Letter to the Editor regarding article on exercise-induced pulmonary haemorrhage at the Hong Kong Jockey Club

The heart beats rhythmically in a sequence called the cardiac cycle—a rapid coordination of contraction (systole) and relaxation (diastole).
The Process
Electrical signals—sent from the sinoatrial (SA) node in the right atrial wall to the atrioventricular (AV) node between the right atrium and right ventricle—cause both atria to simultaneously contract. When the signal reaches the AV node, it pauses for approximately a tenth of a second, allowing the atria to contract and empty blood into the...

Exercise significantly impacts cardiovascular response, which is crucial for understanding patient health and designing effective treatment plans.
Light to moderate physical activity initiates a series of interconnected responses in the body. The heart rate modestly increases in anticipation of the workout, followed by widespread vasodilation as oxygen consumption by skeletal muscles increases. This results in decreased peripheral resistance, increased capillary blood flow, and accelerated...

Cardiac emergencies are critical situations involving the heart that require immediate medical intervention to prevent severe complications or death. These emergencies often arise from underlying heart conditions that impair the heart's ability to function correctly.Types of Cardiac EmergenciesThe most common types of cardiac emergencies include Acute Coronary Syndrome (ACS), myocardial infarction (MI), cardiac arrest, and heart failure.Acute Coronary Syndrome (ACS)Acute Coronary Syndrome (ACS)...