The in-ear region as a novel anatomical site for ECG signal detection: validation study on healthy volunteers.

PURPOSE: Early detection of cardiac arrhythmias is a major opportunity for mobile health, as wearable devices nowadays available can detect single-lead electrocardiogram (ECG). The study aims to validate the in-ear region as a new anatomical site for ECG signal detection and looks towards designing innovative ECG wearable devices. METHODS: We performed ECG using KardiaMobile device (AliveCor®) on 35 healthy volunteers. First, ECG was detected by standard modality using both hands. Then, ECG was detected using the left in-ear region instead of the right hand. All the recorded ECGs were analyzed by the device and by two cardiologists in blind testing. RESULTS: We successfully collected 70 ECGs performed on 35 volunteers (male 54%, age 39.1 ± 10.7 years; BMI 22.9 ± 2.89 kg/m2) with no differences observed by KardiaMobile in ECG reports detected in the two different modalities. All the ECGs were reported as normal by the device and the two cardiologists. Moreover, linear regression analysis showed good correlation between the amplitude (mV) of P (r = 0.76; r2 = 0.57; p < 0.0001) and QRS waves (r = 0.81; r2 = 0.65; p < 0.0001), the intervals (ms) of PR (r = 0.91; r2 = 0.83; p < 0.0001; LOA - 0.60-0.41; CC = 0.91), QRS (r = 0.78; r2 = 0.61; p < 0.0001; LOA - 0.49-0.43; CC = 0.78), QT (r = 0.85; r2 = 0.71; p < 0.0001; LOA - 1.31-1.20; CC = 0.85), and heart rate (r = 0.94; r2 = 0.89; p < 0.0001; LOA - 7.82-7.76; CC = 0.94) detected in two different modalities. CONCLUSION: The in-ear region is a reliable novel anatomical site for ECG signal detection in normal healthy subjects. Further studies are needed to validate this new ECG detection modality also in case of cardiac arrhythmias and to support the development of new wearable devices.

Early abnormalities of left ventricular myocardial characteristics associated with subclinical hyperthyroidism.

The aim of the present study was to analyze heart function in subclinical hyperthyroidism (sHT) in otherwise healthy subjects by new methods using intramyocardial ultrasonic techniques. Twenty-four newly diagnosed and untreated sHT patients (20 women, 4 men; mean age: 42+/-4 yr) and 24 sex- and age-matched healthy volunteers were studied. All subjects were submitted to conventional 2D color-Doppler echocardiography, pulsed wave tissue Doppler imaging (PWTDI) for the analysis of diastolic function, color Doppler myocardial imaging (CDMI) for the analysis of regional strain and strain rate (SR) expression of regional myocardial deformability, and to integrated backscatter (IBS) for the evaluation of intrinsic contractility and tissue characterization. Regional myocardial systolic strain findings were significantly higher in sHT patients when compared with controls (p<0.001). Considering diastolic SR, the early phase of diastolic SR was compromised in sHT subjects as compared with controls (p<0.001). Cyclic variation index (CVI), expression of intrinsic contractility, was significantly higher in sHT subjects in comparison with controls (p<0.0001). IBS values were comparable between the 2 study groups. In conclusion, the present study suggests that in patients with sHT early systolic hyperdeformability and hypercontractility are present, together with impairment of both active and passive phases of diastole. On the contrary, no left ventricular hypertrophy or other structural alterations are documented.

Myocardial systolic strain abnormalities in patients with acromegaly: a prospective color Doppler imaging study.

BACKGROUND: Heart abnormalities are frequent findings in patients with acromegaly: systolic abnormalities are considered to be secondary to diastolic changes. AIM: The aim of the study was to evaluate whether early systolic abnormalities might be revealed in acromegalic patients using the high sensitive color Doppler myocardial imaging (CDMI) technique. PATIENTS AND METHODS: Twenty-two consecutive acromegalic patients with active untreated disease (ACROUNTR) were evaluated at baseline and after a 6-month course with SS analogs (SSa) (ACROSSa); 25 healthy subjects served as controls. All subjects underwent conventional 2D-color Doppler echocardiography, pulse wave tissue Doppler imaging (PW-TDI) and CDMI. RESULTS: Mean left ventricular (LV) ejection fraction did not differ in ACROUNTR and in controls; at variance, ACROUNTR patients had reduced mean LV diastolic function (E/A ratio: 0.96+/-0.3 vs controls: 1.6+/-0.3; p<0.002). Impairment of global LV diastolic function was confirmed by PW-TDI in ACROUNTR patients having a normal systolic function. Regional myocardial systolic strain (epsilon) and strain rate (SR) values, indices of regional systolic heart deformation, were lower in ACROUNTR [epsilonsys (S) -19.8+/-2.9 and epsilonsys (L): -17.7+/-2.2] than in controls [epsilonsys (S): -27.9+/-3.8; p<0.001 and epsilonsys (L): -25.3+/-2.6; p<0.001]. In addition, the early phase of diastolic function, evaluated using SR parameters, was impaired in acromegalic patients (p<0.005 vs controls). Strain and SR values were related to serum GH and IGF-I levels (p<0.02) and greatly improved after a 6-month course with SSa [epsilonsys (S) improved to -23.8+/-3.8 (p<0.05) and epsilonsys (L) improved to -24.7+/-2.4 (p<0.03)]. CONCLUSIONS: Our study confirms that ACROUNTR patients have impaired diastolic function. More important, our study clearly shows that ACROUNTR patients have an impairment of regional myocardial systolic function, which is not secondary to diastolic changes. These intramyocardial functional abnormalities improved during medical treatment of acromegaly. It is conceivable that GH-IGF-I excess has detrimental effects either on the diastolic or the systolic phases of heart function.

Relationship between preclinical abnormalities of global and regional left ventricular function and insulin resistance in severe obesity: a Color Doppler Imaging Study.

BACKGROUND: The aim of this study was to evaluate the relationship between insulin resistance and preclinical abnormalities of the left ventricular structure and function detected in severe obesity by Color Doppler Myocardial Imaging (CDMI). Forty-eight consecutive severely obese patients (Group O) (11 males, 37 females, mean age 32.8+/-7 years) were enrolled. Forty-eight sex- and age-matched non-obese healthy subjects were also recruited as controls (Group C). All subjects underwent conventional 2D-Color Doppler echocardiography and CDMI. The homeostasis model assessment insulin resistance index (HOMA-IR) was used to assess insulin resistance results. Obese subjects had a greater left ventricular mass index (by height) (58.8+/-14 g/m(2.7)) than controls (37+/-8 g/m(2.7)) (P<0.0001), owing to compensation response to volume overload caused by a greater cardiac output (P<0.02). Preload reserve was increased in obese subjects, as demonstrated by a significant increase in left atrial dimension (P<0.0001). Obese patients had a slightly reduced LV diastolic function (transmitral E/A ratio: Group O, 1.1+/-0.8 vs Group C, 1.5 +/-0.5; P<0.002). Cardiac deformation assessed by regional myocardial systolic strain and strain rate (SR) values was significantly lower (abnormal) in obese patients than in controls, both at the septum and lateral wall level. These strain and SR abnormalities were significantly related to body mass index. In addition, the early phase of diastolic function, evaluated using SR, was compromised in obese patients (P<0.001). The HOMA-IR values in obese patients were significantly higher (3.09+/-1.6) than those determined in the control group (0.92+/-0.5) (P<0.0001). The HOMA-IR values, in the obese group, were significantly related to systolic strain and SR values sampled at the septum level (P<0.0001). CONCLUSION: In conclusion, this study has demonstrated that obese patients pointed out systolic structural and functional abnormalities at a preclinical stage, in particular through strain and SR analysis; on the other hand, those altered CDMI parameters well distinguish obese subjects as compared with the control group. Furthermore, another main finding of the study was that myocardial deformation (systolic strain) could have a correlation with insulin resistance level.