Accuracy of smartphone apps for heart rate measurement.

Background Smartphone manufacturers offer mobile health monitoring technology to their customers, including apps using the built-in camera for heart rate assessment. This study aimed to test the diagnostic accuracy of such heart rate measuring apps in clinical practice. Methods The feasibility and accuracy of measuring heart rate was tested on four commercially available apps using both iPhone 4 and iPhone 5. 'Instant Heart Rate' (IHR) and 'Heart Fitness' (HF) work with contact photoplethysmography (contact of fingertip to built-in camera), while 'Whats My Heart Rate' (WMH) and 'Cardiio Version' (CAR) work with non-contact photoplethysmography. The measurements were compared to electrocardiogram and pulse oximetry-derived heart rate. Results Heart rate measurement using app-based photoplethysmography was performed on 108 randomly selected patients. The electrocardiogram-derived heart rate correlated well with pulse oximetry ( r = 0.92), IHR ( r = 0.83) and HF ( r = 0.96), but somewhat less with WMH ( r = 0.62) and CAR ( r = 0.60). The accuracy of app-measured heart rate as compared to electrocardiogram, reported as mean absolute error (in bpm ± standard error) was 2 ± 0.35 (pulse oximetry), 4.5 ± 1.1 (IHR), 2 ± 0.5 (HF), 7.1 ± 1.4 (WMH) and 8.1 ± 1.4 (CAR). Conclusions We found substantial performance differences between the four studied heart rate measuring apps. The two contact photoplethysmography-based apps had higher feasibility and better accuracy for heart rate measurement than the two non-contact photoplethysmography-based apps.

The value of ECG parameters as markers of treatment response in Fabry cardiomyopathy.

OBJECTIVE: Best treatment outcomes in Fabry disease (FD) associated cardiomyopathy can be obtained when treatment is started as early as possible. The rationale of this study was to assess the role of ECG changes for identification of cardiac involvement and patients at an earlier stage of the disease more likely deriving a benefit from enzyme replacement therapy (ERT). METHODS: A retrospective analysis of patient data was performed from an observational, longitudinal, prospective cohort. Treatment response was defined as absence or presence of disease progression, defined as new onset or increase in left ventricular (LV) mass >10%. Demographic, clinical, ECG and echocardiographic parameters at baseline were tested for their value in determining absence or presence of disease progression under ERT at 5-year follow-up. RESULTS: The study population consisted of a total of 38 patients (25 men, mean age 36±13 years, overall median follow-up duration 6.4±1.2 years). Patients in the progression group (14 men, 4 women) had a longer QRS duration (99±11 ms vs 84±13 ms, p<0.05 for men, 93±9 years vs 81±5 years, p<0.05 for women) and QTc interval (401±15 ms vs 372±10 ms, p<0.005 for men) and a higher amount of ECG abnormalities (86% vs 18%, p<0.005 for men and 100% vs 0%, p<0.005 for women) at the time of ERT initiation. An abnormal baseline ECG was significantly associated with disease progression (sensitivity 94.1%, specificity 88.9%, positive likelihood ratio of 8.47, p<0.005). CONCLUSIONS: An abnormal ECG at the time of treatment initiation is significantly associated with cardiac disease progression in FD. This effect seems to be independent of age, gender or LV mass at baseline and suggests maximal treatment benefit when ERT is initiated before ECG abnormalities develop.

Robot-assisted training for heart failure patients - a small pilot study.

OBJECTIVE: The objective of this study was assess robot-assisted gait therapy with the Lokomat® system in heart failure patients. METHODS: Patients (n = 5) with stable heart failure and a left ventricular ejection fraction of less than 45% completed a four-week aerobic training period with three trainings per week and an integrated dynamic resistance training of the lower limbs. Patients underwent testing of cardiac and inflammatory biomarkers. A cardiopulmonary exercise test, a quality of life score and an evaluation of the muscular strength by measuring the peak quadriceps force was performed. RESULTS: No adverse events occurred. The combined training resulted in an improvement in peak work rate (range: 6% to 36%) and peak quadriceps force (range: 3% to 80%) in all participants. Peak oxygen consumption (range: ­3% to + 61%) increased in three, and oxygen pulse (range: ­7% to + 44%) in four of five patients. The quality of life assessment indicated better well-being in all participants. NT-ProBNP (+233 to ­733 ng/ml) and the inflammatory biomarkers (hsCRP and IL6) decreased in four of five patients (IL 6: +0.5 to ­2 mg/l, hsCRP: +0.2 to ­6.5 mg/l). CONCLUSIONS: Robot-assisted gait therapy with the Lokomat® System is feasible in heart failure patients and was safe in this trial. The combined aerobic and resistance training intervention with augmented feedback resulted in benefits in exercise capacity, muscle strength and quality of life, as well as an improvement of cardiac (NT-ProBNP) and inflammatory (IL6, hsCRP) biomarkers. Results can only be considered as preliminary and need further validation in larger studies. (ClinicalTrials.gov number, NCT 02146196)

Robot-Assisted Training Early After Cardiac Surgery.

BACKGROUND: To assess feasibility and safety of a robot-assisted gait therapy with the Lokomat® system in patients early after open heart surgery. METHODS: Within days after open heart surgery 10 patients were subjected to postoperative Lokomat® training (Intervention group, IG) whereas 20 patients served as controls undergoing standard postoperative physiotherapy (Control group, CG). All patients underwent six-minute walk test and evaluation of the muscular strength of the lower limbs by measuring quadriceps peak force. The primary safety end-point was freedom from any device-related wound healing disturbance. Patients underwent clinical follow-up after one month. RESULTS: Both training methods resulted in an improvement of walking distance (IG [median, interquartile range, p-value]: +119 m, 70-201 m, p = 0.005; CG: 105 m, 57-152.5m, p < 0.001) and quadriceps peak force (IG left: +5 N, 3.8 7 N, p = 0.005; IG right: +3.5 N, 1.5-8.8 N, p = 0.011; CG left: +5.5 N, 4-9 N, p < 0.001; CG right: +6 N, 4.3-9.8 N, p < 0.001) in all participants. Results with robot-assisted training were comparable to early postoperative standard in hospital training (median changes in walking distance in percent, p = 0.81; median changes in quadriceps peak force in percent, left: p = 0.97, right p = 0.61). No deep sternal wound infection or any adverse event occurred in the robot-assisted training group. CONCLUSIONS: Robot-assisted gait therapy with the Lokomat® system is feasible and safe in patients early after median sternotomy. Results with robot-assisted training were comparable to standard in hospital training. An adapted and combined aerobic and resistance training intervention with augmented feedback may result in benefits in walking distance and lower limb muscle strength (ClinicalTrials.gov number, NCT 02146196).

Clinical criteria replenish high-sensitive troponin and inflammatory markers in the stratification of patients with suspected acute coronary syndrome.

OBJECTIVES: In patients with suspected acute coronary syndrome (ACS), rapid triage is essential. The aim of this study was to establish a tool for risk prediction of 30-day cardiac events (CE) on admission. 30-day cardiac events (CE) were defined as early coronary revascularization, subsequent myocardial infarction, or cardiovascular death within 30 days. METHODS AND RESULTS: This single-centre, prospective cohort study included 377 consecutive patients presenting to the emergency department with suspected ACS and for whom troponin T measurements were requested on clinical grounds. Fifteen biomarkers were analyzed in the admission sample, and clinical parameters were assessed by the TIMI risk score for unstable angina/Non-ST myocardial infarction and the GRACE risk score. Sixty-nine (18%) patients presented with and 308 (82%) without ST-elevations, respectively. Coronary angiography was performed in 165 (44%) patients with subsequent percutaneous coronary intervention--accounting for the majority of CE--in 123 (33%) patients, respectively. Eleven out of 15 biomarkers were elevated in patients with CE compared to those without. High-sensitive troponin T (hs-cTnT) was the best univariate biomarker to predict CE in Non-ST-elevation patients (AUC 0.80), but did not yield incremental information above clinical TIMI risk score (AUC 0.80 vs 0.82, p = 0.69). Equivalence testing of AUCs of risk models and non-inferiority testing demonstrated that the clinical TIMI risk score alone was non-inferior to its combination with hs-cTnT in predicting CE. CONCLUSIONS: In patients presenting without ST-elevations, identification of those prone to CE is best based on clinical assessment based on TIMI risk score criteria and hs-cTnT.

The clinical value of echocardiography and acoustic cardiography to monitor patients undergoing anthracycline chemotherapy.

BACKGROUND: Investigate the usefulness of echocardiography and acoustic cardiography to monitor patients exposed to anthracycline chemotherapy. HYPOTHESIS: Serial echocardiographies to monitor systolic function may not be neccessary in all patients undergoing anthracycline chemotherapy. METHODS: In a prospective study, consecutive patients undergoing anthracycline-containing chemotherapy were evaluated with echocardiography and acoustic cardiography at baseline, after completion of chemotherapy, and after a median follow-up of 3.8 years. Systolic dysfunction was defined as a left ventricular ejection fraction≤50%. RESULTS: A total of 187 patients (83% female) with a mean age of 55±14 years underwent chemotherapy for breast cancer (73%), malignant lymphoma (23%), and sarcoma (4%). None of the patients had systolic dysfunction at baseline. Patients were treated with doxorubicin 276±74 mg/m2 or epirubicin 317±55 mg/m2. After chemotherapy, 170 (91%) had normal systolic function, 8 (4%) developed systolic dysfunction, and 9 (5%) had died. Of those 8 patients with systolic dysfunction, 4 (50%) improved to normal systolic function, 1 (13%) remained unchanged, and 3 (37%) died. Patients with normal systolic function after chemotherapy had a mortality rate of 3.5%, and 1.8% developed late systolic dysfunction. Acoustic cardiography-derived percent electromechanical activation time>12.4% had a sensitivity of 88% and a specificity of 84% to identify patients with systolic dysfunction (area under the receiver operating characteristic curve 0.87). CONCLUSIONS: Patients with systolic dysfunction early after anthracycline treatment had worse outcome. Acoustic cardiography was able to identify these patients with a high sensitivity and specificity. Based on the findings of this study, we propose a simple algorithm to monitor patients undergoing anthracycline-containing chemotherapy.

Portal vein thrombus and liver failure in a patient with pheochromocytoma crisis.

A 51-year-old man with known pheochromocytoma refused surgical treatment over several years and subsequently presented in catecholamine crisis with shock and multiple organ failure. Laboratory testing revealed liver failure with elevated liver enzymes and coagulation abnormalities, and imaging showed ischemia of extended parts of the right liver lobe. It also revealed a large thrombus in the right portal vein, which together with severe arterial vasoconstriction impaired the dual blood supply of the liver. The patient recovered after effective medical treatment and finally underwent surgical tumor resection. Thereafter, antihypertensive treatment could be stopped. We present this exceptional case of adrenal crisis and discuss the mechanisms leading to liver failure in general and portal vein thrombosis in particular.

Severe left ventricular dysfunction secondary to primary pulmonary hypertension: bridging therapy with bosentan before lung transplantation.

When right ventricular failure develops secondary to primary pulmonary hypertension, right-left ventricular interaction may lead to severe impairment of left ventricular function. In such cases, many experts favor combined heart-lung transplantation by fear that the left ventricle may not recover after transplantation of the lungs alone. We report a case of primary pulmonary hypertension with severely diminished right and left ventricular function. The patient was rendered amenable to isolated pulmonary transplantation with the endothelin-receptor antagonist bosentan. The medication improved right and left ventricular function to the point that heart transplantation no longer appeared necessary. After double-lung transplantation the patient's cardiac function made a full recovery. This approach might be particularly welcome considering both the current donor organ shortage and the limited number of surgical teams with expertise in heart-lung transplantation.