Yoga in Older Cardiac Patients

The Patient Health Questionnaire-9 (PHQ-9) was developed to correspond to symptoms used in the DSMV-IV to diagnose clinical depression. Nine symptoms are rated on a 4-point Likert scale (0 = 'Not at all; 3 = 'Nearly every day'), with possible total scores ranging from 0 to 27 and higher scores indicating higher levels of depressive symptoms.

The Brief Symptom Inventory (BSI), anxiety index, consists of 6 items rated on a 5-point Likert scale (0 = not at all; 4 = extremely). The total score ranges from 0 to 24, with a higher score reflecting greater anxiousness.

The Vulnerable Elders Survey 13 (VES-13) includes four dimensions: age, self-assessment of health, physical function, and living function. Each domain is scored differently. Age is scored as follows: 75-84 years = 1 point, ≥ 85 years = 3 points. Self-rated health is categorized into "fair and poor" or "good", "very good", or "excellent", with only the "fair and poor" category scoring 1 point. The total score ranges from 0 to 15, with higher scores indicating greater vulnerability.

Short-term Heart Rate Variability (HRV) will be collected using the Polar H9 heart rate monitor (Polar Electro OY, Kempele, Finland). The investigator will send a reminder about the precautions to be taken (e.g., avoiding caffeine, alcohol, smoking, and intense physical activity, as these factors could affect the HRV measurement for successful HRV measurement the day before the scheduled test. The investigator will again ask if the instructions have been followed when they arrive for data collection.

Study patients will be instructed to lay supine for 10 minutes without speaking and to remain as still as possible. The investigator will place the Polar H9 heart rate monitor on the center of the sternum to measure HRV. During HRV data collection, the study patients will also wear the ActiGraph on the waist because the Polar H9 communicates with the ActiGraph.

Muscle strengths will be measured using the handheld dynamometry (HHD, Lafayette dynamometer, model01165APP; Lafayette Instrument Company, Lafayette, Ind., USA). This device measures the peak force exerted in kilograms for five seconds during muscle contraction on hips and quadriceps.

Balance will be measured using an Inertial Measurement Unit device (DOTIMU; Xsens Technologies, Enschede., the Netherlands). The investigators attach the IMU sensor (a small device the size of a large watch face) to the participant's lower back at the level of L3 vertebra. Patients will be asked to take off their shoes and stand up on the mat with their hands on their hips for 30 seconds. The investigators will measure balance 3 times, with 30 seconds of rest between assessments. The total estimated time for the balance test is 3-5 minutes. All signal processing, subsequent feature extraction, and analysis will be performed using MATLAB version R2018B (The Mathworks Inc., Natick, MA, USA). The root-mean-square (RMS) value of the acceleration signal will be used to quantify the magnitude and trajectory of postural sway in each direction. The RMS of the magnitude vector of the 3-axis acceleration signal will be used as the summary score.

Physical activity (PA) will be measured using actigraphy, the gold-standard for measuring physical activity. The investigator will use the ActiGraph (GT3X Link model), a triaxial instrument, which is the most widely used wearable accelerometer in clinical research. All patients will be instructed to wear the device for nine consecutive days, including at least one weekend day. Both baseline and 3-month values were calculated in a similar way.

Muscle strengths will be measured using the handheld dynamometry (HHD, Lafayette dynamometer, model01165APP; Lafayette Instrument Company, Lafayette, Ind., USA). This device measures the peak force exerted in kilograms for five seconds during muscle contraction on hips and quadriceps.