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Biomedical subjects

L L Mickleborough

Publications and source records attributed to L L Mickleborough.

At least 19 recordsLinked to original sources
PubMed2001

Reoperative coronary bypass surgery: effect of patent grafts and retrograde cardioplegia.

OBJECTIVE: To determine the effects of patent or diseased aorta-coronary bypass grafts and retrograde cardioplegia on mortality during reoperative coronary bypass surgery. METHODS: We conducted a retrospective review of prospectively gathered data, supplemented by systematic chart review, of all patients (n = 744) undergoing reoperative coronary bypass surgery at our institution between 1990 and 1997. Independent predictors of survival were determined by stepwise logistic regression analysis. RESULTS: At least one patent or stenosed graft to the left anterior descending artery was present in 50% of patients, to the circumflex territory in 27% of patients, and to the right coronary artery territory in 33% of patients. The previous left anterior descending graft was a saphenous vein in 82% and a left internal thoracic artery in 18% of patients. In-hospital mortality occurred in 42 (5.6%) patients. Patent or diseased grafts of any coronary artery territory did not significantly increase the risk of mortality. Retrograde cardioplegia use increased in more recent years, was more frequent in patients with stenosed grafts, and was associated with improved survival. Independent predictors of mortality were as follows (with odds ratios and 95% confidence intervals in parentheses): failure to use retrograde cardioplegia (odds ratio 2.81; 1.28-6.20), New York Heart Association class (odds ratio 2.69; 1.25-5.81), peripheral vascular disease (odds ratio 2.60; 1.25-5.41), and left ventricular grade (2.07; 1.31-3.27). CONCLUSIONS: In this series, patent or stenosed grafts were not associated with an increased risk of mortality during reoperative coronary bypass surgery, possibly because of increased use of retrograde cardioplegia in this patient group. We strongly recommend the routine use of retrograde cardioplegia during redo coronary bypass surgery.

Coronary Artery Bypass↗
PubMed2001

Repair of dyskinetic or akinetic left ventricular aneurysm: results obtained with a modified linear closure.

OBJECTIVE: In patients with a dyskinetic or akinetic area of the left ventricle, controversy exists over who will benefit from resection. This study evaluates results achieved with a modified linear closure in 193 of 196 consecutive cases. Preoperative cases (n = 160 [83%]) were in functional class III or IV with congestive heart failure (n = 115 [60%]), angina (n = 108 [56%]), and syncope (n = 67 [35%]). The ejection fraction was 25% +/- 8%, and echocardiography showed significant mitral regurgitation in 86 (45%) patients. In patients with detailed wall motion analysis, 50 (57%) were akinetic, and 37 (43%) were dyskinetic. METHODS: Repair was completed on the beating heart to minimize ischemia and allow assessment of wall function and viability to guide resection and repair. Additional procedures included coronary artery bypass grafting (n = 175 [91%]), septoplasty (n = 24 [12%]), and arrhythmia ablation (n = 77 [40%]). Ventricular and mitral valve function were assessed by means of preoperative and/or postoperative gated acquisition scans in 171 (90%) patients and Doppler echocardiograms in 170 (88%) patients. RESULTS: Hospital mortality was low (5/193 [2.6%]), although 34 (18%) patients needed perioperative intra-aortic balloon pump support. Actuarial survival at 1 and 5 years was 91% and 84%. Most late deaths were due to congestive heart failure. Seven patients required transplantation (interval, 36 +/- 32 months). As determined by multivariable analysis, factors predicting poor outcome at 5 years were preoperative mitral regurgitation of 2+ or greater, congestive heart failure, and ventricular tachycardia. Among survivors, 126 (80%) of 157 were in functional class I or II, and the average increase in ejection fraction postoperatively was 9.1% +/- 10.0%. Postoperative echocardiograms in 70 patients with significant mitral regurgitation preoperatively showed improved valve function in 40 (57%) of 70 patients. CONCLUSIONS: We conclude that repair of dyskinetic or akinetic aneurysms by means of a modified linear closure plus septoplasty in selected patients can be accomplished in the beating heart with low operative mortality, provides good symptomatic relief and long-term survival, and is associated with objective evidence of improved left ventricular and mitral valve function.

Adult↗
PubMed2000

Results of revascularization in patients with severe left ventricular dysfunction.

OBJECTIVE: In patients with coronary disease and poor left ventricular function, bypass grafting remains a surgical challenge. This study evaluates experience in 125 consecutive patients with ejection fraction less than 20% (study group). METHODS: Preoperative viability studies were not used for patient selection. Clinical data were prospectively collected. The average age of the study subjects was 59 +/- 9 years, and 112 (90%) were male. Most patients (108 [86%]) were in symptom class III or IV. Main indications for surgery included angina in 62 (50%), heart failure and angina in 36 (29%), heart failure in 9 (7%), ventricular arrhythmia in 2 (2%), and critical anatomy in 16 (13%). Significant mitral regurgitation was present in 48 (38%), and distal vessels were poorly visualized in 67 (54%). At surgery, temperature mapping guided an integrated approach to cold cardioplegia. Results in this group were compared with those obtained in case-matched control subjects receiving cardioplegia without temperature mapping (matched for age, sex, functional class, and urgency of operation). RESULTS: Hospital morbidity (intra-aortic balloon pump support) and mortality rates were significantly lower in the study group versus those of control subjects (15% vs 30%, P =. 004; and 4% vs 11%, P =.03, respectively). In study patients the 5-year actuarial survival was 72%. Among survivors, both anginal class and heart failure class improved significantly. By means of multivariate analysis, survival was adversely affected by older age, class IV symptoms, and poorly visualized distal vessels. CONCLUSIONS: These results support the use of coronary artery bypass grafting in patients with severe left ventricular dysfunction without case selection on the basis of viability studies or visibility of distal vessels. Low hospital morbidity and mortality rates have been achieved when temperature mapping guides cardioplegia. Symptoms are improved in most patients, and long-term survival is encouraging.

Case-Control Studies↗
PubMed1998

Decreasing incidence of stroke during valvular surgery.

BACKGROUND: The predictors and causes of stroke after valvular surgery are incompletely defined. We examined the incidence, predictors, and mechanisms of stroke during valvular procedures over a 15-year time period. METHODS AND RESULTS: We retrospectively reviewed prospectively gathered data on 5954 consecutive patients undergoing valvular procedures at our institution from 1982 to 1996. Stroke was defined as persistent central nervous system deficit, usually with confirmatory CT imaging. Patients were divided into 3 groups according to date of operation: group 1, 1982 to 1986 (n = 1819); group 2, 1987 to 1991 (n = 2022); and group 3, 1992 to 1996 (n = 2113). Chart review was undertaken of all patients who developed stroke (n = 189). Stroke occurred in 3.8% of group 1 patients, 3.3% of group 2, and 2.6% of group 3 (P = 0.120). The decreasing incidence of stroke over time was confirmed by multivariable logistic regression analysis, in which earlier date of operation was an independent risk factor for stroke (P < 0.001). Predictors of stroke identified by multivariable logistic regression were (listed in decreasing order): (1) endocarditis (OR, 3.0; 95% CI, 1.8 to 5.0); (2) age > 74 years (OR, 2.3; 95% CI, 1.5 to 3.7); (3) earlier time period of operation (1982 to 1986: OR, 2.2; 95% CI, 1.5 to 3.2; 1987 to 1991: OR, 1.5; 95% CI, 1.0 to 2.2); (4) urgent timing (OR, 2.0; 95% CI, 1.4 to 2.8); (5) concomitant coronary bypass (OR, 2.0; 95% CI, 1.4 to 2.8); and (6) reoperation (OR, 1.7; 95% CI, 1.2 to 2.4). In more recent years of operation, we found an increasing prevalence of age > 74 years (7.4% in group 1, 9.5% in group 2, and 15.3% in group 3; P < 0.001), urgent timing (11%, 26%, and 34%, P < 0.001), and concomitant coronary bypass surgery (25%, 27%, and 33%; P < 0.001). CONCLUSIONS: The incidence of stroke during valvular surgery has decreased with time, despite an increased prevalence of risk factors. Predictors of stroke suggest 3 major causes (multivariable predictors in parentheses): atherosclerotic emboli (elderly age, concomitant coronary bypass), shock (urgent timing, reoperation), and septic emboli (endocarditis).

Aged↗
PubMed1998

Characteristics of local electrograms with diastolic potentials: identification of different components of return pathways in ventricular tachycardia.

BACKGROUND: Diastolic potentials are often sought as a possible site for catheter ablation in post-infarct ventricular tachycardia. However, delivery of energy at such sites is often unsuccessful. The purpose of this study was to determine the characteristics of local electrograms with diastolic potentials and to identify activation pattern which might indicate the critical portion of the return path of the ventricular tachycardia reentry circuit. METHODS: In 17 patients with post-myocardial infarction ventricular tachycardia, 30 ventricular tachycardias were mapped with an 112 bipolar endocardial balloon at the time of surgery. Diastolic mapping of the return tract in ventricular tachycardia was performed. Four activation patterns were observed (15 figure 8 patterns, 2 circular patterns, 2 biregional patterns and 11 monoregional patterns). Of 3,360 local electrograms, 207 (6.2%) demonstrated a diastolic potential in ventricular tachycardia. They were classified into following four categories, based on the appearance and timing of the systolic component. Type A-1 electrogram: systolic activation was of low amplitude (< 2 mV) and was prolonged (> or = 100 msec), but preceded the onset of the surface QRS in ventricular tachycardia. Type A-2 electrogram: systolic activation was of low amplitude, was prolonged, but followed the onset of the surface QRS. Type B electrogram: systolic electrogram was fractionated, but relatively normal amplitude (2.0-3.6 mV). Type C electrogram: systolic electrogram was almost normal. RESULTS: Of all electrograms with diastolic potentials, three type A-1 electrograms (1.4%) were located at the exit of the return pathway, 11 type A-1 electrograms (5.3%) were located at the pre-exit site. No type A-1 was found at an entrance/bystander area. 21 type A-2 electrograms (10.1%) were at the pre-exit and 83 type A-2 electrograms (40.2%) were located at the entrance/bystander area, but such electrograms were never found at the exit site. 71 type B electrograms (34.3%) and 18 type C electrograms (8.7%) were located at the entrance/bystander area. To distinguish the type A-2 electrograms at the pre-exit site from those at the entrance/bystander area, the diastolic potential to QRS interval was measured. This interval at the pre-exit was significantly shorter than that at the entrance/bystander area (-47.2 +/- 10.7 vs -96.3 +/- 31.3 msec, p = 0.0001). CONCLUSION: Type A-1 electrograms indicated the exit or pre-exit site of return pathway. Type A-2 electrograms with diastolic potential to QRS interval < -50 msec indicated the pre-exit site. However, the other types of local electrograms with diastolic potential did not indicate the critical portion of the ventricular tachycardia circuit. These observations may be helpful during catheter mapping and ablation of patients with post-infarct ventricular tachycardia. CONDENSED ABSTRACT: Diastolic potentials are often sought to direct catheter ablation in post-infarct ventricular tachycardia. We investigated the characteristics of local electrograms showing diastolic activity in an attempt to determine whether critical portions of the ventricular tachycardia circuit could be identified by a typical "signature." In 17 patients with a remote myocardial infarction, 30 ventricular tachycardias were mapped with 112 bipolar endocardial balloon at the time of surgery. Diastolic potentials in association with low amplitude (< 2 mV) and prolonged (> or = 100 msec) systolic electrograms preceding the onset of QRS were found at the exit site and pre-exit site of return pathway. A similar systolic electrogram occurring after QRS onset with a diastolic potential to QRS interval of < -50 msec was found at the pre-exit site. However, other local electrograms with diastolic activity were at sites remote from the exit or pre-exit of the return pathway. These observations may be helpful during catheter mapping and ablation in patients with ventricular tachycardia.

Body Surface Potential Mapping↗
PubMed1997

Right heart pulmonary embolism in transit: a review of therapeutic considerations.

Two patients with pulmonary emboli and right heart masses detected on echocardiography are described. One patient underwent successful surgical embolectomy and the other was successfully treated with intravenous thrombolysis. Both were alive and well at six months' follow-up. The presence of a right heart clot in the setting of pulmonary emboli carries a very high mortality rate and warrants urgent therapy, which may include anticoagulation, thrombolysis or surgical embolectomy. Because limited information is available, therapy must be individualized based on patient characteristics, clot location and local expertise. The pertinent literature is reviewed and relevant issues in decision making are discussed.

Aged↗
PubMed1996

Risk factors for stroke in patients undergoing coronary artery bypass grafting.

OBJECTIVE: To determine predictors of stroke in patients undergoing first-time coronary bypass grafting, we prospectively collected data on 1631 consecutive patients. METHODS: Patients with a history of stroke and/or central nervous system symptoms (n = 134) and/or carotid bruits (n = 95) underwent carotid Doppler evaluation. Stenosis greater than 70% was considered significant. Patients with symptomatic disease or asymptomatic bilateral disease were referred for combined coronary bypass and carotid endarterectomy (n = 21). Patients with neurologic symptoms after the operation were assessed by a neurologist and underwent a computed tomographic scan. Events were classified as reversible transient ischemic attack, reversible ischemic neurologic deficit, or irreversible stroke. RESULTS: There were 19 strokes (1.2%) and 20 deaths (1.2%) in this series. In patients with carotid screening, risk of stroke increased with severity of carotid disease and ranged from 0% in patients without stenosis, to 3.2% (1/31) in those with greater than 70% stenosis, and to 27.3% (6/22) in those with carotid occlusion. By stepwise logistic regression analysis six variables were identified as risk factors for stroke. The most important predictor was carotid occlusion with or without contralateral stenosis (odds ratio = 28, 95% confidence interval (8,105). In this group, four of five strokes occurred on the occluded side. Other risk factors were presence of ascending aortic disease at the time of surgery (odds ratio = 12.8, confidence interval 3,48), perioperative myocardial infarction (odds ratio = 8.2, confidence interval 2,33), poor left ventricular function (odds ratio = 4.6, confidence interval 1,19), peripheral vascular disease (odds ratio = 3.2, confidence interval 1,9), and age > 60 years (odds ratio = 2.9, confidence interval 0.8,11). CONCLUSION: We conclude that risk factors for perioperative stroke in patients undergoing coronary artery bypass grafting are multiple. Carotid scanning in patients with neurologic symptoms or carotid bruits can identify patients at increased risk. Patients with carotid occlusion are at high risk for stroke on the occluded side.

Adult↗
PubMed1995

Results of revascularization in patients with severe left ventricular dysfunction.

BACKGROUND: In patients with coronary artery disease and poor ventricular function (ejection fraction, < 20%), bypass grafting remains a surgical challenge. This study evaluates experience with isolated revascularization in such patients. METHODS AND RESULTS: In 79 consecutive patients (69 men, 10 women; average age, 59 +/- 9 years), preoperative ejection fraction was 18 +/- 5%. Indications for surgery were congestive heart failure (CHF) in 5 of 79 patients (6%), CHF and angina in 19 (24%), angina in 41 (52%), ventricular arrhythmias (VAs) in 8 (10%), and critical anatomy in 6 (8%). Some patients had prior VAs (23 of 79; 29%) or mitral regurgitation (18; 23%) and required emergent surgery (25; 32%). At surgery, temperature mapping ensured adequate distribution of antegrade cold cardioplegia, with 3.6 +/- 0.7 grafts per patient, including left internal mammary artery graft in 60 of 79 (76%) and endarterectomy in 14 (18%). Hospital mortality was 3.8%. Perioperative support included intra-aortic balloon pump in 18 of 79 (23%) and drugs for VAs in 28 (35%). Morbidity included myocardial infarction in 2 of 79 (2.5%) and stroke in 2 (2.5%). During follow-up, there were 19 late deaths. Actuarial survival was 94%, 82%, and 68% at 1, 2, and 5 years, respectively, and was similar in patients with severe angina, CHF, mitral regurgitation, or VAs. Freedom from sudden death was 100%, 98%, and 91% at 1, 2, and 5 years, respectively. Among survivors, angina improved in 84% and heart failure improved in 26%. CONCLUSIONS: These data support bypass graft surgery in patients with severe LV dysfunction. With careful cardioplegic techniques, hospital mortality was low (3.8%). Long-term survival is encouraging, with good relief of symptoms in most patients. Perioperative VAs are frequent but respond to medical treatment, with only 23% of patients discharged on antiarrhythmic drugs. Five-year freedom from sudden death is 91%, with only 3 late sudden deaths in this series.

Actuarial Analysis↗
PubMed1995

Is sex a factor in determining operative risk for aortocoronary bypass graft surgery?

BACKGROUND: This study examines trends and sex differences in characteristics of patients referred for bypass graft surgery to identify factors associated with operative morbidity and mortality. METHODS AND RESULTS: Data were collected prospectively on consecutive patients (1132 men and 355 women). Over time, the proportion of patients > 65 years old, with diabetes, or requiring urgent surgery, increased. Predictors of mortality were age > 75 years, urgent surgery, and poor left ventricular (LV) grade. Women were older (62 +/- 9 versus 59 +/- 9 years, P < .001) and had more varicose veins (18% versus 7%, P < .001), diabetes (27% versus 18%, P < .001), hypertension (48% versus 41%, P < .05), peripheral vascular disease (16% versus 12%, P < .05), and more severe angina (P < .001). There were no sex differences in prior myocardial infarction (59% versus 62%) or need for urgent surgery (17% versus 18%). Women had a higher ejection fraction (51% +/- 12% versus 47% +/- 14%, P < .001) and fewer diseased vessels (2.4 +/- 0.7 versus 2.6 +/- 0.6, P < .001) and received fewer grafts (2.9 +/- 0.9 versus 3.3 +/- 0.8, P < .001). Women had smaller body size but were no more likely to have small target vessels (< 1.5 mm). There was no sex difference in operative mortality (1.4% versus 1.1%), perioperative myocardial infarction (4.8% versus 3.5%), need for intra-aortic balloon pump (10% versus 8%), stroke (1.7% versus 1.4%), reexploration for bleeding (1.7% versus 1.7%), or leg infection (2.0% versus 1.4%). Women had fewer sternal wound infections (0.6% versus 2.2%, P < .05). CONCLUSIONS: Predictors of mortality include advanced age, decreased LV function, and need for urgent surgery. With time, despite increasing age, associated diabetes, and increased urgent surgery, operative mortality has decreased. Women were older and had more diabetes and hypertension but less extensive disease and better LV function. Bypass graft surgery was associated with equally low mortality in women and men (1.4% versus 1.1%). Concern over increased operative mortality in women should not bias referral patterns for angiography and coronary bypass graft surgery.

Aged↗
PubMed1995

Left ventricular aneurysmectomy in advanced left ventricular dysfunction.

Despite widespread application in clinical practice and extensive laboratory investigations, many basic issues regarding left ventricular aneurysmectomy remain to be resolved. Analysis of clinical data from the authors' three centers and application of powerful modern imaging techniques provide important information to resolve these issues.

Aged↗
PubMed1995

Ventricular arrhythmias in heart failure.

The management of ventricular arrhythmias in patients with heart failure continues to pose many challenges. Three principles of therapy can be identified: (1) Empiric therapy is not warranted for asymptomatic ventricular arrhythmias. (2) Therapy for asymptomatic ventricular arrhythmias must be individualized. Appropriate management of the underlying cardiac disease is critical, and careful identification of therapeutic goals is necessary. (3) Patients at high risk should be included in prospective, controlled clinical trials whenever possible.

Anti-Arrhythmia Agents↗
PubMed1995

Surgical management of left ventricular aneurysms.

Criteria to identify the presence or absence of a resectable left ventricular aneurysm at the time of surgery are defined. Hemodynamic compromise resulting from aneurysm formation is discussed. The symptoms and natural history of patients with a left ventricular aneurysm are reviewed, and an argument is made for early aneurysm resection before severe left ventricular distention and decompensation occur. Various repair techniques are reviewed, with special attention given to the modified linear closure technique favored by the author, which allows the entire repair to be completed before aortic cross-clamping, thus keeping ischemic time to a minimum. The influence of aneurysm repair on concomitant mitral regurgitation is discussed. Postoperative complications and early and late results are reviewed. It is concluded that with proper patient selection and improved operating room techniques, ventricular aneurysm resection can be performed with low operative mortality, good symptomatic improvement, and excellent 5-year survival.

Aneurysm, False↗
PubMed1994

Are patients receiving amiodarone at increased risk for cardiac operations?

Amiodarone therapy has been implicated as a risk factor for cardiothoracic surgical procedures. In patients undergoing map-guided surgical procedures for the treatment of ventricular tachycardia, we compared the perioperative course of those receiving long-term amiodarone therapy (n = 36) versus that in those not receiving the drug (n = 31). The two groups were similar with respect to age, sex, presenting symptoms, functional class, extent of coronary artery disease, presence of a ventricular aneurysm, technique of ventricular tachycardia ablation, cross-clamp or pump time, the number of vessels grafted, the operative fluid balance, and a need for intraaortic balloon pump or inotropic agent support. In 5 patients receiving amiodarone, epinephrine was required to maintain a normal systemic vascular resistance and adequate arterial pressure. Postoperatively, 6 patients (17%) on amiodarone therapy suffered acute respiratory failure. In spite of aggressive therapy, 3 of these patients died. Only 1 patient not receiving amiodarone died of a stroke. We conclude that amiodarone therapy in patients undergoing open heart operations is associated with an increased risk of severe pulmonary complications (p = 0.03 by Fisher's exact test). Amiodarone therapy should be withheld in patients with ventricular tachycardia until they have been assessed as candidates for possible surgical intervention.

Aged↗
PubMed1994

"Concealed" rupture of the left ventricle: successful surgical repair.

A 70-year-old woman with a history of angina and hypertension presented with a large anterior infarct complicated by rupture and tamponade. Angiography showed triple-vessel disease and a large anteroapical aneurysm. Operative findings included extensive dissection of the septum and rupture of the right ventricular free wall. The patient survived the operation, which included replacement of the left ventricular free wall, extensive patching of the septum, and plication of the infarcted right ventricle.

Aged↗
PubMed1994

Conductance catheter measurements of left ventricular volume in the intact dog: parallel conductance is independent of left ventricular size.

OBJECTIVE: It has recently been suggested that conductance catheter parallel conductance (alpha Vc) is a function of left ventricular volume. To confirm this, alpha Vc was measured in this study over a wide range of steady state volumes. In addition, conductance derived volumes were compared to those obtained by radionuclide angiography to determine if the conductance catheter can be used to measure absolute left ventricular volume accurately in the intact dog heart. METHODS: Seven dogs were anaesthetised and instrumented with left ventricular conductance and pressure tip catheters, a flow through rho cuvette to continually measure blood resistance, a thermodilution catheter, and a venous catheter for volume infusion/withdrawal. Conductance and angiographic data were acquired at 8(SD 1) variably loaded states. Parallel conductance was measured twice at each state using a saline dilution technique and a new non-linear algorithm that allows variability in the observations of both maximum and minimum conductance volumes. RESULTS: The mean value of alpha Vc was 89.1(18.0) ml (71.8 to 111.3 ml) with a mean within-animal coefficient of variation of 7.3(3.4)%. Multiple linear regression using dummy variables to account for the large interanimal variability did not reveal any relationship between alpha Vc and either maximum or minimum left ventricular volume. Furthermore, no difference was found when alpha Vc values measured at the lowest and highest loading levels in each dog were compared. Linear regression showed good agreement between conductance and radionuclide derived end diastolic volumes (slope = 0.94, R = 0.9, p < 0.001). CONCLUSIONS: While alpha Vc varies between animals, it remains constant within any given animal over a broad range of left ventricular volumes. Thus the conductance catheter can provide reliable absolute left ventricular volume measurements under steady state conditions.

Animals↗
PubMed1994

Balloon electric shock ablation. A surgical technique for treatment of ventricular tachycardia: influence of endocardial scar on depth of ablation achieved.

Balloon electric shock ablation is a surgical technique that has been used for treatment of ventricular tachycardia. However, little is known about the energy requirements and precise electrode array best suited to achieve effective ablation of the target area while limiting injury to the surrounding myocardium. This study was designed to determine the effects of endocardial scar (often present at the "site of origin" of clinical ventricular tachycardia) on depth of ablation resulting from balloon electric shock ablation. A chronic canine model of endocardial scar (3.9 +/- 0.6 mm thick) was developed with the use of balloon electric shock ablation techniques. We compared depth of ablation achieved with balloon electric shock ablation with low-energy shocks (22 J per bead) in normal dogs versus those with chronic endocardial scar. No difference was found in depth of ablation in normal dogs and in the scar model (7.2 +/- 1.2 mm versus 6.2 +/- 1.0 mm). Depth of injury expressed as a percentage of wall thickness was not different in the two groups (61% +/- 11% versus 57% +/- 3%). We conclude that the presence of endocardial scar does not influence depth of injury resulting from balloon electric shock ablation. This data provides guidance for clinical application of the technique as a "closed heart" surgical approach for control of ventricular tachycardia. The data are also discussed in relation to energy levels currently used for direct current catheter ablation in patients with ventricular tachycardia.

Animals↗