- Email: [email protected]
Clinical Ecg Audit: A Useful Quality Assurance Tool
Abstracts
Canadian Cardiovascular Society (CCS) Poster POSTER - CLINICAL ELECTROPHYSIOLOGY Friday, October 18, 2013 247 SUBOPTIMAL TIME IN THERAPEUTIC RANGE (TTR) FOR INTERNATIONAL NORMALIZED RATIO (INR) MEASUREMENTS OBSERVED IN AN OUTPATIENT CARDIOLOGY CLINIC: IMPACT OF GENDER, ETHNICITY, DISEASE ETIOLOGY, CHADSVASC SCORE, PHYSICIANS AND CLINIC SITE N Singh, S Premji, S Chandra, D Song, L Yan, D Suh Atlanta, Georgia BACKGROUND:
TTR correlates inversely with ischemic stroke risk. Novel anticoagulants benefit most those patients (pts) with poor TTR. Variations in TTR are common with a range of between 55-60% being the norm and > 70% being optimal. It is not known what factors impact TTR most in the community cardiology setting. METHODS: Retrospective chart review of all pts being treated with warfarin in a single, multi-site suburban, outpt cardiology practice for 1 yr between Jul 2011 and Jul 2012 . RESULTS: In the 523 pts being followed, mean age was 69.6 yrs with 51% males. Hypertension (73%), hyperlipidemia (49%) were common, while diabetes (21%), smoking (6%), alcohol (21%) and aspirin use (20%) were less. The mean EF was 54 + 13%. Atrial fibrillation was the most common reason for treatment (75%) followed by mechanical valves (5%) venous system disease (15%) and arterial system disease (5%). An average of 12+5 INR readings/pt were done over the year. Average time on warfarin was 35+18 months. TTR for the overall group was 44.5 + 22.3%. There was no difference in TTR for males (44.2%) vs females (44.9%), p¼0.51. There were 44% Caucasians, 38% African Americans and 13% Asians. TTR for these ethnicities varied significantly, 49.0% vs 37.7% vs 50.3% respectively, p¼0.000001. INR's were managed by 7 physicians with significant differences (TTR range 39.9% to 49.0%, p¼0.025). TTR also varied significantly between 4 clinic sites (TTR range 36.4% to 51.9%, p¼0.04). The mean CHADSVasc score was 2. No difference in TTR was seen based on CHADSVasc score p¼0.4. Clinics and physicians having a higher proportion of African American pts tended to have lower TTR. TTR was worse in pts with arterial (36.9%) and venous disease (40%) vs atrial fibrillation (46.5%) and mechanical valves (47.6%), p¼0.02. Bleeding rates were low over the year (4%). For atrial fibrillation pts, only 11% had a documented discussion about using novel anticoagulants as a treatment option. CONCLUSION: Our findings suggest that TTR may be substantially worse in clinical practice than previously published literature would suggest. Ethnicity, physicians, clinic site and disease etiology may all contribute to poor
S185
TTR. Novel anticoagulants should be discussed more often, especially in afib pts at higher risk for poor TTR. Confirmation of these findings in a broader population could have significant implications for future anticoagulation management and stroke prevention. 248 CLINICAL ECG AUDIT: A USEFUL QUALITY ASSURANCE TOOL A Khosla, J Kornder, K Bhagirath Vancouver, British Columbia BACKGROUND: The ECG is a vital diagnostic clinical tool. Important decisions regarding treatment often depend on accurate interpretation, and therefore competency in ECG reading is of utmost importance. A formal process to measure ongoing competency in ECG interpretation is not outlined by the Royal College of Physicians and Surgeons of Canada (RCPSC), although this would fall under the College's Maintenance of Certification program; a mandatory requirement for specialists. The 2001 American College of Cardiology (ACC) Competence Statement on Electrocardiography recommends routine participation in quality improvement, specifically advocating for “activities such as having a number of ECGs over-read by colleagues and participating in periodic discussions of systemic issues involving ECG interpretation.” METHODS: The Division of Cardiology at Surrey Memorial Hospital designed a pilot clinical audit of 53 ECG readers throughout the Fraser Health Authority. The audit was designed to retrospectively review 740 adult ECGs interpreted and reported by cardiologists and internists using the MUSE system (General Electric). Fourteen ECGs per interpreting physician were randomly selected and de-identified. The ECGs were over-read by one reviewer (JK) who was blinded to the patient, site and interpreting physician name. Upon review of the ECG and the initial interpretation, the reviewer classified each into one of three groups outlined below:
All moderate or significant discrepancies were reviewed in a blinded fashion by at least 3 further reviewers. Any remaining difference of opinion resulted in the ECG reclassified as Group 1 “no discrepancy”. RESULTS: Of the 740 ECGs randomly selected, 7 were pediatric ECGs and were excluded from the clinical audit. In total, 87.3% (640) were found to have none or minor discrepancies, 10% (74) were classified in the moderate category, and 2.7% (19) had a significant discrepancy. Amongst the 53 ECG readers, there was an average
S186
concordance of 87.3% in initial interpretation. Further analysis of each reader's individual concordance with their peers and frequency of each type of discrepancy was evaluated and provided to the participants. CONCLUSION: This pilot clinical audit demonstrates that there can be major clinically relevant discrepancies in ECG interpretation in up to 3% of cases, thus providing impetus for the development and implementation of a regional ECG audit program. This program can act as a quality assurance tool for administrators and is easily scalable to other regional and provincial health authorities.
249 UNUSUALLY HIGH RATE OF HYPERTHYROIDISM OBSERVED IN PATIENTS EXPOSED TO AMIODARONE IN CALGARY PT Pollak, N Vijayaratnam Calgary, Alberta BACKGROUND:
The high iodine content of amiodarone precludes its use at any dose without at least a magnitude increase in exposure to iodine. A 200 mg tablet contains 75 mg of iodine, or which 7.5 mg is bioavailable, rapidly dwarfing the normal total body content of 14 mg. Hyperthyroidism is observed in about 3.3% of individuals in populations exposed to an increase in environmental iodine through increased salt fortification, water purification or seaweed ingestion. Study of linked prescription/ clinical databases confirms that patients taking amiodarone and thus exposed to excess iodine, also experience hyperthyroidism at a rate of 3-4%. This suggests they are reacting to iodine rather than the peripheral pharmacological effect of amiodarone on thyroxine conversion to triiodothyronine. We studied the incidence of hyperthyroidism in patients enrolling in the Calgary Amiodarone Clinic and compared it to personal experience in other Canadian cities. METHODS: Serial thyroid indices (Thyroid Stimulating Hormone, Free Thyroixine-T4 and Total TriiodothyronineT3), ALT and serum amiodarone concentrations were collected every six months on 115 patients enrolled in clinic for amiodarone dose adjustment and monitoring of hepatic and thyroid function. RESULTS: During three years of follow-up, 12 patients developed FreeT4>30 pmol/L with an mean time of onset of 914 days of therapy and a mean FreeT4 of 44 pmol/L. Serum amiodarone concentration was not high at a mean of 1.04 mcmol/L (target < 2.2 mcmol/L) and there was no evidence of any drug toxicity in the 12 patients with a mean ALT of 37 U/L and no ocular, neurological, pulmonary or dermal symptoms. All cases resolved within 6 months of initiating methimazole therapy (usually 5 mg p.o. TID) without stopping amiodarone.
Canadian Journal of Cardiology Volume 29 2013 CONCLUSION:
The observed rate of hyperthyroidism in a sample of Calgary patients receiving amiodarone was 10.4%, about 3 times that predicted by epidemiology and our experience in London and Halifax. What determines this deviation from the norm remains to be discovered. The literature suggests that hyperthyroidism incidence varies geographically by iodine intake. One might speculate that like the Wupper Valley in Europe, the population of Alberta may have adapted to low environmental iodine and react more vigorously to iodine supplementation from amiodarone. The answer may lie in studying iodine exposure in various cities in Canada by measuring urinary iodine output in patients not receiving amiodarone.
250 EVALUATION OF EXERCISE-INDUCED CHANGES IN QT INTERVAL UNRELATED TO HEART RATE ACCELERATION - THE STRESS QT STUDY L Laroussi, H Nguyen Thanh, B Dube, A Vinet, V Jacquemet, R Leblanc, G Becker, T Kus, R Nadeau, M Sturmer Montréal, Québec BACKGROUND: The QT interval is heart rate dependent. It decreases as heart rate increases. Several correction models have been proposed to normalize its value at an RR interval of 1000 ms. In addition, the autonomic nervous system may affect QT interval duration independently of heart rate. AIM: To compare QT durations during a physiological stress test and during atrial pacing at the same RR intervals. METHODS: We recruited ten ambulatory patients with dual chamber pacemakers or ICDs who were rarely paced in the ventricle. While wearing a Holter monitor in supine position, subjects were stimulated in AAI mode at heart rates of 100 bpm (RR¼600 ms) and 120 bpm (RR¼500 ms) for 2 minutes at each step. Subsequently, they walked on a treadmill to reach comparable average heart rates. The analysis of QT intervals excluded premature ventricular contractions, ventricular paced beats and artifacts. RESULTS: During the stress test, 7 patients were able to reach stable RR intervals close to 100 and 120 bpm for at least 30 seconds. These 7 patients were considered for statistical analysis using 2-way repeated measure ANOVA (PE effect: pacing vs effort, FR effect: 100 vs 120 bpm). The mean RR intervals were similar during pacing and stress for each step (601.80.8 vs 601.79.4 ms and 500.31.6 vs 503.49.9 ms, PE effect: p ¼ 0.635). The mean QT intervals showed a statistically significant difference (341.016.4 vs 334.614.2 ms and 319.014.1 vs 308.615.0 ms) according to both frequency (FR effect, p < 0.001) and pace vs effort (PE effect: p ¼ 0.049), but not according to their interaction (PE*FR effect: p ¼ 0.290).
Canadian Cardiovascular Society (CCS) Poster POSTER - CLINICAL ELECTROPHYSIOLOGY Friday, October 18, 2013 247 SUBOPTIMAL TIME IN THERAPEUTIC RANGE (TTR) FOR INTERNATIONAL NORMALIZED RATIO (INR) MEASUREMENTS OBSERVED IN AN OUTPATIENT CARDIOLOGY CLINIC: IMPACT OF GENDER, ETHNICITY, DISEASE ETIOLOGY, CHADSVASC SCORE, PHYSICIANS AND CLINIC SITE N Singh, S Premji, S Chandra, D Song, L Yan, D Suh Atlanta, Georgia BACKGROUND:
TTR correlates inversely with ischemic stroke risk. Novel anticoagulants benefit most those patients (pts) with poor TTR. Variations in TTR are common with a range of between 55-60% being the norm and > 70% being optimal. It is not known what factors impact TTR most in the community cardiology setting. METHODS: Retrospective chart review of all pts being treated with warfarin in a single, multi-site suburban, outpt cardiology practice for 1 yr between Jul 2011 and Jul 2012 . RESULTS: In the 523 pts being followed, mean age was 69.6 yrs with 51% males. Hypertension (73%), hyperlipidemia (49%) were common, while diabetes (21%), smoking (6%), alcohol (21%) and aspirin use (20%) were less. The mean EF was 54 + 13%. Atrial fibrillation was the most common reason for treatment (75%) followed by mechanical valves (5%) venous system disease (15%) and arterial system disease (5%). An average of 12+5 INR readings/pt were done over the year. Average time on warfarin was 35+18 months. TTR for the overall group was 44.5 + 22.3%. There was no difference in TTR for males (44.2%) vs females (44.9%), p¼0.51. There were 44% Caucasians, 38% African Americans and 13% Asians. TTR for these ethnicities varied significantly, 49.0% vs 37.7% vs 50.3% respectively, p¼0.000001. INR's were managed by 7 physicians with significant differences (TTR range 39.9% to 49.0%, p¼0.025). TTR also varied significantly between 4 clinic sites (TTR range 36.4% to 51.9%, p¼0.04). The mean CHADSVasc score was 2. No difference in TTR was seen based on CHADSVasc score p¼0.4. Clinics and physicians having a higher proportion of African American pts tended to have lower TTR. TTR was worse in pts with arterial (36.9%) and venous disease (40%) vs atrial fibrillation (46.5%) and mechanical valves (47.6%), p¼0.02. Bleeding rates were low over the year (4%). For atrial fibrillation pts, only 11% had a documented discussion about using novel anticoagulants as a treatment option. CONCLUSION: Our findings suggest that TTR may be substantially worse in clinical practice than previously published literature would suggest. Ethnicity, physicians, clinic site and disease etiology may all contribute to poor
S185
TTR. Novel anticoagulants should be discussed more often, especially in afib pts at higher risk for poor TTR. Confirmation of these findings in a broader population could have significant implications for future anticoagulation management and stroke prevention. 248 CLINICAL ECG AUDIT: A USEFUL QUALITY ASSURANCE TOOL A Khosla, J Kornder, K Bhagirath Vancouver, British Columbia BACKGROUND: The ECG is a vital diagnostic clinical tool. Important decisions regarding treatment often depend on accurate interpretation, and therefore competency in ECG reading is of utmost importance. A formal process to measure ongoing competency in ECG interpretation is not outlined by the Royal College of Physicians and Surgeons of Canada (RCPSC), although this would fall under the College's Maintenance of Certification program; a mandatory requirement for specialists. The 2001 American College of Cardiology (ACC) Competence Statement on Electrocardiography recommends routine participation in quality improvement, specifically advocating for “activities such as having a number of ECGs over-read by colleagues and participating in periodic discussions of systemic issues involving ECG interpretation.” METHODS: The Division of Cardiology at Surrey Memorial Hospital designed a pilot clinical audit of 53 ECG readers throughout the Fraser Health Authority. The audit was designed to retrospectively review 740 adult ECGs interpreted and reported by cardiologists and internists using the MUSE system (General Electric). Fourteen ECGs per interpreting physician were randomly selected and de-identified. The ECGs were over-read by one reviewer (JK) who was blinded to the patient, site and interpreting physician name. Upon review of the ECG and the initial interpretation, the reviewer classified each into one of three groups outlined below:
All moderate or significant discrepancies were reviewed in a blinded fashion by at least 3 further reviewers. Any remaining difference of opinion resulted in the ECG reclassified as Group 1 “no discrepancy”. RESULTS: Of the 740 ECGs randomly selected, 7 were pediatric ECGs and were excluded from the clinical audit. In total, 87.3% (640) were found to have none or minor discrepancies, 10% (74) were classified in the moderate category, and 2.7% (19) had a significant discrepancy. Amongst the 53 ECG readers, there was an average
S186
concordance of 87.3% in initial interpretation. Further analysis of each reader's individual concordance with their peers and frequency of each type of discrepancy was evaluated and provided to the participants. CONCLUSION: This pilot clinical audit demonstrates that there can be major clinically relevant discrepancies in ECG interpretation in up to 3% of cases, thus providing impetus for the development and implementation of a regional ECG audit program. This program can act as a quality assurance tool for administrators and is easily scalable to other regional and provincial health authorities.
249 UNUSUALLY HIGH RATE OF HYPERTHYROIDISM OBSERVED IN PATIENTS EXPOSED TO AMIODARONE IN CALGARY PT Pollak, N Vijayaratnam Calgary, Alberta BACKGROUND:
The high iodine content of amiodarone precludes its use at any dose without at least a magnitude increase in exposure to iodine. A 200 mg tablet contains 75 mg of iodine, or which 7.5 mg is bioavailable, rapidly dwarfing the normal total body content of 14 mg. Hyperthyroidism is observed in about 3.3% of individuals in populations exposed to an increase in environmental iodine through increased salt fortification, water purification or seaweed ingestion. Study of linked prescription/ clinical databases confirms that patients taking amiodarone and thus exposed to excess iodine, also experience hyperthyroidism at a rate of 3-4%. This suggests they are reacting to iodine rather than the peripheral pharmacological effect of amiodarone on thyroxine conversion to triiodothyronine. We studied the incidence of hyperthyroidism in patients enrolling in the Calgary Amiodarone Clinic and compared it to personal experience in other Canadian cities. METHODS: Serial thyroid indices (Thyroid Stimulating Hormone, Free Thyroixine-T4 and Total TriiodothyronineT3), ALT and serum amiodarone concentrations were collected every six months on 115 patients enrolled in clinic for amiodarone dose adjustment and monitoring of hepatic and thyroid function. RESULTS: During three years of follow-up, 12 patients developed FreeT4>30 pmol/L with an mean time of onset of 914 days of therapy and a mean FreeT4 of 44 pmol/L. Serum amiodarone concentration was not high at a mean of 1.04 mcmol/L (target < 2.2 mcmol/L) and there was no evidence of any drug toxicity in the 12 patients with a mean ALT of 37 U/L and no ocular, neurological, pulmonary or dermal symptoms. All cases resolved within 6 months of initiating methimazole therapy (usually 5 mg p.o. TID) without stopping amiodarone.
Canadian Journal of Cardiology Volume 29 2013 CONCLUSION:
The observed rate of hyperthyroidism in a sample of Calgary patients receiving amiodarone was 10.4%, about 3 times that predicted by epidemiology and our experience in London and Halifax. What determines this deviation from the norm remains to be discovered. The literature suggests that hyperthyroidism incidence varies geographically by iodine intake. One might speculate that like the Wupper Valley in Europe, the population of Alberta may have adapted to low environmental iodine and react more vigorously to iodine supplementation from amiodarone. The answer may lie in studying iodine exposure in various cities in Canada by measuring urinary iodine output in patients not receiving amiodarone.
250 EVALUATION OF EXERCISE-INDUCED CHANGES IN QT INTERVAL UNRELATED TO HEART RATE ACCELERATION - THE STRESS QT STUDY L Laroussi, H Nguyen Thanh, B Dube, A Vinet, V Jacquemet, R Leblanc, G Becker, T Kus, R Nadeau, M Sturmer Montréal, Québec BACKGROUND: The QT interval is heart rate dependent. It decreases as heart rate increases. Several correction models have been proposed to normalize its value at an RR interval of 1000 ms. In addition, the autonomic nervous system may affect QT interval duration independently of heart rate. AIM: To compare QT durations during a physiological stress test and during atrial pacing at the same RR intervals. METHODS: We recruited ten ambulatory patients with dual chamber pacemakers or ICDs who were rarely paced in the ventricle. While wearing a Holter monitor in supine position, subjects were stimulated in AAI mode at heart rates of 100 bpm (RR¼600 ms) and 120 bpm (RR¼500 ms) for 2 minutes at each step. Subsequently, they walked on a treadmill to reach comparable average heart rates. The analysis of QT intervals excluded premature ventricular contractions, ventricular paced beats and artifacts. RESULTS: During the stress test, 7 patients were able to reach stable RR intervals close to 100 and 120 bpm for at least 30 seconds. These 7 patients were considered for statistical analysis using 2-way repeated measure ANOVA (PE effect: pacing vs effort, FR effect: 100 vs 120 bpm). The mean RR intervals were similar during pacing and stress for each step (601.80.8 vs 601.79.4 ms and 500.31.6 vs 503.49.9 ms, PE effect: p ¼ 0.635). The mean QT intervals showed a statistically significant difference (341.016.4 vs 334.614.2 ms and 319.014.1 vs 308.615.0 ms) according to both frequency (FR effect, p < 0.001) and pace vs effort (PE effect: p ¼ 0.049), but not according to their interaction (PE*FR effect: p ¼ 0.290).