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Objective: To determine the early and late clinical outcomes following multiple stent deployment during a single percutaneous transluminal coronary angioplasty (PTCA) procedure. Methods: All patients who received two or more stents during a single PTCA were reviewed. An analysis was made of 114 patients (mean age = 61.2 years). A total of 268 stents were deployed, range 2–6 stents per PTCA (mean = 2.4). Stenting was performed as a primary procedure in 38 patients, for arterial dissection in 44, and for threatened closure in 32. At least two stents were deployed in the same vessel in 101 (88.6%) patients. Before discharge from hospital, there were 4 (3.6%) deaths, 6 (5.2%) patients required emergency coronary artery bypass grafting (CABG), and 2 (1.8%) patients required repeat PTCA. Three (2.6%) patients sustained acute myocardial infarction (AMI). The mean follow‐up period was 10.6 months. After leaving hospital, there were no deaths, 5 (4.4%) patients required CABG, and 5 (4.4%) had a further PTCA. There was one (0.9%) AMI. The total event rate was 19.2%, which compares well with single stent trials in which event rates of 20.1% and 19.5% were reached. In addition, 19 (16.7%) patients had a recurrence of symptoms. Conclusion: It is possible to deploy multiple stents at a single intervention in the same or different vessels safely and with clinical outcomes that are similar to those in studies of single coronary stenting.

Until 1977, coronary revascularization was only possible using open surgical techniques. Approximately 10 years after the introduction of coronary angioplasty, a series of major clinical trials comparing the outcome of patients treated by surgery and angioplasty were planned and executed. The results of these trials are now becoming available and show that in patients with symptomatic disease affecting one, two, or three vessels, angioplasty is a viable alternative to surgery. From a purely medical point of view, the advantages and disadvantages of the two techniques are so finely balanced that patient preference has become an important parameter in selection of a primary intervention.

The purpose of this study was to assess the early changes in stenosis geometry after insertion of intravascular stents in human coronary arteries. Morphologic changes were evaluated by quantitative coronary angiography (using automated edge detection) and by calculation of the theoretical pressure decrease across the dilated and stented stenosis from the Poiseuille and turbulent resistances assuming a coronary blood flow of either 1 or 3 ml/s. Twenty-six patients* were studied before and after angioplasty, as well as immediately after stent implantation. The stented coronary artery was the left anterior descending artery in 19 cases, the circumflex artery in 2 cases, the right coronary artery in 2 cases and a coronary artery bypass vein graft in 3 cases. After stent implantation, an additional increase in minimal luminal cross-sectional area of the dilated vessel was observed, suggesting that the self-expanding stainless steel endoprosthesis used in this study has a dilating function in addition to its stenting role.

The use of evoked QT-interval and ventricular depolarization gradient as sensors for rate-responsive pacing is described in this article. The QT interval has been used as a biosensor in implantable pacemakers since 1981, and recent refinements have improved the rate response characteristics and simplified the programming of this pacemaker. Recently, QT and activity sensing have been combined to produce a dual-sensor rate-responsive pacemaker that may offer advantages over single-sensor devices. The ventricular depolarization gradient has been incorporated into a closed-loop rate-responsive pacing system and is undergoing clinical evaluation.

1. The early electrophysiological patterns of regional subendocardial ischaemia were studied by using the paced endocardial evoked response and simultaneous endocardial monophasic action potential recordings in 16 experiments in open chested dogs. Ischaemia was produced by transient (1-3 min) coronary artery occlusion. 2. Regional subendocardial isochaemia caused asynchronous activation due to differential conduction delay and shortened repolarization as evaluated by the duration of the paced evoked response from 175±(sd) 18.7 ms to 167 ± 16 ms (P <0.001). These changes occurred within 60 s of occlusion and reversed rapidly after release of the occlusion. 3. In simultaneous endocardial monophasic action potentials there was a decrease in plateau amplitude and the duration of repolarization shortened from 180±(sd) 21.2 ms to 167 ±20.4 ms (P <0.001). 4. The delay in endocardial activation after 2 min ischaemia was 5.5 ms, which is considerably shorter than the conduction delay previously reported in the subepicardial layers. 5. The calcium-channel blocking drug verapamil (infused at 0.4 mg/kg) altered the rate at which shortening of repolarization and asynchronous activation occurred during ischaemia in six experiments. 6. These experiments suggest that intracavitary electrodes could provide earlier and more sensitive detection of regional subendocardial ischaemia and may permit the assessment of therapy on the early electrical changes in the intact heart.

Animal studies have established that there is a rapid increase in extracellular potassium concentration in myocardial tissue after the onset of ischemia. To study this phenomenon in humans, coronary sinus plasma potassium concentration was measured in five patients undergoing therapeutic coronary angioplasty. Recordings were obtained during a total of 22 coronary artery occlusions lasting between 5 and 50 seconds. Though little change was observed during angioplasty balloon inflation, all occlusions that lasted more than 15 seconds were followed by a transient elevation in coronary sinus potassium concentration of between 0.18 and 1.55 mmol liter−1. The majority of occlusions (n = 17) werfe not accompanied by chest pain, electrocardiographic (ECG) changes or alteration of heart rate.

The effects of three ultraviolet excimer laser wavelengths on normal and atheromatous human cadaver aortic wall are presented. Ultraviolet radiation successfully ablates vessel wall; the dose response is greatest at 249 nm followed by 193 nm and 351 nm, where the effect is negligible for the equivalent energy dose. Wavelengths 249 and 193 nm have a selective effect on fibrous atheroma; ablation proceeds at a higher rate in this tissue. Non-linear effects observed at 249 nm may be due to thermal as well as photoablative mechanisms. In addition, blood samples were exposed to all three wavelengths and potassium concentrations were measured; the dose of energy required to produce tissue ablation may also produce significant haemolysis and hyperkalaemia at 249 and 193 nm but not with 351 nm. This finding may be important for coronary angioplasty but less so for peripheral work. The wavelength that produces the strongest dose response is 249 nm; this is the wavelength for which a fibre-optic delivery system should be developed.

Objectives. This study was conducted to determine the procedural success rate, complication rate and long-term outcome of percutaneous transluminal coronary angioplasty in chronically occluded coronary arteries.

Since the introduction of this stent, anticoagulant regimens have changed from an aggressive protocol (aspirin, heparin, and warfarin) to a simplifed regimen (aspirin and ticlopidine). In this study our experience with this stent is reviewed, and acute and chronic outcomes with the two anticoagulant protocols are compared. All patients undergoing ACS Multilink stent implantation between July 1993 and June 1996 were included. The clinical and angiographic characteristics were documented and outcomes recorded. The two anticoagulant groups were compared: 103 patients (94 males, age range 41–80 years, mean 59) received 124 stents: 68% had Canadian Cardiac Society (CCS) grade III or IV angina prior to the procedure; and 73% underwent bail‐out stenting. High pressure inflations (> 14 a) were used in 40% of cases. Eighty‐four (85%) received aspirin and ticlopidine only. The initial success rate was 99%. Two patients underwent emergency surgery. There were no deaths and no cases of subacute stent thrombosis. Clinical follow‐up is available on 66 patients (mean 190 days). Of these, 56 patients (54%) are in CCS grade 0 or 1. One patient has required surgical revascularization. There is one case of documented restenosis within the stented segment.

Amiodarone is a benzofuran derivative with depressant effects on all electrically active cardiac tissues and important antiarrhythmic properties after long-term dosing. We evaluated its short-term effects on myocardial repolarization and refractoriness in eight patients. The duration of repolarization was evaluated by a new method, the paced evoked-response system, which records the dominantly local repolarization that follows a controlled (paced) depolarization from the same site. Intravenous amiodarone (5 mg/kg) prolonged the latency of the stimulus peak-evoked T wave interval an average of 39.4 msec (+15% of control) 10 min after infusion. In animal experiments these changes correlated well with simultaneous increases in the paced monophasic action potentials obtained with suction electrode catheters. There was also a lengthening of the effective refractory period of the atrioventricular node from 270 ± 20 to 295 ± 25 msec. Atrial and ventricular refractoriness were not altered. Amiodarone early activity at the atrial and ventricular level apparently differs from that after long-term therapy and appears to favor changes in action potential duration and not changes in refractoriness.Clinical Pharmacology and Therapeutics (1982) 32, 727–735; doi:10.1038/clpt.1982.229

Explores some of the developments in the design of pacemakers which are capable of providing physiological control of cardiac hemodynamics independent of the requirement to synchronize with atrial activity. Control of cardiac output; Role of atrial systole; Physiological advantages and disadvantages of rate responsive pacing.

<$O_ST_ABS>AUTHORS SYNOPSIS<$C_ST_ABS>In five patients studied 1 to 3 d after coronary artery surgery isoprenaline and nitroglycerine have been used to alter the systolic (TTI) and diastolic (DPTI) pressure time indices. A close correlation with the predicted relationship between diastolic coronary graft flow and the DPTI/TTI ratio has been demonstrated during isoprenaline-induced tachycardia. Nitroglycerine reduced diastolic coronary graft resistance and increased the DPTI/TTI ratio, effects which are desirable for the relief of angina.

Intracavitary recording of monophasic action potentials (MAP) is a sensitive means of detecting the electrophysiological effects of early or subendocardial ischaemia. The effects of nitroglycerin (NTG) on the MAP was evaluated during pacing-induced angina in seven patients with localised, reversible ischaemia. Recordings from the ischaemic zone demonstrated a decrease in MAP amplitude and an abnormal rate-corrected shortening of MAP repolartisation. The "control" right ventricular MAP showed only the expected rate-dependent decrease in duration throughout the pacing stress test. The ischaemic MAP were unchanged following the intracoronary administration of NTG (100 µg). In contrast, intravenous NTG (200 to 300 µg) produced a normalisation of MAP amplitude and duration in spite of continuous pacing at the angina-provoking rate. These changes were preceded by a fall in aortic pressure (from mean 123/84 to 96/62) and subsequent lowering of the rate-pressure product. The major beneficial effects of NTG on the early electrical changes of pacing-induced ischaemia are thus related to decreased oxygen demand due to reduction in cardiac preload.

To the Editor.—Since our foundation in 1975, we have been campaigning against the proposal that the Système International (SI) unit of measurement for pressure, the pascal (Pa) or kilopascal (kPa), should replace the millimeter of mercury (mm Hg) for clinical pressure measurements, such as the blood pressure and intraocular pressure. We have had some success in this. At first there was little governmental opposition to the European Economic Community's directive (71/354) that the kilopascal should replace the millimeter of mercury by 1977, but by alerting European physicians to this proposal, a stay of execution until Dec 31, 1979, has been achieved.However, there is now an urgent need for further action. The World Health Organization seems to take the view that the millimeter of mercury (and other column measurements of pressure) will be retained only "for the time being" and that the kilopascal and pascal will be the future

In laser angioplasty one of the factors influencing the immediate damage (and therefore the risk of acute arterial perforation) is the optical absorption characteristics of the target tissue. In an attempt to evaluate the differences in optical absorptive properties, the transmission spectrograms of samples of normal and atheromatous human postmortem aortic wall were measured over the visible spectrum. Optical transmission varied inversely with sample thickness and directly with wavelength through both normal and atheromatous samples. Over the whole visible spectrum atheromatous tissue transmitted less per unit thickness than normal tissue. This differential effect was, however, most pronounced at 500 nm, where atheromatous tissue transmitted light 5–10 times less strongly than normal aortic wall. Such wavelength dependent differential optical absorption could provide a means for the selective photovaporisation of atheroma in laser angioplasty.

<$O_ST_ABS>AUTHORS SYNOPSIS<$C_ST_ABS>Forty patients were studied by the Swan–Ganz flow directed catheter and the wedge pressure was shown to be identical with that obtained by a Cournand and correlated well with the direct left atrial pressure. It is confirmed that the technique is both simple and rapid.