Relation between initial treatment strategy in stable coronary artery disease and 1-year costs in Ontario: a population-based cohort study.

BACKGROUND: Cardiovascular disease is costly, and annual expenditures are projected to increase. Our objective was to examine the variation in patient-level costs and identify drivers of cost in patients with stable coronary artery disease. METHODS: In this retrospective cohort study using administrative databases in Ontario, Canada, we identified all patients with stable coronary artery disease after index angiography between Oct. 1, 2008, and Sept. 30, 2011. We excluded patients with a myocardial infarction within 90 days before the index, with normal coronaries, or with mild coronary disease. We categorized hospitals into low, medium or high revascularization ratio centres. The primary outcome was cumulative 1-year health care costs. A hierarchical generalized linear model identified patient, physician and hospital characteristics associated with patient costs, with 2 main covariates of interest: treatment allocation (medical v. percutaneous coronary intervention v. coronary artery bypass grafting) and hospital revascularization ratio. RESULTS: A total of 183 630 angiography procedures were performed in Ontario during the study period. The final cohort included 39 126 patients with stable coronary artery disease, of which 15 138 received medical treatment and 23 988 received revascularization. The mean 1-year cost was $24 026 (interquartile range $8235-$30 511). The mean costs for medical management and revascularization were $18 069 and $27 786, respectively. The strongest predictor of costs was revascularization (percutaneous coronary intervention: cost ratio 1.27, 95% CI [confidence interval] 1.24-1.31; coronary artery bypass grafting: cost ratio 2.62, 95% CI 2.53-2.71). Hospital revascularization ratio did not significantly affect costs. There was no significant interaction between treatment and revascularization ratio. INTERPRETATION: Most health care costs were due to acute care hospital admissions, and costs were higher for patients undergoing revascularization than medical therapy. This study suggests that treatment decision has a substantial impact on health care resources.

Management and outcomes of non-ST elevation acute coronary syndromes in relation to previous use of antianginal therapies (from the Canadian Global Registry of Acute Coronary Events [GRACE] and Canadian Registry of Acute Coronary Events [CANRACE]).

Randomized trials have established the efficacy of antianginal medications in the treatment of chronic stable coronary disease. Using data from the Global Registry of Acute Coronary Events (GRACE) and Canadian Registry of Acute Coronary Events (CANRACE), we examined the temporal trends in antianginal use (beta blockers, calcium antagonists, and nitrates) before non-ST-elevation acute coronary syndrome presentation from 1999 to 2008 in 10,019 patients. The relationships among previous antianginal use, clinical characteristics on presentation, and in-hospital management and outcomes were examined. Beta blockers were the most commonly used agents, and there was a significant decline in the use of nitrates over time. Compared with patients not on any antianginal therapy before presentation, those on treatment were more likely to be older, female, and have a history of hypertension, diabetes, previous angina, and myocardial infarction; they were less likely to present with positive biomarkers (all p <0.001). Patients not on antianginal therapy before presentation were more likely to undergo coronary angiography and percutaneous coronary intervention and less likely to have recurrent ischemia during hospitalization (all p <0.001). In multivariable analysis, previous antianginal use was independently associated with lower use of coronary angiography in hospital (p = 0.034) but not with in-hospital mortality. In conclusion, there has significant temporal decline in nitrate use before non-ST-elevation acute coronary syndrome. Patients receiving antianginal therapy before presentation more frequently had preexisting cardiovascular disease and previous revascularization and were less likely to present with non-ST-segment elevation MI compared with patients on no antianginal therapies. Previous antianginal use was independently associated with a lower use of coronary angiography in hospital.

Cardiac rhythm device contact dermatitis.

We present a series of three cases of patch testing confirmed cardiac rhythm device induced contact dermatitis. In the first two cases, there was complete resolution with device extraction and reimplantation with another device with either an absence of the offending agent or a coating with another resin or metal. These cases illustrate the difficulties in diagnosing pain, tenderness, and dermatological manifestations in patients with cardiac rhythm devices (pacemakers and implantable cardioverter defibrillators).

Electromagnetic interference of communication devices on ECG machines.

BACKGROUND: Use of communication devices in the hospital environment remains controversial. Electromagnetic interference (EMI) can affect different medical devices. Potential sources for EMI on ECG machines were systematically tested. HYPOTHESIS: Communication devices produce EMI on ECG machines. EMI impairs ECG interpretation. METHODS: The communication devices tested were: a global system for mobile communication (GSM) receiver, a code division multiple access (CDMA) receiver, an analog phone, a wireless local area network, and an alpha-numeric pager. EMI was tested on 3 ECG machines: MAC 5000, MAC 1200, and ELI 100. The devices were tested at 2 and 1 meter, 50, 25, and 0 cm from the acquisition module. The ECGs were presented to a heterogeneous group of clinical providers, (medical students, residents, nurses, industry representatives from cardiac devices companies, and attending cardiologists) to evaluate the impact of EMI on ECG interpretation skills. RESULTS: EMI was detected on the MAC 5000 ECG machine when activated GSM, CDMA, and analog phones were placed on top of the acquisition module. No EMI was seen on the other ECG machines or when phones were at a longer distance or deactivated. EMI was incorrectly diagnosed in 18% of the cases. EMI was confused most frequently with atrial fibrillation or flutter (52%), ventricular arrhythmias (22%), and pacemaker dysfunction (26%). Medical students (p < 0.003) and non-cardiology residents (p = 0.05) demonstrated significantly worse performance on EMI interpretation. CONCLUSIONS: Digital and analog phones produce EMI on modern ECG machines when activated in direct contact to the acquisition module. EMI impairs ECG interpretation.

WITHDRAWN: "Pseudo-high lateral leads Brugada pattern" due to lead reversal.

Available online August 26, 2008 This article has been withdrawn consistent with Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). The publisher apologizes for any inconvenience this may cause.

Electromagnetic interference produced by a hearing aid device on electrocardiogram recording.

An 85-year-old male was implanted with a single-chamber permanent pacemaker because of atrial fibrillation with slow ventricular response. The patient had a chronic hearing impairment and decided to buy a hearing aid device. The MyLink device (MyLink, Phonak, Stafa, Switzerland) is a multifrequency FM transmitter/receiver (169.40-176.00 MHz and 214.00-220.00 MHz) with a neck-loop antenna that is designed to be used in combination with a second FM transmitter, which detects sound, produced by an audio source or person, and transmits this information to the MyLink wearer. These transmissions are subsequently converted by the MyLink and sent to the patient's existing hearing aids wirelessly. Given the proximity of the receiver to the left-sided pacemaker pocket, a concern about possible interaction was brought to our attention. Normal functioning of the pacemaker was observed during the test. However, potent electromagnetic interference on electrocardiogram (ECG) recording was induced when the MyLink loop antenna was placed on top or near the ECG electrodes.