Major valves of the heart become stiffened and reduce the efficiency of the hearts pumping action. This may not cause symptoms at rest but with exertion, the heart is unable to keep up with increased demands leading to syncope. Aortic stenosis presents with repeated episodes of syncope. Rarely, cardiac tumors such as atrial myxomas can also lead to syncope. Structural cardiopulmonary disease
Diseases involving the shape and strength of the heart can be a cause of reduced blood flow to the brain, which increases risk for syncope. The most common cause in this category is fainting associated with an acute myocardial infarction or ischemic event. The faint in this case is primarily caused by an abnormal nervous system reaction similar to the reflex faints. Women are significantly more likely to experience syncope as a presenting symptom of a myocardial infarction. In general, faints caused by structural disease of the heart or blood vessels are particularly important to recognize, as they are warning of potentially life-threatening conditions.Among other conditions prone to trigger syncope (by either hemodynamic compromise or by a neural reflex mechanism, or both), some of the most important are hypertrophic cardiomyopathy, acute aortic dissection, pericardial tamponade, pulmonary embolism, aortic stenosis, and pulmonary hypertension. Other cardiac causes
Sick sinus syndrome, a sinus node dysfunction, causing alternating bradycardia and tachycardia. Often there is a long pause (asystole) between heartbeats.Adams-Stokes syndrome is a cardiac syncope that occurs with seizures caused by complete or incomplete heart block.
Adverse effects
Angioedema - The ADE of angioedema found in patients using Aliskiren is due to the inhibition of bradykinin degradation which occurs within the Renin-Angiotensin System (RAAS)
High blood potassium level (particularly when used with ACE inhibitors in diabetic patients)
Low blood pressure (particularly in volume-depleted patients)
Diarrhea and other GI symptoms
Headache
Dizziness
Cough

Contraindications
Pregnancy: Other drugs such as ACE inhibitors, also acting on the renin–angiotensin system, have been associated with fetal malformations and neonatal death. Angiotensin cannot be used in patients who are pregnant because it will result in disruption of normal fetal kidney development. Breastfeeding: During animal studies, the drug has been found present in milk. Aliskiren has been shown to increase the likelihood of adverse cardiovascular outcomes in patients with diabetes and kidney or heart disease. Drug interactions
Aliskiren is a minor inhibitor of substrate CYP3A4 and, more importantly, P-glycoprotein:

It reduces furosemide blood concentration. Atorvastatin may increase blood concentration, but no dose adjustment is needed. Due to possible interaction with ciclosporin, the use of ciclosporin and aliskiren at the same time is contraindicated. Caution should be exercised when aliskiren is administered with ketoconazole or other moderate P-glycoprotein inhibitors (itraconazole, clarithromycin, telithromycin, erythromycin, or amiodarone). Recommendations have been made to stop prescribing aliskiren-containing medicines to patients with diabetes (type 1 or type 2) or with moderate to severe kidney impairment who are also taking an ACE inhibitor or ARB. Such patients should consider alternative antihypertensive treatment as necessary. Mechanism of action
Aliskiren is an antagonist to renin. Renin, the first enzyme in the renin–angiotensin–aldosterone system, plays a role in blood pressure control.