Understanding Heart Emergencies: Attack vs. Arrest

We recently encountered an elderly patient who presented with complaints of irregular heartbeats. The individual had a known history of Paroxysmal Supraventricular Tachycardia (PSVT), and the heightened anxiety of both the patient and their attendant prompted inquiries about the potential risk of a heart attack and the necessity of angiography. In such instances, it becomes crucial for people to comprehend the intricate functioning of the heart, particularly in the context of the elderly population. It allows for a better understanding of the specific cardiac condition, dispelling concerns, and promoting informed decision-making regarding further diagnostic and therapeutic interventions.

The heart does its job through two important mechanisms. First, there's an electrical system that makes sure the heart muscles contract and relax together, helping the heart pump blood effectively. Second, there are special blood vessels called coronary arteries that provide the heart with the blood it needs to keep working. These arteries bring oxygen and nutrients to the heart muscle, allowing it to pump blood throughout the body in a steady rhythm.

Electrical Conduction System of Heart:

The electrical conduction of the heart refers to the generation and transmission of electrical signals that regulate the heartbeat. These signals coordinate the contractions of the heart muscle, allowing it to pump blood effectively. The process begins with the sinoatrial (SA) node, often called the heart's natural pacemaker, generating electrical impulses. These impulses travel through the atria, causing them to contract and push blood into the ventricles. The atrioventricular (AV) node then relays the signals to the ventricles, leading to their contraction and the pumping of blood to the rest of the body. This orchestrated electrical conduction ensures the heart functions properly and maintains circulation.

In adults, the normal resting heart rate typically ranges between 60 to 100 beats per minute. Athletes may have lower resting heart rates, while factors like age and overall health can influence the heart rate range. It's essential to note that variations within these ranges can be normal, and individual circumstances should be considered when assessing heart rate.

Blood Circulation of Heart Muscles:

The blood circulation of the heart involves the coronary arteries, which supply oxygen and nutrients to the heart muscle. The heart, being a muscular organ, needs its own blood supply to function properly. The coronary arteries branch off from the aorta, the main artery that carries oxygenated blood from the heart to the rest of the body. These coronary arteries encircle the heart and deliver oxygen-rich blood to ensure the heart muscle can contract and pump blood effectively. Any disruption in this blood supply, such as a blockage in the coronary arteries, can lead to heart-related issues and require medical attention.

What are Blocks in Heart?

Many patients often encounter confusion when reviewing their prescriptions, particularly when they come across the term "block." It's important to note that this term can refer to two distinct aspects in the context of the cardiovascular system. Firstly, in the electrical conduction system of the heart, "block" is commonly associated with conditions like atrioventricular (AV) block, bundle branch block (Written as LBBB or RBBB), or other disturbances in the heart's rhythm. These affect the normal transmission of electrical signals, potentially leading to irregular heartbeats.

Secondly, in the context of coronary arteries, the term "block" is related to the obstruction of blood flow. Conditions like coronary artery disease can cause blockages in these vital vessels, reducing blood supply to the heart muscle and increasing the risk of heart-related complications. Therefore, when patients encounter the term "block" in their prescriptions, it's crucial to clarify with their doctor whether it pertains to the electrical conduction system or the coronary arteries, ensuring a comprehensive understanding of their cardiovascular health.

Cardiac Arrest versus Heart Attack:

Another crucial aspect for patients to grasp is the recognition that issues can arise in both the heart's electrical conduction system and the blood flow to its muscles. When there's a malfunction in the electrical conduction system, it can lead to cardiac arrest, a sudden cessation of heart function. Conversely, a reduction or blockage in the blood flow to the heart muscles results in a heart attack. It's imperative to distinguish between these two conditions, as they involve distinct mechanisms and need different treatment strategies.

Heart Attack:

A heart attack, or myocardial infarction, occurs when the blood flow to a part of the heart muscle is blocked, often by a blood clot. This obstruction can lead to damage or destruction of the heart tissue. Heart Attack, fresh or an old one is a common cause of cardiac arrest.

Signs and Symptoms of a Heart Attack:

• Chest pain or discomfort
• Shortness of breath
• Fatigue
• Nausea or vomiting
• Sweating
• Pain or discomfort in the upper body, such as in the arms, back, neck, jaw, or stomach

Causes of Heart Attack:

• Coronary artery disease
• Atherosclerosis (buildup of fatty deposits in the arteries)
• Blood clot formation
• Spasm in a coronary artery

Prevention of Heart Attacks:

• Adopting a heart-healthy diet (low in saturated fats, cholesterol, and sodium)
• Regular physical activity
• Managing stress
• Quitting smoking
• Monitoring and managing health conditions (hypertension, diabetes)

Diagnosis:

• Electrocardiogram (ECG or EKG) to detect abnormalities.
• Blood tests to measure cardiac enzyme levels.
• Imaging studies like echocardiogram or angiogram.

Treatment for Heart Attack:

• Emergency medical attention
• Medications (aspirin, clot-busters, antiplatelet drugs)
• Coronary angioplasty and stent placement
• Coronary artery bypass surgery

Risk Factors for Heart Attack:

• Age
• Gender (men are generally at higher risk)
• Family history
• Smoking
• High blood pressure
• High cholesterol
• Obesity
• Diabetes

Cardiac Arrest:

Cardiac arrest is a sudden and abrupt loss of heart function, resulting in the cessation of blood circulation. This medical emergency occurs when the heart's electrical system malfunctions, causing an irregular heart rhythm (arrhythmia). As a result, the heart is unable to pump blood effectively to vital organs and tissues. This can lead to a sudden loss of consciousness and breathing.

Signs and Symptoms of Cardiac Arrest:

• Sudden loss of responsiveness
• Absence of normal breathing
• No pulse

Causes of Cardiac Arrest:

• Ventricular fibrillation (irregular heart rhythm)
• Heart attack, old or new
• Electrolyte imbalance
• Trauma
• Drug overdose

Prevention of Cardiac Arrest:

• Early detection and treatment of heart conditions
• Use of automated external defibrillators (AEDs)
• Bystander CPR training
• Managing heart disease risk factors

Diagnosis:

• Immediate clinical assessment.
• Electrocardiogram (ECG or EKG).
• Confirmation through advanced life support measures.

Treatment for Cardiac Arrest:

• Immediate cardiopulmonary resuscitation (CPR)
• Use of automated external defibrillators (AEDs)
• Medications
• Pacemaker

Risk Factors for Cardiac Arrest:

• Previous heart attack
• Family history of cardiac arrest
• Age
• Gender (men are at higher risk)
• Smoking
• Substance abuse
• Obesity
• Certain medical conditions

Understanding the signs, symptoms, causes, prevention strategies, treatments, and risk factors associated with heart attacks and cardiac arrests is crucial for promoting heart health.

Timely medical intervention, adopting a healthy lifestyle, and raising awareness about cardiovascular risks are essential components of reducing the incidence and impact of these life-threatening conditions. Always consult your doctor for personalised advice and care tailored to individual health needs.

BY Prof Upendra Kaul and Dr Zubair Saleem