Tilt Protocol. Protocol

Transcription

1 Tilt Protocol Chelsea and Westminster Hospital Guidelines for diagnosing syncope Guidelines for the diagnosis and management of syncope have been published by the relevant task force of the European Society of Cardiology: Brignole, M. et al. Guidelines on management (diagnosis and treatment) of syncope. European Heart Journal 2001; 22: Causes of syncope When considering head-up tilt testing to aid with the diagnosis of vasovagal syncope, it is important for the physician to remember all other important causes of syncope, including other neurogenic causes, bradyarrhythmias, and tachyarrhythmias (Appendix 1). Indications Protocol Recurrent syncope or pre-syncope Single episode of syncope in patients with high clinical probability of vasovagal syncope Contraindications Clinically severe left ventricular outflow obstruction Severe proximal coronary artery stenosis Mitral stenosis Cerebrovascular stenosis Heart, renal, or liver failure Unable to weight bear Aim The aim of tilt testing is to provoke a heart rate and/or blood pressure drop in association with symptoms, in order that these symptoms can be compared with the symptoms patients experience in real life. If the symptoms experienced during tilt are identical or very similar to those experienced in real life, a diagnosis of vasovagal syncope can be made in patients with a history suggestive of VVS and apparently normal heart and neurological status.

2 Patient preparation It is assumed that, where indicated, patients will have previously been assessed for postural hypotension and carotid sinus hypersensitivity (usually in the outpatient clinic). There should be a request form or referring letter. Patients should have been assessed by the referring doctor for suitability to tilt, taking into account indications and contraindications of tilting. Patients should have fasted for 6 hours prior to the test. Prescribed drugs should generally not be discontinued for the test. Intravenous access is not normally established prior to testing, but full resuscitation facilities including facilities for intravenous administration of atropine are immediately available. Patients are attached to ECG and continuous blood pressure monitoring (Finometer) equipment. Patients are advised that, whilst in the head up tilt position, they should avoid movement of the lower limbs, and to inform the Physiologist of the onset of symptoms.

3 Testing This is based on the Italian protocol : Bartoletti A. et al. The Italian Protocol : a simplified head-up tilt testing potentiated with oral nitroglycerin to assess patients with unexplained syncope. Europace 2000; 2: The test should take place in a quiet, dimly lit room at a comfortable temperature so as to avoid stimuli affecting the autonomic nervous system. Patients are laid down on tilt bed for 5 minutes Patients then tilted to 60 degrees for 20 minutes If no symptoms or haemodynamic changes take place, patients then take one metered dose of 400μg of GTN sublingually and tilt continued for a further 15 minutes or until criteria for termination are reached Test termination The test is interrupted, and the patients are brought down to the supine position in the following situations: (1) Completion of the protocol in the absence of symptoms (test negative) (2) Syncope (test positive) The test is considered as positive whenever syncope (that is, the reproduction of the patient s original symptoms) occurs in association with hypotension, bradycardia or both, with rapid (<5 min) onset. Interruption of the test is suggested at the precise occurrence of syncope, with simultaneous loss of postural tone. For the categorization of the type of response the patterns of heart rate and blood pressure until that moment (but not a later bradycardia) are considered. (3) Progressive, prolonged (>5 min) orthostatic hypotension associated with minor symptoms. The clinical meaning of this response is uncertain because it is observed also in control subjects, and it is possible that it represents another dysfunction of the autonomic nervous system rather than a vasovagal reflex. Since the decision to terminate tilting influences the type of response, for a correct classification of responses tilting should be interrupted at the precise occurrence of loss of consciousness with simultaneous loss of postural tone. Carotid sinus massage If the patient over the age of 40, the HO or SHO should be called to perform carotid sinus massage both in the supine and tilted positions.

4 Appendix 1. Causes of syncope Neurally-mediated reflex syncopal syndromes Vasovagal faint (common faint) Carotid sinus syncope Situational faint Acute haemorrhage Cough, sneeze Gastrointestinal stimulation (swallow, defaecation, visceral pain) Micturition (post-micturition) Post-exercise Others (e.g. brass instrument playing, weightlifting, post-prandial) Glossopharyngeal and trigeminal neuralgia Orthostatic Autonomic failure Primary autonomic failure syndromes (e.g. pure autonomic failure, multiple system atrophy, Parkinson s disease with autonomic failure) Secondary autonomic failure syndromes (e.g. diabetic neuropathy, amyloid neuropathy) Drugs and alcohol Volume depletion Haemorrhage, diarrhoea, Addison s disease Cardiac arrhythmias as primary cause Sinus node dysfunction (including bradycardia/tachycardia syndrome) Atrioventricular conduction system disease Paroxysmal supraventricular and ventricular tachycardias Inherited syndromes (e.g. long QT syndrome, Brugada syndrome) Implanted device (pacemaker, ICD) malfunction Drug-induced proarrhythmia Structural cardiac or cardiopulmonary disease Cardiac valvular disease Acute myocardial infarction/ischaemia Obstructive cardiomyopathy Atrial myxoma Acute aortic dissection Pericardial disease/tamponade Pulmonary embolus/pulmonary hypertension Cerebrovascular Vascular steal syndromes

5 Results Positive result syncope. Positive responses are labelled as one of 6 types of vasovagal syncope (Table 1) Table 1. Positive responses in (6 types of) vasovagal response Type 1 Mixed. Heart rate falls at the time of syncope but the ventricular rate does not fall to less than 40bpm or falls to less than 40bpm for less than 10 s with or without asystole of less than 3 s. Blood pressure falls before the heart rate falls Type 2A Cardioinhibition without asystole. Heart rate falls to a ventricular rate less than 40 bpm for more than 10 s but asystole of more than 3 s does not occur. Blood pressure falls before the heart rate falls Type 2B Cardioinhibition with asystole. Asystole occurs for more than 3s. Blood pressure fall coincides with or occurs before the heart rate fall Type 3 Vasodepressor. Heart rate does not fall more than 10% from its peak at the time of syncope Exception 1. Chronotropic Incompetence. No heart rate rise during the tilt testing (i.e. less than 10% from the pre-tilt rate) Exception 2. Excessive heart rate rise. An excessive heart rate rise both at the onset of the upright position and throughout its duration before syncope (i.e. greater than 130bpm) Negative result - no haemodynamic changes with or without symptoms. SUMMARY of protocol Stabilization phase: 5 min in the supine position Passive phase: 20 min of passive tilt at 60º Provocation phase: further 15 min after sublingual spray of nitroglycerin 400 μg at 60º Test interruption: (1) Completion of the protocol in the absence of symptoms (2) Syncope (3) Progressive (>5 min) symptomatic orthostatic hypotension CSM: At the end of the test, HO or SHO to perform CSM in all patients >40 years, regardless of the result of the tilt, both in supine and tilted positions