Evaluation of a new treadmill exercise protocol to unmask type 1 Brugada electrocardiographic pattern: can we improve diagnostic yield?

AIMS: High precordial leads (HPL) on the resting electrocardiogram (ECG) are widely used to improve diagnostic detection of type 1 Brugada ECG pattern (Br1ECGp). A parasympathetic activation marks the initial recovery phase of treadmill stress testing (TET), and this can be useful for detecting the typical ECG pattern. Our study aimed to evaluate the role of a new HPL-treadmill exercise testing (TET) protocol in detecting Br1ECGp fluctuation compared to resting HPL-ECG. METHODS AND RESULTS: 74 out of 163 patients of a Brugada syndrome (BrS) Brazilian cohort (GenBra Registry) underwent exercise testing with HPL-TET protocol. Precordial leads were displayed in strategic positions in the right and left parasternal spaces. The step-by-step analysis included ECG classification (as presence or absence of Br1ECGp) in standard vs. HPL leads placement in the following sequences: resting phase, maximal exercise, and the passive recovery phase (including 'quick lay down'). For heart rate recovery (HRR) measurements and comparisons, a Student's t-test was applied. McNemar tests compared the detection of Br1ECGp. The significance level was defined as P < 0.05. Fifty-seven patients (57/74; 77%) were male, the mean age was 49.0 ± 14, 78.4% had spontaneous BrS, and the mean Shanghai score was 4.5. The HPL-TET protocol increased Br1ECGp detection by 32.4% against resting HPL-ECG (52.7% vs. 20.3%, P = 0.001) alone. CONCLUSION: Stress testing using HPL with the passive recovery phase in the supine position offers an opportunity to unmask the type 1 Br1ECGp, which could increase the diagnostic yield in this population.

Segmental cardiac strain assessment by two-dimensional speckle-tracking echocardiography in surviving MIS-c patients: Correlations with myocardial flow reserve (MFR) by 13 N-ammonia PET-CT.

BACKGROUND: Multisystem inflammatory syndrome in children (MIS-c) is associated with severe cardiovascular impairment and eventually death. Pathophysiological mechanisms involved in myocardial injury were scarcely investigated, and cardiovascular outcomes are uncertain. Autopsy studies suggested that microvascular dysfunction may be relevant to LV impairment. OBJECTIVE: We aimed to evaluate segmental LV longitudinal strain by 2DST echocardiography and myocardial flow reserve (MFR) by 13 N-ammonia PET-CT, in six surviving MIS-c patients. METHODS: Each patient generated 34 LV segments for combined 2DST and MRF analysis. MFR was considered abnormal when <2, borderline when between 2 and 2.5 and normal when >2.5. RESULTS: From July 2020 to February 2021, six patients were admitted with MIS-c: three males, aged 9.3 (6.6-15.7) years. Time from admission to the follow-up visit was 6.05 (2-10.3) months. Although all patients were asymptomatic and LV EF was ≥55%, 43/102 (42.1%) LV segments showed MFR <2.5. There was a modest positive correlation between segmental peak systolic longitudinal strain and MFR: r = .36, p = .03 for basal segments; r = .41, p = .022 for mid segments; r = .42, p = .021 for apical segments. Median peak systolic longitudinal strain was different among MRF categories: 18% (12%-24%) for abnormal, 18.5% (11%-35%) for borderline, and 21% (12%-32%) for normal MFR (p = .006). CONCLUSION: We provided preliminary evidence that surviving MIS-c patients may present subclinical impairment of myocardial microcirculation. Segmental cardiac strain assessment 2DST seems useful for MIS-c cardiovascular follow-up, given its good correlation with 13 N-ammonia PET-CT derived MFR.

Exercise Testing, Family History, and Subclinical Atherosclerosis Markers for Cardiovascular Risk Reclassification in Middle-Aged Women

Abstract Background Cardiovascular diseases are the main cause of death in women and the accuracy of currently available risk scores is questionable. Objective To reclassify the risk estimated by the Framingham Risk Score (FRS) in asymptomatic middle-aged women by incorporating family history, exercise testing variables, and subclinical atherosclerosis markers. Methods This cross-sectional study included 509 women (age range, 46-65 years) without cardiovascular symptoms. Those at low or intermediate risk by the FRS were reclassified to a higher level considering premature family history of acute myocardial infarction and/or sudden death; four variables from exercise testing; and two variables related to subclinical atherosclerosis markers. The homogeneity of these variables according to the FRS was verified by Pearson chi-square test (p<0.05). Results According to the FRS, 80.2%, 6.2%, and 13.6% of the women were classified as low (<5%), intermediate (5-10%), and high (>10%) risks, respectively. The intermediate-risk stratum showed the highest increase (from 6.2% to 33.3%) with addition of family history; followed by addition of chronotropic index <80% (to 24.2%); functional capacity <85% (22.2%), coronary calcium score >0 (20.6%); decreased one-minute heart rate recovery ≤12 bpm (15.2%); carotid intima-media thickness >1 mm and/or carotid plaque (13.8%) and ST-segment depression (9.0%). The high-risk stratum increased to 14.4% with the addition of reduced heart rate recovery and to 17.1% with the coronary calcium score. Conclusion Incorporation of premature family history of cardiovascular events, exercise testing abnormal parameters, and subclinical atherosclerosis markers into the FRS led to risk reclassification in 3.0-29.7% of asymptomatic middle-aged women, mainly by an increase from low to intermediate risk.

Non Electrocardiographic alterations in exercise testing in asymptomatic women. Associations with cardiovascular risk factors.

OBJECTIVES: To estimate the prevalence of exercise testing alterations in middle-aged women without symptoms of heart disease and to verify the associations of functional capacity and heart rate behavior during and after exercise with cardiovascular risk factors. METHODS: A cross-sectional study was conducted with 509 asymptomatic women aged between 46 and 65 years who underwent clinical evaluations and exercise testing (Bruce protocol). The heart rate behavior was evaluated by the maximal predicted heart rate achieved, chronotropic index and recovery heart rate. RESULTS: The mean age was 56.4±4.8 years, and 13.4% of the patients had a Framingham risk score above 10%. In the exercise treadmill testing, 58.0% presented one or more of the following alterations (listed in order of ascending prevalence): symptoms (angina, dyspnea, and dizziness), ST-segment depression, arrhythmia, reduction in recovery heart rate of ≤12 bpm at 1 minute, altered maximal predicted heart rate achieved, abnormal blood pressure, functional capacity deficiency, and altered chronotropic index. In the multivariate analysis, the following associations (odds ratio) were observed for these alterations: chronotropic index was associated with obesity (2.08) and smoking (4.47); maximal predicted heart rate achieved was associated with smoking (6.45); reduction in the recovery heart rate at 1 minute was associated with age (1.09) and obesity (2.78); functional capacity was associated with age (0.92), an overweight status (2.29) and obesity (6.51). CONCLUSIONS: More than half of middle-aged women without cardiovascular symptoms present alterations in one or more exercise testing parameters. Alterations in the functional capacity or heart rate behavior, as verified by exercise testing, are associated with age, smoking, an overweight status and obesity.

Non Electrocardiographic alterations in exercise testing in asymptomatic women. Associations with cardiovascular risk factors

OBJECTIVES: To estimate the prevalence of exercise testing alterations in middle-aged women without symptoms of heart disease and to verify the associations of functional capacity and heart rate behavior during and after exercise with cardiovascular risk factors. METHODS: A cross-sectional study was conducted with 509 asymptomatic women aged between 46 and 65 years who underwent clinical evaluations and exercise testing (Bruce protocol). The heart rate behavior was evaluated by the maximal predicted heart rate achieved, chronotropic index and recovery heart rate. RESULTS: The mean age was 56.4±4.8 years, and 13.4% of the patients had a Framingham risk score above 10%. In the exercise treadmill testing, 58.0% presented one or more of the following alterations (listed in order of ascending prevalence): symptoms (angina, dyspnea, and dizziness), ST-segment depression, arrhythmia, reduction in recovery heart rate of ≤12 bpm at 1 minute, altered maximal predicted heart rate achieved, abnormal blood pressure, functional capacity deficiency, and altered chronotropic index. In the multivariate analysis, the following associations (odds ratio) were observed for these alterations: chronotropic index was associated with obesity (2.08) and smoking (4.47); maximal predicted heart rate achieved was associated with smoking (6.45); reduction in the recovery heart rate at 1 minute was associated with age (1.09) and obesity (2.78); functional capacity was associated with age (0.92), an overweight status (2.29) and obesity (6.51). CONCLUSIONS: More than half of middle-aged women without cardiovascular symptoms present alterations in one or more exercise testing parameters. Alterations in the functional capacity or heart rate behavior, as verified by exercise testing, are associated with age, smoking, an overweight status and obesity.

Left ventricular function in response to dipyridamole stress: head-to-head comparison between 82Rubidium PET and 99mTc-sestamibi SPECT ECG-gated myocardial perfusion imaging.

PURPOSE: Myocardial perfusion imaging (MPI) with 99mTc-sestamibi (sestamibi) SPECT and rubidium-82 (82Rb) PET both allow for combined assessment of perfusion and left ventricular (LV) function. We sought to compare parameters of LV function obtained with both methods using a single dipyridamole stress dose. MATERIALS AND METHODS: A group of 221 consecutive patients (65.2 ± 10.4 years, 52.9% male) underwent consecutive sestamibi and 82Rb MPI after a single dipyridamole stress dose. Sestamibi and 82Rb summed rest (SRS), stress (SSS) and difference (SDS) scores, and LV end-diastolic (EDV) and end-systolic (ESV) volumes and left ventricular ejection fraction (LVEF) were compared. RESULTS: Bland-Altman analysis showed that with increasing ESV and EDV the difference between the two perfusion tracers increased both at rest and post-stress. The mean difference in EDV and ESV between the two perfusion tracers at rest could both be independently explained by the 82Rb SDS and the sestamibi SRS. The combined models explained approximately 30% of the variation in these volumes between the two perfusion tracers (R2 = 0.261, p = 0.005; R2 = 0.296, p < 0.001, for EDV and ESV respectively). However, the mean difference in LVEF between sestamibi and 82Rb showed no significant trend post-stress (R2 = 0.001, p = 0.70) and only a modest linear increase with increasing LVEF values at rest (R2 = 0.032, p = 0.009). CONCLUSIONS: Differences in left ventricular volumes between sestamibi and 82Rb MPI increase with increasing volumes. However, these differences did only marginally affect LVEF between sestamibi and 82Rb. In clinical practice these results should be taken into account when comparing functional derived parameters between sestamibi and 82Rb MPI.

Myocardial blood flow assessment with 82rubidium-PET imaging in patients with left bundle branch block.

OBJECTIVES: Perfusion abnormalities are frequently seen in Single Photon Emission Computed Tomography (SPECT) when a left bundle branch block is present. A few studies have shown decreased coronary flow reserve in the left anterior descending territory, regardless of the presence of coronary artery disease. OBJECTIVE: We sought to investigate rubidium-82 (82Rb) positron emission tomography imaging in the assessment of myocardial blood flow and coronary flow reserve in patients with left bundle branch block. METHODS: Thirty-eight patients with left bundle branch block (GI), median age 63.5 years, 22 (58%) female, 12 with coronary artery disease (≥70%; GI-A) and 26 with no evidence of significant coronary artery disease (GI-B), underwent rest-dipyridamole stress 82Rb-positron emission tomography with absolute quantitative flow measurements using Cedars-Sinai software (mL/min/g). The relative myocardial perfusion and left ventricular ejection fraction were assessed in 17 segments. These parameters were compared with those obtained from 30 patients with normal 82Rb-positron emission tomography studies and without left bundle branch block (GII). RESULTS: Stress myocardial blood flow and coronary flow reserve were significantly lower in GI than in GII (p<0.05). The comparison of coronary flow reserve between GI-A and GI-B showed that it was different from the global coronary flow reserve (p<0.05) and the stress flow was significantly lower in the anterior than in the septal wall for both groups. Perfusion abnormalities were more prevalent in GI-A (p=0.06) and the left ventricular ejection fraction was not different between GI-A and GI-B, whereas it was lower in GI than in GII (p<0.001). CONCLUSION: The data confirm that patients with left bundle branch block had decreased myocardial blood flow and coronary flow reserve and coronary flow reserve assessed by 82Rb-positron emission tomography imaging may be useful in identifying coronary artery disease in patients with left bundle branch block.

Myocardial blood flow assessment with 82rubidium-PET imaging in patients with left bundle branch block

OBJECTIVES: Perfusion abnormalities are frequently seen in Single Photon Emission Computed Tomography (SPECT) when a left bundle branch block is present. A few studies have shown decreased coronary flow reserve in the left anterior descending territory, regardless of the presence of coronary artery disease. OBJECTIVE: We sought to investigate rubidium-82 (82Rb) positron emission tomography imaging in the assessment of myocardial blood flow and coronary flow reserve in patients with left bundle branch block. METHODS: Thirty-eight patients with left bundle branch block (GI), median age 63.5 years, 22 (58%) female, 12 with coronary artery disease (≥70%; GI-A) and 26 with no evidence of significant coronary artery disease (GI-B), underwent rest-dipyridamole stress 82Rb-positron emission tomography with absolute quantitative flow measurements using Cedars-Sinai software (mL/min/g). The relative myocardial perfusion and left ventricular ejection fraction were assessed in 17 segments. These parameters were compared with those obtained from 30 patients with normal 82Rb-positron emission tomography studies and without left bundle branch block (GII). RESULTS: Stress myocardial blood flow and coronary flow reserve were significantly lower in GI than in GII (p<0.05). The comparison of coronary flow reserve between GI-A and GI-B showed that it was different from the global coronary flow reserve (p<0.05) and the stress flow was significantly lower in the anterior than in the septal wall for both groups. Perfusion abnormalities were more prevalent in GI-A (p=0.06) and the left ventricular ejection fraction was not different between GI-A and GI-B, whereas it was lower in GI than in GII (p<0.001). CONCLUSION: The data confirm that patients with left bundle branch block had decreased myocardial blood flow and coronary flow reserve and coronary flow reserve assessed by 82Rb-positron emission tomography imaging may be useful in identifying coronary artery disease in patients with left bundle branch block.