Even though many types of sick sinus syndrome produce no symptoms, a person may present with one or more of the following signs and symptoms:

- Stokes-Adams attacks – fainting due to asystole or ventricular fibrillation

- Dizziness or light-headedness

- Palpitations

- Chest pain or angina

- Shortness of breath

- Fatigue

- Headache

- Nausea

Third-degree atrioventricular block (AV block), also known as complete heart block, is a medical condition in which the impulse generated in the sinoatrial node (SA node) in the atrium of the heart does not propagate to the ventricles.

Because the impulse is blocked, an accessory pacemaker in the lower chambers will typically activate the ventricles. This is known as an "escape rhythm". Since this accessory pacemaker also activates independently of the impulse generated at the SA node, two independent rhythms can be noted on the electrocardiogram (ECG).

- The P waves with a regular P-to-P interval (in other words, a sinus rhythm) represent the first rhythm.

- The QRS complexes with a regular R-to-R interval represent the second rhythm. The PR interval will be variable, as the hallmark of complete heart block is lack of any apparent relationship between P waves and QRS complexes.

Patients with third-degree AV block typically experience severe bradycardia (an abnormally-low measured heart rate), hypotension, and at times, hemodynamic instability.

Most people with Wenckebach (Type I Mobitz) do not show symptoms. However, those that do usually display one or more of the following:

- Light-headedness

- Dizziness

- Syncope (fainting)

While atrial flutter can sometimes go unnoticed, its onset is often marked by characteristic sensations of the heart feeling like it is beating too fast or hard. Such sensations usually last until the episode resolves, or until the heart rate is controlled.

Atrial flutter is usually well tolerated initially (a high heart rate is for most people just a normal response to exercise), however, people with other underlying heart disease (such as coronary artery disease) or poor exercise tolerance may rapidly develop symptoms, such as shortness of breath, chest pain, lightheadedness or dizziness, nausea and, in some patients, nervousness and feelings of impending doom.

Prolonged atrial flutter with fast heart rates may lead to decompensation with loss of normal heart function (heart failure). This may manifest as exercise intolerance (exertional breathlessness), difficulty breathing at night, or swelling of the legs and/or abdomen.

The annulus of the valve is still in the normal position. The valve leaflets, however, are to a varying degree, attached to the walls and septum of the right ventricle. A subsequent 'atrialization' of a portion of the morphologic right ventricle (which is then contiguous with the right atrium) is seen. This causes the right atrium to be large and the anatomic right ventricle to be small in size.

- S3 heart sound

- S4 heart sound

- Triple or quadruple gallop due to widely split S1 and S2 sounds plus a loud S3 and/or S4

- Systolic murmur of tricuspid regurgitation = Holosystolic or early systolic murmur along the lower left sternal border depending on the severity of the regurgitation

- Right atrial hypertrophy

- Right ventricular conduction defects

- Wolff-Parkinson-White syndrome often accompanies

An enlargement of the aorta may occur; an increased risk of abnormality is seen in babies of women taking lithium during the first trimester of pregnancy (though some have questioned this) and in those with Wolff-Parkinson-White syndrome.

AF is usually accompanied by symptoms related to a rapid heart rate. Rapid and irregular heart rates may be perceived as palpitations or exercise intolerance and occasionally may produce anginal chest pain (if the high heart rate causes ischemia). Other possible symptoms include congestive symptoms such as shortness of breath or swelling. The arrhythmia is sometimes only identified with the onset of a stroke or a transient ischemic attack (TIA). It is not uncommon for a patient to first become aware of AF from a routine physical examination or ECG, as it often does not cause symptoms.

Since most cases of AF are secondary to other medical problems, the presence of chest pain or angina, signs and symptoms of hyperthyroidism (an overactive thyroid gland) such as weight loss and diarrhea, and symptoms suggestive of lung disease can indicate an underlying cause. A history of stroke or TIA, as well as high blood pressure, diabetes, heart failure, or rheumatic fever may indicate whether someone with AF is at a higher risk of complications. The risk of a blood clot forming in the left atrium, breaking off, and then traveling in the bloodstream can be assessed using the CHADS2 score or CHA2DS2-VASc score.

Rapid heart rates may produce significant symptoms in patients with pre-existing heart disease and can lead to inadequate blood flow to the heart muscle and even a heart attack. In rare situations, atrial flutter associated with a fast heart rate persists for an extended period of time without being corrected to a normal heart rhythm and leads to a tachycardia-induced cardiomyopathy. Even in individuals with a normal heart, if the heart beats too quickly for a prolonged period of time, this can lead to ventricular decompensation and heart failure.

The American College of Cardiology (ACC), American Heart Association (AHA), and the European Society of Cardiology (ESC) recommend in their guidelines the following classification system based on simplicity and clinical relevance.

All people with AF are initially in the category called "first detected AF". These patients may or may not have had previous undetected episodes. If a first detected episode stops on its own in less than 7 days and then another episode begins, later on, the category changes to paroxysmal AF. Although patients in this category have episodes lasting up to 7 days, in most cases of paroxysmal AF the episodes will stop in less than 24 hours. If the episode lasts for more than 7 days, it is unlikely to stop on its own, and is then known as persistent AF. In this case, cardioversion can be used to stop the episode. If cardioversion is unsuccessful or not attempted and the episode continues for a long time (e.g., a year or more), the patient's AF is then known as permanent.

Episodes that last less than 30 seconds are not considered in this classification system. Also, this system does not apply to cases where the AF is a secondary condition that occurs in the setting of a primary condition that may be the cause of the AF.

About half of people with AF have permanent AF, while a quarter have paroxysmal AF, and a quarter have persistent AF.

In addition to the above four AF categories, which are mainly defined by episode timing and termination, the ACC/AHA/ESC guidelines describe additional AF categories in terms of other characteristics of the patient.

- "Lone atrial fibrillation" (LAF) – absence of clinical or echocardiographic findings of other cardiovascular disease (including hypertension), related pulmonary disease, or cardiac abnormalities such as enlargement of the left atrium, and age under 60 years

- "Nonvalvular AF" – absence of rheumatic mitral valve disease, a prosthetic heart valve, or mitral valve repair

- "Secondary AF" – occurs in the setting of a primary condition that may be the cause of the AF, such as acute myocardial infarction, cardiac surgery, pericarditis, myocarditis, hyperthyroidism, pulmonary embolism, pneumonia, or other acute pulmonary disease

People with TIC most often present with symptoms of congestive heart failure and/or symptoms related to their irregular heart rhythm. Symptoms of congestive heart failure can include shortness of breath, ankle swelling, fatigue, and weight gain. Symptoms of an irregular heart rhythm can include palpitations and chest discomfort.

The timecourse of TIC is most well-studied in experiments on animals. Researchers have found that animals began to exhibit abnormal changes in blood flow after just one day of an artificially generated fast heart rate (designed to simulate a tachyarrythmia). As their TIC progresses, these animals will have worsening heart function (e.g.: reduced cardiac output and reduced ejection fraction) for 3–5 weeks. The worsened heart function then persists at a stable state until the heart rate is returned to normal. With normal heart rates, these animals begin to demonstrate improving heart function at 1–2 days, and even complete recovery of ejection fraction at 1 month.

Human studies of the timecourse of TIC are not as robust as animal studies, though current studies suggest that the majority of people with TIC will recover a significant degree of heart function over months to years.

Atrial enlargement refers to a condition where the left atrium or right atrium of the heart is larger than would be expected. It can also affect both atria.

Types include:

- Left atrial enlargement

- Right atrial enlargement

Left atrial enlargement can be mild, moderate or severe depending on the extent of the underlying condition. Although other factors may contribute, left atrium size has been found to be a predictor of mortality due to both cardiovascular issues as well as all-cause mortality. Current research suggests that left atrium size as measured by an echo-cardiograph may have prognostic implications for preclinical cardiovascular disease. However, studies that have found LAE to be a predictor for mortality recognize the need for more standardized left atrium measurements than those found in an echo-cardiogram.

Junctional ectopic tachycardia (JET) is a rare syndrome of the heart that manifests in patients recovering from heart surgery. It is characterized by cardiac arrhythmia, or irregular beating of the heart, caused by abnormal conduction from or through the atrioventricular node (AV node). In newborns and infants up to 6 weeks old, the disease may also be referred to as His bundle tachycardia.

Premature atrial contractions (PACs), also known as atrial premature complexes (APC) or atrial premature beats (APB), are a common cardiac dysrhythmia characterized by premature heartbeats originating in the atria. While the sinoatrial node typically regulates the heartbeat during normal sinus rhythm, PACs occur when another region of the atria depolarizes before the sinoatrial node and thus triggers a premature heartbeat. The exact cause of PACs is unclear; while several predisposing conditions exist, PACs commonly occur in healthy young and elderly people. Elderly people that get PACs usually don't need any further attention besides follow ups due to unclear evidence. PACs are often completely asymptomatic and may be noted only with Holter monitoring, but occasionally they can be perceived as a skipped beat or a jolt in the chest. In most cases, no treatment other than reassurance is needed for PACs, although medications such as beta blockers can reduce the frequency of symptomatic PACs.

In the general population, obesity appears to be the most important risk factor for LAE. LAE has been found to be correlated to body size, independent of obesity, meaning that LAE is more common in people with a naturally large body size. Also, a study found that LAE can occur as a consequence of atrial fibrillation (AF), although another study found that AF by itself does not cause LAE. The latter study also showed that the persistent type of AF was associated with LAE, but the number of years that a subject had AF was not.

Obstructive sleep apnea (OSA) may be a cause of LAE in some cases. When an OSA event occurs, an attempt is made to breathe with an obstructed airway and the pressure inside the chest is suddenly lowered. The negative intrathoracic pressure may cause the left atrium to expand and stretch its walls during each OSA event. Over time, the repetitive stretching of the left atrium may result in a persistent left atrial enlargement.

Untreated hearts with RCM often develop the following characteristics:

- M or W configuration in an invasive hemodynamic pressure tracing of the RA

- Square root sign of part of the invasive hemodynamic pressure tracing Of The LV

- Biatrial enlargement

- Thickened LV walls (with normal chamber size)

- Thickened RV free wall (with normal chamber size)

- Elevated right atrial pressure (>12mmHg),

- Moderate pulmonary hypertension,

- Normal systolic function,

- Poor diastolic function, typically Grade III - IV Diastolic heart failure.

Those afflicted with RCM will experience decreased exercise tolerance, fatigue, jugular venous distention, peripheral edema, and ascites. Arrhythmias and conduction blocks are common.

No specific set of criteria has been developed for diagnosis of pacemaker syndrome. Most of the signs and symptoms of pacemaker syndrome are nonspecific, and many are prevalent in the elderly population at baseline. In the lab, pacemaker interrogation plays a crucial role in determining if the pacemaker mode had any contribution to symptoms.

Symptoms commonly documented in patients history, classified according to cause:

- Neurological - Dizziness, near syncope, and confusion.

- Heart failure - Dyspnea, orthopnea, paroxysmal nocturnal dyspnea, and edema.

- Hypotension - Seizure, mental status change, diaphoresis, and signs of orthostatic hypotension and shock.

- Low cardiac output - Fatigue, weakness, dyspnea on exertion, lethargy, and lightheadedness.

- Hemodynamic - Pulsation in the neck and abdomen, choking sensation, jaw pain, right upper quadrant (RUQ) pain, chest colds, and headache.

- Heart rate related - Palpitations associated with arrhythmias

In particular, the examiner should look for the following in the physical examination, as these are frequent findings at the time of admission:

- Vital signs may reveal hypotension, tachycardia, tachypnea, or low oxygen saturation.

- Pulse amplitude may vary, and blood pressure may fluctuate.

- Look for neck vein distension and cannon waves in the neck veins.

- Lungs may exhibit crackles.

- Cardiac examination may reveal regurgitant murmurs and variability of heart sounds.

- Liver may be pulsatile, and the RUQ may be tender to palpation. Ascites may be present in severe cases.

- The lower extremities may be edematous.

- Neurologic examination may reveal confusion, dizziness, or altered mental status.

Sick sinus syndrome (SSS), also called sinus dysfunction, or sinoatrial node disease ("SND"), is a group of abnormal heart rhythms (arrhythmias) presumably caused by a malfunction of the sinus node, the heart's primary pacemaker. Tachycardia-bradycardia syndrome is a variant of sick sinus syndrome in which the arrhythmia alternates between slow and fast heart rates. Tachycardia-bradycardia syndrome is often associated with ischemic heart disease and heart valve disease.

Right atrial enlargement is a form of cardiomegaly. It can broadly be classified as either right atrial hypertrophy (RAH) or dilation. Common causes include right ventricular failure, pulmonary hypertension, tricuspid regurgitation, tricuspid stenosis and atrial septal defect.

It is characterized by a P wave height greater than 2.5 mm.

Tachycardia-induced cardiomyopathy (TIC) is a disease where prolonged tachycardia (a fast heart rate) or arrhythmia (an irregular heart rhythm) cause an impairment of the myocardium (heart muscle), which can result in heart failure. People with TIC may have symptoms associated with heart failure (e.g. shortness of breath or ankle swelling) and/or symptoms related to the tachycardia or arrhythmia (e.g. palpitations). Though atrial fibrillation is the most common cause of TIC, several tachycardias and arrhythmias have been associated with the disease.

There are no formal diagnostic criteria for TIC. Thus, TIC is typically diagnosed when (1) tests have excluded other causes of cardiomyopathy and (2) there is improvement in myocardial function after treatment of the tachycardia or arrhythmia. Treatment of TIC can involve treating the heart failure as well as the tachycardia or arrhythmia. TIC has a good prognosis with treatment, with most people recovering some to all of their heart function.

The number of cases that occur is unclear. TIC has been reported in all age groups.

Second-degree atrioventricular block (AV block) is a disease of the electrical conduction system of the heart. It is a conduction block between the atria and ventricles. The presence of second-degree AV block is diagnosed when one or more (but not all) of the atrial impulses fail to conduct to the ventricles due to impaired conduction. It is classified as a block of the AV node and is categorized in between first-degree (slowed conduction) and third degree blocks (complete block).

People with WPW are usually asymptomatic when not having a fast heart rate. However, individuals may experience palpitations, dizziness, shortness of breath, or infrequently syncope (fainting or near fainting) during episodes of supraventricular tachycardia. The telltale "delta wave" may sometimes be seen on an electrocardiogram (ECG/EKG).

Symptoms may occur at any time, but most often they accompany a change of body position. Pedunculated myxomas can have a "wrecking ball effect", as they lead to stasis and may eventually embolize themselves. Symptoms may include:

- Shortness of breath with activity

- Platypnea – Difficulty breathing in the upright position with relief in the supine position

- Paroxysmal nocturnal dyspnea – Breathing difficulty when asleep

- Dizziness

- Fainting

- Palpitations – Sensation of feeling your heart beat

- Chest pain or tightness

- Sudden Death (In which case the disease is an autopsy finding)

The symptoms and signs of left atrial myxomas often mimic mitral stenosis.

General symptoms may also be present, such as:

- Cough

- Pulmonary edema, as blood backs up into the pulmonary artery, after increased pressures in the left atrium and atrial dilation

- Hemoptysis

- Fever

- Cachexia – Involuntary weight loss

- General discomfort (malaise)

- Joint pain

- Blue discoloration of the skin, especially the fingers (Raynaud's phenomenon)

- Fingers that change color upon pressure or with cold or stress

- Clubbing – Curvature of nails accompanied with soft tissue enlargement of the fingers

- Swelling – any part of the body

- Presystolic heart murmur

These general symptoms may also mimic those of infective endocarditis.

Infra-Hisian block is that of the distal conduction system. Types of infra-Hisian block include:

- Type 2 second degree heart block (Mobitz II) –a type of AV block due to a block within or below the bundle of His

- Left anterior fascicular block

- Left posterior fascicular block

- Right bundle branch block

Of these types of infra-Hisian block, Mobitz II heart block is considered most important because of the possible progression to complete heart block.

Signs and symptoms can arise suddenly and may resolve without treatment. Stress, exercise, and emotion can all result in a normal or physiological increase in heart rate, but can also, more rarely, precipitate SVT. Episodes can last from a few minutes to one or two days, sometimes persisting until treated. The rapid heart rate reduces the opportunity for the "pump" to fill between beats decreasing cardiac output and as a consequence blood pressure. The following symptoms are typical with a rate of 150–270 or more beats per minute:

- Pounding heart

- Shortness of breath

- Chest pain

- Rapid breathing

- Dizziness

- Loss of consciousness (in only the most serious cases)

For infants and toddlers, symptoms of heart arrhythmias such as SVT are more difficult to assess because of limited ability to communicate. Caregivers should watch for lack of interest in feeding, shallow breathing, and lethargy. These symptoms may be subtle and may be accompanied by vomiting and/or a decrease in responsiveness.