ECG signal

Dr Diana R Holdright

Consultant Cardiologist

Dr Diana Holdright

Common Problems - Palpitations, Dizzy Spells and Blackouts

Palpitations are a common symptom that may or may not signify an important underlying heart problem. An occasional awareness of heart beats is common and normal; we all experience extra heart beats from time to time, and in most cases this is not dangerous, although it may initially be concerning to the patient. However, sometimes the heart rhythm can change significantly and this needs investigation, for example with a resting ECG or a 24 hour Holter monitor. More elusive and infrequent symptoms are more likely to require even more prolonged periods of monitoring, such as a 7 day Holter monitor or an external loop recorder (sometimes also called a cardiomemo).

Occasionally a small device, an implantable loop recorder, may be inserted under the skin on the front of the chest to monitor the heart beat continuously, for a period of up to 3 years if required. The device can store precise information about the heart rhythm at the time of a patient’s symptoms, and the information can be downloaded at a later time for analysis. There are many different types of heart rhythm change, which, depending on the precise rhythm abnormality, can be treated in several different ways, for example with regular medication, a permanent pacemaker or an implantable defibrillator.  Some heart rhythms can be successfully treated, often permanently, with the brief application of radiofrequency energy through small catheters passed through the veins into the heart chambers, a technique called radiofrequency ablation.

Dizzy spells and blackouts may be caused by a drop in blood pressure which temporarily reduces the supply of oxygen to the brain. This may occur when getting up quickly from a lying or sitting position (postural hypotension), and can be exacerbated by certain medications, such as those to control high blood pressure. Many dizzy spells and faints do not have a significant underlying cause but they should always be investigated, particularly if they are accompanied by other symptoms, as they can sometimes be indicative of a cardiovascular disorder such as a heart rhythm disturbance or a heart valve problem.

The term “blackout” is frequently and loosely used to describe either loss of consciousness or loss of awareness.  There are many potential causes, though the majority fall into the category of neutrally mediated vasovagal syncope, which covers a broad spectrum of symptoms, from the simple faint to patients with severe, unpredictable and frequent loss of consciousness. The latter is often caused by an inappropriate slowing of the heart rate, dilatation of the blood vessels creating a loss of blood pressure, or a combination of the two.  Cardiac problems, such as a change in heart rhythm, are the second largest cause; far less likely is neurological disease, such as epilepsy or a brain tumour.  Some episodes remain undiagnosed and never recur.

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