E. Winkel

Role of Maximal Oxygen Consumption in Establishment of Heart Transplant Candidacy for Heart Failure Patients With Intermediate Exercise Tolerance

Maximal exercise oxygen consumption (VO2max) was measured in patients with chronic congestive heart failure undergoing evaluation for heart transplantation. Although VO2max correlated with survival for the group as a whole, it did not demonstrate survival discrimination for patients in the intermediate range (VO2max = 12 to 17 ml/kg/min) and should therefore not be used as a benchmark test for determination of appropriateness for cardiac transplantation in this group of patients.

Radiofrequency catheter ablation of atrial flutter after orthotopic heart transplantation: insights into the redefined critical isthmus

We report a case of successful radiofrequency catheter ablation of recurrent atrial flutter in a heart transplant recipient and discuss technical aspects of the procedure. A counterclockwise flutter circuit was defined during endocardial mapping of the donor atrium. Termination of atrial flutter was achieved by creating lines of radiofrequency lesions from the tricuspid ring to the suture line between donor and recipient atria. Creation of bidirectional conduction block in the tricuspid ring-suture line isthmus resulted in abolition of atrial flutter.

Candidate evaluation and selection for heart transplantation.

Because of the increasing discrepancy between the number of identified candidates for heart transplantation and available donor organs, appropriate selection of patients for heart transplantation is critical. The establishment of a cardiac prognosis that is significantly worse than that following heart transplant is central in the determination of candidacy for transplantation. However, with recent improvements in heart failure management, prognosis must be considered a dynamic state involving periodic reassessment to ensure an individuals ongoing suitability for transplantation. There have been many descriptions of prognostic indexes in heart failure, but care must be used when extrapolating observations collected from patients with a broad range of conditions to those with end-stage disease. The contraindications to heart transplantation have also evolved with the increasing success of the transplant process. Many conditions that precluded patients from heart transplant in the past are no longer regarded as absolute. Despite less stringent conditions for recipient candidacy, the need to achieve optimal results with an increasingly valuable donor resource will necessitate careful scrutiny of the posttransplant implications of the various conditions currently regarded as contraindications to heart transplant. Determination of heart transplantation candidacy therefore continues to remain a highly individualized process, requiring clinical judgment and experience.

Characteristics of the Signal-Averaged P Wave in Orthotopic Heart Transplant Recipients

Rejection remains the Achilles heel of Orthotopic cardiac transplantation (OHT). Reliable non‐invasive markers of rejection are desirable for timely therapy and to reduce risks and costs. Changes in atrial electrophysiology may precede ventricular changes during acute rejection. Although P wave duration in the signal‐averaged ECG reflects atrial conduction, the feasibility of such measurement and the range of its values in OHT patients in absence of rejection is uncertain. This study compared the filtered P wave duration in 15 hypertensive OHT patients free of rejection with that in 15 age‐matched hypertensive controls. All OHT patients had biatrial anastomoses. Two electrophysiologists interpreted the tracings independently. Three tracings (2 OHT, 1 control) could not be interpreted by either reader. An adequate P wave signal‐averaged ECG was obtained in the remaining patients, despite the frequent presence of dissociated P waves (recipient and donor atria) on standard ECG in OHT patients. There was good interobserver agreement in the measurement of filtered P wave duration (r = 0.91; P < 0.0001). Conclusions: The filtered P wave duration was significantly shorter in the OHT patients (112 ± 15 ms versus 128 ±14 ms; P= 0.008). Filtered P wave duration can be measured in most OHT. Filtered P wave duration is shorter in OHT patients than in hypertensive controls, possibly as a result of the reduced mass of the truncated donor atria. Further studies are needed to determine whether the signal‐averaged P wave can be useful to predict acute cardiac rejection.

Is outcome after heart transplantation influenced by ethnicity? A comparison of African Americans versus Caucasians.

transplantation increases the risk of postoperative complications. The purpose of our current study was to test this hypothesis by evaluating 50 patients who were transplanted at our facility over the past six years. Seventeen (34%) of these patients had received amiodarone prior to transplantation while the remaining thirtythree (64%)had not. Endpoints of the study included: length of hospital stay, survival to hospital discharge, 30 day mortality, 6 month mortality, 1 year mortality, number of days ventilated, ARDS, hepatic failure, number of days paced, need for permanent pacemaker, refractory hypotension, and bleeding complications. There were no significant differences between the two groups in age, sex, etiology of heart failure, LVEF, preoperative platelet or INR values. Patients in the amiodarone group, however, were more likely to be on an assist device or IABP prior to transplantation compared to the non-amiodarone group (47% vs 12%, p50.005). There were no significant differences between the amiodarone and non-amiodarone groups in length of stay (21 vs 17 days, p50.72), 6 month mortality (29% vs 15%, p50.19), 1 year mortality (27% vs 18%, p50.5), days ventilated (8 vs 6, p50.7), ARDS (6% vs 0, p50.16), hepatic failure (18% vs 9%, p50.4), days paced (2 vs 2, p50.67), need for permanent pacemaker (0 vs 3%, p50.47), or refractory hypotension (18% vs 9%, p50.4). Amiodarone patients were less likely to survive to hospital disharge (71% vs 94%, p50.02) and a trend was seen for 30 day mortality (18% vs 3%, p50.07). They were also more likely to experience a bleeding complication (41% vs 9%, p50.007), even when patients on mechanical assist devices were excluded (33% vs 7%, p50.04). In conclusion, amiodarone patients were not at increased risk of ARDS, bradycardia, hepatic failure, or refractory hypotension. Amiodarone patients did experience more bleeding complications in the postoperative period. This finding has important clinical implications for many cardiac transplantation patients and warrants further investigation.