Allison, Thomas G.

Vascular abnormalities are significant and often underdiagnosed conditions that can have profound implications for athletic performance, limb function, and even life, and multimodality imaging plays an essential role in timely recognition, characterization, and management.

Abstract Background Type 8 long QT syndrome (LQT8) is characterised by prolonged QT interval and a high burden of ventricular repolarisation abnormalities including sudden cardiac death. Purpose Patients and clinicians face uncertainties about the daily risk of cardiac arrest, particularly during physical performance. Therefore, we aim to establish a risk assessment based on systematically collected data. Methods We analysed eight patients genetically confirmed to carry CACNA1C variants, of whom three had cardiac arrests in early childhood, while others were discovered incidentally. One patient met criteria for cardiac-only Timothy syndrome. All patients performed cardiopulmonary exercise testing (CPET) with several having multiple studies over time, resulting in a total of 19 CPETs. Echocardiograms were available for all patients, and Holter monitor results for all but one patient. All CPETs were conducted on beta-blockade. Results On resting ECG the average heart rate was 66.5 ± 10.7 beats per minute (bpm). Average QT at diagnosis was 476.8 ± 47.8 ms, with a corrected QTc of 487.9 ± 37.2 ms. Two patients had sinus arrhythmia and three were atrially paced at rest. No ventricular arrhythmias were observed at rest. On initial CPET, average peak oxygen uptake was 29.3 ± 8.5 ml/kg/min (82 ± 25% predicted) at a peak heart rate of 141.6 ± 24.3 bpm (73 ± 13% predicted). Peak respiratory exchange ratio averaged 1.09 ± 0.13. On initial CPET, four patients developed premature ventricular contractions (PVCs), but only in one patient were more than 5 per minute detected. That patient had a high PVC burden with multiple runs of non-sustained ventricular tachycardia. There were no episodes of syncope or cardiac arrest across all 19 CPETs. Conclusions Our cases demonstrate the safety and utility of exercise testing in CACNA1C-related disease. Longitudinal follow-up revealed diverse electrophysiological findings, including QT prolongation and reduced chronotropic response. From our data it is suggested that CPET is safe to perform on appropriate therapy and exercise should be encouraged.

Abstract Background Inability to reach age-predicted peak heart rate (APPHR) of >85%, or submaximal heart rates, on treadmill exercise stress testing (TMET) is associated with increased mortality risk [1]. Evidence is limited on mortality outcomes with heart rates greater than APPHR, or ‘supramaximal’ heart rates, especially when using heart rate metrics alone. Purpose Use of a comprehensive, compositive assessment of heart rate, termed ‘vigor’, to determine mortality outcomes has yet to be explored, especially for those with supramaximal heart rates. We sought to investigate this relationship. Methods We queried our stress database from 1993-2010 for patients >30 years old without cardiovascular disease and not on antichronotropic therapy. Clinical and mortality outcomes were retrieved from patient records. Patients were stratified into groups based on APPHR as achieved on TMET: <75%, 75-84%, 85-94%, 95-104%, ≥105% of APPHR. For our study, heart rate ‘vigor’ served as a composite assessment of cardiovascular fitness based solely on heart rate. This was derived from resting heart rate, heart rate recovery, and achieved percentage of APPHR. A higher Heart Rate Vigor Score (HRViS) for this study was, by definition, indicative of better cardiac responsiveness and recovery following exertion. Patients were stratified based on their achieved HRViS. Scores were determined as follows: All patients were initially assigned 3 points. 1 point was subtracted for each of the following parameters met: resting heart rate >90 beats per minute (BPM), heart rate recovery <13 BPM, or submaximal heart rates of APPHR <85%. Patients that remained at HRViS 3 and achieved supramaximal heart rates (≥105% APPHR) were assigned an additional point, amounting to HRViS 4. HRViS stratifications are detailed in Table 1. Mortality rates were calculated for all HRViS stratifications, with adjustment for FAC and known confounders. HRViS 3 was used as the referent. Results 18,961 total patients were included. 88 patients were classified with HRViS of 0; 1,763 as HRViS 1; 5,409 as HRViS 2; 9,902 as HRViS 3; and 1,799 as HRViS 4. Those with lower HRViS scores had more comorbid conditions (Table 1). 2,144 patients achieved submaximal APPHR (<85%) on TMET, and 2,917 achieved supramaximal APPHR (≥105%). HRViS 0, 1, and 2 had higher mortality risks compared to referent HRViS 3: 0 [3.76 (2.34-6.04), p<0.0001]; 1 [1.80 (1.53-2.12), p<0.0001]; 2 [1.29 (1.12-1.48), p=0.0004]. HRViS 4 had a non-statistically significant trends towards lower mortality risk compared to 3: 0.85 (0.66-1.08), p=0.1768. Conclusions HRViS 4 had a non-statistical trend towards lower mortality risk. Our findings do not support concern for adverse outcomes with excessive heart rates during exercise, and rather, may indicate a trend towards mortality benefit.HRViS Table 1

Background Patients with single-ventricle physiology are often palliated with the Fontan operation, which may involve the creation of a fenestration. We aimed to evaluate differences in cardiopulmonary exercise test (CPET) performance between patients with fenestrated and non-fenestrated Fontan circulation. Methods Patients with a Fontan circulation referred to CPET between 2006 and 2024 were included and were categorised based on their fenestration status at the time of CPET. Logistic regression analyses were performed to assess the impact of fenestration on peak oxygen consumption (VO 2 ), and Cox proportional hazard to evaluate the impact of fenestration on cardiovascular outcomes (death, heart transplant and Fontan-related hospitalisation). Results Of the 184 patients, 141 were classified as non-fenestrated and 43 as fenestrated. The minute ventilation-carbon dioxide production (V E /VCO 2 slope) was higher in the fenestrated (36.9±7.9) versus (33.2±6.2; p=0.009) in the non-fenestrated group. There was no significant difference in predicted VO 2 between groups (non-fenestrated 51.9%±14.4 vs 51.3%±15.6; p=0.7). Resting oxygen saturation was higher in the non-fenestrated group (93%±4.7 compared with fenestrated group 90.1%±5; p<0.001). Fontan fenestration was not significantly associated with the composite outcome; older patient age at the time of the CPET, cirrhosis and ventricular ejection fraction <40% were significantly associated with higher risk, while higher resting systolic blood pressure, left ventricular morphology and higher predicted peak VO 2 were protective. Conclusions The increased hypoxia and reduced ventilatory efficiency associated with Fontan fenestration offset any potential benefits, resulting in similar exercise performance between the groups. Fontan fenestration was not significantly associated with cardiovascular outcomes.

Abstract Rationale: Cardiopulmonary exercise testing is a unique tool for simultaneously assessing cardiopulmonary and metabolic responses at peak exercise, making it invaluable for diagnosing unexplained dyspnea and fatigue, common issues in cardiovascular and pulmonary clinics. However, its use is often limited by complex guidelines, restricted lab access, technical demands, and high costs. The Veterans Specific Activity Questionnaire (VSAQ), developed by Meyers et al., offers a practical way to estimate metabolic equivalents and maximum oxygen consumption to assess exercise capacity. While primarily validated in a male population, the VSAQ lacks sufficient research in diverse ethnic and gender groups. Broader validation could enhance personalized cardiopulmonary testing, support equitable healthcare resource allocation, and help lower costs. Methods: In this prospective observational study, participants were included if they were 18 years or older and capable of completing a cardiopulmonary exercise test. Participants were excluded if they had known abnormal breathing patterns at baseline and if they had any contraindication for cardiopulmonary exercise and pulmonary function testing. A total of 17 patients without known cardiopulmonary disease provided informed consent and completed the brief self-administered VSAQ following the cardiopulmonary exercise test. The VSAQ was used to estimate maximal exercise capacity in metabolic equivalents, which was then compared to the actual maximal exercise capacity achieved on a bike ergometer, as recorded in the electronic medical records. Results: A linear regression analysis indicated a marginal association between VSAQ results (METS) and CPET METS, accounting for 22.2% of the variance in CPET METS (p=0.056). This finding suggests a potential, though not statistically significant, positive relationship between VSAQ METS scores and CPET MET. A linear regression analysis indicated a marginal association between VSAQ calculated Peak VO₂ and observed CPET Peak VO₂ (o₂/kg/min), explaining 21.6% of the variance in CPET Peak VO₂ (p=0.060). This suggests a potential positive relationship between VSAQ calculated Peak VO₂ and CPET Peak VO₂, though the association did not reach statistical significance. Conclusion: In this preliminary sample of patients without known cardiopulmonary disease, the VSAQ demonstrated accuracy in predicting maximum oxygen consumption at peak exercise. With further validation and larger sample size, the VSAQ could become a valuable adjunctive tool for assessing patients with unexplained dyspnea and fatigue, supporting more efficient diagnostic evaluations. Additionally, the VSAQ may serve as a practical follow-up measure to track clinical improvement after therapeutic interventions in this specific population.

Background Pilots face significant occupational risks affecting cardiometabolic health and are subject to regulatory health screenings. Cardiometabolic risk factors, cardiac screening findings and outcomes among pilots have not been well reported. Objectives This study aimed to investigate cardiac evaluations of asymptomatic aircraft pilots and the association between clinical risk factors and outcomes. Methods Asymptomatic aircraft pilots referred for cardiac assessment between January 1991 and May 2023 were studied. Baseline characteristics, cardiac test findings and outcomes were evaluated. Major adverse clinical event (MACE) was defined as death, myocardial infarction, stroke, major arrhythmia, heart failure event or cardiac-related hospitalisation and estimated using Kaplan-Meier methods. Significant valvular disease by echocardiography was defined as stenosis, regurgitation or prolapse of moderate severity or greater. Aortic dilation by transthoracic echocardiogram (TTE) was defined as measuring ≥40 mm in diameter. Results 212 pilots met eligibility criteria for the study. The majority were white (92.9%) and male (91%) with a mean age of 58.5±10.9 years. Mean body mass index was 27.8±4.8 with comorbid hyperlipidaemia (48%), hypertension (32%), prior cancer (27%), sleep apnoea (15%), arrhythmia (12%) and known coronary artery disease (6%). Imaging revealed significant valvular disease (2.4%) and dilated aortas (16%) based on TTEs. Functional cardiac testing performed showed mean functional aerobic capacity of 109±24.6% reaching 11.89±2.65 metabolic equivalents with <8% showing positive findings per EKG or wall motion abnormalities on exercise TTE. Six patients received coronary angiography based on clinical evaluation, with two undergoing percutaneous coronary intervention. Over a 32-year period with a median (range) follow-up of 5.15 (0.1, 31.82) years, MACE incidence was 15%. Conclusions Asymptomatic aircraft pilots have underlying cardiovascular risk factors but good overall functional capacity, long-term outcomes and life expectancy. Prevalence of cardiac structural findings like aortic dilatation warrants increased attention during examination of these patients.

MRI and CT play an important role in sports cardiology, including preparticipation evaluation, distinguishing adaptive changes of athlete’s heart from pathologic entities, and evaluation following cardiovascular symptoms or adverse events.

This case report describes a woman in her early 60s who went into cardiac arrest immediately after administration of an echocardiogram contrast agent.

Background: Many children born with single ventricle physiology are palliated with Fontan operation, which may include a fenestration creation. This has been demonstrated to improve short-term outcomes after surgery. Reduced exercise capacity has been shown to be a predictor of prognosis in Fontan patients. Aim: We sought to compare cardiopulmonary exercise test (CPET) data between fenestrated and non-fenestrated Fontan patients. Methods: We conducted a retrospective cohort study of 185 patients referred for CPET from 2011 to 2024. Patients with complete CPET data were included. Type of Fontan, comorbidities, and echocardiogram data were ascertained electronically. Patients were divided into 2 different groups according to the fenestration patency. Fisher’s exact test or chi-square was used to compare categorical variables. T-test and Turkey-Kramer were used to compare continuous variables. Adjustment using General Lineal Models procedure were used to identify any confounder that could affect the results. P value <0.05 was considered significant. Results: 142 patients were classified in the non-fenestrated (NF) group, and 43 in the fenestrated group (FF). Baseline characteristics of both groups are shown in Table 1. From the evaluated CPET variables, the minute ventilation-carbon dioxide production (VE/VCO2) was higher in the FF (p=<0.001), and oxygen saturation at peak exercise (SatO2) was lower in this group (p= <0.001) (Figure 1). There was no significant difference between peak oxygen consumption (VO2) between groups. When adjusted by comorbidities only VE/VCO2 nadir, slope and peak SatO2 were statistically significant different between groups (Table 2). Conclusion: Ventilatory variables showed significant differences when fenestration was presented, secondary to V-Q mismatch from increased right to left shunt. Despite the theoretical advantage of increased cardiac output from Fontan fenestration, exercise performance was similar between both groups.