressure recovered to 76.3 +/- 8.9 mm Hg, and its first derivative recovered to 4,282 +/- 585 mm Hg/sec (all measurements not significant compared with control). Examination by an electron microscope revealed no severe mitochondrial injury.

Paced latissimus dorsi used for dynamic cardiomyoplasty of left ventricular aneurysms

Two patients are described, each with a large left ventricular aneurysm and severe coronary artery disease, and each with an ejection fraction lower than 30% and in congestive heart failure. In both, the left latissimus dorsi (LD) muscle was used in the repair of the ventricular aneurysm because preoperative studies demonstrated that there was concomitant coronary artery disease, and there was a strong suggestion that resection of the entire aneurysm would seriously compromise the residual ventricular capacity. One patient had an 18-year history of coronary occlusion with two infarctions. A large, calcified ventricular aneurysm developed, and despite vigorous medical treatment, intractable congestive heart failure and angina persisted. The diffuse coronary artery disease made this patient a poor candidate for bypass grafting. The other patient sustained an acute myocardial infarction 5 months prior to operation. The left anterior descending coronary artery was totally occluded, and a large apical aneurysm developed along with an akinetic anterior wall and septum. After his heart attack, the patient had progressive dyspnea on exertion. Following operation in both patients, the transpositioned LD, then a component in the repair of the left ventricular wall, was electrically trained to synchronously contract with each systole, driven by a standard dual-chamber cardiac pacemaker. Steady improvement and a return to normal activities were observed in both patients. There was an indication of improved ejection fraction with synchronous contraction of the skeletal muscle.

Mechanical support of the failing heart

Mechanical ventricular assist with a centrifugal pump with or without anticoagulation for an extended period has been used in 41 patients with postcardiotomy ventricular failure. Left ventricular, right ventricular, and biventricular assist were required. The efficacy and safety of mechanical ventricular assist have been documented. Marked improvement in survival has been observed in the more recent part of this series, and is attributed to earlier employment of the assist device, maintenance of better flow rates near physiological levels, and use of biventricular assist to provide effective circulatory support. Mechanical ventricular assist is easy to use, and the conversion from ordinary cardiopulmonary bypass is also easy. Therefore, mechanical assist provides a very effective means of temporary circulatory assist.