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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.

To examine outcomes following all first coronary revascularization procedures, isolated coronary artery bypass graft surgery (CABG) and percutaneous coronary intervention (PCI) on British Columbia (BC) resident adults from 1995 to 2001.CABG and PCI data were obtained from the BC Cardiac Registry, and mortality data were obtained from the BC Vital Statistics Agency. Analysis was performed by annual cohorts, and the rates reported are unadjusted.An increasing percentage of revascularization procedures was performed with PCI (62% in 1995 to 73% in 2001; P0.001) due to the increased use of PCI procedures. Except in emergent cases, 30-day mortality improved after PCI (1.8% to 1.1%; P=0.02) and CABG (1.8% to 1.2%; P=0.01). Emergent cases accounted for 9.0% of PCIs and 2.7% of CABGs, the percentage treated by CABG decreasing from 14.5% in 1995 to 7.5% by 2001 (P0.001). Mortality rates among emergent cases was higher at 30 days, with no trend in PCI mortality (12%) but a substantial reduction in 30-day mortality after CABG (28% to 10%; P=0.003). One-year survival free from repeat revascularization following PCI increased from 73% in 1995 to 83% in 2001 (P0.001) and from 94% to 95% (P0.005) following CABG.Improvements in procedure-related mortality observed in trials have extended to clinical practice. With respect to emergent cases, an increasing proportion were treated by PCI with no change in PCI mortality but associated with a drop in surgical mortality. There has been a consistent and substantial drop in the need for repeat procedures within one year for patients selected for PCI.

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.

Bipolar, transvenous, passive-fixation leads (ThinLine, Sulzer Intermedics Inc., Angleton, TX, USA) incorporating coradial individually coated conductor coils, and a redundant external 55D polyurethane insulation sheath were developed. The diameter of the new leads (< 5 Fr) is in the range of available unipolar leads and is considerably smaller than conventional bipolar pacing leads. From January 9, 1994 to November 12, 1996, 1,536 model 432-04 (523 atrial) and 430-10 (1,013 ventricular) leads were implanted in 1,068 patients at 50 US and 5 Canadian centers to evaluate their safety and efficacy. The study included a general phase, with follow-ups at 1, 3, 6, 12, 18, and 24 months; and a randomized intensive phase with collection of more data and additional 2- and 6-week follow-ups. Capture and sensing thresholds, lead impedance, and handling characteristics were evaluated. Clinical events were monitored and performance was compared to that of two commercially available conventional (coaxial) leads: Sulzer Intermedics models 432-03 (atrial) and 430-07 (ventricular). During a total of 17,530 device months, there were two lead failures, no lead related deaths, 32 explants, 37 complications, and no unexpected adverse device effects. Capture thresholds were lower than those for coaxial controls with identical electrodes, sensing was comparable, lead impedances were within clinically acceptable ranges, and investigators found overall handling characteristics good to excellent. ThinLine coradial bipolar leads are safe and effective for cardiac pacing and sensing.

Seymour (Sy) Furman was a challenging and dedicated teacher, a loyal mentor and guide, a colleague and friend throughout our respective professional lives. He was admired and respected both in Canada and in Europe and contributed greatly to our pacing community. The following are some individual reflections. I first met Sy in 1970 as a young staff surgeon at Toronto General Hospital. My chief Wilfred Bigelow (of pacemaker fame) asked me to ‘look after the pacemaker problem’ (unanticipated battery failure, runaway units, fractured leads, erratic follow-up). I had read about an organized pacemaker clinic at Montefiore Hospital and called Sy Furman who immediately invited me to the Bronx, NY, USA. I recall his enthusiasm and willingness to introduce me to the team, to demonstrate the workings of the clinic, the telephone monitoring system, and the data collection mechanism. I returned to Toronto to start a similar clinic with dramatic results in terms of patient safety. Sy had a need to participate and contribute to major meetings and he was both concerned and frustrated about not being involved enough in the organization of the Sixth World Symposium on Cardiac Pacing that was about to be held in Montreal, October 1979. Because I was working closely with Claude Meere, the chairman, Sy kept calling me to stay abreast of progress—he was ultimately most satisfied. He had a sincere desire to promote cardiac pacing and increase physician awareness and involvement. He invited David McGregor, Frank Tyers, and me to be the Canadian founding or original members of NASPE to ensure that this was indeed a truly North American effort, and this proved to be a great stimulus to cardiac pacing in Canada. His commitment to those of us in pacing was total and complete—he appointed me to the Editorial Board of the new …

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 unacceptable rate of mechanical failures, threshold problems, and recalls experienced with many coaxial bipolar cardiac pacing lead designs are reviewed in detail. To address these problems, redundant insulation coradial atrial and ventricular tined leads (AL and VL, respectively) with iridium oxide electrodes were developed and subjected to extensive accelerated testing. There were no mechanical failures. The new lead body design proved to be much more durable than widely used trifilar MP35N configurations. The data reviewed and early and current test results are strongly supportive of tightly coupled insulation being a major factor in improving lead durability as long as the insulating material is not stressed. In addition to improving flex life, insulation adherence to the conductor may reduce the potential for ionic degradation. Pacing and sensing thresholds in animal studies of the new leads were within the reported range for leads with steroid eluting electrodes. A multicenter Canadian clinical trial was initiated with the first implant in early January 1994. By November 1995, 110 VL and 82 AL had been placed in 124 patients and followed for a mean of 11 +/- 6 months; maximum 21, total 1355. There were 60 males and 64 females with a mean age of 64 +/- 16 years, range 15-88. Primary indications for pacing were AV block in 61 patients, sick sinus syndrome in 53, vasovagal syncope in 4, and congestive heart failure in 7. Many patients had associated or primary tachyarrhythmias, including 111 with supraventricular and 12 with ventricular. Forty-two percent of patients (52/124) had prior cardiac procedures, including 18 open heart surgeries and 20 AV nodal ablations. At implant, 8 lead characteristics were rated good or excellent in 90% (746/829) of evaluations. X-ray visibility was of concern in 10% of patients (12/124). Three perioperative complications occurred, including displacement of one AL (1.2%) and one VL (0.9%). There were no subsequent mechanical (connector, conductor, or insulation) or functional (exit block, micro or macro displacement, or over- or undersensing) problems. Implant pacing thresholds (PT) at 0.45 ms were AL, 0.6 +/- 0.2 (74) and VL 0.4 +/- 0.2 V; impedance (Z) at 3.5 V output AL 373 +/- 77 (82) and VL 497 +/- 117 omega. Sensing thresholds (ST) were AL 3.1 +/- 1.6 (74) and VL 10.3 +/- 4.9 mV. Ventricular lead data were obtained for all patients (N = 110). Atrial lead data are incomplete, because some patients were in atrial fibrillation during implantation. After 12 months, AL PT at 1.5 V output was 0.18 +/- 0.10 ms (21) and at 2.5 V was 0.10 +/- 0.053 (22). Associated AL ST was 3.3 +/- 0.9 mV (21) AL Z 500 +/- 65 omega (25). After 18 months VL PT at 1.5 V was 0.15 +/- 0.10 ms (9) and at 2.5 V output was 0.09 +/- 0.04 ms (9). Associated VL ST was > 7.5 +/- 2.4 mV (9) and VL Z 497 +/- 105 omega (9). Follow-up time discrepancy is due to the VL being available 6 months earlier than the AL. There were no 30-day deaths and only one late death at 10 months in a patient with chronic atrial fibrillation. Death was unrelated to pacer or lead function. At 1 year, 68% AL (15/22) and 62% (24/39) captured at 0.5 V and < or = 1 ms pulse width output. Innovative adherent insulation coradial bipolar lead conductors of the design studied combined with coated iridium oxide electrodes provide for a negligible incidence of mechanical or functional failure with clinical follow-up now approaching 3 years. Excellent acute and chronic sensing and pacing thresholds have been documented. Late thresholds have continued to improve gradually. Long-term clinical pacing at < or = 1.5 V output with a large safety margin is feasible in essentially all patients. This coradial design produces very flexible < 5 French bipolar redundantly insulated lead bodies allowing both AL and VL to simultaneously pass through a single 10 French introducer sheath. (ABSTRACT TRUNCATED)

Background The influence of unilateral (UL) and bilateral (BL) mammary artery revascularization, within age groups ≤60 years and >60 years, on patient survival, ischemic-related events, and interventional management was studied in 1142 patients who had coronary artery bypass graft surgery between 1984 and 1992. Methods and Results UL revascularization was performed in 765 (67%) and BL in 377 (33%) patients with supplemental vein grafts. The overall early and hospital mortality rate was 2.7%. For UL in the age group ≤60 years, it was 1.1%; for BL ≤60 years, 1.3% ( P =NS); for UL >60 years, 4.3%; and for BL >60 years, 2.8% ( P =NS). Twenty-five preoperative patient characteristics representing demographics, extent of disease, concomitant disease, ventricular dysfunction, previous surgery, and status did not differentiate the patient groups ( P =NS). Patient survival at 5 years was not different: 94% for UL ≤60 years, 95% for BL ≤60 years, 91% for UL >60 years, and 86% for BL >60 years ( P =NS). The freedom from ischemic-related events was not different at 5 years ( P =NS). The freedom from recurrent angina was 78% for UL ≤60 years, 88% for BL ≤60 years, 82% for UL >60 years, and 83% for BL >60 years ( P = NS). The myocardial infarction freedom was 98% for UL ≤60 years, 96% for BL ≤60 years, 99% for UL >60 years, and 97% for BL >60 years ( P =NS). The freedom from sudden unexpected death and cardiac death did not differentiate the groups ( P =NS). The freedom from angioplasty and reoperation did not differentiate the groups ( P =NS). The freedom from all ischemic-related and interventional events was 76% for UL ≤60 years, 84% for BL ≤60 years, 81% for UL >60 years, and 79% for BL >60 years ( P =NS). A trend exists for less angina pectoris in the bilateral population ≤60 years, which reflects in the trend in the freedom from overall events. Conclusions UL and BL mammary artery revascularizations have the same early mortality regardless of age but do not reveal any advantage for BL revascularization at 5 to 7 years.

The Carpentier-Edwards standard (CE-S) porcine bioprosthesis was implanted in 1214 operations (1975 to 1985) and the Carpentier-Edwards supraannular (CE-SAV) bioprosthesis was implanted in 2,489 operations (1982 to 1992 inclusive). The early mortality was 7.6% and 7.4% for the CE-S and CE-SAV groups, respectively; the late mortality was 5.3% per patient-year and 4.9% per patient-year, respectively. The cumulative follow-up was 9,968 patient-years for the CE-S group and 12,784 patient-years for the CE-SAV group. Concomitant procedures were performed in 26.8% of the patients who received a CE-S and in 40.9% of those who received a CE-SAV (p0.05). The mean age of the patients receiving a CE-S was 57.3 years (range, 8 to 85 years) and was 64.1 years (range, 6 to 89 years) in those receiving a CE-SAV. The CE-S group consisted of 578 atrial valve replacements (AVRs), 512 mitral valve replacements (MVRs), and 115 multiple valve replacements (MRs). The CE-SAV group consisted of 1,335 AVRs, 938 MVRs, and 200 MRs. There was a total of 165 cases of structural valve deterioration (SDV) in the CE-SAV group (AVR, 35; MVR, 98; and MR, 32). The effect of trimming the aortic wall was also considered: 20 of the 931 trimmed prostheses used for MVRs and MRs and none of the 207 reduced-trimmed prostheses exhibited SVD. The cumulative follow-up was 5,422 years for the patients with trimmed prostheses and 470 for those with reduced-trimmed prostheses.(ABSTRACT TRUNCATED AT 250 WORDS)

Prosthetic valve replacement remains the most viable alternative for the treatment of severely diseased heart valves. The cumulative experience of mechanical protheses and bioprostheses was evaluated for a 10-year performance comparison: Carpentier-Edwards standard porcine bioprosthesis (CE-S), 1,214 operations; Carpentier-Edwards supraannular porcine bioprosthesis (CE-SAV), 2,489; and mechanical prostheses, 1,364 operations (St. Jude Medical, Carbomedics, Duromedics, and Björk-Shiley Monostrut). The freedom from thromboembolism and hemorrhage at 10 years was 82% for CE-S, 78% for CE-SAV, and 65% for mechanical prostheses (p0.05). The relationship existed for major thromboembolism and hemorrhage, 91% (CE-S), 87% (CE-SAV), and 88% (mechanical) (p0.05), without clinical relevance. The freedom from structural valve deterioration and valve-related reoperation favored mechanical prostheses (p0.05) at 10 years (structural failure: 78% for CE-S, 81% for CE-SAV, and 99% for the mechanical group; reoperation: 74% for CE-S, 76% for CE-SAV, and 88% for mechanical prostheses). The freedom from fatal reoperation was not clinically different: 96% for CE-S, 99% for CE-SAV, and 99% for mechanical prostheses (p0.05) at 10 years. The freedom from valve-related mortality was not different (p = not significant) at 10 years: 87% for CE-S; 92% for CE-SAV; and 91% for mechanical. The freedom from permanent impairment or residual morbidity, primarily from thromboembolism, was 95% for CE-S, 92% for CE-SAV, and 95% for mechanical group (p0.05) but not clinically relevant.(ABSTRACT TRUNCATED AT 250 WORDS)

A retrospective review of complications with connectors and lead-to-header interfaces was performed following 649 pacing procedures between 1980 and 1990. There were 88 lead revisions (13.6%), 81 device replacements or modifications (12.5%), and 480 new implants (74%) using devices of five manufacturers. Two basic connector types were studied, one utilizing a set screw and the other using a side-lock compression fitting. The set screw makes electrical contact and mechanically secures the lead connector pin with a set screw insulated by a self-sealing grommet or an integral or separate set screw cover. The side-lock makes electrical contact with an automatic spring mechanism while the plastic lead terminal is secured in the connector block of the pacemaker by a Delrin side-lock compression fitting. Four hundred fifty-nine set screw connector devices were followed for up to 12 years with 14 complications (3.1%) whereas 82 side-lock connector devices were followed for up to 5 years with one complication (1.2%). The set screw and side-lock connectors were reliable over the period of follow-up. Although the complication rate appeared lower with the side-lock, follow-up was shorter and the number of implants smaller. With the leads used in this study, the side-lock proved to be a desirable feature due to simplicity, speed, safety, and ease of use. One limitation is the requirement for a precise IS-1 connector terminal diameter.

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.

The Carpentier-Edwards standard porcine bioprosthesis was implanted in 1190 patients (1201 operations, 1303 valves) between January 1975 and June 1986; most implants were before 1982. The mean age of the patients was 57.2 years (range 8 to 85 years). The early mortality was 7.6% (aortic valve replacement 5.1%, mitral valve replacement 8.8%, and multiple valve replacement 15.3%). Late mortality was 3.9% per patient-year (aortic valve replacement 3.6%, mitral valve replacement 4.2%, and multiple valve replacement 3.8%). The total cumulative follow-up period was 6737 years. Thromboembolism was 1.5% per patient-year (fatal 0.4% per patient-year) (minor 0.6%, major 0.9%); antithromboembolic therapy-related hemorrhage was 0.5% (fatal 0.1%); prosthetic valve endocarditis was 0.6% (fatal 0.2%); nonstructural dysfunction was 0.5% (fatal 0.2%); and structural valve deterioration and/or primary tissue failure was 1.5% per patient-year (fatal, 0.2% per patient-year). Thromboembolism and structural valve deterioration were the significant complications, structural valve deterioration occurring primarily between the sixth and 10th year of evaluation. The overall patient survival was 65.0% for aortic valve replacement and 54.8% for mitral valve replacement (p

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.

Biventricular pacing is an emerging technology for treatment of congestive heart failure. Left ventricular leads are most commonly placed through the coronary sinus (CS) into an epicardial coronary vein. Cannulation of the CS can be difficult and standard guiding catheters have a tendency to displace during lead advancement. This study found that transesophageal echocardiography facilitated CS cannulation in complex cases requiring antecedent lead extraction.

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.

A higher rate of complications and need for reoperation has been identified with epicardial and endocardial defibrillator systems. Improved reliability may be achieved with alternate designs that use coated wire and coated coil conductors. Six-year reliability in the 98% range is reported for one bipolar design, the Sulzer Intermedics Intervene® lead.

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.

A new type of endocardial bipolar pacing lead has been designed to overcome the potential drawbacks of the conventional coaxial bipolar pacing lead. We prospectively evaluated the new co-radial bipolar pacing leads (Intermedics Thin-Line), which are thinner (5 Fr vs 6-8 Fr) than standard coaxial bipolar leads. X-ray visibility and lead handling were subjectively assessed (excellent, good, adequate, or poor) at implant; lead impedance, sensitivity threshold, and pacing threshold were measured at implant, then at 1, 3, 6, 12, and 18 months. The results were as follows: 103 patients (51 M; age 63.8 +/- 17.4 years) received 71 atrial (A) and 89 ventricular (V) leads. X-ray visibility was excellent in 59/103; good in 23/103; adequate in 11/103; and poor in 10/103. Overall handling was excellent in 56/71 A and 69/89 V; good in 11/71 A and 18/89 V; adequate in 3/71 A and 1/89 V; poor in 1/71 A and 1/89 V. There were two perioperative complications. At implant: impedance in A and V were 370.1 +/- 74.7 and 501.5 +/- 124.4 omega, sensing thresholds in A and V were 3.0 +/- 1.5 and 9.9 +/- 5.0 mV, pacing thresholds at 0.45 ms in A and V were 0.59 +/- 0.21 and 0.41 +/- 0.15 volt, respectively. At 1, 3, 6, 12, and 18 months of follow-up: no pacing lead related complications were reported; pacing lead characteristics remained outstanding and stable. This new lead appears to have significant clinical advantages over the conventional coaxial bipolar pacing lead. Long-term follow-up is required to confirm its reliability and chronic performance characteristics.

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 clinical performance of tricuspid valve replacement with bioprostheses and mechanical prostheses was assessed in a series of 5,489 total valve replacement operations performed from 1975 to 1992. There were 97 (1.8%) tricuspid valve replacements in 94 patients (16 men, 78 women) with a mean age of 55.4 ± 13.8 years. Bioprostheses (mean patient age, 55.9 ± 14.1 years) were used in 83 operations and mechanical prostheses (mean patient age, 52.1 ± 11.9 years) were used in 14 operations. There were 30 isolated tricuspid valve replacements and 67 tricuspid valve replacements incorporated in multiple valve replacements. The total cumulative follow-up was 360 patient-years (bioprostheses, 321 years; mechanical prostheses, 39 years) (96.8% complete). The mean follow-up was 3.7 years (bioprostheses, 3.9 years; mechanical prostheses, 2.8 years) ( p = not significant). The early mortality was 14.4% (bioprostheses, 14.5%; mechanical prostheses, 14.3%) ( p = not significant) (isolated replacement, 13.3%; multiple replacement, 14.9%). The late mortality was 9.2% per patient-year (isolated replacement, 12.2% per patient-year; multiple replacement, 7.9% per patient-year). The freedom from structural valve deterioration at 5 and 7 years was 100% for mechanical prostheses and 97.1% ± 2.9% for bioprostheses ( p = not significant). For isolated tricuspid valve replacement, the freedom from structural valve deterioration for bioprostheses was 90.9% ± 8.7% at 5 years and at 7 years ( p = not significant). For the mechanical prostheses, the freedom was 100%. The freedom from valve-related reoperation for mechanical prostheses was 86.7% ± 12.4% at 5 and 7 years; for bioprostheses, it was 97.1% ± 2.9% at 5 years and 92.5% ± 5.2% at 7 years ( p = not significant). There was one reoperation among the isolated replacements with bioprostheses (one of four), and freedom from reoperation for bioprostheses was 90.9% ± 8.7% at 5 years and at 7 years ( p = not significant). With multiple tricuspid valve replacement, the freedom from reoperation for mechanical prostheses was 84.6% ± 14.2% at 5 and 7 years; for bioprostheses, it was 100% at 5 years and 93.8% ± 6.1% at 7 years ( p = not significant). Thrombosis was different ( p p = not significant). Tricuspid valve replacement carries a high early and late mortality rate. Bioprostheses are recommended because of the low rate of structural valve deterioration and avoidance of thrombosis.

The clinical performance of the Medtronic Intact porcine bioprosthesis was evaluated in 1,084 patients (mean age 66.4 years, range 9 to 91 years) who had a total of 1,099 implantations between 1985 and 1992, inclusive. There were 709 aortic valve replacements, 297 mitral valve replacements, and 80 multiple valve replacements. Concomitant procedures were performed in 432 (39.3%). The age group distribution (years) was 35 or younger in 20 patients, 36 to 50 in 64, 51 to 64 in 274, 65 to 69 in 225, 70 or older in 500. The total follow-up time was 2,741 patient-years (mean, 2.5 years) and was 97.5% complete. The early mortality rate was 7.1% and late mortality was 3.9% per patient-year. The overall patient survival at 7 years was 70% ± 3%. The freedom from major thromboembolism was 94% ± 1% at 7 years ( p = not significant for valve positions). The freedom from reoperation at 7 years was 93% ± 1%; freedom from valve-related mortality was 89% ± 2%. The freedom from structural valve deterioration at 7 years was 97% ± 1% (aortic valve replacement 97% ± 1%; mitral valve replacement 97% ± 2%). The freedom from structural valve deterioration among age groups was not different for the overall population, aortic valve replacement, or mitral valve replacement. Hemodynamic assessment revealed obstructive properties for aortic valve replacement sizes of 21 and 23 mm and for mitral valve replacement sizes of 25 and 27 mm. The Medtronic Intact porcine bioprosthesis shows excellent freedom from structural failure at 7 years for all valve positions and age groups, but obstructive properties for small aortic and mitral valve sizes.

The Carpentier-Edwards supraannular porcine bioprosthesis, a second-generation biologic prosthesis, has had clinical performance assessment to 12 years. This bioprosthesis was used in 2,489 operations in 2,444 patients between 1982 and 1992, inclusive (mean age 64.1 years, age range 6 to 89 years). There were 1,335 aortic valve replacements (AVR), 938 mitral valve replacements (MVR), and 200 multiple valve replacements (MR). Concomitant procedures were performed in 1,017 cases (40.9%). The age group distribution was: 35 years or younger, 83 patients; 36 to 50 years, 245; 51 to 64 years, 728; 65 to 69 years, 458; and 70 years and older, 975. The total follow-up was 12,785 patient-years (mean, 5.1 years) and was 96% complete. The early mortality rate was 7.4% (185 patients), and the late mortality was 4.9%/patient year (623). Concomitant procedures influenced both early and late mortality ( p p MVR, MR). The freedom from thromboembolism was not different by valve position. The freedom from major thromboembolism at 12 years was 82% ± 4% ( p = not significant by valve position). The overall freedom from antithromboembolic hemorrhage was 96% ± 1% at 12 years ( p MVR > MR). The overall freedom from valverelated reoperation at 12 years was 58% ± 5% ( p MVR, MR), and from valve-related mortality 89% ± 2% ( p MVR > MR). The freedom from residual morbidity (permanent impairment) at 12 years was 87% ± 4% ( p = not significant by valve position). The freedom from structural valve deterioration overall at 12 years was 63% ± 5%; at 10 years it was 90% ± 2% for AVR, 72% ± 3% for MVR, and 61% ± 8% for MR ( p MVR, MR). The freedom from structural valve deterioration by age groups by valve position was not significant for 35 years and less, but was significant for 36 to 50, 51 to 64, and 70 years and older ( p MVR > MR), and for 65 to 69 years ( p MR > MVR). The freedom from structural valve deterioration at 10 years after AVR by valve position for age groups was 36 to 50 years, 85% ± 6%; 70 years and older, 99% ± 1%; 51 to 64 years, 84% ± 4%; and 65 to 69 years, 96% ± 2% ( p

From 1975 through 1992 inclusive, reoperative valve replacement (REOP) was required by 12.9% of patients (708/5,499). Of 1,355 patients with mechanical prostheses (MP), 46 (3.4%) came to REOP versus 662 of 4,144 patients (16%) with biological prostheses (BP). Early REOP mortality rate was 17.4% (8/46) for MP and 10.6% (70/662) for BP (p = not significant). It was higher with age greater than 75 years (p0.05) and trended higher with concomitant procedures and with increasing number of REOPs (p = not significant). The percentage freedom from REOP at 5 and 10 years for all BP was 96.0% +/- 0.4% and 74.9% +/- 1.1% compared with 93.6% +/- 1.2% and 87.9% +/- 2.5% for MP. The most common cause of REOP in the BP patients was structural valve deterioration, which was uncommon in patients with MP (72% versus 2% of REOP but only 15% versus 0.1% of initial implants). Nonstructural dysfunction was the leading cause of REOP in the MP group (65% versus 11%). Prosthetic valve endocarditis (18% versus 10%) and thromboembolic complications (10% versus 1%) were also more frequent causes of REOP in MP patients. However, the increased relative role of these factors with MP is due to the minimal incidence of structural valve deterioration. When related to the original choice of MP versus BP, only thromboembolic complication (3.8 times) was more prevalent as a cause of REOP in patients receiving MP at their previous procedure (p = not significant). For patients who previously received BP, structural valve deterioration (69 times) was more likely to lead to REOP than with MP (p0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Recommendations regarding the safe waiting period between discontinuing chronic oral propranolol therapy and beginning cardiopulmonary bypass have varied from a few hours to 2 weeks. In the present study, utilizing adult dogs, propranolol was discontinued 8 or 48 hours prior to surgery. A reduction in cardiac output and elevations of left ventricular end-diastolic pressure, peak systolic pressure, and systemic resistance were noted when cardiac function was evaluated following the induction of anesthesia and prior to undertaking cardiopulmonary bypass. The magnitude of these differences was directly related to the degree of volume loading and inversely related to the interval between the last dose of propranol and the determination of cardiac function. Reduction of heart rate was the most evanescent of propranolol's hemodynamic effects as the marked bradycardia which persisted throughout the course of propranolol therapy was no longer evident 8 hours after the last oral dose of the drug. Following total cardiopulmonary bypass of 1 hour's duration, undertaken 8 hours after the last oral dose of propranolol, cardiac output and left ventricular end-diastolic pressure had returned to normal but peak systolic pressure and systemic resistance remained significantly elevated, When 48 hours had elapsed between discontinuing propranolol and beginning cardiopulmonary bypass, postbypass cardiac function was essentially normal with only slight persistent elevations of peak systolic pressure and systemic resistance detected. When the combined effects of ischemic heart disease and propranolol therapy, the altered metabolic and hemodynamic effects of different routes of drug administration, and the varying durations of cardiopulmonary bypass are taken into consideration, some of the discrepancies between previously reported clinical and experimental findings regarding the duration of persistent propranolol effects can be understood. The clinical course is usually benign in patients who have received propranolol to within a few hours of surgery without specific indication. However, it is often complicated when the drug is continued until just prior to surgery in patients dependant on propranolol for pain or arrhythmia control. In patients demonstrating propranolol dependence, control of symptoms with intra-aortic balloon counterpulsation is recommended followed by the gradual withdrawal of propranolol and elective aortocoronary bypass surgery.

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.