Treatment of acute embolic occlusions of the subclavian and axillary arteries using a rotational thrombectomy device

Acute embolic or local thrombotic ischaemia of the upper limbs can be treated by embolectomy or by endovascular techniques. We report here on the endovascular thrombectomy of acute embolic occlusions of subclavian and axillary arteries in two patients using a rotational thrombectomy device and give an overview about the actual literature. Two female patients, each with a history of multivessel coronary disease and intermittent atrial fibrillation, complained of sudden onset of pain at rest and paleness of the left and right arm, respectively. Duplex ultrasound showed a localized embolic occlusion of the left subclavian artery and the bifurcation of the brachial artery in the first patient and a localized embolic occlusion of the distal right subclavian and axillary artery in the second patient. In the first patient, the left subclavian artery was reopened using a 8F-Rotarex device via the femoral access, while the bifurcation of the brachial artery was reopened by local thrombolysis using 25 mg rt-PA because of the insufficient length of the thrombectomy device of 80 cm. In the second patient, the right subclavian and axillary arteries were reopened using a 6F-Rotarex device. Follow-up examinations before discharge and after 6 months showed normalized perfusion of the arms of both patients.

[Normal values for the internal thoracic artery by Doppler ultrasound and modification of the Doppler curve after bypass to the left anterior descending artery]

AIM

In coronary heart disease, the surgical therapy of choice is the construction of an artenal bypass of the left anterior descending artery (LAD) using the internal thoracic artery 8ITA). We define age dependent normal values for the ITA such as diameter of the lumen (LD), peak systolic (Vs) and diastolic (Vd) flow velocity and the ratio of these two values (SDR) measured by duplex ultrasound. Furthermore, the modification and pathological changes of the Doppler curve after minimal invasive bypass of the LAD (MIDCAB) are described.

MATERIAL AND METHODS

96 people, age 18 - 87 years, subdivided into 6 age groups were examined by duplex to define the normal values of the ITA, and 55 patients (mean age 63 +/- 10 years, 48 men, 7 women) were evaluated after MIDCAB-surgery to describe the postoperative modification of the Doppler curve. The examinations were performed using a 4 - 7 MHz linear ultrasound transducer in the right and left 1. or 2. intercostal space parasternally.

RESULTS

In all 96 people, the ITA was detectable on both sides presenting a typical bi- or triphasic Doppler flow profile. A linear age dependent increase in the LD of 1.95 +/- 0.15 mm (right ITA) and 1.93 +/- 0.27 mm (left ITA) respectively to 2.65 +/- 0.48 mm and 2.55 +/- 0.43 mm was found. No significant side difference was found for Vs and Vd, nor were there any age dependent differences for Vs. The SDR showed an age dependent linear increase on the right side from 3.5 +/- 1.1 to 6.1 +/- 2.2, p < 0.0012, and on the left from 3.9 +/- 1.2 to 6.7 +/- 1.7, p < 0.0001. Postoperatively, the Doppler spectrum was modified into a mono- or biphasic Doppler curve with a reduced Vs and an increased Vd resulting in a significantly decreased SDR on the left side compared with the right side (1.3 +/- 0.8 vs. 5.4 +/- 2.0, p < 0.00001). Three patients with angiographically proven graft failure had an SDR of 2.6 - 5.2 (mean 3.8), as opposed to a value of < 2.0 in case of a patent bypass. An SDR > 2.0 has a sensitivity of 100 % and a specificity of 97 % in the detection of a haemodynamically relevant (>70 %) ITA-graft-stenosis.

CONCLUSIONS

With rising age, there is an increase in the LD of the ITA and the peripheral resistance, expressed as SDR. After MIDCAB surgery the former triphasic Doppler flow curve changes into a mono- or biphasic curve corresponding to the coronary blood flow. An SDR >2.0 is a strong indicator of bypass failure.

[First experiences with a 6F-sheath compatible self-expanding nitinol stent]

BACKGROUND

To evaluate the efficacy, safety and limitation of a new 6F-compatible nitinol stent (Dynalink(TM).

MATERIAL AND METHODS

We treated 50 patients (17 women, 33 men, mean age 72 +/- 8 years) by implanting 80 Dynalink(TM)-stents into 75 vessels during a 6-month period. Target lesions were: iliac artery: 25, femoral artery: 31, popliteal artery: 16, femoro-popliteal bypass: 5, subclavian vein: 3. Preinterventional Rutherford classifications: Class 1 : 3 legs (5 %), class 2 : 27 legs (51 %), class 3 : 16 legs (31 %), class 4 : 2 legs (4 %), class 5 : 5 legs (9 %). 40 % stents each were implanted ipsilateral, 60 % cross-over.

RESULTS

All interventions were successful regardless of a sometimes anatomically difficult access to the lesion. The device was characterised by a high flexibility and radial force and the stent did not shorten.

COMPLICATIONS

One distal stent dislocation during placement occurred, no puncture site complication. The mean diameter stenosis was reduced from 91 +/- 10 % (75 - 100 %) to 4 +/- 8 % (0 - 30 %). The ankle-brachial index was improved from 0.46 +/- 0.22 to 0.75 +/- 0.23 (p < 0.001). Post-interventional Rutherford classifications: Class 0 : 43 legs (81 %), class 1 : 5 legs (4,5 %), class 5 : 5 legs (4,5 %).

CONCLUSIONS

The new 6F-sheath compatible nitinol stent is characterised by a good flexibility, radial force, and a lack of shortening. By the reduction of the diameter of the device to 6F, the potential risk of a local bleeding complication may be reduced and 6F sealing devices will be usable. Disadvantages are the 0.018 inch guide-wire lumen and the limited stent sizes.

Hemodynamics and exercise tolerance after bisoprolol, nifedipine, and their combination in patients with angina pectoris

The different mechanisms of action of beta-blockers and calcium antagonists could result in an additive therapeutic effect in patients with angina pectoris. Twenty-one male patients aged between 41 and 68 years and suffering from chronic stable angina pectoris and coronary artery disease confirmed by angiography took part in a randomized, double-blind study to examine the acute effect of 10 mg of bisoprolol, 20 mg of nifedipine, and a combination of the two drugs on hemodynamics at rest and during exercise [heart rate (HR), systolic blood pressure (SBP), rate-pressure product (RPP), cardiac index (CI), total peripheral resistance (TPR), and pulmonary capillary wedge pressure (PCP)], the behavior of the ST segment (ST), and exercise tolerance until occurrence of an ST-segment depression of 0.1 mV (W-ST01) and until onset of anginal pain (W-AP1). Following a baseline exercise test, 11 patients were given 10 mg of bisoprolol orally, whereas 10 patients received placebo. Two hours later, a second exercise test was carried out. All patients in both groups then received 20 mg of N orally. A third exercise test was performed 2 h later. On exercise, bisoprolol resulted in significant changes in HR (-16%), RPP (-22%), and CI (-16%), as well as in TPR (+ 13%); PCP was not significantly affected. Nifedipine led to significant changes in CI (+9%) and PCP (-34%). The effects of bisoprolol on HR and RPP and of nifedipine on PCP were retained in the combination. Competition was detectable as regards the opposing effects on CI and TPR. Measured by W-ST01 and ST, bisoprolol had a marked anti-ischemic effect, whereas that of nifedipine was distinctly less. There was an increase in effect after combination of the drugs (not significant). In patients with chronic angina pectoris due to coronary artery disease, bisoprolol and nifedipine had different hemodynamic profiles after acute administration; when the two drugs were combined, these effects were partly intensified and partly canceled out. There was a tendency for the effect of bisoprolol to be intensified by nifedipine in the combination. The combination of bisoprolol and nifedipine was well tolerated in the doses selected.

[The Straub-Rotarex thrombectomy system: initial experiences]

BACKGROUND

To evaluate the efficacy, safety and limitations of a new rotational thrombectomy device (Straub-Rotarex) in clinical practice.

MATERIAL AND METHODS

The Straub-Rotarex catheter is a new, wire-guided rotational thrombectomy device for the treatment of acute and subacute occlusions of the femoro-popliteal arteries. Over a 6-month period, 28 patients (64% male, mean age 69 +/- 9.5, 51-91 years) with 31 legs, mean duration of occlusion 4.4 +/- 4 (0-20) weeks, mean occlusion length 22 +/- 11 (5-40) cm were treated with the device, 5 of them in a cross-over technique. Target lesions: Aortic-femoral bypass, common iliac artery, external iliac artery, common femoral artery: 1 each, superficial femoral artery: 23, popliteal artery: 17. Initial stage of claudication: IIa: 6%, IIb: 72%, III: 16%, IV: 6%.

RESULTS

Primary success rate: 90% (ipsilateral: 100%, cross-over: 40%). Stage of claudication after intervention: I: 85%, IIa: 7%, III: 4%, IV 4%, one amputation. 3-months follow-up: stage I: 86% (n = 24), IIa: 14% (n = 4), one femoro-popliteal bypass. Restenosis rate 18%. 6-months follow-up: stage I: 56% (n = 9), IIa: 31% (n = 5), IIb: 13% (n = 2). Restenosis rate 56%.

COMPLICATIONS

32% (5 perforations, three cases of embolism after PTA, one wire-induced dissection, one retroperitoneal bleeding coming from the puncture site).

CONCLUSIONS

The new device is a useful tool for the treatment of (sub)acute long-distance occlusions of the SFA and popliteal artery and in-stent restenosis as well in antegrade technique. Main complications are perforations. Cross-over interventions can only be done in special cases.

[Color duplex ultrasound imaging of renal arteries and detection of hemodynamically relevant renal artery stenoses]

AIM

Although colour coded Doppler ultrasound (CCDU) is established as a non-invasive diagnostic tool for detecting renal artery stenoses (RAS), no uniform criterion for defining a hemodynamically relevant stenosis (i.e. angiographic stenosis of > or = 70% of the diameter) exists. We therefore investigated the predictive value of the renal-aortic flow-velocity ratio (RAR) > 3.5 m/s and a difference of < 0.05 between the left and right side for the resistance index according to Pourcelot (dRI) in the detection of a relevant RAS.

PATIENTS AND METHODS

We analysed 500 consecutive CCDU examinations of patients with hypertension retrospectively. An RAR > 3.5 and/or a lateral inequality of the RI < 0.05 were used as stenosis criterion.

RESULTS

In 448 patients (90%) both renal arteries could be found, in 11 patients (2%) only the right artery, in 6 patients (1%) the left artery, and in 35 patients (7%) no renal artery was detectable. In 98 patients (19.6%), RAS was diagnosed, 69 (71%) of them underwent angiography. 38 patients presented an RAR > 3.5 plus dRI > 0.05. In 29 of these, angiography was performed. 96% of them presented with an RAS of > or = 70% and 4% showed an RAS of 40-69% (specificity 97%, sensitivity 76%). In 54 patients the RAR was > 3.5, but dRI < 0.05. 24% of the patients undergoing angiography (n = 37) presented with an RAS of > or = 70%, 68% with an RAS of 40-69%, and 8% with an RAS of < 40% (specificity 60%, sensitivity 100%). 44 hypertensive patients who underwent angiography after a CCDU examination not suggesting the presence of RAS were used as control group.

CONCLUSION

An experienced physician using a high quality colour-coded duplex-machine can reliably detect the renal arteries. The presence of RAS can be diagnosed with certainty by CCDU applying the criterion of RAR > 3.5, but the diagnosis of a one-sided haemodynamically relevant RAS can only be certain if the criterion of dRI > 0.05 is used in addition.

Ultrasound-guided strategy for provisional stenting with focal balloon combination catheter: results from the randomized Strategy for Intracoronary Ultrasound-guided PTCA and Stenting (SIPS) trial

BACKGROUND

Intracoronary ultrasound (ICUS) has provided insights into vascular pathology and interventional therapy. The Strategy for ICUS-Guided PTCA and Stenting (SIPS) trial tested the hypothesis that routine ICUS guidance of coronary interventions improves outcome.

METHODS AND RESULTS

A single-center consecutive-patient randomized design (with 6-month angiographic and 2-year clinical follow-up) was used. Consecutive patients (no chronic total occlusions or emergency procedures) were randomized to ICUS-guided provisional stenting or standard angiographic guidance. Quantitative angiographic minimal lumen diameter (MLD), angiographic restenosis, clinically driven target lesion revascularization, and major adverse cardiac events (MACEs) were evaluated. A total of 291 procedures (356 lesions) were included. Procedure success was higher in the ICUS-guided group than the group randomized to standard guidance (94. 7% versus 87.4%, respectively; P:=0.033), whereas time (65.2+/-31.0 versus 60.5+/-34.0 minutes, P:=0.18) and contrast use (209.3+/-94.1 versus 197.5+/-89.5 mL, P:=0.23) were not significantly different. Stenting rates were similar (49.7% versus 49.5%, P:=0.89). Acute gain was greater in the ICUS-guided group than in the standard guidance group (1.85+/-0.72 versus 1.67+/-0.76 mm, respectively; P:=0.02). Angiographic 6-month analysis revealed no difference in MLD (1.71+/-0.94 versus 1.57+/-0.90, P:=0.19) or binary restenosis rate (>50% diameter stenosis) (29% versus 35%, P:=0.42). Clinical follow-up (602+/-307 days) showed a significant decrease in clinically driven target lesion revascularization in the ICUS group compared with the standard guidance group (17% versus 29%, respectively; P:=0.02).

CONCLUSIONS

Although angiographic MLD did not differ significantly after 6 months, ICUS-guided provisional stenting improved 2-year clinical results after intervention.

A randomized comparison of clopidogrel and aspirin versus ticlopidine and aspirin after the placement of coronary-artery stents

BACKGROUND

The introduction of an effective antiplatelet therapy with aspirin and ticlopidine after the placement of coronary-artery stents has decreased the risk of thrombotic stent occlusions (TSO) and hemorrhagic complications. However, the use of ticlopidine is limited by hematological and gastrointestinal adverse effects. The safety and efficacy of clopidogrel after stenting remains to be established.

METHODS AND RESULTS

After successful coronary stenting during elective or emergency percutaneous transluminal coronary angioplasty, 700 patients with 899 lesions were randomly assigned to receive a 4-week course of either 500 mg ticlopidine (n=345) or 75 mg clopidogrel (n=355), in addition to 100 mg aspirin. All the following clinical events reflecting TSO were included in the prespecified primary cardiac endpoint: cardiac death, urgent target vessel revascularization, angiographically documented TSO, or nonfatal myocardial infarction within 30 days. The primary noncardiac endpoint was defined as noncardiac death, stroke, severe peripheral vascular or hemorrhagic events, or any adverse event resulting in discontinuation of study medication. Cardiac events occurred in 17 patients [11 (3.1%) with clopidogrel and 6 (1.7%) with ticlopidine (P=0.24)]. The primary noncardiac endpoint was observed in 16 patients (4.5%) assigned to receive clopidogrel versus 33 patients (9.6%) assigned to receive ticlopidine (P=0.01).

CONCLUSIONS

After the placement of coronary-artery stents in unselected patients, antiplatelet therapy with aspirin and clopidogrel seems to be comparably safe and effective as aspirin and ticlopidine. Noncardiac events were significantly reduced with clopidogrel.

Left ventricular function during interval and steady state exercise

PURPOSE

Interval training (INT) is a commonly used method of exercise training in both athletic and clinical populations. Although we generally understand left ventricular (LV) function during steady state (SS) exercise, there are no data regarding LV function during INT.

METHODS

We studied eight healthy, physically active volunteers during upright cycle ergometry during 15 min of both SS and INT, at the same average power output (90% individual anaerobic threshold), using first pass radionuclide ventriculography. During INT (60s/60s), measures of LV function were made during work (220 W) after 4 and 12 min and during recovery (120 W) after 7 and 15 min. These were compared with the average of four temporally matched measures made during SS (170 W).

RESULTS

During INT, LV ejection fraction increased from rest (67 +/- 6%) to 77 +/- 5, 80 +/- 5, 77 +/- 5 and 79 +/- 4% after 4, 7, 12, and 15 min, respectively. During SS, LV ejection fraction was not significantly different at rest (70 +/- 4%) or during exercise (76 +/- 4, 79 +/- 4, 80 +/- 3, and 81 +/- 3%) after 4, 7, 12, and 15 min, respectively. Other measures of LV function (HR, BP, LV volumes, cardiac output, systemic vascular resistance, peak emptying, and filling rates) were likewise similar during temporally matched measurements during INT and SS.

CONCLUSIONS

Although there were the expected transitions of ejection fraction with work and recovery, the overall hemodynamic picture during INT was very similar to SS. These data suggest that LV function during INT is not substantially different to that during SS.

Symptomatic myocardial ischemia and everyday life: implications for clinical use of interactive monitoring

In coronary heart disease (CHD), pathological myocardial ischemic changes do not always occur with the symptom of heart pain. Methodological problems make it difficult to examine the factors that influence silent and symptomatic myocardial ischemia in everyday life. This study uses a computer-assisted monitoring system with an interactive Holter ECG, an actometer, and an electronic diary. Self-report measurements indicate that symptomatic patients tend toward increased neuroticism, whereas asymptomatic patients engage in beneficial and active coping skills more frequently. The results of the monitoring study demonstrate the same degree of ischemia in silent and symptomatic episodes. However, these episodes show differences in certain psychological context variables. Symptomatic episodes are linked to high subjective strain and severe tension. Because angina pectoris is not a reliable warning signal of myocardial ischemia, the use of the interactive monitoring system is recommended for educating CHD patients on how to cope with excessive strain in everyday life.

[Lipid intervention and coronary heart disease in men less than 56 years of age. The Coronary Intervention Study: CIS]

The CIS was undertaken with the aim to evaluate the effects of lipid modifications on angiographic progression and regression of CAD in patients with CAD and hypercholesterolemia. The design included a multicenter randomized, double-blind, parallel, placebo-controlled comparison, with target and safety limits for adjusting the trial medication depending on the LDL cholesterol level (LDL-C) achieved, i.e., up to 40 mg of simvastatin (S) or placebo (P) daily, add-on medication (up to 3 x 4 g Colestyramin), and diet counselling. Male patients, average age 49 (< or = 56) years, were included with angiographic CAD and a screening total cholesterol of 207-350 mg/dl, who were not due to undergo coronary bypass surgery or PTCA, who did not suffer from serious other disease (e.g., diabetes mellitus), and who had not undergone coronary bypass surgery previously.

RESULTS

All baseline variables were comparable in the treatment groups, with 129 patients taking S and 125 taking P. Of these 254 patients 217 had their final study visit and 207 underwent a second angiography after an average treatment time of 2.3 years under an average daily dose of 37 mg S. 205 pairs of films were available for analysis. Vital information was obtained of all patients until closure of the data bank, half a year after the last study angiography. Five deaths occurred within the study period, 12 through March 15, 1995 (S: 1/6, P: 4/6). 37 patients (S: 18, P: 19) discontinued trial drug and protocol. Concomitant CAD medication was comparable in both groups, except lipid-lowering add-on medication which was significantly higher in the P group (38% versus 13%). Significant changes in lipid levels, on treatment, were observed in the S group amounting to a mean difference in LDL-C of -35%, in Apo-Protein B (ApoB) of -30%, in VLDL-C of -37%, and in triglycerides (TG) of -27%, and in HDL-C of +6%, in comparison to the control group; these differences were even greater in 137 fully compliant patients: -41, -36, -39, -31, and +7%, respectively. Progression in the S group was significantly less, as defined by the two primary target criteria: 1) the minimum obstruction diameter (MOD), determined by quantitative coronary angiography (QCA), decreased about five times less in comparison to the control group (S: by -0.017; P: -0.0954 mm), and 2) the standardized visual global change score (GCS) deteriorated almost three times less in the S group (by +0.20) than in the P group (+0.58). Of the secondary target criteria, the mean lumen diameter (QCA) also developed a significant difference (S: -0.20; P: +0.23 mm; p = 0.0006) with a trend toward regression in the S group. The QCA-%-stenosis deteriorated three- to four-times less in the S group as compared to the control group (S: by 0.69%; P: by 2.73%; p = 0.0022), and the number of patients with angiographic progression was nearly halved (S: 30%; P: 56%; p < 0.0000). These differences were determined by intention to treat analysis (ITT), and they were obtained in spite of lipid lowering add-on medication in 38% of the P patients; they turned out to be more pronounced in 137 fully compliant patients, in an analysis "as treated". The mean decrease in LDL-C serum level caused by S was significantly correlated to the decrease in progression, and multivariate regression analysis of both treatment groups identified LDL-C (or ApoB) and TG as independent predictors of progression. Progression appeared to be most pronounced in low and medium sized lesions, and the beneficial effect of lipid intervention dominated in lesions with 12-56% QCA stenosis severity. A small fraction of patients who suffered from exercise-induced angina, with ST-segment-depression at the beginning of the study, experienced a significant improvement under S as compared to P treatment. Although the study was not designed to show differences in clinical events, the combined number of all major cardiovascular events tended to be less frequent in the S than in the C gr

Comparison of left ventricular function during interval versus steady-state exercise training in patients with chronic congestive heart failure

This study sought to assess the safety of interval exercise training in patients with chronic congestive heart failure (CHF) with respect to left ventricular (LV) function. For effective rehabilitation in CHF, both aerobic capacity and muscle strength need to be improved. We have previously demonstrated in both coronary artery bypass surgery and patients with CHF that interval exercise training (IET) offers advantages over steady-state exercise training (SSET). However, because LV function during IET has not yet been studied, the safety of this method in CHF remains unclear. To assess LV function during IET and SSET, at the same average power output, 11 patients with stable CHF were compared with 9 stable coronary patients with minimal LV dysfunction (control group). Using first-pass radionuclide ventriculography, changes in LV function were assessed during work versus recovery phases, at temporally matched times between the fifth and sixteenth minute of IET and SSET. In CHF during IET, there were no significant variations in the parameters measured during work and/or recovery phases. During the course of both IET and SSET, there was a significant increase in LV ejection fraction (5 vs 4 U; p <0.05 each), accompanied by increased heart rate (6 vs 8 beats/min; p <0.05 each) and cardiac output (2.4 vs 1.8 L/min; p <0.01 and p <0.05). In CHF, the magnitude of change in LV ejection fraction during IET was similar to that seen in controls. Both LV ejection fraction and the clinical status in patients with CHF remained stable during IET. Because IET appears to be as safe as SSET with respect to LV function, IET can be recommended for exercise training in CHF to apply higher peripheral exercise stimuli and with no greater LV stress than during SSET.

AV nodal re-entry tachycardia in elderly patients: clinical presentation and results of radiofrequency catheter ablation therapy

BACKGROUND

Modification of AV nodal conduction by means of radiofrequency catheter ablation has become the accepted mode of therapy for patients with symptomatic AV nodal re-entry tachycardias (AVN-RT). The published results demonstrate high success rates and a low incidence of severe complications. However, published series have primarily dealt with relatively young patient populations. Little is known about the efficacy and risks of radiofrequency catheter ablation of AVN-RT in the elderly.

METHODS

We retrospectively analysed our data of 404 patients who underwent a catheter ablation therapy for AVN-RT between 1992 and June 1997. Nine patients were excluded from further analysis because of presence of more than one tachycardia mechanism. The ablation procedure was performed at the time of the diagnostic electrophysiologic study.

RESULTS

The mean age of 395 patients undergoing catheter ablation for AVN-RT was 52.3 years (19-90 years); 85 patients were 65 years old or older. Compared with the younger subgroup, these elderly patients (mean age 70.4 years) more often had organic heart disease (coronary heart disease with or without myocardial infarction 19.3% versus 2.6%; P < 0.02), more often had syncopes or presyncopes with AVN-RT (43.2% versus 29.8%; P < 0.05), had more hospitalisations and emergency treatments because of their symptoms (56.8% versus 39.5%; P < 0.05) although the cycle length of the induced AVN-RT was significantly shorter in the younger patient group (325 ms versus 368 ms; P < 0.001). Slow pathway ablation was performed in 94% of the young and 82% of the elderly (P < 0.001). In 17.5% of the elderly patients versus 6.5% of the young (P < 0.05) the fast pathway approach was chosen as the first therapy or tried after an unsuccessful approach to the slow pathway. The overall success rate (96.8% in the young and 95.3% in the elderly) and the recurrence rate (5.8% in the elderly versus 4.9% in the young) were similar in both patient groups. There were no differences regarding the total procedure of fluoroscopy time, radiation exposure or the incidence of high-degree AV-block necessitating pacemaker implantation (2.3% in the elderly versus 1.6% in the young).

CONCLUSIONS

In patients older than 65 years, AVN-RT may lead to severe, sometimes life-threatening symptoms, despite the fact that the tachycardia is not as fast as in younger patients. Radiofrequency catheter ablation can be performed effectively and safely and should be offered to these patients as first-choice therapy.

Effect of breathing rate on oxygen saturation and exercise performance in chronic heart failure

BACKGROUND

In chronic heart failure (CHF), impaired pulmonary function can independently contribute to oxygen desaturation and reduced physical activity. We investigated the effect of breathing rate on oxygen saturation and other respiratory indices.

METHODS

Arterial oxygen saturation (SaO2) and respiratory indices were recorded during spontaneous breathing (baseline) and during controlled breathing at 15, six, and three breaths per min in 50 patients with CHF and in 11 healthy volunteers (controls). 15 patients with CHF were randomly allocated 1 month of respiratory training to decrease their respiratory rate to six breaths per min. Respiratory indices were recorded before training, at the end of training, and 1 month after training.

FINDINGS

During spontaneous breathing, mean SaO2 was lower in CHF patients than in controls (91-4% [SD 0.4] vs 95.4% [0.2], p<0.001). Controlled breathing increased SaO2 at all breathing rates in patients with CHF. Compared with baseline, minute ventilation increased at 15 breaths per min (+45.9% [9.8], p<0.01), did not change at six breaths per min, and decreased at three breaths per min (-40.3% [4.8], p<0.001). In the nine CHF patients who had 1 month of respiratory training, resting SaO2 increased from 92.5% (0.3) at baseline to 93.2% (0.4) (p<0.05), their breathing rate per min decreased from 13.4 (1.5) to 7.6 (1.9) (p<0.001), peak oxygen consumption increased from 1157 (83) to 1368 (110) L/min (p<0.05), exercise time increased from 583 (29) to 615 (23) min/s (p<0.05), and perception of dyspnoea reduced from a score of 19.0 (0.4) to 17.3 (0.9) on the Borg scale (p<0.05). There were no changes in the respiratory indices in the patients who did not have respiratory training.

INTERPRETATION

Slowing respiratory rate reduces dyspnoea and improves both resting pulmonary gas exchange and exercise performance in patients with CHF.

Delayed VO2 kinetics during ramp exercise: a criterion for cardiopulmonary exercise capacity in chronic heart failure

PURPOSE

Kinetics of VO2 at onset of constant work rate exercise was previously shown to be slowed in patients with chronic heart failure (CHF) compared with that in healthy normals. Because bicycle ergometry with ramp protocol is usually used for exercise testing with CHF patients, it would be of practical importance if it can be shown that a delay in the time interval of linear increase of VO2 (TILIV) to work rate occurs after beginning ramp exercise. Data of central hemodynamics (CHF) and noninvasive cardiopulmonary parameters (CHF, normals) should also correlate with VO2 delay time if this parameter is related to cardiopulmonary exercise capacity.

METHODS

Fifteen males with CHF (mean +/- SEM: age 52 +/- 2 yr; ejection fraction 32 +/- 4%; peak cardiac index 3.9 +/- 0.3 L x m(-2) x min(-1)) and 28 healthy males (50 +/- 1 yr) were assessed. During ramp bicycle ergometry (3 min unloaded, work rate increments of 12.5 W x min(-1)), VO2 was measured breath by breath.

RESULTS

After the onset of ramp exercise, there was a difference in the TILIV between patients and normals (83.7 +/- 3.6 vs 66.8 +/- 2.9 s; P < 0.001). Significant differences between both groups were also found for VO2 at ventilatory threshold (VT) (10.1 +/- 0.1 vs 15.2 +/- 0.7 mL x kg(-1) x min(-1); P < 0.0001), VO2 at VT relative to predicted VT (58 +/- 4 vs 97 +/- 4%; P < 0.0001), peak VO2 (13.2 +/- 1.0 vs 34 +/- 1.4 mL x kg(-1) x min(-1), P < 0.001), and increase of systolic blood pressure (36 +/- 7 vs 71 +/- 5 mm Hg; P < 0.0001). In CHF, the TILIV correlated significantly with peak cardiac index and VO2 at VT (r = -0.71; P < 0.005 each), relative value of VO2/kg at VT (r = -0.61; P < 0.03), peak VO2/kg (r = -0.63; P < 0.01), and increase of systolic blood pressure (r = -0.52; P < 0.02). In the normals only VO2/kg at VT correlated significantly with TILIV (r = -0.41; P < 0.03). In patients, stepwise regression analysis identified three predictors which could explain 79% of the variance of TILIV: VO2/kg at VT (r2 = 0.51), peak cardiac index (r2 = 0.20), and peak VO2/kg (r2 = 0.08).

CONCLUSION

TILIV, determined at the onset of ramp exercise, is prolonged in CHF patients compared with that in normals and reflects severity of functional impairment because of reduced cardiac index and aerobic capacity. TILIV can provide information about changes in cardiopulmonary exercise capacity and thus can be used for follow-up and treatment studies in CHF.

[Improvement of aerobic capacity in chronic congestive heart failure. Which training method is appropriate?]

Standardized guidelines for exercise training for patients with chronic congestive heart failure (CHF) have not been established. In the past, CHF patients involved in exercise training studies demonstrated a wide range of cardiac and functional impairment, with an ejection fraction between 18 and 35% and a peak VO2 between 12.2 and 25.4 ml/kg/min on average. For determination of training intensity, a VO2 between 40 and 70% of peak VO2 and/or training heart rate between 60 and 80% of peak heart rate was used. There was also a wide range for frequency (between 3 and 7 times per week) and duration of training (between 20 and 60 min per session). For aerobic exercise training only continuous training methods were applied. We have developed a new interval training method which allows intense exercise stimuli on peripheral muscles with minimal cardiac strain. After only three weeks of training, the improvement in aerobic capacity was similar to that reported after longer training periods using continuous methods. To determine work rate for work phases of interval training, a special steep ramp test was developed. By analysis of acute physical responses to this testing procedure and to the interval training, both were proven to be tolerable in CHF patients, even if their ejection fraction is as low as 13%, or peak cardiac index not greater than 1.61/m2/min, and peak VO2 less than 8.5 ml/kg/min.

Signs of vagal reinnervation 4 years after heart transplantation in spectra of heart rate variability

Several investigators have shown signs of possible sympathetic but not parasympathetic reinnervation in heart transplanted patients. Spectral analysis of heart rate and blood pressure variability is a noninvasive tool appropriate to detect a functional autonomous reinnervation to the heart. In a follow-up study, 13 patients after heart transplantation (HTx) were investigated, mean age 50.6+/-8.5 years, 18 healthy volunteers were selected as control group. For each patient two recordings were performed which took part 14+/-5 months respectively 42+/-8 months after HTx. ECG and systolic blood pressure (SBP) have been recorded simultaneously for 5 min in supine position during controlled respiratory rate of 12 or 15 cycles/min. No graft rejection has been detected in the endomyocardial biopsy performed right after the recordings. Power spectral densities (PSD) were calculated for the beat-to-beat time series of RR-intervals (distance of two following QRS complexes) and SBPs. The area of PSD in the range of 0.05-0.17 Hz was defined as low frequency (LF) and that of 0.18-0.35 Hz as high frequency (HF). LF and HF are indicative of efferent sympathetic respectively parasympathetic activity at the sinus node. A significant increase of LF (226%) and HF (213%) during a mean period of 28 months could be found. No differences were to be shown for systolic blood pressure variability. Previous findings confirm that LF band increases 4 years after transplantation, suggesting a possible sympathetic reinnervation of the heart. On the other hand an increase of the HF band also suggests a parasympathetic reinnervation.

Predictors of response to exercise training in severe chronic congestive heart failure

We prospectively assessed whether baseline central hemodynamics and exercise capacity can predict improvement of VO2 at ventilatory threshold (VT) after exercise training in patients with severe chronic congestive heart failure. Eighteen patients (mean +/- SEM; age 52 +/- 2 years), half of them listed for transplant, underwent 3 weeks of exercise training (interval cycle and treadmill walking; 5 x/week) and 3 weeks of activity restriction in a random-order crossover trial. Baseline data were not significantly different for groups with exercise training first and activity restriction first: cardiac index at rest (2.1 +/- 0.1 L/m2/min), maximum cardiac index (3.1 +/- 0.2 L/m2/min) (Fick), and echocardiographic ejection fraction (21 +/- 1%). The same was true for cardiopulmonary exercise data (cycle ergometry; up 12.5 W/min): VO2 at VT (9.3 +/- 0.4 ml/kg/min), maximum VO2 (12.2 +/- 0.7 ml/kg/min), VT in percentage of predicted maximum VO2 (31 +/- 2%), heart rate at VT (95 +/- 4 beats/min), and decrease of dead space-to-tidal volume ratio from rest to VT (33 +/- 1 --> 29 +/- 1). Improvement of VO2 at VT after training (2.2 +/- 0.4 ml/kg/min; p <0.001) was not related to baseline central hemodynamics (r = <0.10 for each), but was greater in patients with a lower baseline VO2 at VT (r = -0.65; p <0.01), peak VO2 (r = -0.66; p <0.01), VT in percentage of predicted maximum VO2 (r = -0.74; p <0.001), heart rate at VT (r = -0.63; p <0.01), and smaller decrease of dead space-to-tidal volume ratio from rest to VT (r = 0.65; p <0.01). Ejection fraction after exercise training (24 +/- 2%) and activity restriction (23 +/- 2%) did not differ significantly compared with baseline, and patient status (heart failure and cardiac rhythm) remained stable. Three parameters accounted for 84% of the variance of improvement in VO2 at VT: VO2 at VT in percent predicted maximum VO2, decrease of dead space-to-tidal volume ratio, and heart rate at VT. The findings suggest that there was a greater increase in VO2 at VT after exercise training in patients with greater peripheral deconditioning at baseline. The improvement was unrelated to central hemodynamics. Clinically stable patients with severe chronic congestive heart failure, potential heart transplant candidates, and those awaiting transplantation may benefit from involvement in a short-term exercise training program.

Short-term reproducibility of cardiopulmonary measurements during exercise testing in patients with severe chronic heart failure

Eleven men with severe chronic heart failure (peak cardiac index 4.0 +/- 0.2 L/m2/min), six on a heart transplantation waiting list, were prospectively assessed. To determine reproducibility of cardiopulmonary and hemodynamic variables for clinical purposes during ramp bicycle ergometry, the patients underwent two ramp bicycle ergometer tests (3 minutes unloaded, work rate increments of 12.5 W/min) with a 1-week interval between tests. Oxygen uptake (VO2) carbon dioxide production (VCO2), and ventilation were measured breath by breath, and calculations were performed to determine gas exchange ratio, oxygen pulse, ventilatory equivalents of oxygen and carbon dioxide, and end-tidal partial pressure for oxygen and carbon dioxide. Additionally, heart rate, blood pressure, and lactate levels were assessed. Measurements were performed at submaximum work rate levels of 25 W, 50 W, and 75 W at ventilatory threshold and at peak work rate. At all measurement points, the coefficient of variation for cardiopulmonary variables was between 1.4% and 7.1% for submaximum work rate levels, between 1.2% and 4.4% at ventilatory threshold, and between 2.4% and 7.1% at peak work rate. For heart rate, blood pressure, and lactate levels, coefficient of variation was between 2.7% and 5.7% for submaximum work rate levels, between 1.4% and 6.1% at ventilatory threshold, and between 1.2% and 5.5% at peak work rate. The data suggest high reproducibility for duplicate measurements of cardiopulmonary and hemodynamic variables during ramp bicycle ergometry in patients with severe chronic heart failure. The results may be used to determine whether any variable in a single patient is significantly different from that obtained in a previous exercise test or if the change is within experimental error.

Single device approach to ultrasound-guided percutaneous transluminal coronary angioplasty and stenting: initial experience with a combined intracoronary ultrasound/variable diameter balloon

We evaluated the use of both intracoronary ultrasound (ICUS) information and unique balloon characteristics provided by a combined ICUS/variable diameter balloon catheter during coronary interventions to achieve the maximal residual lumen using the least number of devices. In 47 patients, 64 coronary lesions were treated with either sequential percutaneous transluminal coronary angioplasty (PTCA) (n = 40) or stenting (primary [n = 17], secondary [n = 7]). The result after PTCA was judged satisfactory if the lumen cross sectional area (by ICUS) in the lesion exceeded 65% of the mean reference area. Stent implantation was judged according to revised MUSIC trial criteria. PTCA or stenting was successful in all 64 lesions using 47 combination devices and 10 conventional balloons (mean number of balloons per lesion: 0.90). PTCA group: diameter stenosis decreased from 78 +/- 11 to 23 +/- 13% following inflation at 10.3 +/- 3.0 atm. ICUS lumen area was 4.6 +/- 1.9 mm2 (proximal reference: 7.4 +/- 3.3 mm2, distal reference: 5.7 +/- 1.8 mm2) resulting in a residual area stenosis of 28 +/- 15%. Stent group: diameter stenosis was reduced from 77 +/- 14 to 10 +/- 10% after stenting. ICUS defined minimal lumen area in the stent was 8.2 +/- 2.2 mm2 (proximal reference: 8.7 +/- 2.6 mm2, distal reference: 8.0 +/- 2.2 mm2) resulting in a residual area stenosis of 7.2 +/- 14.6%. No patient death, myocardial infarction, or emergency surgery occurred and only one target lesion required re-PTCA during hospitalization. In conclusion, use of a combined ICUS/variable diameter balloon catheter allows a single device strategy for ICUS-guided PTCA and stenting in the majority (84%) of unselected lesions.

Effects of exercise training and activity restriction on 6-minute walking test performance in patients with chronic heart failure

Eighteen hospitalized patients with severe chronic heart failure (ejection fraction [mean +/- SEM] 21% +/- 1%) underwent 3 weeks of exercise training (interval bicycle ergometer and treadmill walking training exercises) and 3 weeks of activity restriction in a random-order crossover trial. Before and after exercise training and after activity restriction, a 6-minute walking test was performed to determine the maximum distance walked, hemodynamic and cardiopulmonary responses, norepinephrine levels, and ratings of leg fatigue and dyspnea while walking. A ramp test on bicycle ergometer (increments of 12.5 W/min) was performed before and after exercise training and activity restriction to determine peak oxygen uptake. After training, the maximum distance walked was increased by 65% (from 232 +/- 21 m at baseline to 382 +/- 20 m; p < 0.001), whereas after activity restriction (253 +/- 19 m) there was no significant difference compared with baseline. No significant differences in hemodynamic and cardiopulmonary parameters (with the exception of the ventilatory equivalent for carbon dioxide and perceived exertion) or norepinephrine levels were observed during walking tests. Improvement in maximum distance walked correlated significantly with training-induced increase in peak oxygen uptake measured during bicycle ergometry (r = 0.47, p < 0.05). The lower the maximum distance walked at baseline, the more pronounced the training-induced prolongation of maximum distance (r= -0.73; p < 0.001). These data support the value of exercise training in patients with severe chronic heart failure for improving maximum distance walked, as documented by the 6-minute walking test. The impairment of walking test performance during activity restriction suggests a need for long-term exercise training programs.

Interval training in patients with severe chronic heart failure: analysis and recommendations for exercise procedures

This study analyzes a new exercise training procedure, which includes interval exercise training on cycle ergometer (IntCT) (30-s work phases/60-s recovery phases) and on treadmill (60-s work and recovery phases each). Training was applied for 3 wk in 18 patients with severe chronic heart failure (CHF) ((mean +/- SEM) age 52 +/- 2 yr, ejection fraction 21 +/- 1%). Peak VO2 was increased from 12.2 +/- 0.7 to 14.6 +/- 0.7 ml-kg-1 min-1 owing to training (P < 0.001). A specific steep ramp test (work rate increments 25 W.10 s-1) was developed to derive exercise intensity for work phases in IntCT, which was 50% of the maximum work rate achieved. Steep ramp test was performed at the start of the study to determine the initial training work rate, then weekly to readjust it. Since the maximum work rate achieved from this test increased weekly (144 +/- 10 W -->172 +/- 10 W-->200 +/- 11 W; P < 0.001), the training work rate also increased (72 +/- 4 W-->86 +/- 6 W-->100 +/- 7 W; P < 0.001). Physical responses to IntCT were measured. There was no significant change in heart rate, blood pressure, and ratings of perceived exertion (RPE) using a Borg Scale between the first and the third week of training (heart rate 88 +/- 3 b.min-1; blood pressure 115 +/- 4/80 +/- 2 mm Hg; leg fatigue 12 +/- 1; dyspnea 10 +/- 1). Mean lactate concentration (1.70 +/- 0.09 mmol-1-1) indicated an overall aerobic range of training intensity. When compared with the commonly used intensity level of 75% peak VO2 from an ordinary ramp test (work rate increments 12.5 W.min-1), the performed training work rate was more than doubled (240%; P < 0.0001) while cardiac stress was lower (86%; P < 0.01). Values of norepinephrine and epinephrine as well as of RPE corresponded to those measured at 75% peak VO2. Interval exercise training is thus recommended for selected patients with CHF as it allows intense exercise stimuli on peripheral muscles with minimal cardiac strain. Using a steep ramp test, training work rate can be determined and readjusted weekly during initial training period.

The effect of simvastatin on progression of coronary artery disease. The Multicenter coronary Intervention Study (CIS)

BACKGROUND

In several angiographic trials, HMG-CoA reductase inhibitors have shown a beneficial effect on the progression of coronary artery disease. Using 20 mg simvastatin, day-1, a treatment period of up to 4 years was necessary to show a significant reduction in coronary artery disease progression. The question remains however whether higher dosages of simvastatin would be more advantageous in respect to the magnitude of the effect and the required time interval to demonstrate treatment efficacy.

METHODS AND RESULTS

In the Coronary Intervention Study (CIS), a multicentre randomized double-blind placebo-controlled study, the effects of lipid-lowering therapy with simvastatin on progression of coronary artery disease in 254 men with documented coronary artery disease and hypercholesterolaemia were investigated. Following a period of lipid-lowering diet, treatment with 40 mg simvastatin or placebo was maintained for an average of 2.3 years. Two primary angiographic endpoints were chosen: the global change score (visual evaluation according to the method of Blankenhorn) and the per patient mean change of minimum lumen diameter (evaluated by the CAAS I system). The mean simvastatin dose was 34.5 mg day-1. In the placebo group, the serum lipids remained unchanged; in comparison to the placebo group the simvastatin group showed a 35% LDL-cholesterol decrease. Coronary angiography was repeated in 205 patients (81%) and 203 film pairs (80%,) were evaluable by quantitative coronary angiography. In the simvastatin and placebo groups, the mean global change scores were +0.20 and +0.58 respectively, demonstrating a significantly slower progression of coronary artery disease in the treatment group (P = 0.02). The change in minimum lumen diameter assessed by computer-assisted quantitative evaluation with the CAAS I system was -0.02 mm in the simvastatin group and -0.10 mm in the placebo group (P = 0.002). In the simvastatin group, there was a significant correlation between the LDL cholesterol levels achieved therapeutically and the per patient mean loss of minimum lumen diameter (r = 0.29; P = 0.003). During the study period, there was no significant difference in the incidence of serious cardiac events (15 of 129 patients in the simvastatin group and 19 of 125 patients in the placebo group, ns).

CONCLUSION

Treatment with 40 mg simvastatin day-1 reduces serum cholesterol and slows the progression of coronary artery disease significantly within a short period of treatment time. In the treatment group, retardation of progression is inversely correlated to the LDL-cholesterol levels achieved.

Age-dependent differences in the anticoagulant effect of phenprocoumon in patients after heart valve surgery

OBJECTIVE

An enhanced response to warfarin and an increased risk of major bleeding has been observed in older patients. The reason for this increase in sensitivity remains unknown. It could be due to pharmacodynamic reasons, pharmacokinetic reasons, or both.

METHODS

We therefore followed an anticoagulant regimen with phenprocoumon in 19 older (76 years) and 19 younger patients (50 years) following heart valve replacement. INR values were determined frequently. At the 4th and around the 24th day after starting treatment with phenprocoumon, we also measured the total and unbound plasma concentration of phenprocoumon.

RESULTS

The dose requirement to obtain the desired anticoagulant effect was significantly lower in the older patients than in the younger patients (26.3 vs. 37.3 micrograms.kg-1.day-1). The total plasma concentration (2.19 vs. 2.43 micrograms.ml-1), the percentage unbound drug in the plasma (0.61 vs. 0.64%) and the unbound plasma concentration (13.8 vs. 15.1 ng.ml-1) did not differ significantly between older and younger patients. The dose-adjusted INR (INR/dose) was higher in the older patients (110 vs. 67) but the INR adjusted for the unbound plasma concentration (INR/Cuss) which reflects the intrinsic sensitivity to the drug, was not significantly different (192 vs. 173). However, the older patients had an about 30% significantly lower metabolic clearance based on unbound drug (84 vs. 115 ml.kg-1.h-1).

CONCLUSIONS

Older patients (> 70 years) require a dose approximately 30% lower than younger patients (< 160 years). Pharmacokinetic reasons (reduced metabolic clearance) are mainly responsible for the lower dose requirement of the older patients after heart valve surgery.

Alterations of breathing in chronic heart failure: clinical relevance of arterial oxygen saturation instability

1. In patients with chronic heart failure (CHF) alterations of breathing such as Cheyne-Stokes respiration (CSR) or periodic breathing, (PB) have been frequently described during both day- and night-time. These respiratory rhythm disorders are associated with marked oscillations of arterial oxygen saturation (SaO2) which may expose the patients to prolonged hypoxia. 2. In 40 stable CHF patients and 8 controls during awake day-time, we studied the relationship between alterations of breathing and SaO2, to verify the effect of voluntary control of respiration or oxygen therapy on the instability of SaO2 (analyzed as standard deviation (SD) of the mean value). Simultaneous recordings of ECG, lung volumes and SaO2 were made during 10 min. resting and 4 min. controlled breathing In a subgroup of 5 CHF the effect of oxygen therapy was compared to that of controlled breathing. 3. It was found that 62% of CHF had CSR or PB. Mean SaO2 and SD of SaO2 were significantly different in CHF as compared to controls (respectively 92.4 +/- 2.5 vs 95.4 +/- 0.5%, p < 0.002 and (1.27 +/- 0.9 vs 0.28 +/- 0.13%, p < 0.01), but among CHF pts those with CSR and PB had a lower SaO2 and a more pronounced instability of SaO2. Controlled breathing eliminated apneas and reduced or abolished the variation of tidal volume. In both control and CHF it resulted in an increase of mean SaO2 while a significant reduction of SaO2 instability was observed only in CHF, particularly if CSR or PB were present. Voluntary control of respiration was similar to oxygen therapy in increasing SaO2, but more effective on SaO2 SD. 4. It is concluded that in stable CHF, resting SaO2 is reduced and showed a marked instability particularly when periodic alterations of breathing were present. Continuous beat-to-beat recording of SaO2 may detect patients who have PB or CSR. Training to produce more regular breathing, regardless of the amount of ventilation, may represent a useful intervention.

Cardiopulmonary determinants of functional capacity in patients with chronic heart failure compared with normals

BACKGROUND

Patients with chronic heart failure (CHF) are characterized by abnormal gas exchange and ventilatory responses to exercise.

HYPOTHESIS

This study compares variables obtained from cardiopulmonary exercise testing in 35 patients with CHF with 35 age- and weight-matched healthy subjects. A second goal was to obtain cardiopulmonary variables measured at ventilatory threshold to distinguish patient changes from those of healthy subjects.

METHODS

Exercise testing was carried out using bicycle ergometry with ramplike protocol (work rate increments 12.5 W/min). Gas exchange and ventilation were measured breath by breath.

RESULTS

Compared with healthy subjects, the VO2 in patients was lower at identical work rates (p < 0.004) and at ventilatory threshold (p < 0.0001), and the slope of the VO2 curve during incremental exercise was flatter (p < 0.05). With the exception of heart rate, the variables for VO2, VCO2, ventilation, O2 pulse, ventilatory equivalents for O2 and CO2, and VD/VT (physiologic deadspace to tidal volume ratio), as well as lactate differed significantly at identical work rates. With the exception of VD/VT, all cardiopulmonary variables showed significant differences in their slopes during exercise. By means of a discriminant analysis, VCO2 and ventilation proved to be the most distinguishing variables at ventilatory threshold between patients with CHF and healthy subjects.

CONCLUSIONS

These results indicate the clinical usefulness of cardiopulmonary exercise testing when assessing functional impairment due to CHF. For treatment evaluation, not only VO2 but also VCO2 and ventilation responses to exercise should be considered.

Clinical relevance of heart rate variability changes after heart transplantation

Heart rate variability (HRV) of the healthy innervated heart is controlled and regulated by the autonomous nervous system and is influenced by respiratory frequency. Physiologically, there are slow and fast variations of heart rate which are of sympathetic or parasympathetic origin respectively. Spectral analysis of heart rate variability permits a selective quantification of these periodic influences of autonomous neural control. In the absence of neural influence on the pacemaker of the donor heart, we do not expect a high periodic heart rate variability (HRV). Due to the almost rigid heart rhythm we only anticipate a slight deviation of the R-R intervals from their mean value. Interventions such as valsalva maneuvers, controlled respiration and tilt table result in a very small but significant change of heart rate variability. These changes are most likely due to local influences at the donor sinus node. Neural influences from reinnervation may also play an important role in patients long after transplantation.

Effects of short-term exercise training and activity restriction on functional capacity in patients with severe chronic congestive heart failure

Previous exercise training studies in patients with chronic congestive heart failure (CHF) were performed for periods lasting > 2 months, and effects of activity restriction on exercise induced-benefits were not systematically assessed. With one exception study, patients were not reported to be transplant candidates. In this random-order crossover study, effects of 3 weeks of exercise training and 3 weeks of activity restriction on functional capacity in 18 hospitalized patients with severe CHF [(mean +/- SEM) age 52 +/- 2 years; ejection fraction 21 +/- 1%; half of them on a transplant waiting list] were assessed. The training program consisted of interval exercise with bicycle ergometer (15 minutes) 5 times weekly, interval treadmill walking (10 minutes), and exercises (20 minutes), each 3 times weekly. With training, the onset of ventilatory threshold was delayed (p < 0.001), with increased work rate by 57% (p < 0.001) and oxygen uptake by 23.7% (p < 0.001). On average, there was a 14.6% decrease in slope of ventilation/carbon dioxide production before the onset of ventilatory threshold (p < 0.05), and ventilatory equivalent of carbon dioxide production by 10.3% (p < 0.01). At the highest comparable work rate (56 +/- 5 W) the following variables were decreased: heart rate (7.3%; p < 0.05), lactate (26.6%; p < 0.001), and ratings of perceived leg fatigue and dyspnea (14.5% and 16.5%; p < 0.001 each). At peak exercise, oxygen uptake was increased by 19.7% (p < 0.01) and oxygen pulse by 14.2% (p < 0.01). There was a correlation of baseline peak oxygen uptake and increase of peak oxygen uptake due to training (r = -0.75; p < 0.004). Independently of the random order, data after activity restriction did not differ significantly from data measured at baseline. Patients with stable, severe CHF can achieve significant improvements in aerobic and ventilatory capacity and symptomology by short-term exercise training using interval exercise methods. Impairments due to activity restriction suggest the need for long-term exercise training.

Influence of different exercise protocols on functional capacity and symptoms in patients with chronic heart failure

This study compares hemodynamic, metabolic, and gas exchange responses, catecholamine levels, and symptoms in 35 male patients with chronic heart failure (CHF) ([mean +/- SD] age 53 +/- 11 yr; ejection fraction 24 +/- 11%) during three differently graded exercise test protocols. On three consecutive days patients performed cycle ergometry supine, with prolonged steps (prol BE) and right heart catheterization, ramplike cycle ergometry sitting (ramp BE), and ramplike treadmill walking (TMW). As in routine clinical practice, the prol BE was terminated when pathologic central hemodynamics and/or increased symptomology occurred, and ramp BE and TMW due to increased symptomology and/or physician's decision. During prol BE at ventilatory threshold (VT) the VO2 (8.6 +/- 1.8 ml.kg-1.min-1) was lower than during ramp BE (9.3 +/- 2.1 ml.kg-1.min-1) (P < 0.017) and TMW (11.8 +/- 2.3 ml.kg-1.min-1) (P < 0.0001). Prol BE, ramp BE, and TMW also differed significantly with respect to ventilation (22 +/- 7 l.min-1; 26 +/- 6 l/min-1; 29 +/- 7 l.min-1; P < 0.01) and heart rate (100 +/- 15 beats.min-1; 103 +/- 18 beats.min-1; 110 +/- 16 beats.min-1; P < 0.017). No differences were found in lactate levels, catecholamine levels, and ratings of leg fatigue and dyspnea. At test termination, the peak VO2 during prol BE (100.8 +/- 3.3 ml.kg-1.min-1) was lower than during ramp BE (13.3 +/- 4.1 ml.kg-1.min-1) (P < 0.0001) and TMW (14.7 +/- 3.4 ml.kg-1.min-1) (P < 0.0001). Peak norepinephrine value during ramp BE (4.531 +/- 2.788 nmol.l-1) was higher than during prol BE (3.707 +/- 2.262 nmol.l-1) (P < 0.001). Among the three tests, no significant differences were found for peak values of heart rate, lactate, and ratings of dyspnea. Although the VO2.kg-1 at VT was significantly higher during ramp BE and TMW compared to prol BE (P < 0.001), the values expressed as a percent of peak VO2.kg-1 were significantly lower (70 +/- 4%; 72 +/- 6%; 79 +/- 3%; P < 0.017). A systematic effect on aerobic capacity with reduced peak values during ramp BE and TMW was demonstrated when test termination was based primarily on pathological findings of central hemodynamics from prol BE.

Aerobic capacity and functional classification of patients with severe left-ventricular dysfunction

Classes I/II and III of the classification systems of the New York Heart Association (NYHA), Canadian Cardiovascular Society (CCS) and American Medical Association (AMA) were compared with each other and with the Weber classification (O2 uptake, VO2/kg during treadmill walking) in 35 male patients with severe left ventricular dysfunction. Measured end points were ventilatory threshold (VT) and peak exercise. Also investigated was whether the CCS and AMA scales, due to their more stringent differentiation, are more precise than the NYHA system in determining a limited physical capacity and whether there are other differentiating factors useful in classification which may be derived from cardiopulmonary exercise testing. At the VT, the mean VO2/kg did not differ significantly in any classification system between classes I/II and III (12.8 +/- 2.5 vs. 11.1 +/- 2.3 ml/kg/min) and corresponded to Weber class B. At peak exercise, the mean VO2/kg only differed significantly within the NYHA classification; classes I/II (16.3 +/- 3.1 ml/kg/min) corresponded to Weber class B, and class III (13 +/- 3 ml/kg/min) to Weber class C. The individual values displayed a large scatter. Factors differing in classes I/II and III of all three systems at peak exercise were the ventilatory equivalent of O2 and CO2 as well as end-tidal partial pressure for O2 and CO2. At VT these factors showed a separating character only in the AMA classification. It is not possible to determine objective functional impairment by use of the NYHA, CCS and AMA systems because they are not analogous to the Weber system. Nevertheless, these classification systems can be used for clinical assessment and follow-up.

Physical responses to different modes of interval exercise in patients with chronic heart failure--application to exercise training

METHOD

In exercise training with chronic heart failure patients, working muscles should be stressed with high intensity stimuli without causing cardiac overstraining. This is possible using interval method exercise. In this study, three interval exercise modes with different ratios of work/ recovery phases (30/60 s, 15/60 s and 10/60 s) and different work rates were compared during cycle ergometer exercise in heart failure patients. Work rate for the three interval modes was 50% (30/60 s), 70% (15/60 s) and 80% (10/60 s) of the maximum achieved during a steep ramp test (increments of 25 w/10 s) corresponding to 71, 98 and 111 watts on average. Metabolic and cardiac responses to the three interval exercises were then examined including catecholamine levels and perceived exertion. Parameters measured during interval exercise were compared with an intensity level of 75% peak VO2, determined during an ordinary ramp exercise test (increments of 12.5 W.min-1).

RESULTS

(mean +/- SEM) (1) In all three interval modes, VO2, ventilation and lactate did not increase significantly during the course of exercise. Mean values during the last work phase were between 754 +/- 30 and 803 +/- 46 ml.min-1 for VO2, between 26 +/- 3 and 28 +/- 1 l.min-1 for ventilation and between 1.24 +/- 0.14 and 1.29 +/- 0.10 mmol.l-1 for lactate. (2) In mode 10/60 s, heart rate and systolic blood pressure increased significantly (82 +/- 4 --> 85 +/- 4 beats.min-1; 124 +/- 5 --> 134 +/- 5 mmHg; P < 0.05 each), while in mode 15/60 s catecholamines increased significantly (norepinephrine 0.804 +/- 0.089 --> 1.135 +/- 0.094 nmol.l-1; P < 0.008; epinephrine 0.136 +/- 0.012 --> 0.193 +/- 0.019 nmol.l-1; P < 0.005). (3) In all three modes, rating of leg fatigue and dyspnoea increased significantly during exercise but remained within the range of values considered 'very light to fairly light' on the Borg scale. (4) Compared to an intensity level of 75% peak VO2, work rate during interval work phases was between 143 and 221%, while cardiac stress (rate-pressure product) was significantly lower (83-88%).

CONCLUSION

All three interval modes resulted in physical response in an acceptable range of values, and thus can be recommended.

Digital pulse plethysmography as a non-invasive method for predicting drug-induced changes in left ventricular preload

OBJECTIVE

Changes in the contour of the plethysmographically recorded digital pulse curve after nitrate ingestion are well known, but it has not been fully established whether these changes reflect nitrate action on left ventricular (LV) preload or afterload. Therefore, we compared the pulse wave contour after administration of equieffective doses of nitroglycerin and nifedipine.

METHODS

In 20 patients with coronary artery disease we measured aortic blood pressure curve in the aorta ascendens, digital volume pulse curve with a photoelectric pulse pickup, Riva Rocci blood pressure and heart rate after administration of either 0.8 mg nitroglycerin or 10 mg nifedipine.

RESULTS

Peak plasma concentrations of nitroglycerin and nifedipine were achieved 5 min and 20 min after ingestion of the drugs. Systolic aortic blood pressure decreased after both nitroglycerin and nifedipine to 19.4 mmHg, but diastolic blood pressure decreased only after nifedipine by 10.5 mmHg (P < 0.05). Riva Rocci blood pressures showed a similar time course. Heart rate increased from 67.4 to 70.9 beats.min-1 after nitroglycerin and from 58.9 to 69.4 beats.min-1 after nifedipine. The calculated a/b ratio of the aortic pressure curve increased after both medications (nitroglycerin, from 1.66 to 1.99; nifedipine, from 1.66 to 1.93) and its time course mimicked that of the systolic blood pressure. The a/b ratio of the digital pulse curve did not change after nifedipine, but showed a pronounced rise after nitroglycerin from 1.29 to 1.84. With regard to pharmacological actions, nitroglycerin causes a reduction in LV preload and afterload, whereas nifedipine has only LV-afterload-reducing activity.

CONCLUSION

We conclude, that the reduction in afterload did not cause the typical changes in wave contour of the peripheral pulse curve which occur with organic nitrates. Most likely changes in the a/b ratio reflect changes in LV preload.

Short-term hemodynamic, anti-ischemic, and antianginal effects of pirsidomine, a new sydnonimine

Pirsidomine is a new sydnonimine compound in clinical development. As a prodrug, it is transformed into a nitric oxide-releasing metabolite in vivo. In animal tests there were no signs of tolerance with repeated administration. The short-term effects of 10, 20, and 40 mg of the drug on pulmonary hemodynamics and ischemic parameters were examined at rest and during exercise in a double-blind, randomized, placebo-controlled study. The study included 48 patients with documented coronary artery disease and exercise-induced ST-segment depression. Compared with the baseline test, there was a reduction of diastolic pulmonary artery pressure with pirsidomine at rest (placebo: -0.4 +/- 0.5 mm Hg; 10 mg: - 1.5 +/- 2.4 mm Hg; 20 mg: - 1.4 +/- 1.1 mm Hg; 40 mg: - 2.3 +/- 1.3 mm Hg [p < 0.05 ]) and at the highest comparable workload (placebo: -2.8 +/- 1.9 mm Hg; 10 mg: -7.3 +/- 6.8 mm Hg; 20 mg: -8.4 +/- 7.9 mm Hg [p <0.05]; 40 mg: -13.8 +/- 7.1 mm Hg [p <0.05]). ST-segment depression decreased at the highest comparable workload (placebo: -0.33 +/- 0.49 mm; 10 mg: -1.33 +/- 1.37 mm [p <0.05]; 20 mg: -1.33 +/- 0.83 mm [p <0.05]; 40 mg: -1.96 +/- 0.86 mm [p <0.05]) and total exercise time increased (placebo: 15 +/- 48 s; 10 mg: 98 +/- 126 s; 20 mg: 165 +/- 251 s [p <0.05]; 40 mg: 155 +/- 174 s [p <0.05]). Of 40 patients who complained of angina pectoris symptoms in the baseline test, 15 became free of angina pectoris with pirsidomine. Compared with placebo, blood pressure, heart rate during exercise, and cardiac output during exercise showed no significant change. Plasma concentration response relations of the metabolite revealed concentrations that caused a half-maximum effect of 6 ng/ml, 13 ng/ml, 20 ng/ml, and 28 ng/ml in reduction of ST-segment depression, reduction of diastolic pulmonary artery pressure, relief of angina pectoris symptoms, and an increase in exercise duration, respectively. Thus, pirsidomine is an effective anti-ischemic and antianginal agent. A significant preload reduction was obtained with plasma metabolite concentrations lower than those necessary to achieve a satisfactory antianginal effect.

Ventilatory and lactate threshold determinations in healthy normals and cardiac patients: methodological problems

In healthy normal individuals (n = 69), coronary patients with myocardial ischaemia (n = 27) and patients with chronic heart failure (CHF, n = 33), four widely applied methods to determine ventilatory threshold (VT) were analysed: V-slope, ventilatory equivalent for O2 (EqO2), gas exchange ratio (R) and end-tidal partial pressure of oxygen. Lactate threshold [LAT, log lactate vs log oxygen uptake (VO2)] was also determined. Analysis focused on rate of success of threshold determination, comparability of threshold methods, reproducibility and interobserver variability. Cycle ergometry protocols with ramp-like mode and graded steady-state mode used in exercise testing were considered separately. In healthy normal individuals and coronary patients with myocardial ischaemia, at least three VT could be determined during ramp-like mode and two VT during graded steady-state mode, 82% of the time. For CHF patients, the rate of successful determination of VT was lower. Compared to LAT, VO2 at VT was significantly higher using R and EqO2 methods of VT determination in healthy normal subjects (P < 0.01), and significantly higher when using all four methods in coronary patients (P < 0.01 or P < 0.05, respectively). No difference was observed between VO2 at VT and LAT in CHF patients. In healthy normal individuals, day-to-day reproducibility of VT and LAT was high (error of a single determination from duplicate determinations was between 3.9% and 6.2% corresponding to a VO2 of 52.2 and 89.2 ml.min-1). Interobserver variability was low (error between 0.3% and 5% corresponding to a VO2 of 9.8 and 68 ml.min-1). In CHF patients, interobserver variability was moderately greater (error between 4.6% and 8.2%, corresponding to a VO2 of 35.1 and 62.4 ml.min-1). To optimize threshold determination, standardized procedures are suggested.

A comparison of surgical and medical therapy for atrial septal defect in adults

BACKGROUND

The surgical closure of an atrial septal defect is frequently recommended for patients over 40 years of age. However, the prognosis for such patients with unrepaired defects is largely unknown, and the outcome for patients operated on after the fourth decade of life has not yet been compared with that for medically treated patients in a controlled follow-up study.

METHODS

In a retrospective study, we examined the clinical course of 179 consecutive patients with isolated atrial septal defects diagnosed after the age of 40. The 84 patients (47 percent) who underwent surgical repair were compared with the 95 patients (53 percent) who were treated medically. The mean (+/-SD) follow-up period was 8.9 +/- 5.2 years (range, 1 to 26).

RESULTS

Multivariate analysis revealed that surgical closure of the defect significantly reduced mortality from all causes (relative risk, 0.31; 95 percent confidence interval, 0.11 to 0.85). The adjusted 10-year survival rate of surgically treated patients was 95 percent, as compared with 84 percent for the medically treated patients. In addition, surgical treatment prevented functional deterioration, as measured by the New York Heart Association class (relative risk, 0.21; 95 percent confidence interval, 0.08 to 0.55). However, the incidence of new atrial arrhythmias or of cerebrovascular insults in the two groups was not significantly different.

CONCLUSIONS

The surgical repair of an atrial septal defect in patients over 40 years of age, as compared with medical therapy, increases long-term survival and limits the deterioration of function due to heart failure. However, surgically treated patients should be followed closely for the onset of atrial arrhythmias so as to reduce the risk of thromboembolic complications.

Relationship between ventilatory threshold and onset of ischaemia in ECG during stress testing

The study was carried out to determine the relationship between ventilatory threshold and the onset of ischaemia, as shown on the ECG (horizontal and/or descending ST depression of 0.05 mV, on average). Twenty-seven male patients (aged 58 +/- 7 years) with angiographically documented coronary artery disease (CAD) were assessed by cardiopulmonary exercise testing without medication. Oxygen uptake (VO2), heart rate (HR), rate-pressure-product (RPP) and blood lactate were measured and/or calculated every 30 s during exercise. In addition, 10 patients, comparable with the above group, were examined to find out the acute effects of isosorbide dinitrate (ISDN) at ventilatory threshold in relation to ischaemic threshold. The first cardiopulmonary exercise test was carried out without medication, the second 1 h later with 5 mg ISDN, taken sublingually 30 min before the test.

RESULTS

(means, SD): (1) The mean ventilatory threshold preceded the ischaemic threshold in relation to exercise capacity (48 +/- 14 vs 55 +/- 20 watts; P < 0.05), VO2.kg-1 (10.0 +/- 2.2 vs 12.0 +/- 2.9 ml.kg-1.min; P < 0.05), HR (93 +/- 15 vs 100 +/- 16.min-1; P < 0.01), RPP (15095 +/- 4424 vs 17166 +/- 5245; P < 0.01) and blood lactate (1.28 +/- 0.53 vs 1.44 +/- 0.60 mmol.l-1; P < 0.05). (2) This relationship was observed more often in the subgroup of patients with angina during cardiopulmonary exercise testing or with myocardial infarction or with three-vessel disease than in patients without angina or infarction or with one- and two-vessel disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevention of bacterial endocarditis in Germany

The goal of this study was to assess the current practice of endocarditis prophylaxis in Germany. We conducted a survey using a standardized questionnaire, which was sent to 100 hospital cardiologists, to 430 cardiologists in office practice and to 389 dentists and oral surgeons. In addition, 364 patients with valvular or congenital heart disease were interviewed in our outpatient clinic. Seventy five percent of cardiologists informed their patients by both written and oral instructions. Half recommended the use of penicillin, according to the German Society of Cardiology, while the rest followed recommendations of other societies. Sixty-three percent of patients who had undergone a procedure requiring prophylaxis against bacterial endocarditis within the year prior to the questionnaire, had actually received it. This is higher than previously reported, but is far from acceptable. The indications for prevention of endocarditis, as seen by the dentists, deviated markedly from official recommendations. Although 77% administered antibiotics themselves, in only 57% did the type of prophylaxis applied correspond to one of the available recommendations. Recommendations on the prevention of bacterial endocarditis are not well known dentists and oral surgeons who perform procedures for which it is indicated. Further patient- and physician-oriented strategies are urgently needed to improve compliance with prevention of endocarditis in Germany.