Twenty year smoking trends in a community-based cardiovascular diseases prevention programme: Results from the North Karelia Project

Objectives: to evaluate long-term changes associated with acommunity-based cardiovascular disease prevention programmeon smoking. Methods: the North Karelia Project was started in1972 to carry out a comprehensive community-based programmeto reduce the exceptionally high rates of cardiovascular diseases(CVD) in North Karelia, an eastern province in Finland. Amongthe main intermediate objectives was the reduction of smokingrates, particularly among the male population. The programmewas evaluated by standardized examinations of large representativecross-sectional population samples in 1972, 1977, 1982, 1987and 1992 in North Karelia and in the Kuopio province, anotherprovince in eastern Finland, which was initially chosen as referencearea for the first project period. Results: in men the percentageof current smokers decreased during the 20 years from 52 to32% in North Karelia and from 50 to 37% in the initial referencearea (p<0.05). Smoking declined faster in the first 10 years(from 1972 to 1982) than in the last 10 years. During the first10 years the decline was more remarkable in North Karelia thanin the reference area. The main reason for the decline in smokingduring the first 10 years was smoking cessation and during thelast 10 years the increase in the number of people who had neversmoked regularly. Among women the proportion of smokers increasedin both areas from approximately 10 to approximately 20%. Thisincrease was greatest in the youngest age group. Conclusions:the community-based cardiovascular disease prevention programmewas an effective way to reduce smoking in the general populationin men and sustained decline could be achieved.     

Magnetocardiographic Pacemapping for Nonfluoroscopic Localization of Intracardiac Electrophysiology Catheters

The purpose of the study was to validate, in patients, the accuracy of magnetocardiography (MCG) for three-dimensional localization of an amagnetic catheter (AC) for multiple monophasic action potential (MAP) with a spatial resolution of 4 mm2. The AC was inserted in five patients after routine electrophysiological study. Four MAPs were simultaneously recorded to monitor the stability of endocardial contact of the AC during the MCG localization. MAP signals were band-pass filtered DC-500 Hz and digitized at 2 KHz. The position of the AC was also imaged by biplane fluoroscopy (XR), along with lead markers. MCG studies were performed with a multichannel SQUID system in the Helsinki BioMag shielded room. Current dipoles (5mm; 10mA), activated at the tip of the AC, were localized using the equivalent current dipole (ECD) model in patient-specific boundary element torso. The accuracy of the MCG localizations was evaluated by: (1) anatomic location of ECD in the MRI, (2) mismatch with XR. The AC was correctly localized in the right ventricle of all patients using MRI. The mean three-dimensional mismatch between XR and MCG localizations was 6 ± 2 mm (beat-to-beat analysis). The coefficient of variation of three-dimensional localization of the AC was 1.37% and the coefficient of reproducibility was 2.6 mm. In patients, in the absence of arrhythmias, average local variation coefficients of right ventricular MAP duration at 50% and 90% ofrepolarization, were 7.4% and 3.1%, respectively. This study demonstrates that with adequate signal-to-noise ratio, MCG three-dimensional localizations are accurate and reproducible enough to provide nonfluoroscopy dependant multimodal imaging for high resolution endocardial mapping of monophasic action potentials.     

Thallium Scintigraphy in Prediction of Occlusion of Bypass Grafts in Asymptomatic and Symptomatic Patients

ABSTRACT To evaluate thallium scintigraphy in predicting coronary artery bypass graft patency, exercise thallium scintigraphy and selective graft and native vessel angiograms were performed in 22 asymptomatic and 29 symptomatic consecutive patients three months after coronary artery bypass grafting (CABG). Twelve out of 22 asymptomatic patients (55%) had reversible thallium defects on postoperative images; in 10 patients the postoperative scans were normal. The graft patency was significantly lower in asymptomatic patients with abnormal thallium perfusion compared to those with normal perfusion after CABG (68% vs. 91%. p<0.05). The rate of graft patency in symptomatic patients was 66/87 (76%). Thallium scintigraphy was 77% sensitive and 78% specific in detecting one or more stenosed or occluded bypass grafts in patients without angina (accuracy 77%). When data from exercise electrocardiography were combined with scintigraphy, all but one patient with incomplete revascularization could be detected (positive predictive accuracy 92%). In symptomatic patients, thallium scintigraphy accurately predicted the presence or absence of graft occlusion in 24/29 (83%) cases. Thus, abnormal myocardial perfusion due to stenosis or occlusion of bypass grafts is common in both asymptomatic and symptomatic patients after CABG. Thallium scintigraphy together with exercise electrocardiography appear to be useful non-invasive methods in detecting painless myocardial ischemia and in predicting bypass graft occlusion after CABG.     

Extensive Variation in the Signal Amplitude of the Atrial Floating VDD Pacing Electrode

The dependence of atrial signal amplitude on the site of the ntrial sensing dipole of a single-pass lead was examined in 29 patients. The vertical location of the dipole was documented in supine fluo-roscopy during quiescent and deep breathing and in upright chest roentgenogram, and was expressed as a proportion of the, right atrial height. As the group average, the atrial signal amplitude was equal when tested in supine, sitting, standing, and right- or left-side positions in follow-up determinations. The signal amplitude varied markedly between postures, showing a coefficient of variation of 45%± 24% within the group. Coefficient of variation within the 6-month fallow-up period in each tested position ranged from 31%−4 4%, Correlation between postures was weak (range of r = 0.53–0.81). Vertical location of the atrial dipole had no relationship to the signal amplitude. At least in one posture or test occasion the atrial signal amplitude was very low, ≤ 0.35 mV in 20 patients, and below detection limit (0.25 mV) in 5 patients. Programmed to high sensitivity, atrial undersensing was rare in ambulatory electrocardiography, ranging from 0–9,000 missed atrial beats (0%–8%), with a median of 100 beats/24 hours. In conclusion, temporary variation in atrial signal amplitude is extensive. Despite occasionally measured large signal amplitudes atrial sensitivity in single lead VDD pacemakers should be programmed high, and if poor atrial tracking is suspected, other methods besides routine sensitivity testing should be adapted.