The high cost of missed arrythmias – the negligence behind a delayed diagnosis of irregular heartbeat
An arrhythmia is an abnormality in the way the heart beats. Instead of maintaining a steady, coordinated rhythm, the heart may beat too quickly, too slowly, or in an irregular or erratic pattern.
This disturbance arises from problems within the heart’s electrical system, the network that normally produces impulses in the sinoatrial node and conducts them smoothly through the heart muscle. When this system is disrupted, the heart’s timing becomes unreliable. Sometimes the issue stems from electrical signals firing from the wrong place; in other cases, the impulse becomes trapped in a loop, or it fails to conduct properly through damaged tissue. Structural heart disease, previous heart attacks, cardiomyopathy, electrolyte imbalances, thyroid disorders, infection, and even alcohol or certain medications can all predispose someone to developing an arrhythmia.
Diagnosis begins with understanding a patient’s symptoms, which may be dramatic, such as palpitations, fainting or near fainting episodes, breathlessness, and chest discomfort, or can be subtle, presenting only as fatigue or a vague sense of unease. Because arrhythmias may come and go, capturing one at the right moment can be difficult. A standard ECG is the cornerstone of diagnosis, but if the abnormal rhythm is not present at the time, the trace may look completely normal.
In these cases, clinicians often turn to longer term monitoring such as Holter devices, patch monitors, or implantable loop recorders. Blood tests help uncover contributing factors, and an echocardiogram allows assessment of any underlying structural heart problem. In more complex cases, an electrophysiology study can map the heart’s electrical pathways directly.
Treatment depends on the type of arrhythmia and the symptoms it causes. For some people, correcting underlying issues, such as restoring electrolyte balance, treating thyroid abnormalities, or modifying alcohol or caffeine intake, is enough. Others benefit from medications that slow the heart rate, stabilise the rhythm, or reduce the risk of stroke in conditions like atrial fibrillation. More definitive measures include electrical cardioversion, pacemaker implantation for slow or unreliable heartbeats, defibrillators for dangerous ventricular rhythms, and catheter ablation procedures that target and neutralise the source of the abnormal electrical activity.
Missed arrythmias
However, despite the tools available, arrhythmias can be missed. Their intermittent nature means that a patient may feel symptoms long before an ECG captures anything abnormal. Many symptoms are non-specific and can easily be mistaken for anxiety, stress, or other benign conditions, particularly in younger people or women. Short duration monitoring may fail to detect infrequent episodes, and subtle ECG changes can be overlooked or misinterpreted. When the underlying cause is not fully investigated – for example, when thyroid tests or electrolyte levels are not checked – an important clue may be missed. In some cases, warning signs such as syncope, near syncope, or persistently fast heart rates are underestimated, delaying appropriate escalation.
This combination of intermittent symptoms, diagnostic subtlety, and the need for careful interpretation means arrhythmias can stay hidden for longer than they should. Recognising their varied presentations and pursuing thorough investigation when suspicion persists is essential for avoiding preventable delays in diagnosis.
When the heart’s rhythm is disturbed, it does not always cause dramatic symptoms at first. Many people with an arrhythmia may simply feel a few missed beats, occasional fluttering, or spells of dizziness that come and go. Because these symptoms can be vague, a diagnosis may be delayed. But when an arrhythmia is left unrecognised and therefore untreated, it can create conditions in which a serious event, such as a cardiac arrest or a stroke, could have been prevented.
The risks of a delayed diagnosis
A delayed diagnosis matters because the heart relies on a steady, coordinated electrical pattern to pump blood effectively. If that rhythm becomes dangerously fast, extremely chaotic, or too slow, the heart may no longer be able to pump blood around the body. In some arrhythmias, particularly those that originate from the lower chambers of the heart, the electrical activity can collapse into a life-threatening state where the heart quivers instead of beating properly. If this is not detected and treated early, it can lead to a cardiac arrest, where the heart effectively stops pumping. Many of these dangerous rhythms can be stabilised or even prevented with medication, implantable devices, or corrective procedures, but only if the underlying arrhythmia has been identified in time.
Delayed diagnosis can also increase the risk of stroke, especially in people with atrial fibrillation, a common irregular heartbeat. In this condition, the upper chambers of the heart beat so irregularly that blood can pool and form clots. If a clot travels to the brain, it can block a blood vessel and cause a stroke. The tragedy is that strokes linked to atrial fibrillation are very often preventable: once the arrhythmia is recognised, blood thinning medication can dramatically reduce the chance of a clot forming. Without a diagnosis, however, the person remains at risk without knowing it.
In many cases, earlier recognition of the arrhythmia, through an ECG, longer term heart monitoring, or proper investigation of symptoms, allows doctors to intervene before harm occurs. That intervention might be as simple as prescribing a medication or as involved as correcting the faulty electrical pathway in the heart. Either way, timely diagnosis can make the difference between a manageable condition and a life-changing or life-threatening event.
Alison Johnson, partner in the medical negligence team at Penningtons Manches Cooper, who has experience of investigating cases arising out of avoidable cardiac arrests and strokes, comments: “Arrhythmias themselves are often treatable, but the consequences of missing them can be severe. When symptoms are investigated early and thoroughly, many strokes and cardiac arrests that arise from undiagnosed arrhythmias can be avoided.”