Symmetric and asymmetric left ventricular hypertrophy in patients with end-stage renal failure on long-term hemodialysis

BACKGROUND

Patients with end-stage renal disease on regular hemodialysis have an increased prevalence of left ventricular (LV) hypertrophy that is associated with morbidity and mortality. Asymmetric septal hypertrophy and impairment of LV outflow can occur in these patients and may contribute to adverse outcomes. More insight into the prevalence, extent, geometry, and promoting factors of LV hypertrophy is important.

METHODS

An unselected group of 62 patients (31 women), aged 55 +/- 14 years, on maintenance hemodialysis was investigated by Doppler echocardiography. Eight patients with valvular heart disease were excluded from further analysis. We assessed prevalence of LV hypertrophy and asymmetric septal hypertrophy, as well as parameters of LV geometry and LV filling and outflow dynamics.

RESULTS

Prevalence of LV hypertrophy was 65%. Patients were analyzed according to LV mass and geometry. Mean LV mass index was normal (105 +/- 17 g/m2) in Group 1 without LV hypertrophy (n = 19); it was markedly elevated in Group 2 (symmetric hypertrophy, n = 22) and Group 3 (asymmetric hypertrophy with systolic anterior movement of mitral valve, n = 7), and highest (191 +/- 54 g/m2) in Group 4 (asymmetric hypertrophy without systolic anterior movement of mitral valve, n = 6, p < 0.001). Age, body mass index, and duration of hypertension were associated with LV hypertrophy and asymmetric septal hypertrophy (p = 0.01). Group 3 with systolic anterior motion of mitral valve had the smallest end-diastolic LV diameters (p = 0.02); increased heart rates, and increased ejection velocities in the LV outflow tract (p = 0.03, and p = 0.005, respectively, vs. Groups 1, 2, and 4) which pointed to an impairment of LV outflow.

CONCLUSIONS

Symmetric LV hypertrophy and asymmetric septal hypertrophy are frequent in patients on maintenance hemodialysis. Predictors for LV hypertrophy were age and body mass index, and, particularly for asymmetric septal hypertrophy, age and hypertension duration. Volume withdrawal during hemodialysis may lead to symptomatic hypotension due to dynamic obstruction in some patients with severe asymmetric septal hypertrophy.

The Impact of Statin Treatment on Presentation Mode and Early Outcomes in Acute Coronary Syndromes

OBJECTIVES

The role of statin use in the treatment of acute coronary syndromes (ACS) is not clear. The aim of our study was to evaluate the role of statins in ACS.

METHODS

Using data from the Acute Myocardial Infarction in Switzerland (AMIS Plus) Project, we compared the effects of chronic statin use, statin therapy after admission and no statin therapy on presentation mode and outcomes in ACS.

RESULTS

Available data from the period 2001-2006 including 11,603 patients were analyzed. Major cardiac event rates and in-hospital mortality were more common in statin-naive patients compared to patients who received statins.

CONCLUSIONS

Our results support the importance of statin treatment in ACS. Chronic statin therapy seems to alter the initial presentation of ACS but it is questionable whether it provides an additional effect on early outcomes compared to the establishment of statin therapy after admission in statin-naive patients.

Quality of life and exercise capacity in patients with prolonged PQ interval and dual chamber pacemakers: a randomized comparison of permanent ventricular stimulation vs intrinsic AV conduction

AIMS

The aim of this study was to assess quality of life (QoL) and exercise capacity during permanent ventricular stimulation (PVS) compared with intrinsic atrioventricular conduction (IAVC) in patients with dual chamber pacemakers (PMs) and an intrinsic PQ interval >210 ms. Dual chamber PMs in patients with atrioventricular (AV) block are usually programmed to PVS in VDD or DDD mode, although IAVC is preserved, but prolonged. This results in PVS, although long periods of IAVC may occur.

METHODS AND RESULTS

Fourteen consecutive patients (age 76 +/- 6 years; intermittent high degree AV block in six patients, binodal disease in eight patients) were enroled in a prospective, randomized, single blind, crossover study of IAVC vs PVC. To permit IAVC, programmed AV delays were prolonged. At the end of each phase, QoL scores were assessed using a questionnaire and echocardiography and cardiopulmonary stress tests were performed. During the study period with IAVC, 95 +/- 10% of the beats were conducted intrinsically. QoL scores (28.3 +/- 11 vs 29.3 +/- 13; P = 0.68), peak exercise capacity (5.4 +/- 2.4 vs 5.2 +/- 2.9 METs; P = 0.35) and peak oxygen uptake (19.8 +/- 4.5 vs 18.8 +/- 5.2 ml/kg/min; P = 0.16) were comparable during IAVC and PVS, respectively. Similar echocardiographic values were found for left ventricular (LV) ejection fraction (50 +/- 9% vs 51 +/- 10%; P = 0.67) and velocity time integral at the left ventricular outflow tract (24 +/- 5 vs 22 +/- 6 cm; P = 0.20), respectively.

CONCLUSIONS

We conclude that in patients with dual chamber PMs and intermittent high degree AV block neither PVS nor IAVC is superior with respect to QoL or exercise capacity. Therefore, pulse generators may be programmed to IAVC to extend their longevity.

[Acute coronary syndrome and myocardial infarct--new definitions]

Until recently a general consensus existed for the clinical entity diagnosed as myocardial infarction using the world health organisation (WHO) definition. According to the WHO definition myocardial infarction was defined by a combination of two of three typical characteristics: typical symptoms, rise of cardiac enzymes (CK, CK-MB), and a typical ECG pattern involving the development of Q waves. New insights into the development of acute myocardial infarction, the superiority of the biochemical characteristics of cardiac troponin assays over CK and CK-MB measurements in blood, and new therapeutic concepts made a new definition of myocardial infarction, e.g. of the acute myocardial infarction, necessary. Timing of the diagnosis of myocardial necrosis is of outmost importance relative to the time of observation (acute, evolving, healing, healed MI), as is the classification of the extent of myocardial damage (microscopic, small, medium or large). The term "acute coronary syndrome" (ACS) has been established as a working diagnosis for choosing the appropriate therapeutic strategy. In patients with ACS and ST elevation ischemia (STEMI ACS, true posterior ischemia inclusive) as well as in patients with presumably new LBBB, immediate reperfusion therapy should be performed (primary PTCA or thrombolytic therapy), whereas in patients with ECG changes other than ST elevation or new LBBB (NSTEMIACS) additional antiplatlet therapy on top of aspirin and heparin is indicated. In contrast to the acute phase of infarction when troponin in blood often is not detectable yet, the diagnosis of definitive myocardial infarction is based primarily on troponin elevation. Hard criteria for established infarction are the development of pathologic Q waves or healing or healed myocardial necrosis in pathology; troponin may be normal then, depending of time relapsed.

Hemodynamic effects of bosentan in patients with chronic heart failure

A role of the potent and long-acting vasoconstrictor peptide endothelin-1 and the pathophysiology of chronic human heart failure has been postulated based upon indirect evidence such as elevated plasma endothelin-1 levels and their with the degree of hemodynamic impairment. The advent of specific of endothelin-1 receptor antagonists has provided the opportunity not only to directly evaluate its pathophysiological role but also to assess its potential role as a new approach to heart failure therapy. This brief review summarizes the evidence linking endothelin-1 to the pathophysiology of chronic heart failure and the clinical results obtained in patients during acute, intravenous and more prolonged, oral administration with bosentan, a mixed ET(A)/ET(B)-receptor antagonist. Bosentan acutely and during short-term oral therapy markedly improved hemodynamics in patients in addition to standard heart failure therapy, including an ACE-inhibitor. These effects were associated with a reduced responsiveness of the renin-angiotensin system to diuretic therapy and reduced basal plasma aldosterone levels. Although the hemodynamic and neurohumoral profile of short-term bosentan therapy looks promising for the treatment of patients with chronic heart failure appropriate trials will have to be performed to document clinical benefit during long-term therapy. Finally, the question remains open whether mixed endothelin-1 receptor antagonists like bosentan will have similar effects as compared to antagonists which block the ET(A) receptor only.

Rationale and perspective of endothelin-1 antagonism in acute heart failure

A role of the potent and long-acting vasoconstrictor peptide endothelin (ET)- I in the pathophysiology of chronic human heart failure has been postulated, based upon indirect evidence such as elevated plasma ET-1 levels and their relationship to the degree of haemodynamic impairment. Acute heart failure shares many features of chronic heart failure, albeit in an exaggerated fashion. As both the mixed ETA/ETB-receptor antagonist bosentan and the selective ETA receptor antagonist BQ 123 acutely improved the haemodynamics of chronic heart failure patients, there seems to be good reason to believe that ET-1 receptor antagonism may also be of benefit in the setting of acute heart failure. However, appropriate trials will have to be performed to document the clinical benefit of such an approach. Finally, the question remains open as to whether mixed ET-1 receptor antagonists like bosentan will prove better, worse or equal to antagonists that block the ETA, receptor only.

Sudden cardiac death after coronary artery bypass grafting is not predicted by signal-averaged ECG

BACKGROUND

Sudden cardiac death (SCD) is a major cause of death despite successful revascularization in patients with coronary artery disease. The signal-averaged ECG (SAECG) is a sensitive predictor of SCD and could be used in the screening strategy to select patients for prophylactic cardioverter implantation.

METHODS

The SAECG was recorded in 561 patients (mean age: 60 +/- 8.8 years) within 10 days of coronary artery bypass grafting. Signal-averaged ECG was performed with a bandpass filtering of 40 to 250 Hz for more than 250 beats until a noise level of 0.6 microV was achieved. All patients were followed for 5.5 +/- 1.2 years after the procedure.

RESULTS

Preoperative angiographic ejection fraction was at least 60% in 393 patients (72%), 40% to 60% in 126 patients (23%), and 40% or less in 28 patients (5%). There were 34 deaths, 10 of which were SCD. Late potentials were found in a total of 150 patients (27%) and were equally frequent preoperatively and postoperatively and among patients with (30%) and without (27%) SCD. The only predictors for overall mortality were age and a reduced ejection fraction.

CONCLUSIONS

Signal-averaged ECG did not predict prognosis in low-risk patients undergoing coronary artery bypass grafting.

The dual endothelin receptor antagonist tezosentan acutely improves hemodynamic parameters in patients with advanced heart failure

BACKGROUND

Endothelin-1, a potent vasoconstrictor, is elevated in congestive heart failure and is postulated to play a major role in the pathogenesis of the disease. Endothelin receptor antagonism may be a specific therapeutic approach. This study was designed to determine the effective dosage range, hemodynamic effects, and tolerability of tezosentan, an intravenous dual endothelin receptor antagonist, in patients with advanced heart failure.

METHODS

This randomized, double-blind, placebo-controlled multicenter trial enrolled 38 patients with symptomatic stable heart failure (New York Heart Association class III, left ventricular ejection fraction <35%) undergoing right heart catheterization. Patients were equally randomized to a 4-hour intravenous infusion of placebo or tezosentan in ascending doses (5, 20, 50, and 100 mg over 1 hour each). Angiotensin-converting enzyme inhibitors and diuretics were withheld 24hours before the study. Hemodynamics were measured during and for 4 hours after the infusion.

RESULTS

Compared with placebo, tezosentan treatment produced a significant increase in cardiac index (treatment difference 0.59 L/min/m(2), P =.0001) and decreases in pulmonary and systemic vascular resistances (P </=.01) without changes in heart rate. Consistently greater decreases in pulmonary capillary wedge pressure, mean right atrial pressure, and pulmonary and arterial pressures with tezosentan did not reach statistical significance. Hemodynamic changes were dose dependent with maximal effects at 20 and 50 mg per hour. Tezosentan was well tolerated. Despite increased endothelin-1 concentrations, hemodynamic rebound was not observed.

CONCLUSION

Tezosentan rapidly and dose dependently improved hemodynamics. The favorable effects on cardiac index and pulmonary and systemic vascular resistances without changes in heart rate may be beneficial in the treatment of acute heart failure.

Elevation of troponin I in sepsis and septic shock

OBJECTIVE

To detect myocardial damage in severe systemic inflammation by cTnI measurements in patients without acute coronary syndromes.

DESIGN

Prospective case control study.

SETTING

Tertiary referral center.

PARTICIPANTS

Twenty patients with sepsis, septic shock, and systemic inflammatory response syndrome (SIRS) were examined and compared to controls without coronary artery disease or myocarditis.

MEASUREMENTS AND RESULTS

cTnI levels were assessed in patients with SIRS, sepsis, and septic shock. Eight patients (two female/six male) suffered from septic shock, nine (three female/six male) from sepsis without shock, and three (three male) from SIRS. Seventeen patients (85%) showed elevated cTnI (median 0.57 microg/l; 0.17-15.4), whereas no patient in the control group showed elevated cTnI (P < 0.0001). Six patients (30%),--three with septic shock and three with sepsis--died during hospitalization, five of them with elevated cTnI. Four out of five autopsies showed normal coronary arteries. Coronary angiography, autopsy, and stress echocardiography ruled out significant coronary artery disease in ten cTnI-positive patients (59%). In 41 % of cTnI-positive patients, Streptococcus pneumoniae could be cultured, whereas no cTnI-negative or control patient showed signs of infection due to S. pneumoniae.

CONCLUSION

Cardiac troponin I was elevated in 85% of patients with sepsis, septic shock or SIRS in our study. A high percentage showed infection caused by S. pneumoniae. In what way microorganisms cause cTnI elevations is not yet understood.

[Interventional treatment of acute myocardial infarct]

BACKGROUND

Randomised trials have shown that primary percutaneous angioplasty (PTCA) may offer advantages over thrombolysis in treating acute myocardial infarction (vessel patency is achieved more often, mortality and reinfarction rate are lower, cerebrovascular accidents are less frequent). Data from several foreign registries have been less clear. Up to now no registry data have been available for Switzerland. Data from registries are very important in planning optimal treatment under "real world" conditions.

METHOD

All patients receiving acute PTCA during the first 24 hours of acute myocardial infarction were prospectively included in a registry at a single centre. We assessed times until revascularisation, as well as clinical, angiographic and outcome data.

RESULTS

503 patients (age 59 +/- 12 years, 15% women) were included from 1. 1. 1995 to 30.6.2000. Primary PTCA was performed in 334 patients, and rescue PTCA in 169. Diabetes mellitus was present in 36% of the total. Multivessel disease was present in 61%, anterior infarction in 36%, and 16% were in cardiogenic shock before intervention. The pre-hospital delay was 2:12 h (median). In-hospital decision delay (hospital admission until contact to cardiologist) in patients with primary PTCA was 31 minutes (median). The time from vessel puncture to recanalisation was 19 minutes (median). 273 patients were transferred for coronary angiography and intervention by other hospitals (218 by ground ambulance, 55 per helicopter transfer). The total transfer time (calculated from time of decision to arrival in the catheterization laboratory) was 57 minutes (median). PTCA was successful angiographically in 97% and TIMI 3 flow was obtained in 93% of all patients. Hospital mortality was low in view of the high proportion of patients in cardiogenic shock prior to PTCA (mortality in shock patients was 33%). Mortality in patients without pre-existing cardiogenic shock was 2%.

CONCLUSION

Patients with acute myocardial infarction, especially high-risk patients, can be treated successfully by acute PTCA around the clock in Switzerland, in accordance with the strict international recommendations for time delays. The treatment results are similar to those in randomised trials. Transfer of patients from referral hospital is safe, with acceptable delays. Optimisation of the decision process and transport logistics may further improve outcome by reducing the total ischaemia time.

A prospective randomized trial comparing stenting to internal mammary artery grafting for proximal, isolated de novo left anterior coronary artery stenosis: the SIMA trial. Stenting vs Internal Mammary Artery

OBJECTIVE

To compare coronary artery bypass grafting (CABG) with percutaneous transluminal coronary angioplasty (PTCA) in patients with proximal, isolated de novo left anterior descending coronary artery disease and left ventricular ejection fraction of 45%.

PATIENTS AND METHODS

In the multicenter Stenting vs Internal Mammary Artery (SIMA) study, patients were randomly assigned to PTCA and stent implantation or to CABG (using the internal mammary artery). The primary clinical composite end point was event-free survival, including death, myocardial infarction, and the need for additional revascularization. Secondary end points were functional class, antianginal treatment, and quality of life. Analyses were by intention to treat.

RESULTS

Of 123 patients who accepted randomization, 59 underwent CABG, and 62 were treated with stent implantation (2 patients were excluded because of protocol violation). At a mean +/- SD follow-up of 2.4+/-0.9 years, a primary end point had occurred in 19 patients (31%) in the stent group and in 4 (7%) in the CABG group (P<.001). This significant difference in clinical outcome is due to a higher incidence of additional revascularization in the stent group, the incidence of death and myocardial infarction being similar (7% vs 7%, respectively; P=.90). The functional class, need for antianginal drug, and quality-of-life assessment showed no significant differences.

CONCLUSIONS

Both stent implantation and CABG are safe and highly effective treatments to relieve symptoms in patients with isolated, proximal left anterior descending coronary artery stenosis. Both are associated with a low and comparable incidence of death and myocardial infarction. However, similar to PTCA alone, a percutaneous approach using elective stent placement remains hampered by a higher need for repeated intervention because of restenosis.

An uncommon cause of recurrent strokes: Tropheryma whippelii endocarditis

BACKGROUND

Cardiac involvement in Whipple's disease is not an uncommon phenomenon in autopsies, but its clinical occurrence is often overshadowed by gastrointestinal symptoms. We report a very atypical manifestation of this disorder.

SUMMARY OF REPORT

An extraordinary presentation of an extremely long-lasting, culture-negative endocarditis caused by Tropheryma whippelii is described, the clinical consequence of which has become apparent in recurrent strokes.

CONCLUSIONS

Cardiac involvement of Whipple's disease should always be considered in culture and serologically negative endocarditis. The polymerase chain reaction technique may be a useful tool to confirm a presumed diagnosis of T whippelii endocarditis and consequently to apply an effective treatment regimen.

The acute effects of transvenous biventricular pacing in a patient with congestive heart failure

The management of congestive heart failure remains an issue of great interest. Encouraging data emerged over the last 2 years supporting the use of multisite pacing in patients with severe congestive heart failure and intraventricular conduction delay. We present a case of acute biventricular pacing in a 81-year old man with dilated cardiomyopathy and symptomatic congestive heart failure. This novel form of pacemaker treatment resulted in a rapid hemodynamic and clinical improvement.

Myocardial infarction caused by a large coronary artery aneurysm

A large coronary aneurysm, originating from a side branch of the right coronary artery, caused recurrent ischemia resulting in myocardial infarction. Successful surgical excision, without concomitant coronary artery bypass grafting, is described.

[Pharmacoeconomic evaluation of pravastatin in coronary secondary prevention in patients with myocardial infarct or unstable angina pectoris. An analysis based on the LIPID Study]

BACKGROUND

Secondary coronary prevention with lipid lowering drugs have become a major issue in health policy formulation due to the large upfront investment in drug therapy. The recently completed LIPID trial with pravastatin in secondary prevention immediately raise the question whether pravastatin might be cost-effective in Switzerland.

METHODS

We conducted a cost-effectiveness analysis from the perspective of third party payers. The following costs were included in the analysis: daily treatment costs of pravastatin, non fatal myocardial infarction, coronary bypass operations and stroke. Life years gained was obtained by applying the declining exponential approximation of life expectancy. All calculations were standardized to 1000 treated patients.

RESULTS

The net costs of treating 1000 patients (i.e. drug costs minus the costs of sequelae and interventions) are Fr. 3.6 Mio. In addition, a total of 430 life-years may be saved through treatment. The corresponding cost-effectiveness of pravastatin treatment is Fr. 8341 (nominal) Fr. 6985 (discounted).

CONCLUSIONS

The results suggest that the cost-effectiveness of pravastatin in secondary prevention lie well within the threshold of other commonly accepted medical interventions and may be considered an economically viable approach for secondary coronary prevention.

Regulation of aldosterone secretion in patients with chronic congestive heart failure by endothelins

We studied acute (day 1) and long-term (day 14) effects of endothelin (ET) receptor blockade with the mixed ET(A/B) antagonist bosentan (1 g twice daily; n = 18) or placebo (n = 12) on plasma angiotensin II and aldosterone in 30 patients with symptomatic chronic heart failure taking angiotensin-converting enzyme inhibitors, diuretics, and digoxin. Hormones were determined before and 3 hours after morning doses of diuretics and digoxin and the double-blind study drug, respectively, on days 1 and 14. On day 1, angiotensin II increased from 16.1+/-17.9 to 27.6+/-5.6 ng/L (p <0.05) with bosentan and similarly with placebo (15.5+/-9.3 and 36.0+/-49.1 ng/L, p = 0.06) after the morning dose of diuretics and digoxin. Aldosterone tended to increase from 322+/-239 to 362+/-254 pmol/L (bosentan) and from 271+/-70 to 297+/-136 pmol/L (placebo). On day 14, before drug intake, angiotensin II was unchanged compared with day 1 in both groups. However, aldosterone was lower than on day 1 with bosentan (213+/-124 vs. 322+/-239 pmol/L, p<0.05) and remained below baseline values 3 hours after drug intake, whereas it was unchanged with placebo. Thus, short-term ET(A/B) receptor antagonism decreases basal aldosterone secretion independently of angiotensin II, suggesting that ET participates in the regulation of aldosterone in patients already treated with angiotensin-converting enzyme inhibitors and diuretics.

A double-blind, randomized study of the effect of immediate intravenous nitroglycerin on the incidence of postprocedural chest pain and minor myocardial necrosis after elective coronary stenting

BACKGROUND

Anginal chest pain without creatine kinase (CK) elevation is frequently observed in the first hours after coronary stenting. Possible causes of ischemic episodes are microembolism, side branch occlusion, coronary vasospasm, and disturbances of microvascular circulation. In a prospective, double-blind, randomized trial, we tested the effect of intravenous nitroglycerin on the incidence of angina and minor myocardial necrosis (MMN), as detected by cardiac troponin I increase, after elective coronary stenting.

METHODS AND RESULTS

One hundred patients were randomly assigned to intravenous nitroglycerin (group A: n = 50, goal dose 100 microgram/min) or placebo (group B: n = 50, NaCl 0.9%) during 12 hours after stenting. Patients with acute myocardial infarction, known intolerance to nitrates, and hemodynamic instability during angioplasty were excluded. The 2 groups were comparable in respect to baseline and interventional variables, except for age (group A: 60 +/- 9 years, group B: 56 +/- 10 years; P =.04). The incidence of chest pain was not influenced by nitroglycerin (group A: 18%, group B: 22%; P = not significant). However, the occurrence of MMN was significantly reduced by nitroglycerin (group A: 5%, group B: 19%, P =.036). A rise in CK with significant CK-MB fraction was observed in only 2 patients in group B (both less than twice upper limit). Only 4 of the 10 patients with MMN also had chest pain.

CONCLUSIONS

Routine use of intravenous nitroglycerin after coronary stenting significantly reduced the occurrence of minor myocardial necrosis. However, the incidence of postprocedural chest pain remained unchanged.

Hospital transfer for primary coronary angioplasty in high risk patients with acute myocardial infarction

OBJECTIVE

To investigate the feasibility, safety, and associated time delays of interhospital transfer in patients with acute myocardial infarction for primary percutaneous transluminal coronary angioplasty (PTCA).

DESIGN AND PATIENTS

Prospective observational study with group comparison in a single centre. 68 consecutive patients with acute myocardial infarction transferred for primary PTCA from other hospitals (group A) were compared with 78 patients admitted directly to the referral centre (group B).

MAIN OUTCOME MEASURES

Patient groups were analysed with regard to baseline characteristics, time intervals from onset of chest pain to balloon angioplasty, hospital stay, and follow up outcome.

RESULTS

Patients in group A presented with a higher rate of cardiogenic shock initially than patients in group B (25% v 6%, p = 0.01) and had been resuscitated more frequently before PTCA (22% v 5%, p = 0.01). No deaths or other serious complications occurred during interhospital transfer. Median transfer time was 63 (range 40-115) minutes for helicopter transport (median 42 (28-122) km, n = 14), and 50 (18-110) minutes by ground ambulance (median 8 (5-68) km, n = 54). The median time interval from the decision to perform coronary arteriography to balloon inflation was 96 (45-243) minutes in group A and 52 (17-214) minutes in group B (p = 0.0001). In transferred patients (group A) the transportation associated delay and the longer in-hospital median decision time (50 (10-1120) minutes in group A v 15 (0-210) minutes in group B, p = 0.002) concurred with a longer total period of ischaemia (239 (114-1307) minutes in group A v 182 (75-1025) minutes in group B, p = 0.02) since the beginning of chest pain. Success of PTCA (TIMI 3 flow in 95% of all patients), in-hospital mortality (7% v 9%, mortality for patients not in cardiogenic shock 0% v 4%), and follow up after median 235 days was similarly favourable in groups A and B, respectively. Only one hospital survivor (group A) died during follow up.

CONCLUSION

Interhospital transport for primary PTCA in high risk patients with acute myocardial infarction is safe and feasible within a reasonable period of time. Short and medium term outcome is favourable. Optimising the decision process and transport logistics may further improve outcome by reducing the total time of ischaemia.

A randomized evaluation of early revascularization to treat shock complicating acute myocardial infarction. The (Swiss) Multicenter Trial of Angioplasty for Shock-(S)MASH

AIM

To test whether emergency revascularization improves survival in patients with acute myocardial infarction and shock.

METHODS AND RESULTS

Patients with acute myocardial infarction and early shock were randomized either to undergo emergency angiography, followed immediately by revascularization when indicated, or to receive initial medical management. In five of the nine participating centres, patients with shock but not randomized were entered in a registry. Only 55 patients could be randomized. Of the 32 patients in the invasive group, 30 (94%) underwent early angiography, 27 (84%) PTCA, and one (4%) CABG. Twenty-two (69%) died within 30 days in the invasive group vs 18/23 (78%) in the medically managed group (ns, RR=0.88, 95% confidence interval 0.6-1.2). Among the registry patients, 24/51 were excluded from randomization solely because of patient or physician preference for the invasive approach: 23 (96%) of them underwent emergency angiography, 21 (88%) PTCA, and 12 (50%) died within 30 days. Among the remaining registry patients (n=27) only nine (33%) underwent early angiography, nine (33%) PTCA and 20 (74%) died.

CONCLUSION

We failed to demonstrate that emergency PTCA significantly improves survival in patients with acute myocardial infarction and early cardiogenic shock. Because the study was stopped prematurely, due to an insufficient patient inclusion rate, a clinically meaningful benefit of early reperfusion may have been missed.

Dual chamber pacing with a single-lead DDD pacing system

The successful application of single-lead VDD pacing during the last few years has generated the idea of single-lead DDD pacing. Preliminary data from several single-lead VDD studies attempting to pace the atrium by a floating atrial dipole are unsatisfactory, causing an unacceptably high current drain of the device. We studied the feasibility as well as the short- and long-term stability of atrioventricular sequential pacing, using a new single-pass, tined DDD lead. In eight consecutive patients (age 73+/-16 years) with symptomatic higher degree AV block and intact sinus node function, this new single-pass DDD lead was implanted in combination with a DDDR pacemaker. Correct VDD and DDD function was studied at implantation; at discharge; and at 1, 3, and 6 months of follow-up. At implant, the atrial stimulation threshold was 0.6+/-0.1 V/0.5 ms. During follow-up, the atrial pacing thresholds in different every day positions averaged 2.1+/-0.5 V at discharge, 2.9+/-0.5 V at 1 month, 3.8+/-0.4 V at 3 months, and 3.4+/-0.4 V at 6 months (pulse width always 0.5 ms). The measured P wave amplitude at implantation was 4.5+/-2.2 mV; during follow-up the telemetered atrial sensitivity thresholds averaged 2.1+/-0.3 mV. Phrenic nerve stimulation at high output pacing (5.0 V/0.5 ms) was observed in three (38%) patients at discharge and in one (13%) patient during follow-up; an intermittent unmeasurable atrial lead impedance at 3 and 6 months follow-up was documented in one (13%) patient. This study confirms the possibility of short- and long-term DDD pacing using a single-pass DDD lead. Since atrial stimulation thresholds are still relatively high compared to conventional dual-lead DDD pacing, further improvements of the atrial electrodes are desirable, enabling lower pacing thresholds and optimizing energy requirements as well as minimizing the potential disadvantage of phrenic nerve stimulation.

[Possible future of the project for quality assurance of indications and outcome in interventional cardiology and gynecology]

In the last few years the basis for national guidelines for the indications of coronary angiography, coronary revascularisation and hysterectomy has been established. The guidelines have been published and are accessible to medical doctors and patients on the Internet using a database system called "Second Opinion System": http:/(/)sos.inf.ethz.ch Dissemination, implementation and validation of the guidelines will be of major importance in the near future. With reference to validation, the question remains whether the established guidelines are correct for the everyday treatment of patients. A suitable method of answering this important question is comparison between the appropriateness and necessity rates of the various indication groups, combined with outcome measurements. The Internet-based second opinion system (SOS) may be used for data collection in order to verify hypotheses. Because of the database architecture, only relevant information about the patients is collected via Internet, independent of time and place. In addition, the system allows users to evaluate their individual data, and special attention is given to data protection. The discussion about priorities in health care (rationing) will be increasingly important in the near future. The present project may offer a way of maintaining adequate access to health care services for patients. Therefore, the participation of as many institutions as possible in the project "quality assurance of indication and outcome in interventional cardiology and in gynaecology" is of great importance.

Epicardial, biatrial synchronous pacing for prevention of atrial fibrillation after cardiac surgery

About 30% of patients develop AF after open heart surgery. Biatrial synchronous pacing (BSP) has been shown to promote sinus rhythm in patients with paroxysmal AF refractory to drug therapy. We conducted a prospective, randomized study to test the effect of BSP via epicardial electrodes on the incidence of AF after heart surgery, as compared to conventional therapy. To apply BSP, we attached two epicardial electrodes to the right and one to the left atrium. Immediately following surgery, BSP was initiated in the AAI-Mode at a rate of 10 beats/min above the underlying rhythm (maximum 110 beats/min) and continued for 3 days, during which the rhythm was continually monitored. After 21 (age 63 +/- 9 years) of the planned 200 patients, the study was prematurely aborted because of the proarrhythmic effect of BSP: 6 of the 12 patients treated with BSP developed sensing failure (P amplitude < 1 mV), which provoked AF in 5 of these 6 patients. BSP was discontinued due to diaphragmal stimulation in two patients and due to ventricular stimulation by a dislocated left atrial electrode in one patient. Two patients in the control group (n = 9) developed AF. Using the available standard technology, BSP via epicardial electrodes is not suitable to suppress AF after heart surgery, primarily due to postoperative deterioration of atrial sensing and its profibrillatory effect. In patients requiring atrial pacing after heart surgery, sensing thresholds must be closely monitored to prevent induction of AF.

Short-term oral endothelin-receptor antagonist therapy in conventionally treated patients with symptomatic severe chronic heart failure

BACKGROUND

The vasoconstrictor peptide endothelin-1 (ET-1) is important for increased vascular tone in patients with chronic heart failure, but the effects of endothelin-receptor blockade in addition to conventional triple therapy are unknown.

METHODS AND RESULTS

Thirty-six men (mean age+/-SD, 55+/-8 years) with symptomatic heart failure (NYHA class III; left ventricular ejection fraction, 22.4+/-4.5%) despite treatment with diuretics, digoxin, and ACE inhibitors received, in a double-blind and randomized fashion, either additional oral bosentan (1.0 g BID; n=24) or placebo (n=12) over 2 weeks. Hemodynamic and hormonal (plasma ET-1, norepinephrine, renin activity, and angiotensin II) measurements were obtained before and repeatedly for 24 hours after administration of bosentan on days 1 and 14. Bosentan was discontinued in 1 patient with symptomatic hypotension, and 2 patients (bosentan group) declined hemodynamic investigations on day 14. Compared with placebo, bosentan on day 1 significantly decreased mean arterial pressure (difference from baseline over 12 hours [95% CIs], -13.9% [-16.0% to -11.7%]), pulmonary artery mean (-12.9% [-17. 4% to -8.3%]) and capillary wedge (-14.5% [-20.5% to -8.5%]) pressures, and right atrial pressure (-20.2% [-29.4% to -11.0%]). Cardiac output increased (15.1% [10.7% to 19.7%]), but heart rate was unchanged. Both systemic (-24.2% [-28.1% to -20.3%]) and pulmonary (-19.9% [-28.4% to -11.4%]) vascular resistance were reduced. After 2 weeks, cardiac output had further increased (by 15. 2% [10.8% to 19.6%]) and systemic (-9.3% [-12.3% to -6.4%]) and pulmonary (-9.7% [-16.3% to -3.1%]) vascular resistances further decreased compared with day 1. Heart rate remained unchanged. Plasma ET-1 levels increased after bosentan, but baseline levels of the other hormones were unchanged.

CONCLUSIONS

Additional short-term oral endothelin-receptor antagonist therapy improved systemic and pulmonary hemodynamics in heart failure patients who were symptomatic with standard triple-drug therapy. Further investigations are warranted to characterize the effects of long-term endothelin-receptor antagonist therapy on symptoms, morbidity, and mortality in such patients.

[Cardiogenic shock]

Cardiogenic shock (CS), defined as forward failure combined with systolic blood pressure < 90 mm Hg and reduced organ perfusion despite adequate volume loading, still has a grim prognosis with mortality rates of 80-100% if the causes are left untreated. The most frequent conditions underlying CS are acute myocardial infarction, acute and severe aortic or mitral incompetence, rapidly progressive dilatative cardiomyopathy and hypertrophic obstructive cardiomyopathy. Whereas correct conservative management by drugs and pacing may be life saving in the latter, the other conditions require early invasive management. Indications for cardiac surgery and circulatory assistance are given for mechanical complications leading to CS. In CS complicating myocardial infarction, comprehensive management with early invasive revascularization and intraaortic balloon pumping may result in improved survival compared with the disappointing outcome of medical treatment, including fibrinolysis. This strategy can be offered to the majority of infarct patients in CS, who are primarily admitted to hospitals not equipped for interventional cardiology or cardiac surgery. Between-hospital transfer of these patients for PTCA (or surgery) and advanced intensive care has been shown to be feasible and safe.

[Acute myocardial infarct in Switzerland: results from the PIMICS Heart Infarct Register. PIMICS Project (Prospective Ischemia Myocardial Infarction Captopril Survey)]

The aim of the PIMICS project was to create, for the first time in Switzerland, a registry of data concerning epidemiology and therapy in patients hospitalised for acute myocardial infarction covering all regions of the country. During 1995/96 73 Swiss hospitals of all categories took part in the PIMICS project. The ratio between males and females in the 3877 registered patients was 2.6:1 (2791 men vs. 1086 women). Female patients were significantly older than males (70.4 +/- 12.0 years vs. 63.4 +/- 12.6 years; p < 0.0001). The prevalence of risk factors differed between men and women: significantly more women had hypertension or diabetes, whereas smoking was more prevalent in males. The median delay between onset of symptoms and arrival at the hospital was 5.5 hours. Thrombolysis and primary angioplasty were more frequently performed in men (40.4% vs. 31.2% in women, p < 0.0001, and 5.7% in men vs. 3.5% in women, p = 0.005 respectively). During the acute phase males were treated more frequently with betablockers. The overall in-hospital mortality was 9.1%. It was significantly higher in female patients (13.5% vs. 7.4% in men; p < 0.0001) and in patients with reinfarction (14.5% vs. 7.1%; p < 0.0001). The mean hospital stay was 12.6 +/- 5.3 days. Only 7.7% of all patients with acute myocardial infarction were discharged within 6 days. At discharge, 51.7% were treated with betablockers and 69.3% with aspirin; 44.8% received ACE-inhibitors and only 13.8% lipid-lowering drugs. Follow-up measures such as coronary angiography and/or angioplasty or bypass surgery were performed significantly more often in males (45.0% vs. 32.9%; p < 0.0001). Likewise, men were more frequently assigned to a rehabilitation program than women (38.2% vs. 32.9%; p = 0.0004). The pre-hospital delay in patients with acute myocardial infarction remains too long. Primary and secondary prevention should be intensified in high risk groups, particularly in females. Thrombolysis and primary angioplasty as mainstays of treatment in acute myocardial infarction are generally used too sparingly, especially in women. With such measures the hospital stay could be shortened further.

[Mechanisms and prevention of restenosis after coronary angioplasty]

The success of PTCA is limited by late restenosis, which occurs in 30-50% of all cases, chiefly within the first six months after the intervention. Restenosis is due to the proliferation of smooth muscle cells and especially to overproduction of extracellular matrix in the arterial wall. The coronary intervention is followed by a not fully defined constrictive process of wound healing, so-called remodeling. Various alternative intervention techniques were investigated but did not show any clear advantage concerning restenosis compared to PTCA. Although the rate of restenosis is reduced by stent implantation, which hinders remodeling, the remaining intimal hyperplasia often leads to restenosis. In spite of promising results in animal models, to date no effective human pharmacological therapy has been found to prevent restenosis. To determine whether antioxidants, endovascular radiation or gene therapy show any benefit will require further, larger trials.

Recurrent myocardial infarction caused by a giant coronary aneurysm

We report on a patient with a giant aneurysm arising from the right coronary artery leading to infarction due to a steal phenomenon. Emergency coronary angiography was performed. The orifice of the aneurysm was occluded by balloon catheter restoring blood flow and resolving ischemia. Aneurysmectomie was done subsequently. The patient recovered very soon, and the following course was uneventful. This case illustrates that occasionally causes other than usual coronary atherosclerosis may lead to acute coronary syndromes.

A new approach for DDD(R) pacing using a single-pass DDD lead

Short- and long-term results for DDD pacing using a single-pass DDD lead are presented for 3 patients. Single-lead DDD pacing is feasible and may provide major advantages by eliminating the necessity of a second lead.

[After care of acute myocardial infarct: what are the 4 most important points?]

The variable prognosis after myocardial infarction necessitates an individual tailoring of follow-up treatment. Therapeutic decisions must be based on a complete risk stratification including assessment of persisting ischemia, left ventricular function, rhythmic instability and cardiovascular risk factor profile. High risk patients (prognostic indication) as well as symptomatic patients (symptomatic indication) should be referred for coronary angiography to assess the need for revascularisation procedures (PTCA, CABG). The individual risk profile also defines drug therapy for secondary prevention (not more than 3-4 drugs): anti-platelet agents or anticoagulation in every patient; beta blockers in all but the lowest risk group; ACE-inhibitors in heart failure or asymptomatic, substantial left ventricular dysfunction; liberal use of cholesterol-reducing drugs. Life style alterations should be encouraged in almost every patient. Information about the necessary measures to be taken upon occurrence of angina at rest or other cardiac symptoms must be repeatedly given to all patients.

[Secondary prevention in chronic coronary heart disease]

To assess the quality of secondary prevention in patients with known coronary artery disease (CAD) we analyzed prospectively 278 consecutive patients on admission who were hospitalized for acute coronary syndromes (infarction 46%, unstable angina 54%). CAD was known in 155 patients (110 males: acute myocardial infarction 50, unstable angina 105; history of infarction 55%, chronic angina 41%, after CABG 13%, after PTCA 7%, coronary stenoses on angiography 6%). In these patients, aspirin was being administered in 58%, anticoagulation in 12%, betablockers in 43%, angiotensin converting enzyme inhibitors (ACEI) in 20%, and lipid lowering agents in 12%. Calcium blockers were given in 40% (nifedipine 8%). Patients with previous invasive diagnosis and treatment were more frequently treated with drugs of proven prognostic benefit than patients after myocardial infarction and patients with angina only, while overall cardiovascular treatment was similar. The respective rates of treatment were: for aspirin 78%, 60% and 39% respectively (p = 0.0005); for betablockers 59%, 46% and 24% (p = 0.004); for lipid lowering drugs 27%, 7% and 4% (p = 0.002). 12 of 19 patients with known congestive heart failure had ACEI. Only one fourth of dyslipidemic patients had lipid lowering drugs. We conclude that the prevalence of secondary prophylaxis in patients with known CAD is too low despite proven benefit, invasively treated patients having better prophylaxis.

[Splenic infarct, lactate acidosis, and pulmonary edema as manifestations of a pheochromocytoma]

The case of a 45-year-old woman with pheochromocytoma, who presented with severe abdominal pain and headache, diabetes mellitus, lactic acidosis and pulmonary edema, is described and discussed. Spleen infarction, not so far described as an ischemic complication of pheochromocytoma, was seen in computer tomography. After medical pretreatment with labetalol, a pheochromocytoma (2 x 2 cm) of the left adrenal gland was removed. The postoperative course was uneventful.

Acute and short-term effects of the nonpeptide endothelin-1 receptor antagonist bosentan in humans

In recent years, evidence from various animals experiments has accumulated that emphasizes the role of endothelin-1 in the pathophysiology of several cardiovascular diseases, including congestive heart failure. The recent advent of potent antagonists of this system now allows the assessment of the involvement of endothelin-1 in the maintenance of vascular tone in animals and humans. We report hemodynamic data from two trails in patients with chronic severe congestive heart failure (i.e., reduced left ventricular ejection fraction of < 30%, elevated resting pulmonary capillary wedged pressure > 15 mmHg, and/or reduced cardiac index of 2.5 L/min/m2 or less) who were treated with the mixed endothelin-type A and type B-receptor antagonist bosentan. In the first study, the acute effect of bosentan (300 mg, intravenous) on hemodynamics and neurohormones was investigated. Bosentan was well tolerated and significantly improved impaired hemodynamics due to systemic and venous vasodilation. In the second, trial, bosentan was given orally (0.5 g bid) for 14 days, in addition to conventional triple treatment for congestive heart failure, including digitalis, angiotensin-converting enzyme inhibitors, and diuretics. Cardiac hemodynamics were monitored during the first 24 hours of treatment, and measurements were repeated during the last day of bosentan therapy. Bosentan was well tolerated in these patients as well, and hemodynamic measures were compatible with an additional effect of bosentan after 2 weeks. However, there was a slight increase in heart rate as well. Our result underline the importance of endogenously generated endothelin-1 in congestive heart failure and suggest a potential benefit of endothelin antagonism in such patients. However, long-term studies are needed to establish whether chronic endothelin antagonism has beneficial clinical effects and is capable of improving survival and/or symptoms in severe heart failure patients who remain symptomatic despite standard triple therapy.

A comparison of quality-of-life in patients with dual chamber pacemakers and individually programmed atrioventricular delays

Dual chamber pacemakers are increasingly implanted to achieve optimal hemodynamics by AV synchrony, but the effect of AV delay programming on the patient's quality-of-life has been less well studied. The influence of an individually programmed AV delay between 100 and 250 ms on quality-of-life was investigated in a randomized, double-blind crossover study of 13 patients (69 +/- 10 years of age) with dual chamber pacemakers implanted because of high degree AV block. During radionuclide ventriculography at rest, the "optimal AV delay" with the maximal left ventricular ejection fraction and the "most unfavorable AV delay" with the least ejection fraction were determined. The ejection fraction at rest with the "optimal AV delay" was 51% +/- 10%, and with the "most unfavorable AV delay," 44% +/- 11% (P < 0.0001). The optimal AV delay determined by radionuclide ventriculography correlated well with the optimal AV delay determined by Doppler echocardiography using flow velocity integrals (r = 0.78, P < 0.0016). Each patient was assigned in random order to either AV delay during a 2-week period and then the pacing mode was switched for another 2-week period. At the end of each period, patients were assessed by a functional status questionnaire to assess physical capability and two further questionnaires to quantify cardiovascular symptoms or self-perceived health. There were no differences in the two AV delays regarding the patient's perceived physical capability and specific symptoms. The patient's total judgment was identical to the optimal AV delay (score 36% +/- 19%) and the most unfavorable AV delay (33% +/- 21%). Thus, in patients with a dual chamber pacemaker, an individually programmed AV delay affects left ventricular function at rest, but has no influence on quality-of-life. The determination of the flow velocity integral by Doppler echocardiography is a simple and reliable method to optimize the AV delay if necessary.

[Heart surgery in acute heart infarct. Indications and results]

The therapy of acute myocardial infarction has made major advances in the last 10 years. Cardiac surgeons have to adapt their strategies to the more aggressive management of acute myocardial infarction. Only in mechanical complications of acute myocardial infarction is cardiac surgery nowadays the therapy of choice. In cardiac rupture and ventricular septal defect, surgery is the only therapeutic option. In ischemic mitral regurgitation, cardiac surgery is required in the event of concomitant cardiogenic shock and pulmonary edema after intra-aortic balloon pump placement. Coronary artery bypass surgery my be indicated at low risk in patients with unstable angina pectoris when PTCA is not feasible or has failed, or in catheter emergencies.

Pressure gradients across bileaflet aortic valves by direct measurement and echocardiography

BACKGROUND

Pressure gradients calculated from echo-cardiography after aortic valve replacement are commonly much higher than would be expected from in vitro measurements.

METHODS

The mean, peak-to-peak, and maximal gradients across bileaflet aortic prostheses (St. Jude Medical) were measured invasively in 52 patients at high and low heart rate, cardiac index, and stroke volume. One week after operation the gradients were calculated from a standard transthoracic echocardiogram (delta p = 4v2(2)). In a second study 3 to 12 months later, gradients were calculated using the standard, simplified Bernoulli equation, and with the equation considering subvalvular flow velocities (delta p = 4(v2(2-)v1(2)). Invasive and echocardiographic measurements were matched and compared.

RESULTS

Invasively measured mean gradients for 21 to 29-mm valves ranged from 7.4 +/- 4.9 to 4.3 +/- 1.6 mm Hg at systolic flow rates from 11.3 +/- 0.7 to 16.2 +/- 1.8 L.min-1.m-2. Mean echocardiographic gradients were 15.1 +/- 4.5 to 7.5 +/- 2.2 mm Hg (p < 0.001) with the standard method, and 10.5 +/- 1.9 to 5.6 +/- 1.5 mm Hg when considering the subvalvular flow velocity (p < 0.001).

CONCLUSIONS

Mean gradients across bileaflet prostheses are generally low, even in small valves and with high systolic flow. The correlation of the invasive in vivo with in vitro gradients is good. Standard echocardiography overestimates gradients across bileaflet heart valves and high gradients are not due to valve dysfunction. Gradients obtained by echocardiography considering the subvalvular flow velocity correlate better to invasively measured and in vitro gradients.

[Heart failure in elderly patients]

The incidence and prevalence of congestive heart failure increase exponentially with advancing age. Congestive heart failure in the elderly is characterized by a multifactorial etiology, a high proportion of accompanying degenerative changes of the cardiovascular system and age-specific problems regarding diagnosis and treatment. The treatment strategy is the same as in younger patients, but the higher incidence of adverse effects and complications demands special awareness. The majority of decompensations leading to hospitalization are precipitated by insufficient compliance in life style change and drug intake.

Evidence for endothelin-1-mediated vasoconstriction in severe chronic heart failure

Heart failure is commonly associated with high plasma concentrations of endothelin-1, a powerful vasoconstrictor produced by endothelium. The role of endogenously released endothelin-1 in the maintenance of vascular tone in chronic heart failure was assessed by acute administration of an endothelin receptor antagonist, bosentan. 24 patients with chronic heart failure received randomly and double blind two intravenous infusions of either placebo or bosentan (100 mg followed after 60 min by 200 mg). Systemic haemodynamics and plasma endothelin-1 and big-endothelin-1 concentrations were determined before and repeatedly during the 120 min observation period. Baseline endothelin-1 and big-endothelin-1 concentrations, which were above the normal range in all patients, correlated directly with the extent of pulmonary hypertension, with left and right heart filling pressures, and with pulmonary vascular resistance and inversely with cardiac index. Compared with placebo, bosentan reduced mean arterial pressure by 7.7% (95% CI 7.1-9.7), pulmonary artery pressure by 13.7% (10.5-16.9), right atrial pressure by 18.2% (12.0-24.4), and pulmonary artery wedged pressure by 8.6% (5.3-12.0); it increased cardiac index by 13.6% (9.1-18.2), decreased systemic vascular resistance by 16.5% (13.2-19.8), and decreased pulmonary vascular resistance by 33.2% (22.4-44.0). Heart rate did not change. Plasma endothelin-1 concentrations rose more than twofold from baseline in bosentan recipients while big-endothelin-1 concentrations were unchanged. These findings indicate that, in patients with chronic heart failure who have high circulatory endothelin-1 concentrations, this peptide contributes to maintenance of vascular tone. The acute haemodynamic effects of bosentan suggest that chronic endothelin antagonism could be beneficial in such patients.

Influence of coronary artery bypass grafting on ventricular late potentials as a predictive factor for ventricular arrhythmias during short- and long-term follow-up

Ventricular late potentials have been identified as a prognostic factor in the prediction of ventricular arrhythmias in patients after myocardial infarction. In this prospective study the possible impact of late potentials on the prediction of ventricular arrhythmias in the short- and long-term follow-up after coronary artery bypass grafting was evaluated. In 188 patients (165 men, 23 women, age 57 +/- 8 years) with chronic coronary heart disease 48 (26%) had late potentials before bypass grafting; after the procedure this was reduced to 39 (21%) (ns). In 16 (33%) of the 48 patients with late potentials before bypass grafting, late potentials were no longer present in the short-term follow-up (9 +/- 6 days). Conversely, seven (5%) of the 140 patients without late potentials before bypass grafting had late potentials in the short-term follow-up after grafting. Nine (19%) of the 48 patients with late potentials before bypass grafting had ventricular arrhythmias in the peri-operative phase, which had to be treated with antiarrhythmic agents. In contrast, only three (2%) of the 140 patients without late potentials before bypass grafting had to be treated for ventricular arrhythmias (P < 0.001). In the long-term follow-up of 29 +/- 3 months, there were no events in the group of 149 patients without late potentials after grafting. In the 39 patients with late potentials after grafting, there were two (5%) events (two patients with arrhythmic syncope).

CONCLUSIONS

(1) Patients with late potentials before bypass grafting have a markedly higher risk of developing serious ventricular arrhythmias in the peri-operative period than patients without late potentials. (2) Patients without late potentials have a very low risk of developing serious ventricular arrhythmias in the peri-operative period. (3) During long-term follow-up there was only a low probability of developing symptomatic ventricular arrhythmias in patients with or without late potentials.

Physical work capacity with rate responsive ventricular pacing (VVIR) versus dual chamber pacing (DDD) in patients with normal and diminished left ventricular function

To determine the benefit of atrial contribution on work capacity in relation to left ventricular ejection fraction, we studied 17 patients (68 +/- 13 years) with dual chamber pacemakers (DDD) implanted for high degree atrioventricular (AV) block. In random order they were assigned to rate responsive ventricular (VVIR) and to atrial triggered ventricular (VDD) stimulation. Maximum oxygen uptake (max VO2), that correlates best with work capacity, was measured by spiroergometry at a respiratory quotient of 1.1 during treadmill exercise test. Left ventricular ejection fraction at rest was determined by radionuclide ventriculography during VDD-stimulation and an AV delay of 150 ms. There were no differences between these two pacing modes relating heart rate, blood pressure, minute ventilation, exercise duration and maximal work load. In eight patients with an ejection fraction > 50% (60 +/- 10%), but not in nine patients with an ejection fraction < 50% (41 +/- 10%), maximum oxygen uptake was significantly higher (P < 0.01) during atrial triggered ventricular pacing (1440 +/- 533 ml/min) compared with rate responsive ventricular pacing (1328 +/- 536 ml/min). Thus, rate responsive single chamber pacemakers largely enable the same work capacity as dual chamber pacemakers in patients with high degree AV block. Patients with normal left ventricular function may profit most from preserved AV synchrony as shown by the higher maximum oxygen uptake on exercise.

The internal mammary artery malperfusion syndrome: incidence, treatment and angiographic verification

Internal mammary artery (IMA) malperfusion syndrome is caused by an acute imbalance between myocardial demand and nutritional support through the mammary artery. In a consecutive series of 2326 isolated myocardial revascularizations-with at least one IMA to the left anterior descending branch (LAD) in 91.3% (2125/2326)-we identified 45 patients (1.9%) with a perioperative course suggesting IMA malperfusion syndrome. Additional saphenous vein graft to the distal segment of the LAD was performed during normothermic ventricular fibrillation in all patients. Hospital mortality was 4.4% (2/45), intra-aortic balloon pumping was required in 15.5% (7/45) and anterior myocardial infarction occurred in 28.8% (13/45). Coronary angiography was performed in all survivors between 3 and 24 months postoperatively. Wide patent IMA graft and patent saphenous vein graft were observed in 56% (24/43), narrowed but patent IMA graft and patent vein graft in 35% (15/43), while patent vein graft and not visualized IMA in 7% (3/43); in one patient with severely diseased peripheral LAD, no flow could be demonstrated in the IMA graft or in the additional vein graft (1/43, 2.4%). No major differences were found between early and late coronary angiography in these patients. Additional vein graft to distal LAD is the treatment of choice in acute IMA malperfusion syndrome. Despite patent vein graft with superior blood flow, early and late postoperative IMA flow to LAD is maintained in the majority of patients.