Immediate recruitment of dormant coronary collaterals can provide more than half of normal resting perfusion during coronary occlusion in patients with coronary artery disease.

BACKGROUND: Dormant coronary collaterals are highly prevalent and clinically beneficial in cases of coronary occlusion. However, the magnitude of myocardial perfusion provided by immediate coronary collateral recruitment during acute occlusion is unknown. We aimed to quantify collateral myocardial perfusion during balloon occlusion in patients with coronary artery disease (CAD). METHODS: Patients without angiographically visible collaterals undergoing elective percutaneous transluminal coronary angioplasty (PTCA) to a single epicardial vessel underwent two scans with 99mTc-sestamibi myocardial perfusion single-photon emission computed tomography (SPECT). All subjects underwent at least three minutes of angiographically verified complete balloon occlusion, at which time an intravenous injection of the radiotracer was administered, followed by SPECT imaging. A second radiotracer injection followed by SPECT imaging was performed 24 h after PTCA. RESULTS: The study included 22 patients (median [interquartile range] age 68 [54-72] years. The perfusion defect extent was 19 [11-38] % of the LV, and the collateral perfusion at rest was 64 [58-67]% of normal. CONCLUSION: This is the first study to describe the magnitude of short-term changes in coronary microvascular collateral perfusion in patients with CAD. On average, despite coronary occlusion and an absence of angiographically visible collateral vessels, collaterals provided more than half of the normal perfusion.

Low diagnostic yield of ST elevation myocardial infarction amplitude criteria in chest pain patients at the emergency department.

OBJECTIVES: To evaluate the diagnostic yield of the ECG criteria for ST-elevation myocardial infarction in a large cohort of emergency department chest pain patients, and to determine whether extended ECG criteria or reciprocal ST depression can improve accuracy. Design: Observational, register-based diagnostic study on the accuracy of ECG criteria for ST-elevation myocardial infarction. Between Jan 2010 and Dec 2014 all patients aged ≥30 years with chest pain who had an ECG recorded within 4 h at two emergency departments in Sweden were included. Exclusion criteria were: ECG with poor technical quality; QRS duration ≥120 ms; ECG signs of left ventricular hypertrophy; or previous coronary artery bypass surgery. Conventional and extended ECG criteria were applied to all patients. The main outcome was acute myocardial infarction (AMI) and an occluded/near-occluded coronary artery at angiography. Results: Finally, 19932 patients were included. Conventional ECG criteria for ST elevation myocardial infarction were fulfilled in 502 patients, and extended criteria in 1249 patients. Sensitivity for conventional ECG criteria in diagnosing AMI with coronary occlusion/near-occlusion was 17%, specificity 98% and positive predictive value 12%. Corresponding data for extended ECG criteria were 30%, 94% and 8%. When reciprocal ST depression was added to the criteria, the positive predictive value rose to 24% for the conventional and 23% for the extended criteria. Conclusions: In unselected chest pain patients at the emergency department, the diagnostic yield of both conventional and extended ECG criteria for ST-elevation myocardial infarction is low. The PPV can be increased by also considering reciprocal ST depression.

Electrocardiographic changes in the differentiation of ischemic and non-ischemic ST elevation.

Objectives. Pericarditis, takotsubo cardiomyopathy and early repolarization syndrome (ERS) are well-known to mimic ST elevation myocardial infarction (STEMI). We aimed to study whether ECG findings of reciprocal ST depression, PR depression, ST-segment convexity or terminal QRS distortion can discriminate between ST elevation due to ischemia and non-ischemic conditions. Design. Eighty-five patients with STEMI and 94 patients with non-ischemic ST elevation were included. All patients had acute chest pain and at least 0.1 mV ST elevation. Presence of PR depression, ST-segment convexity, terminal QRS distortion or reciprocal ST depression was assessed in each ECG. Results. In anterior ST elevation, ST depression in lead II (≥0.025 mV) occurred in 40% of patients with STEMI but in none of the non-ischemic cases. In inferior ST elevation, ST depression in lead I (≥0.025 mV) was present in 83% of patients with STEMI but in none of the non-ischemic cases. Chest-lead PR depression was uncommon in STEMI (12%) compared to non-ischemic cases (38%; p < .001). Convex ST elevation occurred in 22% of STEMI cases and in 9% of non-ischemic cases (p = .01). Terminal QRS distortion was more prevalent in STEMI (40%) than in non-ischemic ST elevation (7%). In multivariable analysis, reciprocal ST depression was associated with an ischemic diagnosis, whereas ST depression in aVR and chest-lead PR depression were associated with a non-ischemic diagnosis. Conclusions. Identification of true STEMI among patients with different ST-elevation etiology may be improved by considering reciprocal ST depression, ST depression in aVR and chest-lead PR depression.

Pheochromocytoma - An ECG diagnosis?

Pheochromocytoma is a rare catecholamine-secreting tumor in the adrenal medulla. In some cases, the first symptoms are cardiovascular. We report on two patients with pheochromocytoma, who both presented with bidirectional ventricular tachycardia (BDVT). We elaborate on the mechanisms of BDVT in the setting of pheochromocytoma.

Erroneous computer-based interpretations of atrial fibrillation and atrial flutter in a Swedish primary health care setting.

Objective: To describe the incidence of incorrect computerized ECG interpretations of atrial fibrillation or atrial flutter in a Swedish primary care population, the rate of correction of computer misinterpretations, and the consequences of misdiagnosis.Design: Retrospective expert re-analysis of ECGs with a computer-suggested diagnosis of atrial fibrillation or atrial flutter.Setting: Primary health care in Region Kronoberg, Sweden.Subjects: All adult patients who had an ECG recorded between January 2016 and June 2016 with a computer statement including the words 'atrial fibrillation' or 'atrial flutter'.Main outcome measures: Number of incorrect computer interpretations of atrial fibrillation or atrial flutter; rate of correction by the interpreting primary care physician; consequences of misdiagnosis of atrial fibrillation or atrial flutter.Results: Among 988 ECGs with a computer diagnosis of atrial fibrillation or atrial flutter, 89 (9.0%) were incorrect, among which 36 were not corrected by the interpreting physician. In 12 cases, misdiagnosed atrial fibrillation/flutter led to inappropriate treatment with anticoagulant therapy. A larger proportion of atrial flutters, 27 out of 80 (34%), than atrial fibrillations, 62 out of 908 (7%), were incorrectly diagnosed by the computer.Conclusions: Among ECGs with a computer-based diagnosis of atrial fibrillation or atrial flutter, the diagnosis was incorrect in almost 10%. In almost half of the cases, the misdiagnosis was not corrected by the overreading primary-care physician. Twelve patients received inappropriate anticoagulant treatment as a result of misdiagnosis.Key pointsData regarding the incidence of misdiagnosed atrial fibrillation or atrial flutter in primary care are lacking. In a Swedish primary care setting, computer-based ECG interpretations of atrial fibrillation or atrial flutter were incorrect in 89 of 988 (9.0%) consecutive cases.Incorrect computer diagnoses of atrial fibrillation or atrial flutter were not corrected by the primary-care physician in 47% of cases.In 12 of the cases with an incorrect computer rhythm diagnosis, misdiagnosed atrial fibrillation or flutter led to inappropriate treatment with anticoagulant therapy.

Bigeminal sandwiches galore.

A long run of PVCs "sandwiched" in between the sinus beats resulting in an almost doubling of the heart rate-interpolated PVCs in bigeminy-is described. This case illustrates three interesting aspects of interpolated PVCs. Although they are not uncommon, long runs of interpolated PVCs in bigeminy are rare findings. In this case, the arrhythmia had a duration of 3 minutes. Second, it illustrates the "age-old wisdom" of partial retrograde conduction. Also, even though the arrhythmia resulted in an almost doubling of the heart rate, the patient remained asymptomatic.

Chest-lead ST-J amplitudes using arm electrodes as reference instead of the Wilson central terminal in smartphone ECG applications: Influence on ST-elevation myocardial infarction criteria fulfillment.

BACKGROUND: "Smartphone 12-lead ECG" for the assessment of acute myocardial ischemia has recently been introduced. In the smartphone 12-lead ECG either the right or the left arm can be used as reference for the chest electrodes instead of the Wilson central terminal. These leads are labeled "CR leads" or "CL leads." We aimed to compare chest-lead ST-J amplitudes, using either CR or CL leads, to those present in the conventional 12-lead ECG, and to determine sensitivity and specificity for the diagnosis of STEMI for CR and CL leads. METHODS: Five hundred patients (74 patients with ST elevation myocardial infarction (STEMI), 66 patients with nonischemic ST deviation and 360 controls) were included. Smartphone 12-lead ECG chest-lead ST-J amplitudes were calculated for both CR and CL leads. RESULTS: ST-J amplitudes were 9.1 ± 29 µV larger for CR leads and 7.7 ± 42 µV larger for CL leads than for conventional chest leads (V leads). Sensitivity and specificity were 94% and 95% for CR leads and 81% and 97% for CL leads when fulfillment of STEMI criteria in V leads was used as reference. In ischemic patients who met STEMI criteria in V leads, but not in limb leads, STEMI criteria were met with CR or CL leads in 91%. CONCLUSION: By the use of CR or CL leads, smartphone 12-lead ECG results in slightly lower sensitivity in STEMI detection. Therefore, the adjustment of STEMI criteria may be needed before application in clinical practice.

The Olson method for detection of acute myocardial ischemia in patients with coronary occlusion.

An automated ECG-based method may provide diagnostic support in the management of patients with acute coronary syndrome. The Olson method has previously proved to accurately identify the culprit artery in patients with acute coronary occlusion. METHODS: The Olson method was applied to 360 patients without acute myocardial ischemia and 52 patients with acute coronary occlusion. RESULTS: This study establishes the normal variation of the Olson wall scores in patients without acute myocardial ischemia, which provides the basis for implementation of the Olson method for triage of patients with acute coronary syndrome. All patients with acute occlusion had Olson wall scores above the upper limit of normal. CONCLUSION: The Olson method can be used for ischemia detection with very high sensitivity. Future studies are needed to explore specificity in patients with non-ischemic ST elevation.

A patient with non-ST-segment elevation acute coronary syndrome: Is it possible to predict the culprit coronary artery?

In acute coronary syndromes without ST-segment elevation (NSTE-ACS), identification of the culprit artery is, most often, not possible. In this case report, we elaborate on the likelihood of different culprit arteries in a patient with NSTE-ACS. While her symptoms were progressing, typical ECG findings of ischemia in the left coronary territories were diminishing. Instead, dynamic T-wave changes in the inferior leads were present and were most likely postischemic and "reischemic." Although the culprit artery could not be identified with certainty by means of these subtle changes, they correlated well with the findings on angiography and the ECG recorded afterward. This case report demonstrates the importance of analyzing ECG and its temporal changes in conjunction with evolving symptoms.

Heart rate response and recovery in cycle exercise testing - normal values and association with mortality.

AIM: Chronotropic incompetence and impaired heart rate (HR) recovery are related to mortality. Guidelines lack specific reference values for HR recovery. We defined normal values and studied blunted HR response and recovery, and mortality risk. METHODS: We included 9,917 subjects (45% females) aged 18-85 years who performed a cycle exercise test. We defined normal values for peak HR, HR reserve, and HR recovery at 1 and 2 minutes (HRR1 and HRR2) based on individuals apparently healthy (N=2,242). Associations between blunted HR indices (<5th percentile) and mortality over a median follow-up of 8.6 years were analysed using Cox regression and competing risk analysis. RESULTS: All HR indices were age-dependent and independent predictors of all-cause and CV mortality. The 5th percentiles of HR reserve, HRR1, and HRR2 correlated weakly with existing reference values. HR recovery variables were the strongest predictors of all-cause mortality (HRR1, hazard ratio 1.70 [95% confidence interval, 1.49-1.94] and HRR2, 1.57 [1.37-1.79]), including in subjects with normal exercise capacity (HRR1, 1.96 [1.61-2.39] and HRR2, 1.76 [1.46-2.12]). Combining HR indices appeared to increase the risk of all-cause (HRR1 and HRR2, 1.96 [1.68-2.29] and peak HR and HRR1, 1.87 [1.56-2.23]) and CV mortality, although no specific combination was superior for predicting CV mortality. CONCLUSIONS: All HR variables were age-dependent and associated with all-cause and CV mortality. Blunted HR recovery variables were the strongest predictors of all-cause mortality, even in subjects with normal exercise capacity. Combined blunted HR indices appeared to add prognostic value.

We provide a detailed description on the physiologic HR response and recovery kinetics in a population apparently CV risk-free referred for cycle exercise testing. When assessed in a larger population, blunted HR response and recovery were associated with increased mortality. HR response and recovery are age-dependent. We provide novel reference values.All blunted HR indices (peak HR, HR reserve, HRR1 and HRR2) are strong predictors of all-cause and CV mortality, and combined HR indices appeared to add prognostic value in all the analyses.Blunted HRR1 followed by HRR2 are the strongest predictor of all-cause mortality even in subjects with normal exercise capacity, highlighting the importance of their assessment in standard exercise testing.

Exercise systolic blood pressure response during cycle ergometry is associated with future hypertension in normotensive individuals.

AIMS: We aimed to investigate the association between the exercise systolic blood pressure (SBP) response and future hypertension (HTN) in normotensive individuals referred for cycle ergometry, with special regard to reference exercise SBP values and exercise capacity. METHODS AND RESULTS: In this longitudinal cohort study, data from 14 428 exercise tests were cross-linked with Swedish national registries on diagnoses and medications. We excluded individuals with a baseline diagnosis of cardiovascular disease or HTN. The peak exercise SBP (SBPpeak) was recorded and compared with the upper limit of normal (ULN) derived from SBPpeak reference equations incorporating age, sex, resting SBP, and exercise capacity. To evaluate the impact of exercise capacity, three SBP to work rate slopes (SBP/W-slopes) were calculated, relative to either supine or seated SBP at rest or to the first exercise SBP. Adjusted hazard ratios [HRadjusted (95% confidence interval, CI)] for incident HTN during follow-up, in relation to SBP response metrics, were calculated. We included 3895 normotensive individuals (49 ± 14 years, 45% females) with maximal cycle ergometer tests. During follow-up (median 7.5 years), 22% developed HTN. Higher SBPpeak and SBPpeak > ULN were associated with incident HTN [HRadjusted 1.19 (1.14-1.23) per 10 mmHg, and 1.95 (1.54-2.47), respectively]. All three SBP/W-slopes were positively associated with incident HTN, particularly the SBP/W-slope calculated as supine-to-peak SBP [HRadjusted 1.25 (1.19-1.31) per 1 mmHg/10 W]. CONCLUSION: Both SBPpeak > ULN based on reference values and high SBP/W-slopes were associated with incident HTN in normotensive individuals and should be considered in the evaluation of the cycle ergometry SBP response.

We examined the systolic blood pressure (SBP) response during maximal bicycle exercise testing in individuals without hypertension (HTN) or established cardiovascular disease and found that:When applying reference values for peak SBP during cycling exercise, accounting for age, sex, resting blood pressure (BP), and exercise capacity, exceeding the upper limit of normal was associated with twice as high relative risk of future HTN, compared with having a peak SBP within normal limits.A steep increase in exercise SBP in relation to the increase in work rate was also associated with future HTN but did not always coincide with elevated peak SBP.

Comparison of diagnostic accuracy of current left bundle branch block and ventricular pacing ECG criteria for detection of occlusion myocardial infarction.

BACKGROUND: Electrocardiographic detection of patients with occlusion myocardial infarction (OMI) can be difficult in patients with left bundle branch block (LBBB) or ventricular paced rhythm (VPR) and several ECG criteria for the detection of OMI in LBBB/VPR exist. Most recently, the Barcelona criteria, which includes concordant ST deviation and discordant ST deviation in leads with low R/S amplitudes, showed superior diagnostic accuracy but has not been validated externally. We aimed to describe the diagnostic accuracy of four available ECG criteria for OMI detection in patients with LBBB/VPR at the emergency department. METHODS: The unweighted Sgarbossa criteria, the modified Sgarbossa criteria (MSC), the Barcelona criteria and the Selvester criteria were applied to chest pain patients with LBBB or VPR in a prospectively acquired database from five emergency departments. RESULTS: In total, 623 patients were included, among which 441 (71%) had LBBB and 182 (29%) had VPR. Among these, 82 (13%) patients were diagnosed with AMI, and an OMI was identified in 15 (2.4%) cases. Sensitivity/specificity of the original unweighted Sgarbossa criteria were 26.7/86.2%, for MSC 60.0/86.0%, for Barcelona criteria 53.3/82.2%, and for Selvester criteria 46.7/88.3%. In this setting with low prevalence of OMI, positive predictive values were low (Sgarbossa: 4.6%; MSC: 9.4%; Barcelona criteria: 6.9%; Selvester criteria: 9.0%) and negative predictive values were high (all >98.0%). CONCLUSIONS: Our results suggests that ECG criteria alone are insufficient in predicting presence of OMI in an ED setting with low prevalence of OMI, and the search for better rapid diagnostic instruments in this setting should continue.

Echocardiographic estimation of pulmonary artery wedge pressure: invasive derivation, validation, and prognostic association beyond diastolic dysfunction grading.

AIMS: Grading of diastolic function can be useful, but indeterminate classifications are common. We aimed to invasively derive and validate a quantitative echocardiographic estimation of pulmonary artery wedge pressure (PAWP) and to compare its prognostic performance to diastolic dysfunction grading. METHODS AND RESULTS: Echocardiographic measures were used to derive an estimated PAWP (ePAWP) using multivariable linear regression in patients undergoing right heart catheterization (RHC). Prognostic associations were analysed in the National Echocardiography Database of Australia (NEDA). In patients who had undergone both RHC and echocardiography within 2 h (n = 90), ePAWP was derived using left atrial volume index, mitral peak early velocity (E), and pulmonary vein systolic velocity (S). In a separate external validation cohort (n = 53, simultaneous echocardiography and RHC), ePAWP showed good agreement with invasive PAWP (mean ± standard deviation difference 0.5 ± 5.0 mmHg) and good diagnostic accuracy for estimating PAWP >15 mmHg [area under the curve (95% confidence interval) 0.94 (0.88-1.00)]. Among patients in NEDA [n = 38,856, median (interquartile range) follow-up 4.8 (2.3-8.0) years, 2756 cardiovascular deaths], ePAWP was associated with cardiovascular death even after adjustment for age, sex, and diastolic dysfunction grading [hazard ratio (HR) 1.08 (1.07-1.09) per mmHg] and provided incremental prognostic information to diastolic dysfunction grading (improved C-statistic from 0.65 to 0.68, P < 0.001). Increased ePAWP was associated with worse prognosis across all grades of diastolic function [HR normal, 1.07 (1.06-1.09); indeterminate, 1.08 (1.07-1.09); abnormal, 1.08 (1.07-1.09), P < 0.001 for all]. CONCLUSION: Echocardiographic ePAWP is an easily acquired continuous variable with good accuracy that associates with prognosis beyond diastolic dysfunction grading.

Noninvasive Imaging Methods for Quantification of Pulmonary Edema and Congestion: A Systematic Review.

Quantification of pulmonary edema and congestion is important to guide diagnosis and risk stratification, and to objectively evaluate new therapies in heart failure. Herein, we review the validation, diagnostic performance, and clinical utility of noninvasive imaging modalities in this setting, including chest x-ray, lung ultrasound (LUS), computed tomography (CT), nuclear medicine imaging methods (positron emission tomography [PET], single photon emission CT), and magnetic resonance imaging (MRI). LUS is a clinically useful bedside modality, and fully quantitative methods (CT, MRI, PET) are likely to be important contributors to a more accurate and precise evaluation of new heart failure therapies and for clinical use in conjunction with cardiac imaging. There are only a limited number of studies evaluating pulmonary congestion during stress. Taken together, noninvasive imaging of pulmonary congestion provides utility for both clinical and research assessment, and continued refinement of methodologic accuracy, validation, and workflow has the potential to increase broader clinical adoption.

Prognostic value of peak work rate indexed by left ventricular diameter.

Left ventricular diameter (LVEDD) increases with systematic endurance training but also in various cardiac diseases. High exercise capacity associates with favorable outcomes. We hypothesized that peak work rate (Wpeak) indexed to LVEDD would carry prognostic information and aimed to evaluate the association between Wpeak/LVEDDrest and cardiovascular mortality. Wpeak/LVEDDrest (W/mm) was calculated in patients with an echocardiographic examination within 3 months of a maximal cycle ergometer exercise test. Low Wpeak/LVEDDrest was defined as a value below the sex- and age-specific 5th percentile among lower-risk subjects. The association with cardiovascular mortality was evaluated using Cox regression. In total, 3083 patients were included (8.0 [5.4-11.1] years of follow-up, 249 (8%) cardiovascular deaths). Wpeak/LVEDDrest (W/mm) was associated with cardiovascular mortality (adjusted hazard ratio (HR) 0.28 [0.22-0.36]), similar to Wpeak in % of predicted, with identical prognostic strength when adjusted for age and sex (C-statistics 0.87 for both). A combination of low Wpeak/LVEDDrest and low Wpeak was associated with a particularly poor prognosis (adjusted HR 6.4 [4.0-10.3]). Wpeak/LVEDDrest was associated with cardiovascular mortality but did not provide incremental prognostic value to Wpeak alone. The combination of a low Wpeak/LVEDDrest and low Wpeak was associated with a particularly poor prognosis.

Reference equations for breathlessness during incremental cycle exercise testing.

Background: Exertional breathlessness is commonly assessed using incremental exercise testing (IET), but reference equations for breathlessness responses are lacking. We aimed to develop reference equations for breathlessness intensity during IET. Methods: A retrospective, consecutive cohort study of adults undergoing IET was carried out in Sweden. Exclusion criteria included cardiac or respiratory disease, death or any of the aforementioned diagnoses within 1 year of the IET, morbid obesity, abnormally low exercise capacity, submaximal exertion or an abnormal exercise test. Probabilities for breathlessness intensity ratings (Borg CR10) during IET in relation to power output (%predWmax), age, sex, height and body mass were analysed using marginal ordinal logistic regression. Reference equations for males and females were derived to predict the upper limit of normal (ULN) and the probability of different Borg CR10 intensity ratings. Results: 2581 participants (43% female) aged 18-90 years were included. Mean breathlessness intensity was similar between sexes at peak exertion (6.7±1.5 versus 6.4±1.5 Borg CR10 units) and throughout exercise in relation to %predWmax. Final reference equations included age, height and %predWmax for males, whereas height was not included for females. The models showed a close fit to observed breathlessness intensity ratings across %predWmax values. Models using absolute W did not show superior fit. Scripts are provided for calculating the probability for different breathlessness intensity ratings and the ULN by %predWmax throughout IET. Conclusion: We present the first reference equations for interpreting breathlessness intensity during incremental cycle exercise testing in males and females aged 18-90 years.