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Tachycardia: Difference between revisions
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==Ventricular tachycardia== | ==Ventricular tachycardia== | ||
''Auteur: Louise R.A. Olde Nordkamp'' | |||
''Supervisor: Jonas S.S.G. de Jong'' | |||
[[Image:SR_VT.svg|thumb|right|400px]] | [[Image:SR_VT.svg|thumb|right|400px]] | ||
Ventricular tachycardias (VT's) are rhythm disturbances that arise in the ventricles. | Ventricular tachycardias (VT's) are rhythm disturbances that arise in the ventricles. | ||
==History== | |||
Symptoms can arise in every ventricular tachycardia, depending on the heart rate, the presence of underlying heart disease and the degree of systolic and diastolic heart failure. Various symptoms are: | Symptoms can arise in every ventricular tachycardia, depending on the heart rate, the presence of underlying heart disease and the degree of systolic and diastolic heart failure. Various symptoms are: | ||
*Palpitations | *Palpitations | ||
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*Cardiogenic shock | *Cardiogenic shock | ||
Additional information about drug use is mandatory. Toxic levels of digoxin and cocain can lead to VT's. Also additional information about family history of sudden cardiac death is helpfull, as it is a strong predictor of susceptibility to ventricular arrhythmias and sudden cardiac death. | Additional information about drug use is mandatory. Toxic levels of digoxin and cocain can lead to VT's. Anti-arrhythmics such as amiodarone can influence VT rate. Also additional information about family history of sudden cardiac death is helpfull, as it is a strong predictor of susceptibility to ventricular arrhythmias and sudden cardiac death. | ||
==Physical Examination== | |||
Although the diagnosis of VT is generally made by a 12 lead ECG, the following physical symptoms may be present: | Although the diagnosis of VT is generally made by a 12 lead ECG, the following physical symptoms may be present: | ||
*Decreased or variable amplitude of the carotid or peripheral pulses. This is related to the intermittent periods of atrial and ventricular synchronization, which transiently augment cardiac output. | *Decreased or variable amplitude of the carotid or peripheral pulses. This is related to the intermittent periods of atrial and ventricular synchronization, which transiently augment cardiac output. | ||
*Cannon "A" waves on the jugular venous pulse in the neck. These represent | *Cannon "A" waves on the jugular venous pulse in the neck. These represent intermittent retrograde propulsion of blood into the jugular veins during right atrial contraction against a closed AV valve. This is evidence of AV dissociation. | ||
*Variable intensity of the first heart sound (although this is difficult with a rapid heart rate). | *Variable intensity of the first heart sound (although this is difficult with a rapid heart rate). | ||
*Variable splitting of the first and second heart sounds, and intermittent presence of a third and/or fourth heart sound. | *Variable splitting of the first and second heart sounds, and intermittent presence of a third and/or fourth heart sound. | ||
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===Diagnostic Evaluation=== | ===Diagnostic Evaluation=== | ||
*'''Exercise testing:''' Exercise testing is recommended in adult patients with ventricular tachycardias who have an intermediate or greater probability of having coronary heart disease by age, gender and symptoms. It is meant to provoke ischemic changes or ventricular arrhythmias. | *'''Exercise testing:''' Exercise testing is recommended in adult patients with ventricular tachycardias who have an intermediate or greater probability of having coronary heart disease by age, gender and symptoms. It is meant to provoke ischemic changes or ventricular arrhythmias. | ||
*'''Ambulatory (Holter) ECG:''' | *'''Ambulatory (Holter) ECG:''' An ambulatory ECG can be necessary if the diagnosis needs to be clarified, by detecting arrhythmias, QT-interval changes, T-wave alternans (TWA) or ST-segment changes. | ||
*'''Echocardiography, Cardiac CT, MRI:''' Echocardiography is recommended in patients with ventricular tachycardias who are suspected of having a structural heart disease. If echocardiography does not provide accurate assessment of the left and right ventricular function and/or structural changes, cardiac CT or MRI can be done. | *'''Echocardiography, Cardiac CT, MRI:''' Echocardiography is recommended in patients with ventricular tachycardias who are suspected of having a structural heart disease. If echocardiography does not provide accurate assessment of the left and right ventricular function and/or structural changes, cardiac CT or MRI can be done. | ||
*'''Exercise testing with an image modality (echocardiography or nuclear perfusion):''' Some patients with ventricular arrhythmias have an intermediate probability of coronary heart disease, but their ECG is less reliable (because of digoxin use, LVH, greater than 1mm ST-segment depression at rest, WPW syndrome or LBBB). For detecting silent ischemia in these patients exercise testing with an image modality can be done. If patients are unable to perform exercise, a pharmacological stress test with an imaging modality can be done. | *'''Exercise testing with an image modality (echocardiography or nuclear perfusion):''' Some patients with ventricular arrhythmias have an intermediate probability of coronary heart disease, but their ECG is less reliable (because of digoxin use, LVH, greater than 1mm ST-segment depression at rest, WPW syndrome or LBBB). For detecting silent ischemia in these patients exercise testing with an image modality can be done. If patients are unable to perform exercise, a pharmacological stress test with an imaging modality can be done. | ||
*'''Coronary angiography:''' Coronary angiography can diagnose or exclude the presence of significant obstructive coronary heart disease in patients with ventricular arrhythmias who have an intermediate or greater probability of having coronary heart disease. | *'''Coronary angiography:''' Coronary angiography can diagnose or exclude the presence of significant obstructive coronary heart disease in patients with ventricular arrhythmias who have an intermediate or greater probability of having coronary heart disease. | ||
*'''Electrophysiological testing:''' Electrophysiological testing can be performed to guide and assess the efficacy of VT ablation in patients with ventricular arrhythmias. It can also be done to clarify the mechanism of broad complex tachycardias in patients with coronary heart disease. | *'''Electrophysiological testing:''' Electrophysiological testing can be performed to guide and assess the efficacy of VT ablation in patients with ventricular arrhythmias. It can also be done to clarify the mechanism of broad complex tachycardias in patients with coronary heart disease. | ||
==Overview of ventricular tachycardias== | ==Overview of ventricular tachycardias== | ||
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