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Transvenous lead extraction can have serious adverse events, such as cardiac or vascular perforation. Risk factors have not been well characterized.The purpose of this study was to identify factors associated with perforation and death, and to characterize lead extraction in a large contemporary population.We performed a retrospective multicenter study examining patients undergoing lead extraction at 8 Canadian institutions from 1996 through 2016. Demographic and clinical data were used to identify variables associated with perforation and mortality using logistic regression modeling.A total of 2325 consecutive patients (age 61.9 ±16.5 years) underwent extraction of 4527 leads. Perforation rate was 2.7% (63/2325) and 30-day mortality was 1.6% (38/2325), with mortality of 0.4% due to perforation (10/2325). Variables associated with perforation included no previous cardiac surgery (odds ratio [OR] 3.33; 95% confidence interval [CI] 1.54-7.19; P = .002), female sex (OR 3.27; 95% CI 1.91-5.60; P.001); left ventricular ejection fraction ≥40% (OR 2.81; 95% CI 1.28-6.14; P = .010); lead age8 years (OR 2.64; 95% CI 1.52-4.60; P.001); ≥2 leads extracted (OR 2.49; 95% CI 1.23-5.04; P = .011); and diabetes (OR 2.12; 95% CI 1.16-3.86; P = .014). Variables associated with death included infection as indication for extraction (OR 3.85; 95% CI 1.38-10.73; P = .010); anemia (OR 3.14; 95% CI 1.38-6.61; P = .003), and patient age (OR 1.04; 95% CI 1.01-1.07; P = .012).Risk factors associated with perforation in lead extraction include no history of cardiac surgery, female sex, preserved left ventricular ejection fraction, lead age8 years, ≥2 leads extracted, and diabetes.

Background— Injuries to cardiac and venous structures during pacemaker and defibrillator lead extraction are serious complications that have been studied poorly. The incidence of these injuries is unknown but likely underestimated. No systematic multicenter review of these injuries or their management has been undertaken. Methods and Results— We interrogated our mandatory administrative database for all excimer laser extractions that sustained a cardiac or venous injury in the province of British Columbia. Injuries were classified according to presentation and compared with respect to nature of injury, type of repair, utilization of cardiopulmonary bypass, and outcome. Of 1082 excimer laser extractions over 19 years, 33 sustained an injury (3.0%). The majority of injuries occurred in women (21/33; 63.6%), and median age of oldest lead extracted was 10.8 (7.5, 12.2) years. A type 1 presentation, defined as circulatory collapse, was found in 12/33 patients (36.4%). A type 2 presentation, defined as progressive hypotension responsive to treatment, was found in 20/33 patients (60.6%). Over half the patients had a moderate or large injury, and cardiopulmonary bypass was required in 13 patients with extensive injury. Despite the presence of devastating injuries, the immediate availability of aggressive salvage measures resulted in a survival of 87.9% of patients at 30 days. Conclusions— The immediate availability of a cardiovascular surgeon, perfusionist, and cardiopulmonary bypass pump facilitates lifesaving repair of injuries sustained during laser lead extraction. The size and complexity of injury correlates closely with the presentation, blood loss, and need for cardiopulmonary bypass to facilitate repair.

Despite the widespread and growing use of implantable cardioverter-defibrillators (ICDs), little information is available regarding their performance or the impact of advanced pacing functions on ICD reliability and longevity.The purpose of this study was to examine the performance of contemporary ICD pulse generators that failed or were replaced because of manufacturers recalls.ICD data were entered prospectively by nine participating centers. ICD pulse generator failure was defined as removal from service because the device was not functioning according to the manufacturer's specifications. A recalled ICD was a normally functioning pulse generator that was replaced as the result of a recall or advisory.From 1998 to 2005, 1,220 ICDs failed and 135 were recalled and replaced. The average implant time of failed ICDs was 4.4 +/- 1.5 years and of recalled ICDs was 1.7 +/- 0.8 years. The average implant time of single- and dual-chamber ICDs with rate responsive or cardiac resynchronization (CRT-D) pacing capabilities was significantly shorter than the average implant time of single- or dual-chamber devices without these features (P.001). ICDs that provided rate responsive or CRT-D pacing failed earlier because of battery depletion (P.001) and were significantly more prone to unexpected electronic or housing failure (9% vs 5%, P = .008) and recalls (25% vs 1%, P.0001). Major adverse events included death (n = 2), failure to convert ventricular tachyarrhythmias (n = 6), and inappropriate shocks (n = 11).Based on our analysis of failed and recalled devices, the performance of contemporary ICDs has been adversely affected by premature battery depletion, electronic failure, and manufacturers' recalls. Additional studies are needed to precisely estimate ICD longevity and to determine the incidence of unexpected ICD failure.

Hauser, R., et al.: Unexpected ICD Pulse Generator Failure Due to Electronic Circuit Damage Caused by Electrical Overstress. Because it is a lifesaving device, the unexpected failure of an ICD can be catastrophic. We report ICD electronic circuit failure due to electrical overstress damage (EOS) to the high voltage hybrid circuit and other electronic components in a series of ICD pulse generator models. Data were obtained from the Multicenter Registry of Pacemaker and ICD Pacemaker and Lead Failures, and from the manufacturers' adverse event reports, that were in the FDA's Manufacturer and User Facility Device Experience (MAUDE) database. Of 16 nonbattery Guidant/CPI ICD pulse generator failures reported to the registry, 6 (38%) have been confirmed by the manufacturer to be EOS related, and Guidant/CPI has reported 273 such failures to the FDA as of 12/29/00. The signs of failure included loss of telemetry and inability to deliver therapy, and some patients have experienced serious adverse events. Hybrid circuit damage may have occurred during capacitor charging or reform, and the majority appears to have happened during normal ICD function. While the incidence of this problem is unknown, a management strategy should be adopted that includes routine follow-up every 3 months and device evaluation after a shock or exposure to external defibrillation or electrosurgical devices. This study suggests that additional data are needed to determine the incidence of this problem, and that our present methods for monitoring the performance of ICDs following market release are inadequate.

Objective: The British Columbia Provincial Cardiac Registry collects demographic and clinical data on all patients who undergo cardiac surgery procedures in the province. The purpose of this study was to compare the reliability of data contained in the Registry with data contained in hospital charts. Methods: Registry and hospital charts were compared for 480 cases. Thirty cases were randomly selected for the province's 16 cardiac surgeons. For each case, 10 distinct fields were selected for analysis and classified as consistent, inconsistent, or rejected (data unavailable in one or other source). Results: The overall rate of consistency between charts and the Registry was 86.4%, with an inconsistency rate of 9.9% and a rejection rate of 3.7%. Consistency rates varied significantly across the 10 fields and among the 16 surgeons. Pairwise comparisons of rates between fields indicated that specific field types were problematic and should be targeted for improvement. In addition, pairwise comparisons of rates between surgeons indicated that further education on Registry use is required. Conclusions: Recommendations for database design and management include provision of standard definitions for all fields; education of users; extension of the number of mandatory fields; revision of check-off box fields to yes/no/unsure fields; and collection of data close to the time that it is generated. (J Thorac Cardiovasc Surg 1997;114:903-10)

BACKGROUND Primary cardiac tumors are infrequent, and few cardiac surgeons have extensive experience in treating them. The majority of the tumors are benign. As noninvasive diagnostic imaging of cardiac masses continues to improve, the number of these tumors that are seen by clinicians will increase. More of the malignant tumors may be curable if detected at an earlier stage. METHODS A retrospective review was conducted of all patients with primary cardiac tumors managed by a university teaching center over a period of 40 years, using hospital medical records and a Provincial cardiovascular surgery database. RESULTS Seventy-one patients (25 males and 46 females) with primary cardiac tumors were identified. Fifty-seven (80%) were benign masses and 14 (20%) were malignant masses. Twenty-eight percent of the tumors in men were malignant (7 of 25) compared with only 15% in women (7 of 46). Seventy-two percent of the masses were located in the left atrium. Forty-three percent of tumors in the right atrium were malignant (6 of 14) compared with only 14% in the left atrium (7 of 51). Complete resection was possible for 50 of 52 benign atrial tumors (96%) but for only 5 of 14 malignant tumors (36%). There was one perioperative death (1.4%). Three patients had no surgery because of their poor medical condition. Two of the patients with unresectable malignant tumors were still alive at last follow-up. The remaining 12 patients with malignancy have all died of their disease. CONCLUSIONS Primary cardiac tumors are uncommon. Most patients present with symptoms of congestive heart failure. The second most common presenting symptom is embolization. Improvement in noninvasive diagnostic technology has increased the number of patients identified with a primary cardiac tumor and has also increased the number referred for surgical resection. The majority of left atrial tumors were benign, whereas up to one-half of tumors found in the right atrium were malignant. A greater proportion of malignant primary tumors were found in men than in women. Malignant cardiac tumors tend to be diagnosed after they have become extensive and the patients already have a very grave prognosis. Cancer 1997; 79:1809-15. © 1997 American Cancer Society.

The Carpentier-Edwards supra-annular porcine bioprosthesis has been utilized at the University of British Columbia since its introduction in 1982. The prosthesis was designed to improve hemodynamics with the supra-annular configuration and to reduce tissue failure with low-pressure glutaraldehyde preservation of the porcine aortic tissue. The prosthesis was inserted in 1,956 patients with 2,129 prostheses between 1982 and 1989. The mean age of the patient population was 62.7 years (range 13 to 87 years). The mean follow-up was 3.7 years per patient. The freedom from thromboembolism and antithromboembolic therapy-related hemorrhage at 8 years was 92% for aortic valve replacement (AVR), 83% for mitral valve replacement (MVR), and 92% for multiple valve replacement (MR) (p less than 0.05, AVR greater than MR greater than MVR). The freedom from structural valve deterioration was 86% for AVR, 73% for MVR, and 96% for MR at 8 years (p less than 0.05, AVR greater than MR greater than MVR). The freedom from nonstructural valve dysfunction and prosthetic valve endocarditis was not different between positions (p = NS). The freedom from valve-related mortality at 8 years was 98% for AVR, 94% for MVR, and 98% for MR (p less than 0.05, AVR greater than MR greater than MVR). The freedom from residual morbidity was not different at 8 years (p = NS). The freedom from treatment failure (valve-related mortality and residual morbidity) was 96% for AVR, 89% for MVR, and 94% for MR (p less than 0.05, AVR greater than MVR greater than MR).(ABSTRACT TRUNCATED AT 250 WORDS)

Knowledge of major adverse clinical events (MACE) associated with ICD and pacemaker (PM) pulse generator (PG) and lead performance may be important for managing patients who have these devices. The aim of our study was to assess MACE in our Multicenter Registry. Participating centers prospectively reported ICD and PM PG and lead failures, and PG replaced for normal battery depletion (NBD). Data included dates of implant and removal, failure signs including the elective replacement indicator (ERI), clinical consequences, and reason for removal. MACE were death, inappropriate shocks (IAS), syncope, heart failure, ischemia, sustained tachyarrhythmias, and replacement of a normally functioning PG or lead due to a manufacturers recall. Since 1998, 6,291 ICD and PM PG and leads were removed from service. Of 5,212 ICD and PM PGs, 4,562 (88%) were removed for NBD, 346 (7%) for a recall, and 304 (5%) for component defects. MACE are shown in the Table . The deaths (n=2) were due to component defects causing an ICD PG to short-circuit and a PM PG to deliver high rate pacing. Thus, of the 304 component defects in our database, 2 resulted in death (0.7%). No deaths were associated with ICD or PM lead failure, but 2 deaths occurred following PM lead extraction. The ERI, signifying NBD, resulted in 48 MACE, primarily syncope (67%). Most MACE are due to replacement of normally functioning recalled devices. However, our experience suggests that death due to ICD and PM PG component or lead failure is rare; this finding may be important for managing patients who have recalled devices. Overall, MACE may be substantially reduced by improving high voltage lead reliability, and by providing physiologic ERIs.

A detachable latex balloon was used to occlude an iatrogenic aortocoronary arterio-venous fistula. The aim of providing retrograde myocardial perfusion was not achieved to any significant degree because of rapid recruitment of collateral venous routes to the coronary sinus. This may have implications for the effectiveness of deliberate grafting of the coronary venous system with proximal venous ligation, as has been recommended when the coronary arterial system is small and diffusely diseased.

Pacemakers have improved the lives of patients worldwide. Unfortunately, the medical community has had little independent information regarding the performance of these vital medical devices.The purpose of this study was to examine the reasons pacemaker pulse generators and transvenous leads were removed from service. We evaluated the causes and major adverse clinical events associated with device end-of-service life behavior and how they were detected and managed.Pulse generator and lead data were entered prospectively using a web-based format. Normal battery depletion was signified by the elective replacement indicator appearing3 years after implant. Lead failure was a device defect causing pacing, sensing, or fixation malfunction, high threshold, or abnormal impedance. Major adverse clinical events were death, angina, heart failure, syncope, and perioperative surgical complications.From 1998 to 2006, 2,652 pulse generator and 615 leads were removed from service. The average pulse generator was implanted for 7.3 +/- 3.1 years (range1 day to 26 years). The majority of pulse generators (n = 2,317 [87%]) were replaced for normal battery depletion. Severe and accelerated battery depletion, manufacturers' advisories, and electronic or connector defects accounted for 13% of pulse generator removals. The proportion of pulse generators removed from service as a result of manufacturers' advisories, electronic failure, and housing defects were 4%, 2%, and 1%, respectively. Models with rate response capability had shorter battery longevities than those without rate response capability. Major adverse clinical events due to pulse generator end-of-service life behavior were related to electronic and connector defects, and both normal and severe battery depletion. Median time to lead failure was 7.2 +/- 5.2 years. Insulation defects caused the majority of lead failures, and most of these leads used polyurethane materials. Lead failure was associated with a 16% incidence of major adverse clinical events. No major adverse clinical events occurred when impending lead failure was detected at routine follow-up. Lead extraction was associated with a 5.6% complication rate, including one death.Overall pulse generator performance was satisfactory. Differences in battery longevity were observed among models. In some patients, elective replacement indicators signifying normal battery depletion resulted in major adverse clinical events. Pacemaker follow-up effectively identified pulse generator end-of-service life and often detected impending lead failure, thus avoiding major adverse clinical events. Long-term studies are needed to assess chronic lead performance so that appropriate clinical management strategies, including recommendations for lead extraction, can be developed.

The Canadian trial of physiologic pacing (CTOPP), published in 2000, demonstrated a reduction in atrial fibrillation (AF), stroke and death with preservation of atrioventricular synchrony, though only the lower rate of AF was statistically significant. The purpose of this study was to determine the effect of CTOPP on pacing mode selection in our region. The British Columbia Cardiac Registry contains prospectively entered data covering a population of 4 millions (M) and 17 implanting centers. It was examined for mode selection trends from 1997 to 2002. At examination, there were data on 22,446 pulse generators (PG) and 29,898 leads. New implant rates per M population were 1997:473; 1998:456; 1999:505; 2000:513; 2001:486; 2002:510. PG replacements also increased, resulting in a total implant rate of 667 PG per M in 2002. Over the 6-year period, DDD use decreased from 321 to 306, but DDDR use, more than doubled from 317 to 750 PG/year. VVI use steadily decreased from 741 to 410 PG/year, while VVIR use increased more modestly from 1997 to 1999, then remained stable. During the 6-year period bracketing CTOPP, use of modes maintaining AV synchrony increased by over 32%, to 53% of PG implanted in 2002. Our PG implant rate was much higher than expected from prior retrospective surveys, and similar to rates in Belgium, France, and Germany. CTOPP did not decrease our use of physiologic pacing but, instead, was associated with a brief pause, then progressively increased in both academic and community centers. Patients' need and widely accepted standards of care proved more important in clinical decision making than the results of a flawed randomized trial.

HAUSER, R.G., ET AL.: Long-Term Structural Failure of Coaxial Polyurethane Implantable Cardioverter Defibrillator Leads. Transvene models 6936/6966, a coaxial polyurethane ICD lead, may be prone to structural failure. These models comprise 54% of ICD lead failures in the authors' Multicenter Registry database. Because ICD leads perform a vital function, the clinical features, causes, and probability of Transvene 6936/6966 lead failure were determined. The Registry and United States Food and Drug Administration databases were queried for the clinical features and structural causes of the Transvene 6936/6966 lead failure, and a five-center substudy estimated the survival probability for 521 Transvene 6936/6966 implants. The mean time to failure was 4.8 ′ 2.1 years, and the estimated survival at 60 and 84 months after implant were 92% and 84%, respectively. Oversensing was the most common sign of failure (76%), and 24 patients experienced inappropriate shocks. The manufacturer's reports indicated that high voltage coil fracture and 80A polyurethane defects were the predominant causes of lead failure. Transvene models 6936 and 6966 coaxial polyurethane ICD leads are prone to failure over time. Patients who have these leads should be evaluated frequently. Additional studies are needed to identify safe management strategies.

Objective: The experience with the St. Jude Medical (SJM) and CarboMedics (CM) bileaflet mechanical prostheses was evaluated to determine thromboembolic and hemorrhagic complications and predictive risk factors. Methods: From 1989 to 1994, a total of 246 patients had multiple valve replacement (SJM, 140; CM, 106); concomitant procedures 20.3% (50) [coronary artery bypass 10.6% (26)] and 53.7% (132) previous cardiac surgery, primarily valve replacement procedures. The pre-operative variables [coronary artery disease, previous cardiovascular surgery, concomitant procedures, valve lesion (except mitral stenosis), status, atrial fibrillation, and NYHA III:IV] did not distinguish the prosthesis-type (pNS). Results: The prosthesis-type and the pre-operative variables, including atrial fibrillation, were not predictive of overall thromboembolism (TE). The linearized rate of total TE events for overall multiple replacements (MR) was 5.4%:patient-year (minor, 2.52; major 2.85); the total TE for CM and SJM was 5.4%:patient-year, respectively. The 530 day major TE crude rate was 0.82%, while the \ 30 day major event rate was 2.7%:patient-year. Of the total (major and minor) TE events 100% (3) of 5 30 days and 72% (29), \ 30 days had an INR B2.5 at or immediately prior to the event. The thrombosis rate (included in total TE events) was 0.67%:patient-year (4 events, 100% INR B2.5). Of the various TE event categories the prosthesis-types (CM and SJM) were not differentiated (pNS). The freedom, at 5 years, from major:fatal TE, thrombosis and hemorrhage from anticoagulation was 89.39 3.8% for CM and 87.99 3.7% for SJM and, 91.393.5% and 89.393.7%, respectively, (pNS) exclusive of early events. Conclusions: The performance of the CarboMedics and St. Jude Medical prostheses in multiple valve replacement surgery in this non-randomized prospective study revealed no significant differences in performance with regard to thromboembolic and hemorrhagic complications. © 1998 Elsevier Science B.V. All rights reserved.

The role of porcine bioprostheses in cardiac valve replacement has been under review for several years. The literature deals primarily with age as a determinant of durability, as well as the intermediate-term performance of various prostheses. The performance of the Carpentier-Edwards first-generation standard porcine bioprosthesis is presented over the long-term with further documentation on age determinants.The "Guidelines for Reporting Morbidity and Mortality After Cardiac Valvular Operations" were used for definitions of valve-related complications, categorization, and statistical methods. The valve-related complications were evaluated in a time-related manner by actuarial life-table techniques. The Lee-Desu statistic test was used for comparison of performance by valve positions and age groups. Hazard function rates were demonstrated for complications and composites.Of the Carpentier-Edwards porcine bioprostheses implanted in 1,195 patients (1,214 operations, 1,315 valves) commencing in 1975 the early mortality was 7.6% (92). The early mortality without concomitant procedures was 6.1% and with 11.7%. The late mortality was 5.3% per patient-year; 4.6% patient-year without and 7.5% per patient-year with concomitant procedures. The valve-related causes of late mortality (131) were thromboembolism (41), antithromboembolic hemorrhage (14), prosthetic valve endocarditis (20), nonstructural dysfunction (12), and structural valve deterioration (44). The valve-related deaths (early, 7; late, 124) were 21.2% of the total 617 total deaths. Reoperation for valve-related complications was performed in 406 patients (4.1% per patient-year), of which 327 were for structural valve deterioration (3.3% per patient-year). Mortality for reoperation was 0.5% per patient-year (49 patients) or 12.1%. Of the 49 deaths, 33 were caused by structural valve deterioration. The linearized occurrence rate for thromboembolism was 1.6% per patient-year (major, 0.9% per patient-year, and minor, 0.7% per patient-year). The fatal thromboembolic rate was 0.4% per patient-year (41), undifferentiated by valve position. The freedom from thromboembolism was 76% at 17 years (p = not significant by valve position) (major, 87%; fatal, 93%). The freedom from prosthetic valve endocarditis was 92% at 17 years (p = not significant by valve position). The freedom from reoperation, at 15 years, was 38%: aortic (AVR), 55%; mitral (MVR), 20%; and multiple valve replacement (MR), 24% (p0.05 AVRMVR, MR). The freedom from structural valve deterioration, at 15 years, was 41%; AVR, 58%; MVR, 21%; MR, 36% (p0.05 AVRMVR, MR). The freedom from structural valve deterioration was greater for advancing age groups (p0.05); AVRor = 70 years 96% at 12 years, and 65 to 69 years 94% at 12 years and 82% at 15 years; MVRor = 70 years 85% at 12 years, and 65 to 69 years 54% at 12 years. The freedom from valve-related mortality was 73% at 17 years: AVR, 80%; ; MVR, 61%; and MR, 67% (p0.05 AVRMVR, MR). The freedom valve-related residual morbidity was 94% (p = not significant by valve position).The Carpentier-Edwards standard porcine bioprosthesis continues to provide satisfactory clinical performance to 17 years. Thromboembolism is a more serious problem than structural failure: 92 major thromboembolic events with 41 fatalities compared with 44 fatalities of which 33 occurred with reoperation. The prosthesis is especially recommended for patients more than 65 years of age for AVR and more than 70 years of age for MVR.

The Carpentier-Edwards standard porcine bioprosthesis was implanted in 1,195 patients in 1,213 operative procedures between 1975 and 1987, with the majority of implants performed prior to 1982 at the University of British Columbia. The mean age of the patient population was 57.2 years (range 8 to 85 years). The mean follow-up was 7.4 years per patient. The freedom from the combination of thromboembolism and antithromboembolic therapy-related hemorrhage at 15 years was 79.5% for aortic valve replacement (AVR), 72% for mitral valve replacement (MVR), and 84% for multiple valve replacement (MR) (p less than 0.05, AVR greater than MR greater than MVR). The freedom from structural valve deterioration at 15 years was 71% for AVR, 41% for MVR, and 41% for MR (14 years) (p less than 0.05, AVR greater than MVR greater than MR). The freedom from nonstructural dysfunction and prosthetic valve endocarditis did not distinguish the valve positions (p = NS). The freedom from valve-related mortality from all causes including reoperation was 92% for AVR, 78% for MVR, and 77% for MR at 15 years (p less than 0.05, AVR greater than MVR greater than MR). The freedom from residual morbidity was not significantly different between valve positions (p = NS). The freedom from treatment failure (valve-related mortality and residual morbidity) at 15 years was 87% for AVR, 72% for MVR, and 75% for MR (p less than 0.05, AVR greater than MR greater than MVR). The freedom from all complications at 14 years was 50% for AVR, 25% for MVR, and 27% for MR (p less than 0.05, AVR greater than MR greater than MVR).(ABSTRACT TRUNCATED AT 250 WORDS)

Cystosarcoma phyllodes is an uncommon breast tumor that rarely metastasizes. A case of dumbbell cystosarcoma phyllodes metastatic to the heart and lung diagnosed antemortem is described. The roles of diagnostic echocardiography and surgical excision are discussed. Atrial extension of a lung malignancy through a pulmonary vein is not an absolute contraindication to operation, but careful patient selection and operative planning are required.

In one third of patients requiring permanent cardiac pacing, sinoatrial response to exercise is inadequate. This has led to the development of a number of nonatrial sensors capable of increasing stimulation rate in response to metabolic demand. Initial sensor-modulated pacemakers were designed for use in the ventricle. This review was undertaken to compare ventricular rate-adaptive pacing with dual chamber and nonrate-adaptive atrial modes. Rate-adaptive ventricular pacing is primarily indicated in patients with complete heart block and nonfunctional atria in whom increased rates are not associated with the development of myocardial ischemia or retrograde conduction. A responsive atrium remains the best measure of metabolic demand, and devices capable of maintaining atrioventricular (AV) sequencing provide superior hemodynamic performance at usual activity levels. In addition, preserved AV relations reduce the incidence of new atrial fibrillation and stroke. Newer devices combining the advantages of atrial and nonatrial rate modulation with the preservation of AV synchrony will best utilize the developing sensor technologies.

The Carpentier-Edwards standard porcine bioprosthesis was implanted in 1,000 operations (988 patients with 1,092 valves) between 1975 and 1981. The mean age of the patients was 56.8 years (range 8 to 85 years). During the years 1975 and 1981, approximately 97% of the total valvular surgery population received the prosthesis. The early mortality was 7.8% (including patients with concomitant procedures including coronary artery bypass and ascending aortic aneurysm resection). Late mortality was 3.8% per patient-year. The total cumulative follow-up was 5,937 years. Thromboembolism (TE) was 1.3% per patient-year (fatal 0.4%/patient-year) (minor 0.4%; major 0.9%); antithromboembolic therapy-related hemorrhage (ATH) 0.5% (fatal 0.1%); prosthetic valve endocarditis (PVE) 0.5% (fatal 0.2%); periprosthetic leak (PPL) 0.4% (fatal 0.2%); clinical valve dysfunction (CVD) 0.2% (fatal 0.02%); and structural valve deterioration (SVD)/primary tissue failure 1.6% per patient-year (fatal 0.2%/pt-yr). Thromboembolism and SVD occurring primarily between the sixth and tenth year of evaluation, were the significant complications. The overall patient survival was 60.5% +/- 2.4% at 10 years. The patients were classified as 93.5% NYHA functional Class III and IV, preoperatively and 93.1% Class I and II, postoperatively. The freedom at 10 years from TE was 82.9% +/- 2.7%; SVD 76.9% +/- 2.9%; and reoperation 70.8% +/- 3.1%. Freedom from all valve-related complications at 10 years was 54.3% +/- 3.1%; valve-related mortality 86.4% +/- 2.3%; mortality and reoperation (valve failure) 64.0% +/- 3.2%; mortality and residual morbidity (treatment failure) 82.3% +/- 2.6%; and mortality, residual morbidity, and reoperation (valve failure and dysfunction) 60.6% +/- 3.2%. There were 61 valve-related deaths of a total 352 deaths (early 7, late 54) (TE 21; ATH 7; CVD 1; PVE 12; PPL 9; and SVD 11). Valve-related reoperations were performed in 128 patients (TE 3; CVD 4; PVE 14; PPL 17; and SVD 90). The standard Carpentier-Edwards porcine bioprosthesis has provided very satisfactory clinical performance and afforded patients excellent quality of life. Primary tissue failure is the significant long-term complication.

The Carpentier-Edwards porcine bioprosthesis compares favorably to other value substitutes, with a low incidence of valve-related complications after up to 6 years' follow-up. From April, 1976, to February, 1978, 397 prostheses were implanted in 355 patients at the University of British Columbia and the Montreal Heart Institute: aortic valve replacement (AVR), 155; mitral valve replacement (MVR), 154; tricuspid valve replacement (TVR), five; multiple replacement (MR), 41 patients. Previous cardiac operations had been performed in 58 patients (16.3%). Concomitant cardiac procedures, including myocardial revascularization, were performed in 66 patients (18.5%). The 30 day mortality was 8.7% (31 patients (AVR, 4.5%; MVR 9.0%; TVR 20%; MR 21.9%). The cumulative follow-up was 1,367 patient-years (range 6 to 81 months, mean 51 months). The late mortality is 3.9% per patient-year (AVR 3.4%, MVR 3.6%, MR 6.3%). The long-term valve-related complication rates (expressed as percent per patient-year and number of events) are as follows; thromboembolism (AVR 1.1 [seven], MVR 1.7 [10], MR 3.2 [four]; prosthetic valve endocarditis (AVR 0.6 [four], MVR 0.3 [two], MR 1.6 [two]); primary tissue failure (AVR 0.16 [one], MVR 1.0 [six], MR 1.6 [two]); anticoagulant-related hemorrhage 0.07 (one); and reoperation (AVR 0.48 [three], MVR 1.32 [eight], MR 2.4 [three]). Actuarial survival rates at 6 years, including operative deaths, are as follows: AVR 81.4% +/- 5.6%, MVR 70.0% +/- 6.7%, and MR 52.1% +/- 12.5%. The overall survival rate was 74.0% +/- 4.5% at 6 years. The freedom from all valve-related complications at 72 months was 83.9% +/- 4.8%. The freedom from valve-related death was 97.3% +/- 1.8% at 72 months. The freedom from valve-related death and reoperation at 72 months was 91.5% +/- 3.8%, and the freedom from reoperation alone was 93.4% +/- 3.5%. There were no deaths due to reoperation for primary tissue failure. Performance to date with the Carpentier-Edwards porcine bioprosthesis has been excellent, with an evaluation interval extending from 60 to 81 months.

Electrode studies have been performed with dead animal tissue and a variety of other materials immersed in saline solution and compared with studies in the canine heart (live and arrested) in an attempt to delineate both normal and anomalous signals sensed by pacemaker electrodes or obtained during diagnostic electrogram recording of cardiac activity. The data from these studies could be useful for defining the origin of artifacts and a variety of other phenomenon such as “fractured” QRS complexes, acute ST segment elevations, His bundle oscillatory signatures, and unexplained potentials synchronously associated with cardiac events. The studies verify that artifacts can be generated in an electrolyte medium by rubbing electrodes against insulators or biologic materials and by inducing motion between common pole materials of an active electrode system. The studies suggest that some of the grasping electrodes in current clinical use may be subject to self-generating artifacts associated with cardiac-induced frictional motion between the constituent materials employed in the electrode design.

Several reports in the literature and our experience prior to 1974 support the thesis that operative risk in patients with acquired heart disease and poor ventricular function (as assessed by a biplane ejection fraction [EF] less than or equal to 0.40) was very significantly increased over the risk in patients with normal ventricular function. These results led to disagreement in the literature regarding the advisability of surgery in patients with poor ventricular function. Various EFs from less than 0.31 to less than 0.50 were suggested as contradicting elective surgery, while more aggressive groups recommended surgery in all patients with angina. Precise comparison of the results reported by different groups was not always possible because of the common reliance on single-plane right anterior oblique ventriculograms, which tend to underestimate EF and overestimate operative risk. Using biplane ventribulograms for accurate estimation of EF, we have demonstrated a significant reduction in 30-day operative risk to a clinically acceptable 3 percent (1/32) for single valve replacement and aortocoronary surgery patients with poor ventricular function (EF less than or equal to 0.40) during 1974. Considering the high risk of medically treated patients with reduced ventricular function, these results support further evaluation of surgical palliation for patients with valvular or coronary heart disease and reduced ventricular function.

Intracoronary injection of 14 meg. of tetrodotoxin into the ischemic isolated rat heart resulted in immediate cessation of mechanical activity. Upon reperfusion with oxygenated, modified Krebs-Henseleit bicarbonate buffer in a modified Langendorff apparatus, all hearts recovered normal rate, rhythm, and contractile vigor after up to 60 minutes of ischemia. In contrast, all hearts not administered tetrodotoxin showed bradycardia, irregular rhythm, and weak contraction upon reperfusion after 30 and 45 minutes of ischemia; after 60 minutes, no mechanical activity was evident. The improved cardiac function following ischemia in the tetrodotoxin-treated hearts was associated with persistence of normal adenosine triphosphate (ATP) levels after up to 30 minutes of ischemia and normal or elevated creatine phosphate (CP) levels after up to 60 minutes of ischemia. On the other hand, ATP and CP levels progressively declined to reach 50 per cent of normal values after 30 minutes in the ischemic hearts without tetrodotoxin. These findings indicate that postarrest A TP and CP levels play an important role in myocardial recovery after ischemic arrest.

During reperfusion, functional and metabolic recovery of the isolated working rat heart from one hour of ischemia was best in hearts selectively cooled at the onset of the ischemic interval by perfusion with 5 to 10 ml. of 10° C. or 15° C. Krebs-Henseleit buffer. Hearts similarly perfused at 4° C., 20° C., and 37° C. recovered significantly less well or not at all. Immediately after the hour of ischemia and prior to reperfusion, the absolute levels of glycogen and high-energy phosphates were best in the hearts perfused at 4° C. However, metabolic function was best preserved in those perfused at 10° C. and 15° C., as evidenced by rapid recovery of high-energy phosphates and glycogen to control levels compared to metabolic deterioration in the 4° C. group.

The investigational Carpentier-Edwards supra-annular valve was implanted in 592 patients from November, 1981, to February, 1984 (aortic valve replacement in 286, mitral valve replacement in 259, and multiple valve replacement in 47, for a total of 638 prostheses). A previous cardiac operation had been performed in 77 patients (13%). Concomitant procedures were performed in 202 patients (34.1%), including coronary artery bypass in 163 patients. The patient evaluation was 98.6% complete. The early mortality was 7.4% (44 patients) and the late mortality was 6.2% per patient-year (41 patients). The valve-related causes of late mortality were thromboembolism (five), anticoagulant-related hemorrhage (one), and prosthetic valve endocarditis (one). The overall patient survival, including operative death, was 85% at 2 years. The linearized occurrence rate for valve-related complications was 5.6% per patient-year (37 events)—thromboembolism 2.7% per patient-year (18), anticoagulant-related hemorrhage 1.2% (eight), prosthetic valve endocarditis 0.8% (five), and periprosthetic leak 0.9% per patient-year (six). There were no cases of primary tissue failure or structural failure. At 2 years, the freedom from valve-related complications was 86.9%, from valve-related mortality, 98.7%, and from valve-related mortality and reoperation, 97.7%. This valve is fixed in glutaraldehyde at low pressure and is designed to improve durability. It has provided a low incidence of valve-related complications without structural failure. The structural design of the prosthesis does not always conform to the anatomy of bicuspid aortic valves.

Summary Acute aortic dissection is a medical emergency that demands immediate recognition and early precise angiographic diagnosis. One hundred seventeen patients were found to have aortic dissection between 1980 and 1986. Clinical presentation is of importance since hypertension favors the presence of type B dissection, whereas normotension or hypotension is usually indicative of a type A lesion. Supportive treatment should allow stabilization for diagnosis by angiography or computerized tomography in order to proceed with early surgical repair of all type A dissections. Management of the acute type B patient should initially be medical, but immediate surgical treatment should be carried out if there is failure to control the hypertension, continued pain, expansion or rupture of the aneurysm (including appearance of a pleural collection), development of a neurologic deficit, or evidence of compromise of a major infradiaphragmatic aortic branch. Any delay in surgical treatment once an indicative complication is identified will have an early adverse effect on prognosis. By applying these guidelines, an overall 65 to 75 percent hospital survival rate should be achieved.

Atrial pacing has the advantages of simplicity, maintenance of AV synchrony, and economy. The major detraction has been the potential for deterioration of atrioventricular conduction. In this study, we followed 43 patients with sick sinus syndrome treated with atrial (AAI) pacing. Excellent initial implant parameters were obtained in all. Three early lead repositionings were required. Minor sensing and pacing problems could all otherwise be handled by reprogramming. Follow-up for a mean of 25 +/- 20 months demonstrated excellent performance of the pacing systems. Pacing and sensing thresholds and lead impedance indicated excellent lead performance. There were no late lead failures. Nine patients have had mild deterioration in atrioventricular conduction and one of these had a change to DDD pacing at the time of elective battery change. All patients are asymptomatic. Thus, chronic atrial pacing in selected patients is safe and reliable with good chronic lead performance and low risk of subsequent conduction system disease.

A ventricular inhibited demand cardiac pacemaker was inhibited in the presence of intimate contact between the active temporary bipolar electrode ring and a retained inactive permanent bipolar electrode tip. Electromagnetic interference effects, lack of insulation, lead breaks, and loose connections were all ruled out as the cause of pacemaker suppression.

Isolated nonworking and working heart preparations are described and recent modifications that increase their reliability and scope are reviewed. Isolated perfused tissues are superior to other models for screening myocardial preservation techniques. The metabolic and functional differences between anoxia and ischemia are stressed, myocardial glycolysis is reviewed, and from basic studies potentially fruitful avenues for investigation of myocardial preservation techniques are outlined. Better application of available knowledge of myocardial metabolism could further reduce the risks of cardiac operation.

Adequate sensing of the cardiac electrogram is a necessary requisite for all demand cardiac pacemakers. In order to define better the effects of position of the sensing electrode on the ability of the pacer to detect the electrogram, a specially designed lead system with a movable, large surface area (50 mm2) proximal ring electrode and a small surface area distal tip electrode was placed transvenously in 12 mongrel dogs. As the sensing electrode was moved away from the right ventricular apex, there were slight but insignificant decreases in R wave amplitude. When the electrode was moved retrograde through the tricuspid valve into the atria there was a marked decrease in R wave sensing; however, this was accompanied by a significant increase in P wave amplitude. Therefore, with a large surface area electrode, direct contact with the myocardium is not needed for the detection of adequate P and R waves. In addition, a pacer lead system utilizing this sliding sensing electrode design could be used to optimize sensing position, either for atrial or ventricular sensing pacemakers.

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.

The Mitral Medical Mitroflow pericardial bioprosthesis was implanted in 99 operations (99 patients with 104 valves) between 1984 and 1987. The mean age of the patients was 62.8 years (range 28 to 94 years). The early mortality was 6.1% (including patients with concomitant procedures--coronary artery bypass and ascending aortic aneurysm resection). Late mortality was 2.3% per patient-year. The total cumulative follow-up was 172 years. Thromboembolism (TE) was 4.1% per patient-year (fatal 1.2% per patient-year) (minor 2.3%; major 1.8%); antithromboembolic therapy-related hemorrhage (ATH) 0.6% (fatal 0.6%); prosthetic valve endocarditis (PVE) 0.6% (fatal 0%); periprosthetic leak (PPL) 0.6% (fatal 0%); clinical valve dysfunction (CVD) 1.2% (fatal 0%); and structural valve deterioration/primary tissue failure (SVD) 1.2% per patient-year (fatal 0% per patient-year). Thromboembolism was the significant complication. SVD occurred in two patients during the third year of evaluation. The overall patient survival was 89.2 +/- 3.3% at four years. The patients were classified as 91.9% NYHA functional Class III and IV preoperatively and 97.7% Class I and II postoperatively. The freedom at four years from TE was 88.5% +/- 4.9%; SVD 92.5 +/- 5.1%; and reoperation 89.8% +/- 5.3%. Freedom from all valve-related complications at four years was 76.8% +/- 6.6%; valve-related mortality 97.2 +/- 2.0%; mortality and reoperation (valve failure) 87.3% +/- 5.5%; mortality and residual morbidity (treatment failure) 95.5% +/- 2.6%; and mortality, residual morbidity, and reoperation (valve failure and dysfunction) 85.6% +/- 5.7%. There were three valve-related deaths of a total of ten deaths (early 2; late 1) (TE 2; ATH 1; CVD 0; PVE 0; PPL 0; and SVD 0). Valve-related reoperation was performed in four patients (TE 0; CVD 0; PVE 1; PPL 1; and SVD 2). The Mitral Medical Mitroflow pericardial bioprosthesis has provided very satisfactory clinical performance and afforded patients excellent quality of life.

The use of bipolar lead systems with demand cardiac pacemakers has been criticized because the small interelectrode distance was thought to decrease sensitivity to cardiac electrical potentials. This study was done to determine if the reduced interelectrode distance inherent in bipolar systems is a limiting factor with the new small surface area electrodes. Three bipolar electrodes of differing surface areas were placed in the right ventricule of 10 anesthetized dogs. Bipolar sensing was compared with unipolar sensing. The results demonstrated three factors which determine the amplitude of the potentials detected: (1) surface area of the electrode; (2) position of the indifferent ring electrode in the bipolar system; and (3) pacemaker sensing circuit impedance. Electrode surface area was the most important determinant and impedance was the least. No significant peak QRS potential differences were detected when bipolar and unipolar sensing with the newer small surface area electrodes were compared.

For 80 elective clinical cardiopulmonary bypasses we alternately used either a commercial microporous Teflon membrane oxygenator or a commercial hybrid bubble-film oxygenator. Setup time was a little longer with the membrane unit (20 minutes), but priming volume (2,250 ml) was the same. No problems were encountered with the hybrid oxygenator. However, despite our monitoring of additional variables, including shim and inlet pressure and recirculation flow, gas exchange abnormalities were encountered in 5 patients on whom the membrane oxygenator was used; in 4 of these cases the abnormalities were encountered prior to our recognition of the potential for occasional internal shunting with this device. There were no hospital deaths. When the two groups, matched except for oxygenator selection, were compared, there were no significant differences clinically or hematologically. For cardiopulmonary bypass of 2 hours or less, both oxygenators studied are definite improvements over previous silicone membrane and high-gas-flow bubble oxygenators. However, lower cost and reduced complexity favor the hybrid oxygenator.

Clinical experience has indicated a high operative risk due to depressed ventricular function in certain patients receiving chronic oral propranolol therapy for control of the symptoms of obstructive coronary artery disease. This has led to the recommendation that propranolol be discontinued 2 wk prior to elective coronary bypass surgery [5]. However, the half-life of propranolol in man is less than 6 hr [3] and other workers have reported no significant difference in mortality rates when comparing coronary artery bypass graft patients who had chronic propranolol therapy discontinued 36-48 hr prior to surgery with graft patients who had never received propranolol[4]. Because of the large number of angina patients receiving propranolol, the increasing performance of emergency coronary artery bypass surgery, and the occasional occurrence of acute myocardial infarction after propranolol withdrawal [l] the residual effects of chronic propranolol therapy on cardiac function after induction of anesthesia and after cardiopulmonary bypass were further investigated.

The modalities of 25 mEq. per liter potassium-induced arrest in a simulated extracellular fluid, and 15° C. perfusion hypothermia were combined and used exclusively for myocardial protection during cardiac surgery in 108 consecutive patients. Over half of the patients had impaired preoperative myocardial function, as assessed by a subnormal ejection fraction and by New York Heart Association Class IV status. Ten patients were semiemergencies and eight were emergencies, including three in cardiogenic shock. The 30-day operative mortality rate was 4.6 percent, and during a mean follow-up of 9 months there were two late deaths-both cerebrovascular. The excellence of the myocardial protection is attested to by spontaneous defibrillation in over 50 percent of the patients, the very infrequent use of pressors, the immediate postoperative improvement in cardiac output, the early improvement in postoperative functional status of almost all of patients, and the very low level of specific myocardial isoenzyme released following the open heart procedures. The significant advantages of 15° C. potassium-induced arrest are (1) simplified high-volume temperature and pressure-monitored aortic root perfusion, effective even with aortic insufficiency, (2) the preclusion of the “calcium paradox,” (3) minimization of defibrillator induced myocardial injury, (4) operating conditions superior to normothermic ischemic arrest or topical hypothermia, (5) avoidance of coronary artery trauma, high and low perfusion pressure injuries, low-flow/high-energy demand situations and low-temperature injury, and (6) extensive clinical and experimental evidence of superior myocardial protection.

The Carpentier-Edwards supra-annular porcine bioprosthesis was implanted in 1,576 operations (1,536 patients with 1,704 valves) between 1981 and 1987. The mean age of the patients was 61.9 years (range 13 to 87 years). During the years 1981 and 1987, approximately 90% of the total valvular surgery population received the prosthesis. The early mortality was 7.0% (included patients with concomitant procedures including coronary artery bypass and ascending aortic aneurysm resection). Late mortality was 4.0% per patient-year. The total cumulative follow-up was 4,237 years. Thromboembolism (TE) was 2.4% per patient-year (fatal 0.4% per patient-year) (minor 1.2%; major 1.3%); antithromboembolic therapy-related hemorrhage (ATH) 0.5% (fatal 0.07%); prosthetic valve endocarditis (PVE) 0.5% (fatal 0.2%); periprosthetic leak (PPL) 0.3% (fatal 0%); clinical valve dysfunction (CVD) 0.3% (fatal 0.02%); and structural valve deterioration/primary tissue failure (SVD) 0.2%/patient-year (fatal 0%). Thromboembolism and structural valve deterioration were the significant complications, SVD occurring primarily between the fourth and fifth year of evaluation. The overall patient survival was 77.1% +/- 1.4% at five years. The patients were classified as 89.6% NYHA functional Class III and IV preoperatively and 96.1% Class I and II postoperatively. The freedom at five years from TE was 90.6% +/- 1.0%; SVD 98.9% +/- 0.5%; and reoperation 95.9% +/- 0.9%. Freedom from all valve-related complications at five years was 84.1% +/- 1.3%; valve-related mortality 96.8% +/- 0.7%; mortality and reoperation (valve failure) 92.9% +/- 1.1%; mortality and residual morbidity (treatment failure) 93.7% +/- 0.9%; and mortality, residual morbidity, and reoperation (valve failure and dysfunction) 90.0% +/- 1.2%. There were 28 valve-related deaths of a total 280 deaths (early 4, late 24) (TE 17; ATH 3; CVD 1; PVE 7; PPL 0; and SVD 0). Valve-related reoperations were performed in 32 patients (TE 2; CVD 4; PVE 7; PPL 11; and SVD 8). The supra-annular Carpentier-Edwards porcine bioprosthesis has provided very satisfactory clinical performance and afforded patients an excellent quality of life. The long-term durability of this low pressure glutaraldehyde fixed prosthesis will be determined by observation over the next five to seven years.

Cardiac myocytes from adult rat ventricles were isolated by perfusion and incubation with buffer containing collagenase and hyaluronidase. This method gave a high yield of viable cells with normal morphology and metabolic properties. The isolated cells can tolerate 2.5 m m extracellular calcium and have physiologic levels of ATP (20 μmol/g protein). The cells metabolized glucose at a linear rate up to 4 h. Glucose utilization was stimulated by insulin and anoxia. Protein synthesis was maintained at a steady rate for 3 h and was significantly stimulated by insulin. A reasonably constant rate of protein degradation was observed for 3 h. Insulin significantly inhibited the rate of protein degradation.

New atrial clip-on and ventricular suture-on temporary pacemaker electrode systems were evaluated in dogs. The ability of these electrodes to sense cardiac electrical activity was evaluated during a 14-day period. At no time did the P-wave potential fall below 3.3 mV and the R-wave potential fall below 6.0 mV. The acute pacing thresholds never exceeded 1.025 V and 1.95 mA. All values are well within acceptable standards for temporary pacing. The lead wires were easily, quickly, and painlessly removed without injury to the myocardium, yet the electrical contact remained tight between the lead wire and electrode preventing premature displacement.

An improved technique for cannulating the ascending aorta has been developed and used in 229 consecutive open-heart procedures without complication. Advantages of the method include speed and ease of cannula insertion, elimination of the need for partial-occlusion clamping of the aorta, minimization of the risk of introducing air, minimization of blood loss, and facilitation of distal cannulation in patients with short aortas.

Tests were conducted on rechargeable mercury-zinc pacemaker batteries under simulated and actual biologic conditions, using a variety of discharge rates and charging schedules. In tests on 96 cells at a 6.4 milliampere (ma) discharge, recharging once every 15 months of simulated pacing at a 25 microampere ( μ a) drain, the earliest cell failure occurred after an equivalent of 50 years of pacing. The mean pacing equivalent for all 96 cells was more than 140 years. In 6.4 ma discharge tests on 24 cells, recharging once every 8 days of simulated pacing, only 1 cell in 24 failed after an equivalent of more than 500 years of pacing (actual time 2 years). In tests on 13 cells pacing at a 200 μ a drain without recharging, the simulated mean duration of pacing before total discharge was 4.8 years. Seven other cells at a 200 μ a drain with periodic recharging continue to function normally after more than 7 years of actual time, simulating 56 years of pacing at a 25 μ a drain. Cardiac pacemakers using the rechargeable mercury-zinc cell have been implanted in animals for more than 2 1/2 years and in patients for more than 1 year with all units continuing to function satisfactorily. It has been demonstrated unequivocally that a rechargeable mercury-zinc pacemaker will function continuously for more than 4 years without recharging and that periodic recharging will extend pacing life far beyond that predicted for lithium and nuclear primary power sources.