Disorders Of The Heart: Broken Heart Syndrome
Extreme stress from such life events as the death of a loved one, an emotional break up, loss of income, or foreclosure of a home may lead to a condition commonly referred to as broken heart syndrome. This condition may also be called Takotsubo cardiomyopathy, transient apical ballooning syndrome, apical ballooning cardiomyopathy, stress-induced cardiomyopathy, Gebrochenes-Herz syndrome, and stress cardiomyopathy.
The recognized effects on the heart include congestive heart failure due to a profound weakening of the myocardium not related to lack of oxygen. This may lead to acute heart failure, lethal arrhythmias, or even the rupture of a ventricle. The exact etiology is not known, but several factors have been suggested, including transient vasospasm, dysfunction of the cardiac capillaries, or thickening of the myocardiumparticularly in the left ventriclethat may lead to the critical circulation of blood to this region. While many patients survive the initial acute event with treatment to restore normal function, there is a strong correlation with death. Careful statistical analysis by the Cass Business School, a prestigious institution located in London, published in 2008, revealed that within one year of the death of a loved one, women are more than twice as likely to die and males are six times as likely to die as would otherwise be expected.
What Controls Heart Rate
Heart rate is controlled by the two branches of the autonomic nervous system. The sympathetic nervous system and the parasympathetic nervous system . The sympathetic nervous system releases the hormones to accelerate the heart rate. The parasympathetic nervous system releases the hormone acetylcholine to slow the heart rate. Such factors as stress, caffeine, and excitement may temporarily accelerate your heart rate, while meditating or taking slow, deep breaths may help to slow your heart rate. Exercising for any duration will increase your heart rate and will remain elevated for as long as the exercise is continued. At the beginning of exercise, your body removes the parasympathetic stimulation, which enables the heart rate to gradually increase. As you exercise more strenuously, the sympathetic system kicks in to accelerate your heart rate even more. Regular participation in cardiovascular exercise over an extended period of time can decrease your resting heart rate by increasing the hearts size, the contractile strength and the length of time the heart fills with blood. The reduced heart rate results from an increase in activity of the parasympathetic nervous system, and perhaps from a decrease in activity of the sympathetic nervous system.
What Is Your Target Zone
Target Heart Rate Zones by Age *
- Age: 20
- Target Heart Rate Zone : ** 120 170
- Predicted Maximum HR: 200
Your Actual Values
- Target HR
* This chart is based on the formula: 220 – your age = predicted maximum heart rate.
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What Is A Normal Heart Rate
A normal resting heart rate is usually between 60 and 100 beats per minute. Your number may vary. Children tend to have higher resting heart rates than adults.
The best time to measure your resting heart rate is just after you wake up in the morning, before you start moving around or have any caffeine.
Correlation Between Heart Rates And Cardiac Output
Initially, physiological conditions that cause HR to increase also trigger an increase in SV. During exercise, the rate of blood returning to the heart increases. However as the HR rises, there is less time spent in diastole and consequently less time for the ventricles to fill with blood. Even though there is less filling time, SV will initially remain high. However, as HR continues to increase, SV gradually decreases due to decreased filling time. CO will initially stabilize as the increasing HR compensates for the decreasing SV, but at very high rates, CO will eventually decrease as increasing rates are no longer able to compensate for the decreasing SV. Consider this phenomenon in a healthy young individual. Initially, as HR increases from resting to approximately 120 bpm, CO will rise. As HR increases from 120 to 160 bpm, CO remains stable, since the increase in rate is offset by decreasing ventricular filling time and, consequently, SV. As HR continues to rise above 160 bpm, CO actually decreases as SV falls faster than HR increases. So although aerobic exercises are critical to maintain the health of the heart, individuals are cautioned to monitor their HR to ensure they stay within the target heart rate range of between 120 and 160 bpm, so CO is maintained. The target HR is loosely defined as the range in which both the heart and lungs receive the maximum benefit from the aerobic workout and is dependent upon age.
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Elevated Heart Rate Most Likely Caused By Medical Condition
May 6, 2011
What is sinus tachycardia? What causes it? How is it treated?
Answer:
Sinus tachycardia is the term used to describe a faster-than-normal heartbeat a rate of more than 100 beats per minute versus the typical normal of 60 to 70 beats per minute. Well over 99 percent of the time, sinus tachycardia is perfectly normal. The increased heart rate doesn’t harm the heart and doesn’t require medical treatment.
The term sinus tachycardia has nothing to do with sinuses around the nose and cheeks. Rather, it comes from the sinus node, a thumbnail-sized structure in the upper right chamber of the heart. This structure controls the heart rate and is called the heart’s natural pacemaker.
The sinus node signals the heart to speed up during exercise or in situations that are stressful, frightening or exciting. For example, a 10- to 15-minute brisk walk typically elevates the heart rate to 110 to 120 beats per minute. Also, the sinus node increases the heart rate when the body is stressed because of illness. In all of these circumstances, the heart rate increase is a normal response.
Likewise, the sinus node signals the heart to slow down during rest or relaxation.
For some patients, the elevated heart rate is the only symptom. Some have a lifelong history of sinus tachycardia in the 110 beats per minute range, and they lead a normal, healthy life. And often the inappropriate sinus tachycardia will improve in time without treatment.
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Effect Of Heart Rate On Cardiac Performance
Heart rate plays a major role in determining cardiac function for various reasons. HR affects preload by determining the length of time for ventricular filling. Because coronary and therefore myocardial blood supply occurs during diastole, HR directly affects subendocardial blood flow. If subendocardial flow is compromised with shorter diastolic filling, ischemia may result. A downward spiral ensues because the ischemic, less-compliant heart resists optimal ventricular filling and preload decreases. Increased HR is critical during exercise to increase CO and meet increased metabolic needs. HR changes as a result of ongoingmultifactorial development the effect of HR on cardiac function is discussed further in this context.
In , 2009
Correlation With Cardiovascular Mortality Risk
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A number of investigations indicate that faster resting heart rate has emerged as a new risk factor for mortality in homeothermic mammals, particularly cardiovascular mortality in human beings. Faster heart rate may accompany increased production of inflammation molecules and increased production of reactive oxygen species in cardiovascular system, in addition to increased mechanical stress to the heart. There is a correlation between increased resting rate and cardiovascular risk. This is not seen to be “using an allotment of heart beats” but rather an increased risk to the system from the increased rate.
Given these data, heart rate should be considered in the assessment of cardiovascular risk, even in apparently healthy individuals. Heart rate has many advantages as a clinical parameter: It is inexpensive and quick to measure and is easily understandable. Although the accepted limits of heart rate are between 60 and 100 beats per minute, this was based for convenience on the scale of the squares on electrocardiogram paper a better definition of normal sinus heart rate may be between 50 and 90 beats per minute.
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How Do I Take My Heart Rate
There are a few places on your body where itâs easier to take your pulse:
- The insides of your wrists
- The insides of your elbows
- The sides of your neck
- The tops of your feet
Put the tips of your index and middle fingers on your skin. Press lightly until you feel the blood pulsing beneath your fingers. You may need to move your fingers around until you feel it.
Count the beats you feel for 10 seconds. Multiply this number by six to get your heart rate per minute
How To Take Your Pulse
Count your pulse: _____ beats in 10 seconds x 6 = _____ beats/minute
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Cardiac Output And Blood Pressure
Cardiac output and blood pressure are two important measures of the health and function of the cardiovascular system. You need to understand these measures as a fitness professional in order to design and deliver safe, effective exercise sessions, and in the case of blood pressure, be able to conduct and interpret blood pressure measurements for your clients.
Intrathoracic Pressure And Left Ventricular Preload
LV preload is dependent on changes in systemic venous return, RV output, and LV filling. In steady state, cardiac output must equal the blood returning to the heart, determined by circuit function.149,153,154 The preload to the LV is affected by the alteration of the RV loading conditions and the RV diastolic Ptm. Higher ITP reduces systemic venous return and RV output and therefore decreases LV preload. Additionally, the RV is a thinner-walled ventricle and therefore much more sensitive to conditions of increased afterload, such as PPV. Thus RV function might be impeded during PPV, further reducing LV preload.191 Finally, the RV also affects LV filling due to ventricular systolic and diastolic interdependence.
Nicholas Ioannou, … David Treacher, in, 2014
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Heart Rate And Heart Rate Variability In Posttraumatic Disorder
Increased heart rate is a determinant of physiological arousal seen in PTSD. Subjects who develop PTSD have been shown to have higher heart rates during the immediate aftermath of the trauma compared to traumatized individuals who do not develop PTSD. The elevated heart rate is caused by the increased noradrenergic tone, suggesting that increased noradrenergic activity immediately after the trauma may play an important role in the neurobiological processes involved in the development of PTSD. From a clinical perspective, this finding suggests that elevated heart rate immediately after the trauma is a predictor of PTSD.
Michael J. Aminoff, in, 2012
Venous Return And Stroke Volume
In the late19th century, Otto Frank found using isolated frog hearts that the strength of ventricular contraction was increased when the ventricle was stretched prior to contraction. This observation was extended by the elegant studies of Ernest Starling and colleagues in the early 20th century who found that increasing venous return to the heart , which increased the filling pressure of the ventricle, led to increased stroke volume . Conversely, decreasing venous return decreased stroke volume. This cardiac response to changes in venous return and ventricular filling pressure is intrinsic to the heart and does not depend on extrinsic neurohumoral mechanisms although such mechanisms can modify the intrinsic cardiac response. In honor of these two early pioneers, the ability of the heart to change its force of contraction and therefore stroke volume in response to changes in venous return is called the Frank-Starling mechanism .
There is no single Frank-Starling curve on which the ventricle operates. Instead, there is a family of curves, each of which is defined by the afterload and inotropic state of the heart.
Frank-Starling curves show how changes in ventricular preload lead to changes in stroke volume. This type of graphical representation, however, does not show how changes in venous return affect end-diastolic and end-systolic volumes. In order to do this, it is necessary to describe ventricular function in terms of pressure-volume diagrams.
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What Is Target Heart Rate
- You gain the most benefits and lessen the risks when you exercise in your target heart rate zone. Usually this is when your exercise heart rate is 60 to 80% of your maximum heart rate. In some cases, your health care provider may decrease your target heart rate zone to begin with 50% .
- In some cases, High Intensity Interval Training may be beneficial. This should be discussed with a healthcare professional before beginning. With HIIT exercise, heart rates zones may exceed 85%.
- Always check with your healthcare provider before starting an exercise program. Your provider can help you find a program and target heart rate zone that matches your needs, goals and physical condition.
- When beginning an exercise program, you may need to gradually build up to a level that’s within your target heart rate zone, especially if you haven’t exercised regularly before. If the exercise feels too hard, slow down. You will reduce your risk of injury and enjoy the exercise more if you don’t try to over-do it!
- To find out if you are exercising in your target zone , stop exercising and check your 10-second pulse. If your pulse is below your target zone , increase your rate of exercise. If your pulse is above your target zone, decrease your rate of exercise.
Input To The Cardiovascular Center
The cardiovascular center receives input from a series of visceral receptors with impulses traveling through visceral sensory fibers within the vagus and sympathetic nerves via the cardiac plexus. Among these receptors are various proprioreceptors, baroreceptors, and chemoreceptors, plus stimuli from the limbic system. Collectively, these inputs normally enable the cardiovascular centers to regulate heart function precisely, a process known as cardiac reflexes. Increased physical activity results in increased rates of firing by various proprioreceptors located in muscles, joint capsules, and tendons. Any such increase in physical activity would logically warrant increased blood flow. The cardiac centers monitor these increased rates of firing, and suppress parasympathetic stimulation and increase sympathetic stimulation as needed in order to increase blood flow.
There is a similar reflex, called the atrial reflex or Bainbridge reflex, associated with varying rates of blood flow to the atria. Increased venous return stretches the walls of the atria where specialized baroreceptors are located. However, as the atrial baroreceptors increase their rate of firing and as they stretch due to the increased blood pressure, the cardiac center responds by increasing sympathetic stimulation and inhibiting parasympathetic stimulation to increase HR. The opposite is also true.
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